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Author: Susanna L. Melson Publisher: ISBN: Category : Carbon cycle (Biogeochemistry) Languages : en Pages : 436
Book Description
Concentration of carbon dioxide (CO2) in the atmosphere has increased over the past 150 years. Because CO2 is one of a number of radiatively active gases, there is concern that global temperatures will rise and climatic conditions will change. Recent research indicates northern hemisphere forests may currently be accumulating carbon (C) from the atmosphere. Live trees hold a large proportion of forest C, however, live-tree C can only be measured indirectly and therefore estimates of live-tree C are subject to numerous uncertainties. The objectives of this research were to estimate how live-tree C stores changed in the Pacific Northwest (Oregon and Washington west of the Cascade crest) between 1963-91 and to assess the factors introducing uncertainty into the estimate of live-tree C storage. The first objective was accomplished by using data from the Forest Service Forest Inventory and Analysis Program (FIA), combined with western Oregon and western Washington annual timber harvest data. The study produced live-tree C estimates for all timberland by land-ownership group. Between 1963-91, C on all timberland in the Pacific Northwest decreased from 1636 to 1392 Tg, or by 15% of the 1963 total. National forest, other public (other federal, state, and local government), forest industry, and miscellaneous private land lost 15, 5 (non-significant), 24, and 18% of their 1963 total timberland live-tree C by 1991, respectively. All landowners except industry experienced significant declines in total timberland area. C density (live-tree C per area) on all timberland dropped by 13% on national forests and by 30% on forest industry, but rose by 1% (non-significant) on other public and 26% on miscellaneous private land. For the Pacific Northwest as a whole, C density on all timberland decreased by 8% over the 28-year study period. C density declined most dramatically between 1963 and 1974. Since 1974, increasing C density on other public and miscellaneous private land balanced declining C density on national forest and forest industry land, resulting a C density ranging between 135-136 Mg C ha−1 on all timberland. The live-tree C estimate is subject to uncertainty arising from sampling, regression, measurement, and model error. We created and implemented a method for assessing uncertainty arising from model error. Volume equations, densities, biomass equations, and C:biomass ratios were compiled for the five major tree species in northwest Oregon: Picea sitchensis, Pseudotsuga menziesii, Tsuga heterophylla, Acer macrophyllum, and Alnus rubra. Volume equations were transformed into biomass by multiplying predicted volume with a range of species-specific measured densities. Biomass derived from volume equations multiplied by densities or from biomass equations was converted to C using a range of C:biomass ratios. For each tree component, species, and diameter at breast height, the maximum and minimum C predicted by equations was captured and stored as lookup tables. Component lookup tables were summed to create estimates of tree total C under three assumptions about within-dbh class correlation between components: perfect positive, zero, or perfect negative correlation. Application of lookup table bounds to individual tree data from the FIA program produced estimates of minimum and maximum C for the five target species in northwest Oregon. The above methods resulted in a base-case live-tree C estimate for northwest Oregon ranging from 28-210 Tg C (±76% uncertainty) assuming perfect positive correlation, and 67-1 54 Tg C (±40% uncertainty) for perfect negative correlation. When height variation was incorporated, C storage uncertainty rose to ±91% for positive and ±51% for negative correlation. A gain in precision was realized when species-specific equations were applied. Replacement of diameter-distribution data by quadratic mean diameter for each species reduced the absolute value of uncertainty, but created a bias when compared to the base case. Our attempt to incorporate regression standard error produced extremely large uncertainties for some equations and therefore was not pursued further. Results indicate that the most substantial reductions in uncertainty could be obtained by accurately assigning individual trees to suitable equations. The magnitude of model error produced by our methods currently precludes determination of significant differences between live-tree C stores of most landowners in the Pacific Northwest, and renders impossible the precise determination of the amount of live-tree C in a given forest area. Nevertheless, this does not necessarily preclude meaningful comparisons of C flux. Results of this study indicate uncertainty from model error in live-tree C could be extremely large. However, by accurately assigning appropriate volume or biomass prediction equations to trees, uncertainty could be greatly reduced.
Author: Susanna L. Melson Publisher: ISBN: Category : Carbon cycle (Biogeochemistry) Languages : en Pages : 436
Book Description
Concentration of carbon dioxide (CO2) in the atmosphere has increased over the past 150 years. Because CO2 is one of a number of radiatively active gases, there is concern that global temperatures will rise and climatic conditions will change. Recent research indicates northern hemisphere forests may currently be accumulating carbon (C) from the atmosphere. Live trees hold a large proportion of forest C, however, live-tree C can only be measured indirectly and therefore estimates of live-tree C are subject to numerous uncertainties. The objectives of this research were to estimate how live-tree C stores changed in the Pacific Northwest (Oregon and Washington west of the Cascade crest) between 1963-91 and to assess the factors introducing uncertainty into the estimate of live-tree C storage. The first objective was accomplished by using data from the Forest Service Forest Inventory and Analysis Program (FIA), combined with western Oregon and western Washington annual timber harvest data. The study produced live-tree C estimates for all timberland by land-ownership group. Between 1963-91, C on all timberland in the Pacific Northwest decreased from 1636 to 1392 Tg, or by 15% of the 1963 total. National forest, other public (other federal, state, and local government), forest industry, and miscellaneous private land lost 15, 5 (non-significant), 24, and 18% of their 1963 total timberland live-tree C by 1991, respectively. All landowners except industry experienced significant declines in total timberland area. C density (live-tree C per area) on all timberland dropped by 13% on national forests and by 30% on forest industry, but rose by 1% (non-significant) on other public and 26% on miscellaneous private land. For the Pacific Northwest as a whole, C density on all timberland decreased by 8% over the 28-year study period. C density declined most dramatically between 1963 and 1974. Since 1974, increasing C density on other public and miscellaneous private land balanced declining C density on national forest and forest industry land, resulting a C density ranging between 135-136 Mg C ha−1 on all timberland. The live-tree C estimate is subject to uncertainty arising from sampling, regression, measurement, and model error. We created and implemented a method for assessing uncertainty arising from model error. Volume equations, densities, biomass equations, and C:biomass ratios were compiled for the five major tree species in northwest Oregon: Picea sitchensis, Pseudotsuga menziesii, Tsuga heterophylla, Acer macrophyllum, and Alnus rubra. Volume equations were transformed into biomass by multiplying predicted volume with a range of species-specific measured densities. Biomass derived from volume equations multiplied by densities or from biomass equations was converted to C using a range of C:biomass ratios. For each tree component, species, and diameter at breast height, the maximum and minimum C predicted by equations was captured and stored as lookup tables. Component lookup tables were summed to create estimates of tree total C under three assumptions about within-dbh class correlation between components: perfect positive, zero, or perfect negative correlation. Application of lookup table bounds to individual tree data from the FIA program produced estimates of minimum and maximum C for the five target species in northwest Oregon. The above methods resulted in a base-case live-tree C estimate for northwest Oregon ranging from 28-210 Tg C (±76% uncertainty) assuming perfect positive correlation, and 67-1 54 Tg C (±40% uncertainty) for perfect negative correlation. When height variation was incorporated, C storage uncertainty rose to ±91% for positive and ±51% for negative correlation. A gain in precision was realized when species-specific equations were applied. Replacement of diameter-distribution data by quadratic mean diameter for each species reduced the absolute value of uncertainty, but created a bias when compared to the base case. Our attempt to incorporate regression standard error produced extremely large uncertainties for some equations and therefore was not pursued further. Results indicate that the most substantial reductions in uncertainty could be obtained by accurately assigning individual trees to suitable equations. The magnitude of model error produced by our methods currently precludes determination of significant differences between live-tree C stores of most landowners in the Pacific Northwest, and renders impossible the precise determination of the amount of live-tree C in a given forest area. Nevertheless, this does not necessarily preclude meaningful comparisons of C flux. Results of this study indicate uncertainty from model error in live-tree C could be extremely large. However, by accurately assigning appropriate volume or biomass prediction equations to trees, uncertainty could be greatly reduced.
Author: Jeremy Steven Fried Publisher: ISBN: Category : Carbon sequestration Languages : en Pages : 32
Book Description
Estimates of forest carbon stores and flux for California circa 1990 were modeled from forest inventory data in support of California's legislatively mandated greenhouse gas inventory. Reliable estimates of live-tree carbon stores and flux on timberlands outside of national forest could be calculated from periodic inventory data collected in the 1980s and 1990s; however, estimation of circa 1990 flux on national forests and forests other than timberland was problematic owing to a combination of changing inventory protocols and definitions and the lack of remeasurement data on those land categories. We estimate annual carbon flux on the 7.97 million acres of timberlands outside of national forests (which account for 24 percent of California's forest area and 28 percent of its live tree aboveground biomass) at 2.9 terragrams per year.
Author: Jack E. Janisch Publisher: ISBN: Category : Carbon cycle (Biogeochemistry) Languages : en Pages : 340
Book Description
As concern over global warming intensifies, sequestration and storage of atmospheric CO2 has become an important scientific and policy issue. Confusion persists, however, over interpretation of forest carbon (C) source-sink dynamics, in part because conclusions drawn depend on temporal and spatial scales of analysis (e.g. day-week scale vs. successional-scale), type of disturbance, and methodology (e.g. massbased vs. flux-based). There is a need to resolve this confusion given that strategies for mitigating anthropogenic CO2 emissions are based on estimates of forest C fluxes during various stages of succession, over which C fluxes and stores may change. Empirical study of changes in forest C stores can help to resolve this confusion by clarifying the C sources-sink dynamics of forests in space and time. To better understand the impacts of disturbance on C source-sink dynamics, changes in C stores of an evergreen-dominated forest on the Wind River Ranger District in Southwestern Washington, U.S.A., were investigated along a 500-year chronosequence of 36 stands. Principle objectives were to evaluate 1) decomposition rates (k) of logs, stumps, and below-ground coarse roots, 2) net primary productivity (NPP) of dominant tree species' boles at the stand level, and 3) successional changes in net ecosystem productivity (NEP) for live trees and coarse woody debris (CWD), here called NEPW. In the case of decomposition, log and stump k values did not differ significantly within the two principle species studied, indicating substitution of log k values for stump k values in models of forest C budgets may be valid when stump decomposition data is lacking. Decomposition rates between species differed, with Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) decomposing more slowly (k = 0.013 yr-1) relative to western hemlock (Tsuga heterophylla (Rafi) Sarg. (k = 0.036 yr-1). This difference in k between species was observed for both above-ground stumps and logs as well as below-ground coarse roots. Given our mean k estimates and adjusting for regenerating stand age, these stands are losing C at a rate of 0.16-0.83 Mg C ha-1 yr-1 (assuming all CWD is P. menziesii) to 0.13-1.68 Mg C ha-1 yr-1 (assuming all CWD is T. heterophylla) from stumps, logs, and snags. Including coarse roots increases these losses to 0.28-1.25 Mg C ha-1 yr-1 and 0.30-2.53 Mg C ha-1 yr-1, respectively. Based on these findings, if fragmentation of these decomposing C pools is ignored, and fragmented fractions have oxidized to CO2, stands thought to be net C sinks could in reality be net C sources to the atmosphere. Net primary production in tree boles (NPPb) of regenerating stands (so called second-growth) ranged between 0.15-5.28 Mg C ha-1 yr-1. NPPb of 500-year old stands ranged between 1.3-3.9 Mg C ha-1 yr-1, similar to NPPb of boles in 20-25 year old secondgrowth. Mean radial increment widths from old-growth stands indicated that NPPb of these stands (neglecting mortality) can increase, decrease, or remain relatively constant. Based on 5-year increments for the previous fifteen years, the majority of old-growth stands sampled showed small increases in radial growth over time. Timing of the transition from negative to positive of NEPW ranged between 0 and 57 years after disturbance and depended strongly on live-tree growth rates as well as the fate of CWD and harvested wood. Estimated maximum and minimum NEPW were 3.9 Mg C ha-1 yr-1 and 14.1 Mg C ha-1 yr-1, respectively. Maximum mean C stores of 393 Mg C ha-1 were reached approximately 200 years after disturbance. At a rotation age of 80 years, regenerating stands stored approximately 50% as much C in woody biomass as a 500-year old primary forest, indicating conversion of older forests to plantations released C to the atmosphere. Given the high biomass of mature and old-growth stands relative to younger regenerating stands in the forest studied, landscape C stores in live wood would appear to be maximized in stands of older age classes.
Author: Publisher: ISBN: Category : Carbon sequestration Languages : en Pages : 224
Book Description
This study presents techniques for calculating average net annual additions to carbon in forests and in forest products. Forest ecosystem carbon yield tables, representing stand-level merchantable volume and carbon pools as a function of stand age, were developed for 51 forest types within 10 regions of the United States. Separate tables were developed for afforestation and reforestation. Because carbon continues to be sequestered in harvested wood, approaches to calculate carbon sequestered in harvested forest products are included. Although these calculations are simple and inexpensive to use, the uncertainty of results obtained by using representative average values may be high relative to other techniques that use site- or project-specific data. The estimates and methods in this report are consistent with guidelines being updated for the U.S. Voluntary Reporting of Greenhouse Gases Program and with guidelines developed by the Intergovernmental Panel on Climate Change. The CD-ROM included with this publication contains a complete set of tables in spreadsheet format.
Author: Kirk Hanson Publisher: Mountaineers Books ISBN: 168051637X Category : Nature Languages : en Pages : 359
Book Description
Throughout Oregon and Washington there are several hundred thousand family forest owners, in addition to millions of forest acres under the care of community forests, municipalities, and Indigenous tribes, all of whom manage trees for sustainable wood harvest as well as recreation, inspiration, and a range of cultural connections. Yet there hasn’t been a complete resource for Pacific Northwest forest stewards until now. In this comprehensive how-to, authors Kirk Hanson and Seth Zuckerman explore all aspects of forest management—everything from how to evaluate a piece of land before you buy it through implementing long-term plans that may include establishing new stands of trees, harvesting mushrooms as well as wood, and protecting your forests far into the future through wildfire risk reduction, climate change adaptation, and conservation easements. Loaded with helpful tables and illustrations that address the pros and cons of various species and how to best care for wildlife and the land, A Forest of Your Own is a clear guide to the many rewards of ecological forestry.
Author: Tara M. Barrett Publisher: ISBN: Category : Carbon cycle (Biogeochemistry) Languages : en Pages : 44
Book Description
Carbon storage and flux estimates for the two national forests in Alaska are provided using inventory data from permanent plots established in 1995-2003 and remeasured in 2004-2010. Estimates of change are reported separately for growth, sapling recruitment, harvest, mortality, snag recruitment, salvage, snag falldown, and decay. Although overall aboveground carbon mass in live trees did not change in the Tongass National Forest, the Chugach National Forest showed a 4.5 percent increase. For the Tongass National Forest, results differed substantially for managed and unmanaged forest: managed lands had higher per-acre rates of sequestration through growth and recruitment, and carbon stores per acre that were higher for decomposing downed wood, and lower for live trees and snags. The species composition of carbon stores is changing on managed lands, with a carbon mass loss for yellow-cedar but increases for red alder and Sitka spruce. On unmanaged lands, the Chugach National forest had carbon mass increases in Sitka spruce and white spruce, and the Tongass National Forest had increases in western redcedar and red alder.
Author: Zhou Publisher: CreateSpace ISBN: 9781505913712 Category : Languages : en Pages : 36
Book Description
Timber availability, aboveground tree biomass, and changes in aboveground carbon pools are important consequences of landscape management. There are several models available for calculating tree volume and aboveground tree biomass pools. This paper documents species-specific regional equations for tree volume and aboveground live tree biomass estimation that might be used to examine consequences of midscale landscape management in the Pacific Northwest. These regional equations were applied to a landscape in the upper Deschutes study area in central Oregon. We demonstrate an analysis of the changes in aboveground tree biomass and wood product availability at the scale of several watersheds on general forest lands under an active fuel-treatment management scenario. Our approach lays a foundation for further landscape management analysis, such as financial analysis of timber product and biomass supply, forest carbon sequestration, wildlife habitat suitability, and fuel reduction related studies.
Author: United States. Congress. Senate. Committee on Energy and Natural Resources. Subcommittee on Public Lands and Forests Publisher: ISBN: Category : Business & Economics Languages : en Pages : 80
Author: Susanna L. Melson
Author: Susanna L. Melson
Author: Jeremy Steven Fried
Author: 
Author: Jack E. Janisch
Author: Richard A. Birdsey
Author: 
Author: Kirk Hanson
Author: Tara M. Barrett
Author: Zhou
Author: United States. Congress. Senate. Committee on Energy and Natural Resources. Subcommittee on Public Lands and Forests