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Institution

Oregon State University

EducationCorvallis, Oregon, United States
About: Oregon State University is a education organization based out in Corvallis, Oregon, United States. It is known for research contribution in the topics: Population & Climate change. The organization has 28192 authors who have published 64044 publications receiving 2634108 citations. The organization is also known as: Oregon Agricultural College & OSU.


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Journal ArticleDOI
TL;DR: In this article, the authors used biological measurements to estimate carbon storage in vegetation and soil pools, net primary productivity, and net ecosystem productivity to examine variation with stand age in ponderosa pine forests.
Abstract: Forest development following stand-replacing disturbance influences a variety of ecosystem processes including carbon exchange with the atmosphere. On a series of ponderosa pine (Pinius ponderosa var. Laws.) stands ranging from 9 to> 300 years in central Oregon, USA, we used biological measurements to estimate carbon storage in vegetation and soil pools, net primary productivity (NPP) and net ecosystem productivity (NEP) to examine variation with stand age. Measurements were made on plots representing four age classes with three replications: initiation (I, 9–23 years), young (Y, 56–89 years), mature (M, 95–106 years), and old (O, 190–316 years) stands typical of the forest type in the region. Net ecosystem productivity was lowest in the I stands (−124 g C m−2 yr−1), moderate in Y stands (118 g C m−2 yr−1), highest in M stands (170 g C m−2 yr−1), and low in the O stands (35 g C m−2 yr−1). Net primary productivity followed similar trends, but did not decline as much in the O stands. The ratio of fine root to foliage carbon was highest in the I stands, which is likely necessary for establishment in the semiarid environment, where forests are subject to drought during the growing season (300–800 mm precipitation per year). Carbon storage in live mass was the highest in the O stands (mean 17.6 kg C m−2). Total ecosystem carbon storage and the fraction of ecosystem carbon in aboveground wood mass increased rapidly until 150–200 years, and did not decline in older stands. Forest inventory data on 950 ponderosa pine plots in Oregon show that the greatest proportion of plots exist in stands ∼ 100 years old, indicating that a majority of stands are approaching maximum carbon storage and net carbon uptake. Our data suggests that NEP averages ∼ 70 g C m−2 year−1 for ponderosa pine forests in Oregon. About 85% of the total carbon storage in biomass on the survey plots exists in stands greater than 100 years, which has implications for managing forests for carbon sequestration. To investigate variation in carbon storage and fluxes with disturbance, simulation with process models requires a dynamic parameterization for biomass allocation that depends on stand age, and should include a representation of competition between multiple plant functional types for space, water, and nutrients.

384 citations

Journal ArticleDOI
TL;DR: This article used the Long-term Intersite Decomposition Experiment Team (LIDET) dataset and model selection techniques to choose and parameterize a model that describes global patterns of litter decomposition Mass loss was best represented by a three-pool negative exponential model, with a rapidly decomposing labile pool, an intermediate pool representing cellulose, and a recalcitrant pool.
Abstract: As atmospheric CO 2 increases, ecosystem carbon sequestration will largely depend on how global changes in climate will alter the balance between net primary production and decomposition The response of primary production to climatic change has been examined using well-validated mechanistic models, but the same is not true for decomposition, a primary source of atmospheric CO 2 We used the Long-term Intersite Decomposition Experiment Team (LIDET) dataset and model-selection techniques to choose and parameterize a model that describes global patterns of litter decomposition Mass loss was best represented by a three-pool negative exponential model, with a rapidly decomposing labile pool, an intermediate pool representing cellulose, and a recalcitrant pool The initial litter lignin/nitrogen ratio defined the size of labile and intermediate pools Lignin content determined the size of the recalcitrant pool The decomposition rate of all pools was modified by climate, but the intermediate pool's decomposition rate was also controlled by relative amounts of litter cellulose and lignin (indicative of lignin-encrusted cellulose) The effect of climate on decomposition was best represented by a composite variable that multiplied a water-stress function by the Lloyd and Taylor variable Q 10 temperature function Although our model explained nearly 70% of the variation in LIDET data, we observed systematic deviations from model predictions Below- and aboveground material decomposed at notably different rates, depending on the decomposition stage Decomposition in certain ecosystem-specific environmental conditions was not well represented by our model; this included roots in very wet and cold soils, and aboveground litter in N-rich and arid sites Despite these limitations, our model may still be extremely useful for global modeling efforts, because it accurately (R 2 = 06804) described general patterns of long-term global decomposition for a wide array of litter types, using relatively minimal climatic and litter quality data

384 citations

Journal ArticleDOI
TL;DR: In this paper, a landscape management framework that incorporates all systems, across the spectrum of degrees of alteration, provides a fuller set of options for how and when to intervene, uses limited resources more effectively, and increases the chances of achieving management goals.
Abstract: The reality confronting ecosystem managers today is one of heterogeneous, rapidly transforming landscapes, particularly in the areas more affected by urban and agricultural development. A landscape management framework that incorporates all systems, across the spectrum of degrees of alteration, provides a fuller set of options for how and when to intervene, uses limited resources more effectively, and increases the chances of achieving management goals. That many ecosystems have departed so substantially from their historical trajectory that they defy conventional restoration is not in dispute. Acknowledging novel ecosystems need not constitute a threat to existing policy and management approaches. Rather, the development of an integrated approach to management interventions can provide options that are in tune with the current reality of rapid ecosystem change.

384 citations

Journal ArticleDOI
03 Sep 2015-Nature
TL;DR: The ubiquity of subsurface water compartmentalization found here, and the segregation of storm types relative to hydrological and ecological fluxes, may be used to improve numerical simulations of runoff generation, stream water transit time and evaporation–transpiration partitioning.
Abstract: Soil water is usually assumed to be equally available for all purposes, supplying plant transpiration as well as groundwater and streamflow; however, a study of hydrogen and oxygen isotopes from 47 globally distributed sites shows that in fact the water used by plants tends to be isotopically distinct from the water that feeds streamflow. Soil water is usually assumed to be available for all purposes in equal measure, supplying plant transpiration as well as groundwater and streamflow. Building on prior but limited studies, Jaivime Evaristo et al. have assembled a dataset of hydrogen and oxygen isotopes — drawn from widely distributed sites — and show that ecohydrological separation is the rule. Water used by plants tends to be isotopically distinct from that used for streamflow, suggesting that hydrological separation of precipitation inputs creates distinct pools of water resources. This finding implies that that existing land surface model parameterizations of plant physiological processes and streamflow can be made more realistic through the incorporation of ecohydrological separation. Current land surface models assume that groundwater, streamflow and plant transpiration are all sourced and mediated by the same well mixed water reservoir—the soil. However, recent work in Oregon1 and Mexico2 has shown evidence of ecohydrological separation, whereby different subsurface compartmentalized pools of water supply either plant transpiration fluxes or the combined fluxes of groundwater and streamflow. These findings have not yet been widely tested. Here we use hydrogen and oxygen isotopic data (2H/1H (δ2H) and 18O/16O (δ18O)) from 47 globally distributed sites to show that ecohydrological separation is widespread across different biomes. Precipitation, stream water and groundwater from each site plot approximately along the δ2H/δ18O slope of local precipitation inputs. But soil and plant xylem waters extracted from the 47 sites all plot below the local stream water and groundwater on the meteoric water line, suggesting that plants use soil water that does not itself contribute to groundwater recharge or streamflow. Our results further show that, at 80% of the sites, the precipitation that supplies groundwater recharge and streamflow is different from the water that supplies parts of soil water recharge and plant transpiration. The ubiquity of subsurface water compartmentalization found here, and the segregation of storm types relative to hydrological and ecological fluxes, may be used to improve numerical simulations of runoff generation, stream water transit time and evaporation–transpiration partitioning. Future land surface model parameterizations should be closely examined for how vegetation, groundwater recharge and streamflow are assumed to be coupled.

383 citations

Journal ArticleDOI
TL;DR: Nanotube-derived bismuth is reported for electrocatalytic reduction of carbon dioxide to formate, with performance that is enhanced by defects, and coupled with silicon photocathodes and achieves high-performance photoelectrochemical carbon dioxide reduction.
Abstract: Formic acid (or formate) is suggested to be one of the most economically viable products from electrochemical carbon dioxide reduction. However, its commercial viability hinges on the development of highly active and selective electrocatalysts. Here we report that structural defects have a profound positive impact on the electrocatalytic performance of bismuth. Bismuth oxide double-walled nanotubes with fragmented surface are prepared as a template, and are cathodically converted to defective bismuth nanotubes. This converted electrocatalyst enables carbon dioxide reduction to formate with excellent activity, selectivity and stability. Most significantly, its current density reaches ~288 mA cm−2 at −0.61 V versus reversible hydrogen electrode within a flow cell reactor under ambient conditions. Using density functional theory calculations, the excellent activity and selectivity are rationalized as the outcome of abundant defective bismuth sites that stabilize the *OCHO intermediate. Furthermore, this electrocatalyst is coupled with silicon photocathodes and achieves high-performance photoelectrochemical carbon dioxide reduction. Carbon dioxide can be electrochemically reduced to form valuable chemical feedstocks, but efficiency of electrocatalysts should be improved. Here the authors report nanotube-derived bismuth for electrocatalytic reduction of carbon dioxide to formate, with performance that is enhanced by defects.

383 citations


Authors

Showing all 28447 results

NameH-indexPapersCitations
Robert Stone1601756167901
Menachem Elimelech15754795285
Thomas J. Smith1401775113919
Harold A. Mooney135450100404
Jerry M. Melillo13438368894
John F. Thompson132142095894
Thomas N. Williams132114595109
Peter M. Vitousek12735296184
Steven W. Running12635576265
Vincenzo Di Marzo12665960240
J. D. Hansen12297576198
Peter Molnar11844653480
Michael R. Hoffmann10950063474
David Pollard10843839550
David J. Hill107136457746
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
2023105
2022375
20213,156
20203,109
20193,017
20182,987