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Forest process models are mathematical representations of biological systems that incorporate our understanding of physiological and ecological mechanisms into predictive algorithms. These models were originally designed and used for research purposes, but are being developed for use in practical forest management. Process models designed for research(More)
Respiration consumes a large portion of annual gross primary productivity in forest ecosystems and is dominated by belowground metabolism. Here, we present evidence of a previously unaccounted for internal CO(2) flux of large magnitude from tree roots through stems. If this pattern is shown to persist over time and in other forests, it suggests that(More)
The effect of planting density (740, 2,220, 3,700, and 4,440 trees/ha –1) on growth efficiency and biomass partitioning was examined in intensively managed stands of 4-yr-old loblolly (Pinus taeda L.) and slash pine (Pinus elliottii Engelm.) stands on the Coastal Plain of southern Georgia. The primary objective of this study was to determine whether(More)
Forest ecosystems experience various disturbances that can affect belowground carbon cycling to different degrees. Here, we investigate if successive annual foliar scorching events will result in a large and rapid decline in soil CO 2 efflux, similar to that observed in girdling studies. Using the fire-adapted longleaf pine (Pinus palustris Mill.) tree(More)
Previous reports have shown that CO(2) dissolved in xylem sap in tree stems can move upward in the transpiration stream. To determine the fate of this dissolved CO(2), the internal transport of respired CO(2) at high concentration from the bole of the tree was simulated by allowing detached young branches of sycamore (Platanus occidentalis L.) to transpire(More)
We grew potted loblolly pine (Pinus taeda L.) seedlings from a single provenance under well watered and fertilized conditions at four locations along a 610 km north–south transect that spanned most of the species range to examine how differences in the above-ground environment would affect growth rate, biomass partitioning and gas exchange characteristics.(More)
Stem CO2 efflux (E S) is an important component of forest ecosystem carbon budgets and net ecosystem CO2 exchange, but little is known about E S in temperate forests in Northeastern China, an area with a large extent of forest. We measured E S along with stem temperature at 1 cm depth (Ts) over a 9 month period in 2007 on ten dominant tree species of(More)
Plants can acquire carbon from sources other than atmospheric carbon dioxide (CO(2)), including soil-dissolved inorganic carbon (DIC). Although the net flux of CO(2) is out of the root, soil DIC can be taken up by the root, transported within the plant, and fixed either photosynthetically or anaplerotically by plant tissues. We tested the ability of Pinus(More)
The thermal dissipation technique is widely used to estimate transpiration of individual trees and forest stands, but there are conflicting reports regarding its accuracy. We compared the rate of water uptake by stems of six tree species in potometers with sap flow (F S) estimates derived from thermal dissipation sensors to evaluate the accuracy of the(More)
Heat wave frequency and intensity are predicted to increase. We investigated whether repeated exposure to heat waves would induce acclimation in Quercus rubra seedlings and considered [CO2] as an interacting factor. We measured gas exchange and chlorophyll fluorescence of seedlings grown in 380 (C A) or 700 (C E) μmol CO2 mol−1, and three temperature(More)