Scholars@Duke
Ram Oren

Ram Oren

Nicholas Distinguished Professor of Earth Systems Science
Earth and Climate Sciences
ramoren@duke.edu
Box 90328, Durham, NC 27708-0328
A246A Lev Sci Res Ctr, Durham, NC 27708

Scholarly Works - Journal articles

Invariable hydraulics and rapidly tapering cross-sectional areas of lateral roots reduce water transport capacity to half at the crown periphery of mature Scots pine

Journal article Agricultural and Forest Meteorology · June 15, 2026 Dynamics of soil water extraction reflect soil texture and moisture, and the three-dimensional architecture and hydraulics of root systems. Lateral roots, placing fine roots at less exploited distances from trees, may become the primary source of water dur ... Full text Cite

Leaf transpiration decreases similarly among five pine species as height increases over stand development.

Journal article Tree physiology · March 2026 With increasing tree height, leaf transpiration (EL) is increasingly restricted by path-length resistance and gravity's discount of the driving force of xylem water flow. The effect of height on leaf transpiration is nearly always assessed using chronosequ ... Full text Cite

Increasing pathlength resistance and within-canopy shading similarly attenuate transpiration in accruing collocated stands of five pine species

Journal article Agricultural and Forest Meteorology · February 15, 2026 In forested regions dominated by management for timber production, quantifying biosphere-atmosphere exchange of mass and energy over accruing forests is essential for accurate estimates of water yield and carbon sequestration. Environmental conditions driv ... Full text Cite

Regulation of tree water use by biophysical factors: Insights based on multi-layer hierarchical residual analysis

Journal article Journal of Hydrology · October 1, 2025 The complex impact of biophysical factors on tree water use in changing environments has been an important topic in the ecohydrological studies. However, understanding how to model tree water use based on key biophysical factors requires an in-depth analys ... Full text Cite

Xylem Hydraulic Properties of Five Pinus Species Grown in Common Environment Vary From Needles to Roots With Needle Length and Native-Range Climate.

Journal article Plant, cell & environment · October 2025 Plant hydraulics govern water transport linking root to mesophyll surfaces, affecting gas-exchange, survival and growth. Xylem and leaf structural and functional characteristics vary widely among Pinus species, even when growing under similar conditions. W ... Full text Cite

Hydraulic conductivity-induced systematic parameter variation in a widely used thermal dissipation sap-flow technique.

Journal article The New phytologist · October 2025 The Granier-type thermal-dissipation method (TDM) is the most widely used sap-flow technique. However, its original calibration coefficients often underestimate high flow rates, limiting their generality. We derived TDM coefficients (scaling factors and ex ... Full text Cite

Water use and carbon accumulation in a pine forest under elevated atmospheric [CO2]

Journal article ARPHA Conference Abstracts · June 2, 2025 The Duke Forest Free-Air CO2 Enrichment (FACE) experiment enriched the air (eCO2) in 30 m diameter plots to a constant +200 ppm CO2, from 1994 to 2010. The experiment was aimed at Full text Cite

Carbon allocation to roots of suppressed Norway spruce increases immediately after selection harvest

Journal article Forest Ecology and Management · June 1, 2025 Selection harvesting in fertile, drained peatlands is an alternative for even-aged forestry, where clearcutting takes place at the end of each rotation period. Avoiding clear-cuts has been promoted due to reducing negative externalities, like nutrient load ... Full text Cite

Similar response of canopy conductance to increasing vapor pressure deficit and decreasing soil conductivity with drought among five morphologically contrasting but co-occurring pine species

Journal article Agricultural and Forest Meteorology · May 1, 2025 Knowledge of plant hydraulics facilitates our understanding of the capabilities of forests to withstand droughts. This common-garden study quantified the hydraulic response to variation in sandy soil conductivity and atmospheric vapor pressure deficit (VPD ... Full text Cite

Extramatrical mycelial biomass is mediated by fine root mass and ectomycorrhizal fungal community composition across tree species.

Journal article The Science of the total environment · November 2024 In many ecosystems, a large fraction of gross primary production is invested in mycorrhiza. Ectomycorrhizal (ECM) mycelium is involved in regulating soil carbon and nutrient cycling. However, little is known about how mycelial biomass, production and turno ... Full text Cite

Overlooked branch turnover creates a widespread bias in forest carbon accounting.

Journal article Proceedings of the National Academy of Sciences of the United States of America · October 2024 Most measurements and models of forest carbon cycling neglect the carbon flux associated with the turnover of branch biomass, a physiological process quantified for other organs (fine roots, leaves, and stems). Synthesizing data from boreal, temperate, and ... Full text Cite

Partitioning seasonal stem carbon dioxide efflux into stem respiration, bark photosynthesis, and transport-related flux in Scots pine.

Journal article Journal of experimental botany · August 2024 Stem CO2 efflux is an important component of the carbon balance in forests. The efflux is considered to principally reflect the net result of two dominating and opposing processes: stem respiration and stem photosynthesis. In addition, transport of CO2 in ... Full text Cite

Seasonal dynamics and punctuated carbon sink reduction suggest photosynthetic capacity of boreal silver birch is reduced by the accumulation of hexose.

Journal article The New phytologist · August 2024 The 'assimilates inhibition hypothesis' posits that accumulation of nonstructural carbohydrates (NSCs) in leaves reduces leaf net photosynthetic rate, thus internally regulating photosynthesis. Experimental work provides equivocal support mostly under cont ... Full text Cite

Increased leaf area index and efficiency drive enhanced production under elevated atmospheric [CO<sub>2</sub> ] in a pine-dominated stand showing no progressive nitrogen limitation.

Journal article Global change biology · February 2024 Enhancement of net primary production (NPP) in forests as atmospheric [CO2 ] increases is likely limited by the availability of other growth resources. The Duke Free Air CO2 Enrichment (FACE) experiment was located on a moderate-ferti ... Full text Cite

Hyposensitive canopy conductance renders ecosystems vulnerable to meteorological droughts.

Journal article Global change biology · April 2023 Increased meteorological drought intensity with rising atmospheric demand for water (hereafter vapor pressure deficit [VPD]) increases the risk of tree mortality and ecosystem dysfunction worldwide. Ecosystem-scale water-use strategy is increasingly recogn ... Full text Cite

The effect of rainfall amount and timing on annual transpiration in a grazed savanna grassland

Journal article Hydrology and Earth System Sciences · November 16, 2022 The role of precipitation (P) variability with respect to evapotranspiration (ET) and its two components, transpiration (T) and evaporation (E), from savannas continues to draw significant research interest given its relevance to a number of ecohydrologica ... Full text Cite

Organic nitrogen enhances nitrogen nutrition and early growth of Pinus sylvestris seedlings.

Journal article Tree physiology · March 2022 Boreal trees are capable of taking up organic nitrogen (N) as effectively as inorganic N. Depending on the abundance of soil N forms, plants may adjust physiological and morphological traits to optimize N uptake. However, the link between these traits and ... Full text Open Access Cite

Contrasting responses of woody and grassland ecosystems to increased CO2 as water supply varies.

Journal article Nature ecology & evolution · March 2022 Experiments show that elevated atmospheric CO2 (eCO2) often enhances plant photosynthesis and productivity, yet this effect varies substantially and may be climate sensitive. Understanding if, where and how water supply regulates CO Full text Cite

The response of coarse root biomass to long-term CO2 enrichment and nitrogen application in a maturing Pinus taeda stand with a large broadleaved component.

Journal article Global change biology · February 2022 Elevated atmospheric CO2 (eCO2 ) typically increases aboveground growth in both growth chamber and free-air carbon enrichment (FACE) studies. Here we report on the impacts of eCO2 and nitrogen amendment on coarse root bioma ... Full text Cite

Rhizosphere water content drives hydraulic redistribution: Implications of pore-scale heterogeneity to modeling diurnal transpiration in water-limited ecosystems

Journal article Agricultural and Forest Meteorology · January 15, 2022 Trees typically survive prolonged droughts by absorbing water from deeper layers. Where soils are shallow, roots may be extract water from the underlying fractured bedrocks. In dry seasons, surface-soil moisture dynamics reflect hydraulic redistribution (H ... Full text Cite

Author Correction: Boreal forest biomass accumulation is not increased by two decades of soil warming (Nature Climate Change, (2019), 9, 1, (49-52), 10.1038/s41558-018-0373-9)

Journal article Nature Climate Change · January 1, 2022 In the version of Letter originally published, there was an error in Fig. 3. Specifically, the y-axis label alongside panels 3a,c, originally reading “Foliar [N] (mg g–1)” should instead have read “Foliar [N] (%)”. ... Full text Cite

Hyposensitive canopy conductance renders ecosystems vulnerable to extreme droughts

Journal article · October 6, 2021 AbstractIncreased drought intensity with rising atmospheric demand for water (hereafter VPD) increases the risk of tree mortality worldwide. Ecosystem-scale water-use strategy (WUSe), quantified here by canopy stomatal ... Full text Cite

How tree species, tree size, and topographical location influenced tree transpiration in northern boreal forests during the historic 2018 drought.

Journal article Global change biology · July 2021 Trees in northern latitude ecosystems are projected to experience increasing drought stress as a result of rising air temperatures and changes in precipitation patterns in northern latitude ecosystems. However, most drought-related studies on high-latitude ... Full text Cite

Global transpiration data from sap flow measurements: The SAPFLUXNET database

Journal article Earth System Science Data · June 14, 2021 Plant transpiration links physiological responses of vegetation to water supply and demand with hydrological, energy, and carbon budgets at the land-atmosphere interface. However, despite being the main land evaporative flux at the global scale, transpirat ... Full text Cite

Rock Water as a Key Resource for Patchy Ecosystems on Shallow Soils: Digging Deep Tree Clumps Subsidize Surrounding Surficial Grass

Journal article Earth S Future · February 1, 2021 Mediterranean mountainous areas of shallow soil often display a mosaic of tree clumps surrounded by grass. The combined role and dynamics of water extracted from the underlying rock, and the competition between adjacent patches of trees and grass, has not ... Full text Cite

Limited vertical CO2 transport in stems of mature boreal Pinus sylvestris trees.

Journal article Tree physiology · January 2021 Several studies have suggested that CO2 transport in the transpiration stream can considerably bias estimates of root and stem respiration in ring-porous and diffuse-porous tree species. Whether this also happens in species with tracheid xylem anatomy and ... Full text Cite

Estimating canopy gross primary production by combining phloem stable isotopes with canopy and mesophyll conductances.

Journal article Plant, cell & environment · September 2020 Gross primary production (GPP) is a key component of the forest carbon cycle. However, our knowledge of GPP at the stand scale remains uncertain, because estimates derived from eddy covariance (EC) rely on semi-empirical modelling and the assumptions of th ... Full text Cite

Partitioning growing season water balance within a forested boreal catchment using sap flux, eddy covariance, and a process-based model

Journal article Hydrology and Earth System Sciences · June 8, 2020 Although it is well known that evapotranspiration (ET) represents an important water flux at local to global scales, few studies have quantified the magnitude and relative importance of ET and its individual flux components in high-latitude forests. In thi ... Full text Cite

Recovering the Metabolic, Self-Thinning, and Constant Final Yield Rules in Mono-Specific Stands

Journal article Frontiers in Forests and Global Change · May 27, 2020 Competition among plants of the same species often results in power-law relations between measures of crowding, such as plant density, and average size, such as individual biomass. Yoda's self-thinning rule, the constant final yield rule, and metabolic sca ... Full text Cite

Fixed and variable components of evapotranspiration in a Mediterranean wild-olive - grass landscape mosaic

Journal article Agricultural and Forest Meteorology · January 15, 2020 Dry regions are typically characterized by heterogeneous ecosystems where trees are competing with the surrounding grasses for limited amount of water. In these regions, evapotranspiration (ET) is the leading loss term in the soil water budget, and its est ... Full text Cite

Mechanisms for minimizing height-related stomatal conductance declines in tall vines.

Journal article Plant, cell & environment · November 2019 The ability to transport water through tall stems hydraulically limits stomatal conductance (gs ), thereby constraining photosynthesis and growth. However, some plants are able to minimize this height-related decrease in gs , regardle ... Full text Cite

Anatomical changes with needle length are correlated with leaf structural and physiological traits across five Pinus species.

Journal article Plant, cell & environment · May 2019 The genus Pinus has wide geographical range and includes species that are the most economically valued among forest trees worldwide. Pine needle length varies greatly among species, but the effects of needle length on anatomy, function, and coordination an ... Full text Cite

Publisher Correction: Boreal forest biomass accumulation is not increased by two decades of soil warming (Nature Climate Change, (2019), 9, 1, (49-52), 10.1038/s41558-018-0373-9)

Journal article Nature Climate Change · March 1, 2019 In the version of the Supplementary Information file originally published with this Letter, ref. 42 — Andersson, P., Berggren, D. & Nilsson, I. Indices for nitrogen status and nitrate leaching from Norway spruce (Picea abies (L.) Karst.) stands in Sweden. ... Full text Cite

Decadal biomass increment in early secondary succession woody ecosystems is increased by CO2 enrichment.

Journal article Nature communications · February 2019 Increasing atmospheric CO2 stimulates photosynthesis which can increase net primary production (NPP), but at longer timescales may not necessarily increase plant biomass. Here we analyse the four decade-long CO2-enrichment experiments ... Full text Open Access Cite

Boreal forest biomass accumulation is not increased by two decades of soil warming

Journal article Nature Climate Change · January 1, 2019 Increased soil organic matter decomposition with increasing temperature has been hypothesized to enhance soil nitrogen availability, consequently stimulating forest biomass production and offsetting decomposition-induced soil carbon losses1–5. T ... Full text Cite

Differential responses of Picea asperata and Betula albosinensis to nitrogen supply imposed by water availability.

Journal article Tree physiology · November 2018 A pot experiment was conducted to investigate the effects of nitrogen (N) addition (0, 20, 40 g N m-2 year-1, N0, N20, N40, respectively) on the growth, and biomass accumulation and allocation of coniferous and deciduous (Picea asperata Mast. and Betula al ... Full text Cite

Evapotranspiration and water yield of a pine-broadleaf forest are not altered by long-term atmospheric [CO2 ] enrichment under native or enhanced soil fertility.

Journal article Global change biology · October 2018 Featured Publication Changes in evapotranspiration (ET) from terrestrial ecosystems affect their water yield (WY), with considerable ecological and economic consequences. Increases in surface runoff observed over the past century have been attributed to increasing atmospheric ... Full text Cite

Water balance of pine forests: Synthesis of new and published results

Journal article Agricultural and Forest Meteorology. · September 2018 The forest hydrologic cycle is expected to have important feedback responses to climate change, impacting processes ranging from local water supply and primary productivity to global water and energy cycles. Here, we analyzed water budgets of pine forests ... Full text Cite

Fruiting and sink competition.

Journal article Tree physiology · September 2018 Full text Cite

Changing Seasonal Rainfall Distribution With Climate Directs Contrasting Impacts at Evapotranspiration and Water Yield in the Western Mediterranean Region

Journal article Earth S Future · June 1, 2018 Over the past century, climate change has been reflected in altered precipitation regimes worldwide. Because evapotranspiration is sensitive to both water availability and atmospheric demand for water vapor, it is essential to assess the likely consequence ... Full text Cite

Photosynthetic refixation varies along the stem and reduces CO2 efflux in mature boreal Pinus sylvestris trees.

Journal article Tree physiology · April 2018 Trees are able to reduce their carbon (C) losses by refixing some of the CO2 diffusing out of their stems through corticular photosynthesis. Previous studies have shown that under ideal conditions the outflowing CO2 can be completely assimilated in metabol ... Full text Cite

Dynamics of soil CO2 efflux under varying atmospheric CO2 concentrations reveal dominance of slow processes.

Journal article Global change biology · September 2017 We evaluated the effect on soil CO2 efflux (FCO2 ) of sudden changes in photosynthetic rates by altering CO2 concentration in plots subjected to +200 ppmv for 15 years. Five-day intervals of exposure to elevated ... Full text Cite

Annual climate variation modifies nitrogen induced carbon accumulation of Pinus sylvestris forests.

Journal article Ecological applications : a publication of the Ecological Society of America · September 2017 We report results from long-term simulated external nitrogen (N) input experiments in three northern Pinus sylvestris forests, two of moderately high and one of moderately low productivity, assessing effects on annual net primary production (NPP) of woody ... Full text Cite

How well do growing season dynamics of photosynthetic capacity correlate with leaf biochemistry and climate fluctuations?

Journal article Tree physiology · July 2017 Accurate values of photosynthetic capacity are needed in Earth System Models to predict gross primary productivity. Seasonal changes in photosynthetic capacity in these models are primarily driven by temperature, but recent work has suggested that photoper ... Full text Cite

Informing climate models with rapid chamber measurements of forest carbon uptake.

Journal article Global change biology · May 2017 Models predicting ecosystem carbon dioxide (CO2 ) exchange under future climate change rely on relatively few real-world tests of their assumptions and outputs. Here, we demonstrate a rapid and cost-effective method to estimate CO2 ex ... Full text Cite

The carbon bonus of organic nitrogen enhances nitrogen use efficiency of plants.

Journal article Plant, cell & environment · January 2017 The importance of organic nitrogen (N) for plant nutrition and productivity is increasingly being recognized. Here we show that it is not only the availability in the soil that matters, but also the effects on plant growth. The chemical form of N taken up, ... Full text Open Access Cite

Ecophysiological variation of transpiration of pine forests: synthesis of new and published results.

Journal article Ecological applications : a publication of the Ecological Society of America · January 2017 Canopy transpiration (EC ) is a large fraction of evapotranspiration, integrating physical and biological processes within the energy, water, and carbon cycles of forests. Quantifying EC is of both scientific and practical importance, ... Full text Cite

Baseliner: An open-source, interactive tool for processing sap flux data from thermal dissipation probes

Journal article Softwarex · July 5, 2016 Estimating transpiration from woody plants using thermal dissipation sap flux sensors requires careful data processing. Currently, researchers accomplish this using spreadsheets, or by personally writing scripts for statistical software programs (e.g., R, ... Full text Cite

Greater carbon allocation to mycorrhizal fungi reduces tree nitrogen uptake in a boreal forest.

Journal article Ecology · April 2016 The central role that ectomycorrhizal (EM) symbioses play in the structure and function of boreal forests pivots around the common assumption that carbon (C) and nitrogen (N) are exchanged at rates favorable for plant growth. However, this may not always b ... Full text Cite

Response to CO2 enrichment of understory vegetation in the shade of forests.

Journal article Global change biology · February 2016 Responses of forest ecosystems to increased atmospheric CO2 concentration have been studied in few free-air CO2 enrichment (FACE) experiments during last two decades. Most studies focused principally on the overstory trees with little attention given to un ... Full text Cite

The way the wind blows matters to ecosystem water use efficiency

Journal article Agricultural and Forest Meteorology. · February 2016 In many regions, atmospheric conditions change frequently with shifts of wind direction, extending maritime influences far inland or continental influences to coastal ecosystems. Climate models predict changes in both wind direction and velocity; these cha ... Full text Cite

Stem compression reversibly reduces phloem transport in Pinus sylvestris trees.

Journal article Tree physiology · October 2015 Featured Publication Manipulating tree belowground carbon (C) transport enables investigation of the ecological and physiological roles of tree roots and their associated mycorrhizal fungi, as well as a range of other soil organisms and processes. Girdling remains the most rel ... Full text Cite

Role of aquaporins in determining transpiration and photosynthesis in water-stressed plants: crop water-use efficiency, growth and yield.

Journal article Plant, cell & environment · September 2015 The global shortage of fresh water is one of our most severe agricultural problems, leading to dry and saline lands that reduce plant growth and crop yield. Here we review recent work highlighting the molecular mechanisms allowing some plant species and ge ... Full text Cite

The hysteresis response of soil CO2 concentration and soil respiration to soil temperature

Journal article Journal of Geophysical Research Biogeosciences · August 1, 2015 Diurnal hysteresis between soil temperature (Ts) and both CO2 concentration ([CO2]) and soil respiration rate (Rs) were reported across different field experiments. However, the causes of these hysteresis pattern ... Full text Cite

Growth and physiological responses of isohydric and anisohydric poplars to drought.

Journal article Journal of experimental botany · July 2015 Understanding how different plants prioritize carbon gain and drought vulnerability under a variable water supply is important for predicting which trees will maximize woody biomass production under different environmental conditions. Here, Populus balsami ... Full text Open Access Cite

A state-space modeling approach to estimating canopy conductance and associated uncertainties from sap flux density data.

Journal article Tree physiology · July 2015 Uncertainties in ecophysiological responses to environment, such as the impact of atmospheric and soil moisture conditions on plant water regulation, limit our ability to estimate key inputs for ecosystem models. Advanced statistical frameworks provide coh ... Full text Cite

Using ecosystem experiments to improve vegetation models

Journal article Nature Climate Change · June 26, 2015 Ecosystem responses to rising CO 2 concentrations are a major source of uncertainty in climate change projections. Data from ecosystem-scale Free-Air CO 2 Enrichment (FACE) experiments provide a unique opportunity to reduce this uncertainty. The recent FAC ... Full text Cite

The space-time continuum: the effects of elevated CO2 and temperature on trees and the importance of scaling.

Journal article Plant, cell & environment · June 2015 To predict how forests will respond to rising temperatures and atmospheric CO₂ concentrations, we need to understand how trees respond to both of these environmental factors. In this review, we discuss the importance of scaling, moving from leaf-level resp ... Full text Cite

Heterogeneity of competition at decameter scale: patches of high canopy leaf area in a shade-intolerant larch stand transpire less yet are more sensitive to drought.

Journal article Tree physiology · May 2015 Small differences in the sensitivity of stomatal conductance to light intensity on leaf surfaces may lead to large differences in total canopy transpiration (EC) with increasing canopy leaf area (L). Typically, the increase of L would more than compensate ... Full text Cite

Increases in atmospheric CO2 have little influence on transpiration of a temperate forest canopy.

Journal article The New phytologist · January 2015 Models of forest energy, water and carbon cycles assume decreased stomatal conductance with elevated atmospheric CO2 concentration ([CO2]) based on leaf-scale measurements, a response not directly translatable to canopies. Where canopy-atmosphere are well- ... Full text Cite

Where does the carbon go? A model-data intercomparison of vegetation carbon allocation and turnover processes at two temperate forest free-air CO2 enrichment sites.

Journal article The New phytologist · August 2014 Elevated atmospheric CO2 concentration (eCO2) has the potential to increase vegetation carbon storage if increased net primary production causes increased long-lived biomass. Model predictions of eCO2 effects on vegetation carbon storage depend on how allo ... Full text Open Access Cite

Evaluation of 11 terrestrial carbon-nitrogen cycle models against observations from two temperate Free-Air CO2 Enrichment studies.

Journal article The New phytologist · May 2014 We analysed the responses of 11 ecosystem models to elevated atmospheric [CO2 ] (eCO2 ) at two temperate forest ecosystems (Duke and Oak Ridge National Laboratory (ORNL) Free-Air CO2 Enrichment (FACE) experiments) to test alternative representations of car ... Full text Open Access Cite

Sensitivity of stand transpiration to wind velocity in a mixed broadleaved deciduous forest

Journal article Agricultural and Forest Meteorology. · April 2014 Wind velocity (U) within and above forest canopies can alter the coupling between the vapor-saturated sub-stomatal airspace and the drier atmosphere aloft, thereby influencing transpiration rates. In practice, however, the actual increase in transpiration ... Full text Cite

Sustained effects of atmospheric [CO2] and nitrogen availability on forest soil CO2 efflux.

Journal article Glob Chang Biol · April 2014 Soil CO2 efflux (Fsoil ) is the largest source of carbon from forests and reflects primary productivity as well as how carbon is allocated within forest ecosystems. Through early stages of stand development, both elevated [CO2] and availability of soil nit ... Full text Link to item Cite

Structural adjustments in resprouting trees drive differences in post-fire transpiration.

Journal article Tree physiology · February 2014 Following disturbance many woody species are capable of resprouting new foliage, resulting in a reduced leaf-to-sapwood area ratio and altered canopy structure. We hypothesized that such changes would promote adjustments in leaf physiology, resulting in hi ... Full text Cite

Evaluation of 11 terrestrial carbon-nitrogen cycle models against observations from two temperate Free-Air CO2 Enrichment studies

Journal article New Phytologist · January 1, 2014 We analysed the responses of 11 ecosystem models to elevated atmospheric [CO2] (eCO2) at two temperate forest ecosystems (Duke and Oak Ridge National Laboratory (ORNL) Free-Air CO2 Enrichment (FACE) experiments) to test alt ... Full text Cite

Comprehensive ecosystem model-data synthesis using multiple data sets at two temperate forest free-air CO2 enrichment experiments: Model performance at ambient CO2 concentration

Journal article Journal of Geophysical Research Biogeosciences · January 1, 2014 Free-air CO2 enrichment (FACE) experiments provide a remarkable wealth of data which can be used to evaluate and improve terrestrial ecosystem models (TEMs). In the FACE model-data synthesis project, 11 TEMs were applied to two decadelong FACE e ... Full text Cite

Forest water use and water use efficiency at elevated CO2 : a model-data intercomparison at two contrasting temperate forest FACE sites.

Journal article Global change biology · June 2013 Predicted responses of transpiration to elevated atmospheric CO2 concentration (eCO2 ) are highly variable amongst process-based models. To better understand and constrain this variability amongst models, we conducted an intercomparison of 11 ecosystem mod ... Full text Cite

Spatial and temporal variability of soil CO2 efflux in three proximate temperate forest ecosystems

Journal article Agricultural and Forest Meteorology. · April 2013 The magnitude of CO2 flux from soil (Fsoil) varies with primary productivity and environmental drivers of respiration, soil temperature (Tsoil) and moisture, all of which vary temporally and spatially. To quantify the sources of Fsoil variability, we first ... Full text Cite

Trenching reduces soil heterotrophic activity in a loblolly pine (Pinus taeda) forest exposed to elevated atmospheric [CO2] and N fertilization

Journal article Agricultural and Forest Meteorology. · November 2012 Forests return large quantities of C to the atmosphere through soil respiration (Rₛₒᵢₗ), which is often conceptually separated into autotrophic C respired by living roots (Rᵣₒₒₜ) and heterotrophic decomposition (Rₕₑₜ) of soil organic matter (SOM). Live roo ... Full text Cite

Evapotranspiration: A process driving mass transport and energy exchange in the soil-plant-atmosphere-climate system

Journal article Reviews of Geophysics · September 1, 2012 The role of evapotranspiration (ET) in the global, continental, regional, and local water cycles is reviewed. Elevated atmospheric CO2 , air temperature, vapor pressure deficit (D), turbulent transport, radiative transfer, and reduced soil moist ... Full text Cite

Simple additive effects are rare: a quantitative review of plant biomass and soil process responses to combined manipulations of CO2 and temperature.

Journal article Global change biology · September 2012 In recent years, increased awareness of the potential interactions between rising atmospheric CO2 concentrations ([ CO2 ]) and temperature has illustrated the importance of multifactorial ecosystem manipulation experiments for validating Earth System model ... Full text Cite

Increased resin flow in mature pine trees growing under elevated CO2 and moderate soil fertility.

Journal article Tree physiology · June 2012 Warmer climates induced by elevated atmospheric CO(2) (eCO(2)) are expected to increase damaging bark beetle activity in pine forests, yet the effect of eCO(2) on resin production--the tree's primary defense against beetle attack--remains largely unknown. ... Full text Cite

Photoperiodic regulation of the seasonal pattern of photosynthetic capacity and the implications for carbon cycling.

Journal article Proceedings of the National Academy of Sciences of the United States of America · May 2012 Although temperature is an important driver of seasonal changes in photosynthetic physiology, photoperiod also regulates leaf activity. Climate change will extend growing seasons if temperature cues predominate, but photoperiod-controlled species will show ... Full text Cite

Abundance and community structure of ammonia-oxidizing bacteria and archaea in a temperate forest ecosystem under ten-years elevated CO₂

Journal article Soil Biology and Biochemistry. · March 2012 Ammonia-oxidizing bacteria (AOB) and archaea (AOA) are considered as the key drivers of global nitrogen (N) biogeochemical cycling. Responses of the associated microorganisms to global changes remain unclear. This study was to determine if there was a shif ... Full text Cite

Spatiotemporal variation of crown-scale stomatal conductance in an arid Vitis vinifera L. cv. Merlot vineyard: direct effects of hydraulic properties and indirect effects of canopy leaf area.

Journal article Tree physiology · March 2012 Vineyards were planted in the arid region of northwest China to meet the local economic strategy while reducing agricultural water use. Sap flow, environmental variables, a plant characteristic (sapwood-to-leaf area ratio, A(s)/A(l)) and a canopy character ... Full text Cite

Message from the editor-in-chief.

Journal article Tree physiology · February 2012 Full text Cite

Elevated CO 2 affects photosynthetic responses in canopy pine and subcanopy deciduous trees over 10 years: A synthesis from Duke FACE

Journal article Global Change Biology · January 1, 2012 Leaf responses to elevated atmospheric CO 2 concentration (C a) are central to models of forest CO 2 exchange with the atmosphere and constrain the magnitude of the future carbon sink. Estimating the magnitude of primary pr ... Full text Cite

Observed increase in local cooling effect of deforestation at higher latitudes.

Journal article Nature · November 2011 Deforestation in mid- to high latitudes is hypothesized to have the potential to cool the Earth's surface by altering biophysical processes. In climate models of continental-scale land clearing, the cooling is triggered by increases in surface albedo and i ... Full text Cite

Modelling understorey light for seedling regeneration in continuous cover forestry canopies

Journal article FORESTRY · October 2011 Continuous cover forestry (CCF) aims at enhancing stand structural diversity and favouring natural regeneration. To give guidance on how to manage a CCF stand to achieve seedling growth below canopy, an estimate of light transmittance is required. So far, ... Full text Cite

Uncertainty analysis of forest carbon sink forecast with varying measurement errors: A data assimilation approach

Journal article Journal of Plant Ecology · September 1, 2011 Aims: Accurate forecast of ecosystem states is critical for improving natural resource management and climate change mitigation. Assimilating observed data into models is an effective way to reduce uncertainties in ecological forecasting. However, influenc ... Full text Cite

Increases in the flux of carbon belowground stimulate nitrogen uptake and sustain the long-term enhancement of forest productivity under elevated CO₂.

Journal article Ecology letters · April 2011 The earth's future climate state is highly dependent upon changes in terrestrial C storage in response to rising concentrations of atmospheric CO₂. Here we show that consistently enhanced rates of net primary production (NPP) are sustained by a C-cascade t ... Full text Cite

Elevated CO₂ enhances leaf senescence during extreme drought in a temperate forest.

Journal article Tree physiology · February 2011 In 2007, an extreme drought and acute heat wave impacted ecosystems across the southeastern USA, including a 19-year-old Liquidambar styraciflua L. (sweetgum) tree plantation exposed to long-term elevated (E(CO(2))) or ambient (A(CO(2))) CO(2) treatments. ... Full text Cite

Analysis of the sensitivity of absorbed light and incident light profile to various canopy architecture and stand conditions

Journal article TREE PHYSIOLOGY · January 2011 We analyzed the effect of simplifying assumptions in canopy representation of radiation transfer models, comparing modeled diffuse non-interceptance and photosynthetic photon flux density with measurements at different layers of complex pine-broadleaved ca ... Full text Cite

Assessing net ecosystem carbon exchange of U.S. terrestrial ecosystems by integrating eddy covariance flux measurements and satellite observations

Journal article AGRICULTURAL AND FOREST METEOROLOGY · January 2011 More accurate projections of future carbon dioxide concentrations in the atmosphere and associated climate change depend on improved scientific understanding of the terrestrial carbon cycle. Despite the consensus that U.S. terrestrial ecosystems provide a ... Full text Cite

Changes implemented in Tree Physiology.

Journal article Tree physiology · January 2011 Full text Cite

The Spatial Factor, Rather than Elevated CO(2), Controls the Soil Bacterial Community in a Temperate Forest Ecosystem

Journal article APPLIED AND ENVIRONMENTAL MICROBIOLOGY · November 2010 The global atmospheric carbon dioxide (CO(2)) concentration is expected to increase continuously over the next century. However, little is known about the responses of soil bacterial communities to elevated CO(2) in terrestrial ecosystems. This study aimed ... Full text Cite

Estimation of long-term basin scale evapotranspiration from streamflow time series

Journal article Water Resources Research · October 29, 2010 We estimated long-term annual evapotranspiration (ETQ) at the watershed scale by combining continuous daily streamflow (Q) records, a simplified watershed water balance, and a nonlinear reservoir model. Our analysis used Q measured from 11 water ... Full text Open Access Cite

Variable conductivity and embolism in roots and branches of four contrasting tree species and their impacts on whole-plant hydraulic performance under future atmospheric CO₂ concentration.

Journal article Tree physiology · August 2010 Anatomical and physiological acclimation to water stress of the tree hydraulic system involves trade-offs between maintenance of stomatal conductance and loss of hydraulic conductivity, with short-term impacts on photosynthesis and long-term consequences t ... Full text Cite

Differential responses to changes in growth temperature between trees from different functional groups and biomes: a review and synthesis of data.

Journal article Tree physiology · June 2010 The response of tree growth to a change in temperature may differ in predictable ways. Trees with conservative growth strategies may have little ability to respond to a changing climate. In addition, high latitude and altitude tree growth may be temperatur ... Full text Cite

Interannual Invariability of Forest Evapotranspiration and Its Consequence to Water Flow Downstream

Journal article Ecosystems. · April 2010 Although drought in temperate deciduous forests decreases transpiration rates of many species, stand-level transpiration and total evapotranspiration is often reported to exhibit only minor interannual variability with precipitation. This apparent contradi ... Full text Cite

A stomatal optimization theory to describe the effects of atmospheric CO2 on leaf photosynthesis and transpiration.

Journal article Annals of botany · March 2010 Background and aimsGlobal climate models predict decreases in leaf stomatal conductance and transpiration due to increases in atmospheric CO2. The consequences of these reductions are increases in soil moisture availability and continental scale r ... Full text Cite

Greater seed production in elevated CO₂ is not accompanied by reduced seed quality in Pinus taeda L

Journal article Global Change Biology · March 2010 For herbaceous species, elevated CO₂ often increases seed production but usually leads to decreased seed quality. However, the effects of increased atmospheric CO₂ on tree fecundity remain uncertain, despite the importance of reproduction to the compositio ... Full text Cite

Re-assessment of plant carbon dynamics at the Duke free-air CO(2) enrichment site: interactions of atmospheric [CO(2)] with nitrogen and water availability over stand development.

Journal article The New phytologist · January 2010 *The potential for elevated [CO(2)]-induced changes to plant carbon (C) storage, through modifications in plant production and allocation of C among plant pools, is an important source of uncertainty when predicting future forest function. Utilizing 10 yr ... Full text Cite

Climate control of terrestrial carbon exchange across biomes and continents

Journal article Environmental Research Letters · 2010 Cite

Challenges in elevated CO2 experiments on forests.

Journal article Trends in plant science · January 2010 Current forest Free Air CO(2) Enrichment (FACE) experiments are reaching completion. Therefore, it is time to define the scientific goals and priorities of future experimental facilities. In this opinion article, we discuss the following three overarching ... Full text Cite

Latitudinal patterns of magnitude and interannual variability in net ecosystem exchange regulated by biological and environmental variables

Journal article GLOBAL CHANGE BIOLOGY · December 2009 Over the last two and half decades, strong evidence showed that the terrestrial ecosystems are acting as a net sink for atmospheric carbon. However the spatial and temporal patterns of variation in the sink are not well known. In this study, we examined la ... Full text Cite

Acclimation of leaf hydraulic conductance and stomatal conductance of Pinus taeda (loblolly pine) to long-term growth in elevated CO(2) (free-air CO(2) enrichment) and N-fertilization.

Journal article Plant, cell & environment · November 2009 We investigated how leaf hydraulic conductance (K(leaf)) of loblolly pine trees is influenced by soil nitrogen amendment (N) in stands subjected to ambient or elevated CO(2) concentrations (CO(2)(a) and CO(2)(e), respectively). We also examined how K(leaf) ... Full text Cite

Nocturnal evapotranspiration in eddy-covariance records from three co-located ecosystems in the Southeastern U.S.: Implications for annual fluxes

Journal article Agricultural and Forest Meteorology. · September 2009 Nocturnal evapotranspiration (ET N ) is often assumed to be negligible in terrestrial ecosystems, reflecting the common assumption that plant stomata close at night to prevent water loss from transpiration. However, recent evidence across a wide range of s ... Full text Cite

Leaf stomatal responses to vapour pressure deficit under current and CO(2)-enriched atmosphere explained by the economics of gas exchange.

Journal article Plant, cell & environment · August 2009 Using the economics of gas exchange, early studies derived an expression of stomatal conductance (g) assuming that water cost per unit carbon is constant as the daily loss of water in transpiration (f(e)) is minimized for a given gain in photosynthesis (f( ... Full text Cite

The effects of elevated atmospheric CO₂ and nitrogen amendments on subsurface CO₂ production and concentration dynamics in a maturing pine forest

Journal article Biogeochemistry. · July 2009 Profiles of subsurface soil CO₂ concentration, soil temperature, and soil moisture, and throughfall were measured continuously during the years 2005 and 2006 in 16 locations at the free air CO₂ enrichment facility situated within a temperate loblolly pine ... Full text Cite

The relationship between reference canopy conductance and simplified hydraulic architecture

Journal article Advances in Water Resources · June 1, 2009 Terrestrial ecosystems are dominated by vascular plants that form a mosaic of hydraulic conduits to water movement from the soil to the atmosphere. Together with canopy leaf area, canopy stomatal conductance regulates plant water use and thereby photosynth ... Full text Cite

Forest fine-root production and nitrogen use under elevated CO₂: contrasting responses in evergreen and deciduous trees explained by a common principle

Journal article Global Change Biology · January 2009 Despite the importance of nitrogen (N) limitation of forest carbon (C) sequestration at rising atmospheric CO₂ concentration, the mechanisms responsible are not well understood. To elucidate the interactive effects of elevated CO₂ (eCO₂) and soil N availab ... Full text Cite

Energy, water, and carbon fluxes in a loblolly pine stand: Results from uniform and gappy canopy models with comparisons to eddy flux data

Journal article Journal of Geophysical Research Biogeosciences · January 1, 2009 This study investigates the impacts of canopy structure specification on modeling net radiation (Rn), latent heat flux (LE) and net photosynthesis (An) by coupling two contrasting radiation transfer models with a two-leaf photosynthes ... Full text Open Access Cite

Estimating components of forest evapotranspiration: A footprint approach for scaling sap flux measurements

Journal article Agricultural and Forest Meteorology. · October 2008 Forest evapotranspiration (ET) estimates that include scaled sap flux measurements often underestimate eddy covariance (EC)-measured latent heat flux (LE). We investigated potential causes for this bias using 4 years of coupled sap flux and LE measurements ... Full text Cite

Role of vegetation in determining carbon sequestration along ecological succession in the southeastern United States

Journal article Global Change Biology · June 2008 Vegetation plays a central role in controlling terrestrial carbon (C) exchange, but quantifying its impacts on C cycling on time scales of ecological succession is hindered by a lack of long-term observations. The net ecosystem exchange of carbon (NEE) was ... Full text Cite

Mycorrhizal and rhizomorph dynamics in a loblolly pine forest during 5 years of free-air-CO₂-enrichment

Journal article Global Change Biology · June 2008 Soil fungi couple plant and ecosystem resource demands to pools of soil resources. Research on these organisms is needed to predict how rising atmospheric CO₂ will influence forest ecosystem processes and soil carbon (C) sequestration potential. We examine ... Full text Cite

Actual and potential transpiration and carbon assimilation in an irrigated poplar plantation

Journal article TREE PHYSIOLOGY · April 2008 We examined the tradeoffs between stand-level water use and carbon uptake that result when biomass production of trees in plantations is maximized by removing nutrient and water limitations. A Populus trichocarpa Torr. x P deltoides Bartr. \& Marsh. planta ... Cite

Fertilization effects on mean stomatal conductance are mediated through changes in the hydraulic attributes of mature Norway spruce trees

Journal article TREE PHYSIOLOGY · April 2008 Stomatal conductance was quantified with sap flux sensors and whole-tree chambers in mature Norway spruce (Picea abies (L.) Karst.) trees after 3 years of exposure to elevated CO2 concentration ({[}CO2]) in a 13-year nutrient optimization experiment. The l ... Cite

Olevi Kull's lifetime contribution to ecology.

Journal article Tree physiology · April 2008 In this article dedicated to Olevi Kull (June 22, 1955-January 31, 2007), we draw on his writings (in English and translated) to outline his thoughts on the relationship between scientists and science. We provide a brief synthesis of his most important wor ... Full text Cite

Fine root dynamics in a loblolly pine forest are influenced by free-air-CO₂-enrichment: a six-year-minirhizotron study

Journal article Global Change Biology · March 2008 Efforts to characterize carbon (C) cycling among atmosphere, forest canopy, and soil C pools are hindered by poorly quantified fine root dynamics. We characterized the influence of free-air-CO₂-enrichment (ambient +200 ppm) on fine roots for a period of 6 ... Full text Cite

Irreconcilable differences: fine-root life spans and soil carbon persistence.

Journal article Science (New York, N.Y.) · January 2008 The residence time of fine-root carbon in soil is one of the least understood aspects of the global carbon cycle, and fine-root dynamics are one of the least understood aspects of plant function. Most recent studies of these belowground dynamics have used ... Full text Cite

Estimation of net ecosystem carbon exchange for the conterminous United States by combining MODIS and AmeriFlux data

Journal article AGRICULTURAL AND FOREST METEOROLOGY · 2008 Eddy covariance flux towers provide continuous measurements of net ecosystem carbon exchange (NEE) for a wide range of climate and biome types. However, these measurements only represent the carbon fluxes at the scale of the tower footprint. To quantify th ... Cite

Canopy nitrogen, carbon assimilation, and albedo in temperate and boreal forests: Functional relations and potential climate feedbacks

Journal article PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA · 2008 The availability of nitrogen represents a key constraint on carbon cycling in terrestrial ecosystems, and it is largely in this capacity that the role of N in the Earth's climate system has been considered. Despite this, few studies have included continuou ... Cite

Stochastic dynamics of plant-water interactions

Journal article Annual Review of Ecology Evolution and Systematics · December 1, 2007 Describing water flow from soil through plants to the atmosphere remains a formidable scientific challenge despite years of research. This challenge is not surprising given the high dimensionality and degree of nonlinearity of the soil-plant system, which ... Full text Cite

Temporal dynamics and spatial variability in the enhancement of canopy leaf area under elevated atmospheric CO2

Journal article GLOBAL CHANGE BIOLOGY · December 2007 Increased canopy leaf area (L) may lead to higher forest productivity and alter processes such as species dynamics and ecosystem mass and energy fluxes. Few CO2 enrichment studies have been conducted in closed canopy forests and none have shown a sustained ... Full text Cite

Estimation of light interception properties of conifer shoots by an improved photographic method and a 3D model of shoot structure.

Journal article Tree physiology · October 2007 The spherical mean of the shoot silhouette-to-total leaf area ratio (STAR) and the shoot transmission coefficient (c) are two key structural parameters in radiative transfer models for calculating canopy photosynthesis and leaf area index. The standard opt ... Full text Cite

Increases in nitrogen uptake rather than nitrogen-use efficiency support higher rates of temperate forest productivity under elevated CO2.

Journal article Proceedings of the National Academy of Sciences of the United States of America · August 2007 Forest ecosystems are important sinks for rising concentrations of atmospheric CO(2). In previous research, we showed that net primary production (NPP) increased by 23 +/- 2% when four experimental forests were grown under atmospheric concentrations of CO( ... Full text Cite

Effects of hydraulic architecture and spatial variation in light on mean stomatal conductance of tree branches and crowns.

Journal article Plant, cell & environment · April 2007 In a Pinus taeda L. (loblolly pine) plantation, we investigated whether the response to vapour pressure deficit (D) of canopy average stomatal conductance (G(S)) calculated from sap flux measured in upper and lower branches and main stems follows a hydraul ... Full text Cite

The likely impact of elevated [CO2], nitrogen deposition, increased temperature and management on carbon sequestration in temperate and boreal forest ecosystems: a literature review.

Journal article The New phytologist · January 2007 Temperate and boreal forest ecosystems contain a large part of the carbon stored on land, in the form of both biomass and soil organic matter. Increasing atmospheric [CO2], increasing temperature, elevated nitrogen deposition and intensified management wil ... Full text Cite

Eco-hydrological controls on summertime convective rainfall triggers

Journal article GLOBAL CHANGE BIOLOGY · 2007 Triggers of summertime convective rainfall depend on numerous interactions and feedbacks, often compounded by spatial variability in soil moisture and its impacts on vegetation function, vegetation composition, terrain, and all the complex turbulent entrai ... Cite

Aboveground sink strength in forests controls the allocation of carbon below ground and its [CO2]-induced enhancement.

Journal article Proceedings of the National Academy of Sciences of the United States of America · December 2006 The partitioning among carbon (C) pools of the extra C captured under elevated atmospheric CO2 concentration ([CO2]) determines the enhancement in C sequestration, yet no clear partitioning rules exist. Here, we used first principles and published data fro ... Full text Cite

Canopy leaf area constrains [CO2]-induced enhancement of productivity and partitioning among aboveground carbon pools.

Journal article Proceedings of the National Academy of Sciences of the United States of America · December 2006 Net primary productivity (NPP) is enhanced under future atmospheric [CO2] in temperate forests representing a broad range of productivity. Yet questions remain in regard to how elevated [CO2]-induced NPP enhancement may be affected by climatic variations a ... Full text Cite

Net ecosystem exchange of grassland in contrasting wet and dry years

Journal article Agricultural and Forest Meteorology. · October 2006 Full text Cite

Interaction of ice storms and management practices on current carbon sequestration in forests with potential mitigation under future CO(2) atmosphere

Journal article JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES · August 2006 {[}1] Ice storms are disturbance events with potential impacts on carbon sequestration. Common forest management practices, such as fertilization and thinning, can change wood and stand properties and thus may change vulnerability to ice storm damage. At t ... Full text Cite

Multiscale model intercomparisons of CO₂ and H₂O exchange rates in a maturing southeastern US pine forest

Journal article Global Change Biology · July 2006 We compared four existing process-based stand-level models of varying complexity (physiological principles in predicting growth, photosynthesis and evapotranspiration, biogeochemical cycles, and stand to ecosystem carbon and evapotranspiration simulator) a ... Full text Cite

Estimating the uncertainty in annual net ecosystem carbon exchange: spatial variation in turbulent fluxes and sampling errors in eddy-covariance measurements

Journal article Global Change Biology · May 2006 Above forest canopies, eddy covariance (EC) measurements of mass (CO₂, H₂O vapor) and energy exchange, assumed to represent ecosystem fluxes, are commonly made at one point in the roughness sublayer (RSL). A spatial variability experiment, in which EC meas ... Full text Cite

Modeling nighttime ecosystem respiration from measured CO2 concentration and air temperature profiles using inverse methods

Journal article Journal of Geophysical Research Atmospheres · April 27, 2006 A major challenge for quantifying ecosystem carbon budgets from micrometeorological methods remains nighttime ecosystem respiration. An earlier study utilized a constrained source optimization (CSO) method using inverse Lagrangian dispersion theory to infe ... Full text Cite

Adjustments in hydraulic architecture of Pinus palustris maintain similar stomatal conductance in xeric and mesic habitats.

Journal article Plant, cell & environment · April 2006 We investigated relationships between whole-tree hydraulic architecture and stomatal conductance in Pinus palustris Mill. (longleaf pine) across habitats that differed in soil properties and habitat structure. Trees occupying a xeric habitat (characterized ... Full text Cite

The porous media model for the hydraulic system of a conifer tree: Linking sap flux data to transpiration rate

Journal article Ecological Modelling · February 5, 2006 Linking sap flow in tree boles to plant transpiration continues to be a fundamental and practical research problem in physiological ecology and forest hydrology. Many models have been proposed to describe water movement within trees with varying degrees of ... Full text Cite

Modeling seed dispersal distances: implications for transgenic Pinus taeda.

Journal article Ecological applications : a publication of the Ecological Society of America · February 2006 Predicting forest-tree seed dispersal across a landscape is useful for estimating gene flow from genetically engineered (GE) or transgenic trees. The question of biocontainment has yet to be resolved, although field-trial permits for transgenic forest tree ... Full text Cite

Separating the effects of climate and vegetation on evapotranspiration along a successional chronosequence in the southeastern US

Journal article GLOBAL CHANGE BIOLOGY · 2006 We combined Eddy-covariance measurements with a linear perturbation analysis to isolate the relative contribution of physical and biological drivers on evapotranspiration (ET) in three ecosystems representing two end-members and an intermediate stage of a ... Cite

Forest response to elevated CO2 is conserved across a broad range of productivity.

Journal article Proceedings of the National Academy of Sciences of the United States of America · December 2005 Climate change predictions derived from coupled carbon-climate models are highly dependent on assumptions about feedbacks between the biosphere and atmosphere. One critical feedback occurs if C uptake by the biosphere increases in response to the fossil-fu ... Full text Cite

Finite element tree crown hydrodynamics model (FETCH) using porous media flow within branching elements: A new representation of tree hydrodynamics

Journal article Water Resources Research · November 1, 2005 [1] Estimating transpiration and water flow in trees remains a major challenge for quantifying water exchange between the biosphere and the atmosphere. We develop a finite element tree crown hydrodynamics (FETCH) model that uses porous media equations for ... Full text Cite

Temporal variability in (13)C of respired CO(2) in a pine and a hardwood forest subject to similar climatic conditions.

Journal article Oecologia · January 2005 Temporal variability in the (13)C of foliage (delta(13)C(F)), soil (delta(13)C(S)) and ecosystem (delta(13)C(R)) respired CO(2) was contrasted between a 17.2-m tall evenly aged loblolly pine forest and a 35-m tall unevenly aged mature second growth mixed b ... Full text Cite

Variability in net ecosystem exchange from hourly to inter-annual time scales at adjacent pine and hardwood forests: a wavelet analysis

Journal article TREE PHYSIOLOGY · 2005 Orthonormal wavelet transformation (OWT) is a computationally efficient technique for quantifying underlying frequencies in nonstationary and gap-infested time series, such as eddy-covariance-measured net ecosystem exchange of CO2 (NEE). We employed OWT to ... Cite

Time series diagnosis of tree hydraulic characteristics.

Journal article Tree physiology · August 2004 An in vivo method for diagnosing hydraulic characteristics of branches and whole trees is described. The method imposes short-lived perturbations of transpiration and traces the propagation of the hydraulic response through trees. The water uptake response ... Full text Cite

Impact of elevated atmospheric CO2 on forest floor respiration in a temperate pine forest

Journal article Global Biogeochemical Cycles · June 1, 2004 The effects of elevated atmospheric CO2 (COe2) on soil respiration were evaluated using inverse models and static chamber measurements collected over 4.5 years in a maturing loblolly pine forest. The chamber measurements of ... Full text Cite

Stomatal sensitivity to vapor pressure deficit and its relationship to hydraulic conductance in Pinus palustris.

Journal article Tree physiology · May 2004 We studied the response of stomatal conductance at leaf (gS) and canopy (GS) scales to increasing vapor pressure deficit (D) in mature Pinus palustris Mill. (longleaf pine) growing in a sandhill habitat in the coastal plain of the southeastern USA. Specifi ... Full text Cite

Progressive nitrogen limitation of ecosystem responses to rising atmospheric carbon dioxide

Journal article Bioscience · January 1, 2004 A highly controversial issue in global biogeochemistry is the regulation of terrestrial carbon (C) sequestration by soil nitrogen (N) availability. This controversy translates into great uncertainty in predicting future global terrestrial C sequestration. ... Full text Cite

Carbon dioxide and water vapor exchange in a warm temperate grassland.

Journal article Oecologia · January 2004 Grasslands cover about 40% of the ice-free global terrestrial surface, but their contribution to local and regional water and carbon fluxes and sensitivity to climatic perturbations such as drought remains uncertain. Here, we assess the direction and magni ... Full text Cite

Exposure to an enriched CO2 atmosphere alters carbon assimilation and allocation in a pine forest ecosystem

Journal article Global Change Biology · October 1, 2003 We linked a leaf-level CO2 assimilation model with a model that accounts for light attenuation in the canopy and measurements of sap-flux-based canopy conductance into a new canopy conductance-constrained carbon assimilation (4C-A) model. We est ... Full text Cite

Reduction of forest floor respiration by fertilization on both carbon dioxide-enriched and reference 17-year-old loblolly pine stands

Journal article Global Change Biology · June 1, 2003 Elevated atmospheric carbon dioxide (CO2e) increases soil respiration rates in forest, grassland, agricultural and wetland systems as a result of increased growth, root biomass and enhanced biological activity of soil microorganisms. ... Full text Cite

Relationship between plant hydraulic and biochemical properties derived from a steady-state coupled water and carbon transport model

Journal article Plant Cell and Environment · March 1, 2003 There is growing evidence that plant stomata have evolved physiological controls to satisfy the demand for CO2 by photosynthesis while regulating water losses by leaves in a manner that does not cause cavitation in the soil-root-xylem hydraulic ... Full text Cite

Species differences in stomatal control of water loss at the canopy scale in a mature bottomland deciduous forest

Journal article Advances in Water Resources · January 1, 2003 In order to evaluate factors controlling transpiration of six common eastern deciduous species in North America, a model describing responses of canopy stomatal conductance (GS) to net radiation (RN), vapor pressure deficit (D) and re ... Full text Cite

Mechanisms of long-distance dispersal of seeds by wind.

Journal article Nature · July 2002 Long-distance dispersal (LDD) is central to species expansion following climate change, re-colonization of disturbed areas and control of pests. The current paradigm is that the frequency and spatial extent of LDD events are extremely difficult to predict. ... Full text Cite

Modelling night-time ecosystem respiration by a constrained source optimization method

Journal article Global Change Biology · February 2002 One of the main challenges to quantifying ecosystem carbon budgets is properly quantifying the magnitude of night-time ecosystem respiration. Inverse Lagrangian dispersion analysis provides a promising approach to addressing such a problem when measured me ... Full text Cite

Water deficits and hydraulic limits to leaf water supply.

Journal article Plant, cell & environment · February 2002 Many aspects of plant water use -- particularly in response to soil drought -- may have as their basis the alteration of hydraulic conductance from soil to canopy. The regulation of plant water potential (Psi) by stomatal control and leaf area adjustment m ... Full text Cite

Modelling the limits on the response of net carbon exchange to fertilization in a south-eastern pine forest

Journal article Plant Cell and Environment · January 1, 2002 Using a combination of model simulations and detailed measurements at a hierarchy of scales conducted at a sandhills forest site, the effect of fertilization on net ecosystem exchange (NEE) and its components in 6-year-old Pinus taeda stands was quantified ... Full text Cite

Multiscale analysis of vegetation surface fluxes: From seconds to years

Journal article Advances in Water Resources · November 1, 2001 The variability in land surface heat (H), water vapor (LE), and CO2 (or net ecosystem exchange, NEE) fluxes was investigated at scales ranging from fractions of seconds to years using eddy-covariance flux measurements above a pine forest. Becaus ... Full text Cite

Effects of nutrition and soil water availability on water use in a Norway spruce stand.

Journal article Tree physiology · August 2001 We investigated effects of nutrition and soil water availability on sap flux density, transpiration per unit leaf area (EL), and canopy stomatal conductance (GS) of Norway spruce (Picea abies L. (Karst.)) in northern Sweden during the 1996 growing season. ... Full text Cite

Mean canopy stomatal conductance responses to water and nutrient availabilities in Picea abies and Pinus taeda.

Journal article Tree physiology · August 2001 We compared sap-flux-scaled, mean, canopy stomatal conductance (GS) between Picea abies (L.) Karst. in Sweden and Pinus taeda (L.) in North Carolina, both growing on nutritionally poor soils. Stomatal conductance of Picea abies was approximately half that ... Full text Cite

Quantification of insect nitrogen utilization by the venus fly trap Dionaea muscipula catching prey with highly variable isotope signatures.

Journal article Journal of experimental botany · May 2001 Dionaea is a highly specialized carnivorous plant species with a unique mechanism for insect capture. The leaf is converted into an osmotically driven trap that closes when an insect triggers sensory trichomes. This study investigates the significance of i ... Full text Cite

Soil fertility limits carbon sequestration by forest ecosystems in a CO2-enriched atmosphere.

Journal article Nature · May 2001 Northern mid-latitude forests are a large terrestrial carbon sink. Ignoring nutrient limitations, large increases in carbon sequestration from carbon dioxide (CO2) fertilization are expected in these forests. Yet, forests are usually relegated to sites of ... Full text Cite

Transpiration in response to variation in microclimate and soil moisture in southeastern deciduous forests.

Journal article Oecologia · May 2001 Responses of forests to changes in environmental conditions reflect the integrated behavior of their constituent species. We investigated sap flux-scaled transpiration responses of two species prevalent in upland eastern hardwood forests, Quercus alba in t ... Full text Cite

Estimating maximum mean canopy stomatal conductance for use in models

Journal article Canadian Journal of Forest Research · April 17, 2001 Fertilized (F) and irrigated and fertilized (IF) stands of Pinus taeda L. produced twice the leaf area index of irrigated (I) and control (C) stands. Based on sap flux-scaled mean stomatal conductance (GS), we found that stomatal conductance in ... Full text Cite

Intra- and Inter-Annual Variation in Transpiration of a Pine Forest

Journal article Ecological Applications · April 2001 Full text Cite

Carbon sequestration and southern pine forests

Journal article JOURNAL OF FORESTRY · April 1, 2001 Link to item Cite

Meeting Global Policy Commitments: Carbon Sequestration and Southern Pine Forests

Journal article Journal of Forestry · April 1, 2001 In managed forests, the amount of carbon further sequestered will be determined by (1) the increased amount of carbon in standing biomass (resulting from land-use changes and increased productivity); (2) the amount of recalcitrant carbon remaining below gr ... Cite

The effect of crown dimensions on transparency and the assessment of tree health

Journal article Ecological Applications · January 1, 2001 Assessment of forest health on a national scale is a difficult task. One parameter used to rapidly classify tree health is crown transparency, or the amount of sky seen through the crown. Previous investigations of sources of error in estimating crown tran ... Full text Cite

Intra- and inter-annual variation in transpiration of a pine forest

Journal article Ecological Applications · January 1, 2001 A study on the long-term water use of stands dominated by loblolly pine (Pinus taeda) and associated species was conducted in Duke Forest, North Carolina, USA. Associated species included sweetgum (Liquidambar styraciflua), willow oak (Quercus phettos), re ... Full text Cite

Sensitivity of mean canopy stomatal conductance to vapor pressure deficit in a flooded Taxodium distichum L. forest: hydraulic and non-hydraulic effects.

Journal article Oecologia · January 2001 We measured the xylem sap flux in 64-year-old Taxodium distichum (L.) Richard trees growing in a flooded forest using Granier-type sensors to estimate mean canopy stomatal conductance of the stand (G S). Temporal variations in G S wer ... Full text Cite

Quantifying the complexity in mapping energy inputs and hydrologic state variables into land-surface fluxes

Journal article Geophysical Research Letters · January 1, 2001 This study explores the complexity (or disorder) in mapping energy (Rn) forcing to land surface fluxes of sensible heat (Hs), water vapor (LE), and carbon dioxide (or net ecosystem exchange, NEE) for different soil water states (θ). S ... Full text Cite

Modeling CO2 and water vapor turbulent flux distributions within a forest canopy

Journal article Journal of Geophysical Research Atmospheres · November 16, 2000 One-dimensional multilayer biosphere-atmosphere models (e.g., CANVEG) describe ecosystem carbon dioxide (CO2) and water vapor (H2O) fluxes well when cold temperatures or the hydrologic state of the ecosystem do not induce stomatal clo ... Full text Cite

Influence of nutrient versus water supply on hydraulic architecture and water balance in Pinus taeda

Journal article Plant Cell and Environment · October 21, 2000 We investigated the hydraulic consequences of a major decrease in root-to-leaf area ratio (A(R):A(L)) caused by nutrient amendments to 15-year-old Pinus taeda L. stands on sandy soil. In theory, such a reduction in A(R):A(L) should compromise the trees' ab ... Full text Cite

Influence of soil porosity on water use in Pinus taeda.

Journal article Oecologia · September 2000 We analyzed the hydraulic constraints imposed on water uptake from soils of different porosities in loblolly pine (Pinus taeda L.) by comparing genetically related and even-aged plantations growing in loam versus sand soil. Water use was evaluated relative ... Full text Cite

Analyses of assumptions and errors in the calculation of stomatal conductance from sap flux measurements.

Journal article Tree physiology · May 2000 We analyzed assumptions and measurement errors in estimating canopy transpiration (E(L)) from sap flux (J(S)) measured with Granier-type sensors, and in calculating canopy stomatal conductance (G(S)) from E(L) and vapor pressure deficit (D). The study was ... Full text Cite

Modelling vegetation-atmosphere CO2 exchange by a coupled Eulerian-Langrangian approach

Journal article Boundary Layer Meteorology · January 1, 2000 A Eulerian-Lagrangian canopy microclimate model was developed with the aim of discerning physical from biophysical controls of CO2 and H2O fluxes. The model couples radiation attenuation with mass, energy, and momentum exchange at dif ... Full text Cite

Sap flux of co-occurring species in a western subalpine forest during seasonal soil drought

Journal article Ecology · January 1, 2000 Co-occurring species may utilize vastly different strategies to cope with limited water resources, particularly in areas subjected to predictable and recurring drought. While these physiological responses have commonly been measured at the leaf level, in s ... Full text Cite

The effect of tree height on crown level stomatal conductance

Journal article Plant Cell and Environment · January 1, 2000 Variation in stomatal conductance is typically explained in relation to environmental conditions. However, tree height may also contribute to the variability in mean stomatal conductance. Mean canopy stomatal conductance of individual tree crowns (G(Si)) w ... Full text Cite

Survey and synthesis of intra- and interspecific variation in stomatal sensitivity to vapour pressure deficit

Journal article Plant Cell and Environment · December 1, 1999 Responses of stomatal conductance (g(s)) to increasing vapour pressure deficit (D) generally follow an exponential decrease described equally well by several empirical functions. However, the magnitude of the decrease - the stomatal sensitivity - varies co ... Full text Cite

Spatial variability of turbulent fluxes in the roughness sublayer of an even-aged pine forest

Journal article Boundary Layer Meteorology · December 1, 1999 The spatial variability of turbulent flow statistics in the roughness sublayer (RSL) of a uniform even-aged 14 m (= h) tall loblolly pine forest was investigated experimentally. Using seven existing walkup towers at this stand, high frequency velocity, tem ... Full text Cite

Sap-flux-scaled transpiration responses to light, vapor pressure deficit, and leaf area reduction in a flooded Taxodium distichum forest.

Journal article Tree physiology · May 1999 We used 20-mm-long, Granier-type sensors to quantify the effects of tree size, azimuth and radial position in the xylem on the spatial variability in xylem sap flux in 64-year-old trees of Taxodium distichum L. Rich. growing in a flooded forest. This infor ... Full text Cite

Carry-over effects of water and nutrient supply on water use of Pinus taeda

Journal article Ecological Applications · January 1, 1999 A study of the effects of nutrients and water supply (2 x 2 factorial experiment) was conducted in a 12-yr-old stand of loblolly pine (Pinus taeda L.) during a period in which soil moisture was not augmented by irrigation because of frequent rain events. I ... Full text Cite

Elevated carbon dioxide does not affect average canopy stomatal conductance of Pinus taeda L.

Journal article Oecologia · November 1998 While photosynthetic responses of C3 plants to elevated CO2 are fairly well documented, whole-plant water use under such conditions has been less intensively studied. Woody species, in particular, have exhibited highly variable stomat ... Full text Cite

Canopy conductance of Pinus taeda, Liquidambar styraciflua and Quercus phellos under varying atmospheric and soil water conditions.

Journal article Tree physiology · May 1998 Sap flow, and atmospheric and soil water data were collected in closed-top chambers under conditions of high soil water potential for saplings of Liquidambar styraciflua L., Quercus phellos L. and Pinus taeda L., three co-occurring species in the southeast ... Full text Cite

Scaling xylem sap flux and soil water balance and calculating variance: A method for partitioning water flux in forests

Journal article Annales Des Sciences Forestieres · January 1, 1998 To partition evapotranspiration between canopy and subcanopy components in a 12-m-tall Pinus taeda forest and to assess certain aspects of environmental regulation of canopy transpiration, we quantified water flux in a forest using three approaches: 1) mea ... Full text Cite

Water balance delineates the soil layer in which moisture affects canopy conductance

Journal article Ecological Applications · January 1, 1998 To link variation in canopy conductance to soil moisture in the rooting zone, measurements of throughfall (P(T)), volumetric soil moisture (θ) to 0.7 m, transpiration from trees >10 mm in diameter (E(C)), and vapor pressure deficit (D) were made in a fores ... Full text Cite

Responses of sap flux and stomatal conductance of Pinus taeda L. trees to stepwise reductions in leaf area

Journal article Journal of Experimental Botany · January 1, 1998 Herbivory or artificial foliage removal has been shown to affect gas exchange and canopy water relations. In this study, canopy architecture and water relations in response to progressive defoliation were examined in a stand of 8-year-old loblolly pine (Pi ... Full text Cite

A comparison of daily representations of canopy conductance based on two conditional time-averaging methods and the dependence of daily conductance on environmental factors

Journal article Annales Des Sciences Forestieres · January 1, 1998 In hydrological models which incorporate vegetated surfaces, non-steady state responses in stem sap flow to diurnal evaporative demand can lead to unreasonable values of computed canopy conductance, which corrupt diurnal courses and daily averages. Conduct ... Full text Cite

A comparison of sap flow and eddy fluxes of water vapor from a boreal deciduous forest

Journal article Journal of Geophysical Research Atmospheres · December 26, 1997 Water flux to the atmosphere was measured from a mature stand of aspen (Populus tremuloides Michx.) in Saskatchewan, Canada, as part of the Boreal Ecosystem-Atmosphere Study (BOREAS). Diurnal and seasonal changes in transpiration were monitored using two s ... Full text Cite

Winter and spring thaw as observed with imaging radar at BOREAS

Journal article Journal of Geophysical Research Atmospheres · December 26, 1997 Measurements of the length of the growing season in the boreal regions, during which significant carbon exchange due to metabolic activity occurs, may improve current estimates of annual CO2 fluxes at high northern latitudes. For coniferous, eve ... Full text Cite

Time constant for water transport in loblolly pine trees estimated from time series of evaporative demand and stem sapflow

Journal article Trees Structure and Function · August 1, 1997 The use of stem sap flow data to estimate diurnal whole-tree transpiration and canopy stomatal conductance depends critically upon knowledge of the time lag between transpiration and water flux through the stem. In this study, the time constant for water m ... Full text Cite

Lagrangian dispersion model for predicting CO2 sources, sinks, and fluxes in a uniform loblolly pine (Pinus taeda L.) stand

Journal article Journal of Geophysical Research Atmospheres · April 27, 1997 A canopy Lagrangian turbulent scalar transport model for predicting scalar fluxes, sources, and sinks within a forested canopy was tested using CO2 concentration and flux measurements. The model formulation is based on the localized near-field t ... Full text Cite

Soil water depletion by oak trees and the influence of root water uptake on the moisture content spatial statistics

Journal article Water Resources Research · January 1, 1997 The space-time statistical structure of soil water uptake by oak trees was investigated in a 3.1-m-diameter closed top chamber using a three-dimensional measurement grid of soil moisture and pressure, and measurements of tree transpiration. Using the time ... Full text Cite

Radial patterns of xylem sap flow in non-, diffuse- and ring-porous tree species

Journal article Plant Cell and Environment · January 1, 1996 We investigated radial patterns of sap flux density and wood properties in the sapwood of young loblolly pine (Pinus taeda L.), mature white oak (Quercus alba L.) and sweetgum (Liquidambar styraciflua L.), which represent three major classes of wood anatom ... Full text Cite

Latent and sensible heat flux predictions from a uniform pine forest using surface renewal and flux variance methods

Journal article Boundary Layer Meteorology · January 1, 1996 A surface renewal model that links organized eddy motion to the latent and sensible heat fluxes is tested with eddy correlation measurements carried out in a 13 m tall uniform Loblolly pine plantation in Duke Forest, Durham, North Carolina. The surface ren ... Full text Cite

Leaf and canopy responses to elevated CO2 in a pine forest under free-air CO2 enrichment.

Journal article Oecologia · October 1995 Physiological responses to elevated CO2 at the leaf and canopy-level were studied in an intact pine (Pinus taeda) forest ecosystem exposed to elevated CO2 using a free-air CO2 enrichment (FACE) technique. Normalized canopy ... Full text Cite

Response of magnesium-deficient saplings in a young, open stand of Picea abies (L.) Karst. to elevated soil magnesium, nitrogen and carbon.

Journal article Environmental pollution (Barking, Essex : 1987) · January 1995 A decline in a Picea abies L. (Karst.) stand in the Fichtelgebirge, NE-Bavaria, FRG has been attributed to a nutritional disharmony-a seasonal imbalance between a high supply of nitrogen, caused by high nitrogen deposition, and a low supply of soil magnesi ... Full text Cite

Imaging radar for ecosystem studies

Journal article Bioscience · January 1, 1995 Full text Cite

Dielectric and hydraulic response of selected forest canopies at the boreas test sites in Canada

Journal article International Geoscience and Remote Sensing Symposium IGARSS · January 1, 1995 The Board Ecosystem-Atmosphere Study (BOREAS) is a multidisciplinary field and remote sensing study with the goal of obtaining an improved understanding of the interactions between the boreal forest biome and the atmosphere in order to clarify their roles ... Cite

Xylem dielectric constant, water status, and transpiration of young Jack Pine (Pinus banksiana Lamb.) in the southern boreal zone of Canada

Journal article International Geoscience and Remote Sensing Symposium IGARSS · January 1, 1995 Diurnal changes of xylem dielectric constant (XDC), microclimate, and tree water status were studied in a young Jack Pine (Pinus banksiana Lamb.) stand in the southern boreal zone of Canada. Tree water status of trees was also manipulated by changing the c ... Cite

Microclimate, water potential, transpiration, and bole dielectric constant of coniferous and deciduous tree species in the continental boreal ecotone of central Alaska

Journal article International Geoscience and Remote Sensing Symposium IGARSS · December 1, 1994 In situ investigations of the water stress in deciduous and coniferous tree species in the boreal zone of central Alaska were conducted and the corresponding changes of the bole dielectric constant and tree transpiration were studied. It was verified that ... Cite

Element concentrations in the xylem sap of Picea abies (L.) Karst. seedlings extracted by various methods under different environmental conditions.

Journal article Tree physiology · February 1994 We used a Scholander pressure chamber to assess the effects of various extraction methods under different environmental conditions on element concentrations in xylem sap of 3-year-old Picea abies (L.) Karst. seedlings. Sap from excised shoots contained hig ... Full text Cite

Evaluating the Type and State of Alaska Taiga Forests with Imaging Radar for Use in Ecosystem Models

Journal article IEEE Transactions on Geoscience and Remote Sensing · January 1, 1994 Changes in the seasonal CO2 flux of the boreal forests may result from increased atmospheric CO2 concentrations and associated global warming patterns. To monitor this potential change, a combination of information derived from remote sensing data, includi ... Full text Cite

Hydrologic and dielectric properties of woody plant tissue: Implications for remote sensing of canopy water status

Journal article International Geoscience and Remote Sensing Symposium IGARSS · December 1, 1993 The measurement of xylem water potential provides information about the current water available to plants. Furthermore, the knowledge of actual stand transpiration and canopy water conductance provides essential information for estimating canopy carbon, wa ... Cite

Chlorophyll-nutrient relationships identify nutritionally caused decline in Picea abies stands

Journal article Canadian Journal of Forest Research · January 1, 1993 Increasing needle chlorosis at a declining Norway spruce site in NE Bavaria, Germany, as well as in other declining stands in S Germany, was associated with a decrease in the concentrations of both chlorophyll a and b, and, to a lesser extent, of carotenoi ... Full text Cite

The use of stable isotopes in ecosystem research. First results of a field study with 15N

Journal article Isotopenpraxis Isotopes in Environmental and Health Studies · September 1992 Full text Cite

Performance of two Picea abies (L.) Karst. stands at different stages of decline : VII. Nutrient relations and growth.

Journal article Oecologia · November 1988 A declining, closed-canopy Picea abies (L.) Karst. stand produced as much crown biomass as a healthy stand, although some trees were chlorotic due to magnesium deficiency. The production of wood per unit of leaf area in both stands was related to the folia ... Full text Cite

Performance of two Picea abies (L.) Karst. stands at different stages of decline : VI. Nutrient concentration.

Journal article Oecologia · November 1988 A declining Picea abies (L.) Karst. stand produced as much foliage and branches as a healthy stand but less stemwood at a similar leaf area index and climate. Nutrient analyses revealed that most biomass components at the declining site had lower concentra ... Full text Cite

Performance of two Picea abies (L.) Karst. stands at different stages of decline : IV. Xylem sap concentrations of magnesium, calcium, potassium and nitrogen.

Journal article Oecologia · October 1988 The nutrient relations (nitrogen, magnesium, calcium, potassium, and manganese) of the xylem sap of spruce trees, Picea abies (L.) Karst., growing at a healthy and a declining site in Northern Bavaria, were followed on a diurnal and seasonal basis between ... Full text Cite

Performance of two Picea abies (L.) Karst. stands at different stages of decline : V. Root tip and ectomycorrhiza development and their relations to above ground and soil nutrients.

Journal article Oecologia · October 1988 The development of root tips and apparent ectomycorrhizas was compared in the Fichtelgebirge (FRG) over one growing season in two 30-year-old Picea abies stands, both on soils derived from phyllite but showing varying symptoms of decline. Visual symptoms o ... Full text Cite

Performance of two Picea abies (L.) Karst. stands at different stages of decline : III. Canopy transpiration of green trees.

Journal article Oecologia · September 1988 The water relations of Picea abies in a healthy stand with green trees only and a declining stand with trees showing different stages of needle yellowing were investigated in northern Bavaria. The present study is based on observations of trees differing i ... Full text Cite

Performance of two Picea abies (L.) Karst. stands at different stages of decline : II. Photosynthesis and leaf conductance.

Journal article Oecologia · September 1988 CO2 assimilation rate (A) and leaf conductance (g) were measured in the field on intact branches of 35-year-old Picea abies (L.) Karst. trees, in five plots each in a healthy and a declining stand. The declining site included trees with yellow n ... Full text Cite

Performance of two Picea abies (L.) Karst. stands at different stages of decline : I. Carbon relations and stand growth.

Journal article Oecologia · February 1988 This is the first in a series of papers on the growth, photosynthetic rate, water and nutrient relations, root distribution and mycorrhizal frequency of two Norway spruce forests at different stages of decline. One of the stands was composed of green trees ... Full text Cite

Twenty-four years of ponderosa pine growth in relation to canopy leaf area and understory competition.

Journal article Forest Science · January 1, 1987 Data generally supported the hypothesis that Pinus ponderosa stand growth is directly correlated with the development of the forest canopy, eg growth is proportional to canopy leaf area. At very low leaf area indices, wood production per unit of leaf area ... Cite

Estimating photosynthetic rate and annual carbon gain in conifers from specific leaf weight and leaf biomass.

Journal article Oecologia · September 1986 Canopy photosynthesis is difficult to measure directly or to predict with complex models demanding knowledge of seasonal variation in environmental and physiological properties of the canopy. Trees in particular offer a challenge with their large, aerodyna ... Full text Cite

TREE VIGOR AND STAND GROWTH OF DOUGLAS-FIR AS INFLUENCED BY LAMINATED ROOT-ROT

Journal article CANADIAN JOURNAL OF FOREST RESEARCH-REVUE CANADIENNE DE RECHERCHE FORESTIERE · 1985 Full text Cite

Attacks of mountain pine beetle as related to tree vigor of ponderosa pine.

Journal article Forest Science · January 1, 1983 In central Oregon, Pinus ponderosa vigor (stem growth per unit of leaf area) decreased as both tree density (basal area) and leaf area index increased. Low vigor trees were more often attacked by Dendroctonus ponderosae than high vigor trees. Attacks incre ... Cite

Application of the pipe model theory to predict canopy leaf area.

Journal article Canadian Journal of Forest Research · January 1, 1982 Validates the pipe model theory which presents the idea that a unit weight of tree foliage (here, western US conifers) is serviced by a specific cross-sectional area of conducting sapwood in the crown. Below the crown, a large fraction of the tree bole may ... Full text Cite