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The U.S. Department of Agriculture Forest Service (USFS) manages one-fifth of the area of forestland in the United States. The Forest Service Roadmap for responding to climate change identified assessing and managing carbon stocks and change as a major element of its plan. This study presents methods and results of estimating current forest carbon...
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... as defined here is ‘‘ Land at least 36.6 meters wide and 0.405 hectare in size with at least 10 % cover (or equivalent stocking) by live trees of any size, including land that formerly had such tree cover and that will be naturally or artificially regenerated ’’ (Smith et al. 2009). All carbon pools on forestland are included (Smith et al. 2006): above- and belowground live tree biomass, understory vegetation, standing dead trees, down dead wood, forest floor, and soil organic carbon to the depth of one meter. (See Appendix A: Table A1 for definitions of component pools.) Carbon in HWP is the sum of changes in products in use, and changes in carbon in landfills. For reporting carbon change, we convert carbon to units of carbon dioxide by multiplying by 44/12 (the molecular weight of CO /C) because change in greenhouse gas inventories is reported in terms of CO 2 . Indeed, the GHG inventories use units of carbon dioxide equivalents, CO 2 e, which is a way to report on emissions for all types of GHGs, but we use the label CO 2 for CO 2 e. In terms of signs, a negative CO 2 change means carbon is taken out of the atmosphere and carbon is increased in forests; a positive CO 2 change means carbon is added to the atmosphere by forest-related emissions. This sign convention is used for consistency with national and international GHG reporting. We present stocks in terms of carbon, but when we present change we use units of CO 2 to indicate how atmospheric CO 2 is affected by changes in forest carbon. This study focuses on administrative NFS regions (Fig. 1), rather than strictly ecologically- based areas, because management responses will be implemented by these regions. Regions are a major organizational unit within the Forest Service, and information summarized by region is important for implementation and interpreta- tion. Individual national forest units within ...
Similar publications
The tree biomass equation, which is also called the tree allometric equation, is the most commonly used method to estimate tree and forest biomass at various spatial-temporal scales because of its high accuracy, efficiency and conciseness. For decades, many tree biomass equations have been reported in diverse types of literature (e.g., journals, bo...
In this work, the results of above-ground biomass (AGB) estimates from Landsat Thematic Mapper 5 (TM) images and field data from the fragmented landscape of the upper reaches of the Heihe River Basin (HRB), located in the Qilian Mountains of Gansu province in northwest China, are presented. Estimates of AGB are relevant for sustainable forest manag...
Citations
... Results from this analysis suggest that the combined carbon storage of pine plantations and resulting HWPs have the potential to grow over time, despite the temporary loss of carbon storage on forested stands that results from harvests. Many studies have come to similar conclusions for both southern pine [8,23,75,76] and other forest types [77][78][79]. However, we find that future carbon storage and emissions are sensitive to both silvicultural management and parameters along the wood product flow. ...
Background
Wood products continue to store carbon sequestered in forests after harvest and therefore play an important role in the total carbon storage associated with the forest sector. Trade-offs between carbon sequestration/storage in wood product pools and managed forest systems exist, and in order for forest sector carbon modeling to be meaningful, it must link wood product carbon with the specific forest system from which the products originate and have the ability to incorporate in situ and ex situ carbon synchronously over time.
Results
This study uses elements of a life cycle assessment approach, tracing carbon from US southern pine timber harvests to emission, to create a decision support tool that practitioners can use to inform policy design around land- and bioproduct-based mitigation strategies. We estimate that wood products from annual loblolly and shortleaf pine timber harvests across the southern US store 29.7 MtC in the year they enter the market, and 11.4 MtC remain stored after 120 years. We estimate fossil fuel emissions from the procurement, transportation, and manufacturing of these wood products to be 43.3 MtCO2e year⁻¹. We found that composite logs, used to manufacture oriented strand board (OSB), were the most efficient log type for storing carbon, storing around 1.8 times as much carbon as saw logs per tonne of log over 120 years.
Conclusions
Results from our analysis suggest that adjusting rotation length based on individual site productivity, reducing methane emissions from landfills, and extending the storage of carbon in key products, such as corrugated boxes, through longer lifespans, higher recycling rates, and less landfill decomposition could result in significant carbon gains. Our results also highlight the benefits of high site productivity to store more carbon in both in situ and ex situ pools and suggest that shorter rotations could be used to optimize carbon storage on sites when productivity is high.
... The northeast Pacific coastal temperate rainforest (NPCTR) is an excellent setting for evaluating the role of stream processing on DOM composition. The ecosystem is a hotspot for carbon storage with areas of aboveground biomass approaching 950 Mg ha −1 and regional soil organic carbon stocks averaging 228 ± 111 Mg ha −1 (Buma et al., 2016;Heath et al., 2011;McNicol et al., 2019). These high carbon densities combined with the abundant precipitation in the region fuel substantial stream export of DOM. ...
Dissolved organic matter (DOM) composition in small watersheds depends on complex antecedent conditions that ultimately influence DOM generation, processing, and stability downstream. Here, we used ultrahigh resolution Fourier‐transform ion cyclotron resonance mass spectrometry and total dissolved nitrogen and dissolved organic carbon concentrations to investigate how DOM is produced in distinct sub‐catchment types (poor fen, forested wetland, and upland forest) and transported through a watershed in the northeast Pacific coastal temperate rainforest (NPCTR). We traced a suite of previously identified source‐specific marker formulae from vegetation and soil downstream and used them to test models of terrestrial DOM inputs. Marker formulae escaped microbial degradation and were exported from the watershed, demonstrating strong land‐to‐ocean connectivity through the transfer of unmodified tree DOM from specific tree species into the marine environment. Simple hydrologic and temperature variables were better able to predict inputs of soil‐sourced DOM into the stream network than tree‐sourced DOM, highlighting the role of antecedent conditions (e.g., plant growth stage) in DOM source availability and hydrologic flow connectivity, particularly for plant‐derived material. Forested wetland pore waters featured thousands of nitrogen‐containing molecular formulae that potentially provide a path of direct organic nitrogen uptake to organisms. The modified aromaticity index peaked in midsummer (up to 0.55 for fen headwaters) suggesting DOM inputs from freshly produced vegetation provide a strong summertime terrestrial signal. As the climate changes, new watershed‐scale conditions may further complicate predictions of DOM source availability, flow connectivity, and downstream fate in NPCTR watersheds.
... Federal agencies must take into account objectives including conservation of protected species, access to recreation, and local timber sectors (Spies et al. 2010), while private landowners may manage their forests to maximize economic opportunities or for noncommercial uses, subject to state-and federal-level regulations such as the Endangered Species Act (Christensen et al. 2016;Ager et al. 2017;Charnley et al. 2017). These management decisions influence vegetation structure and composition, which in turn influences fire probability; publicly owned forests typically have higher biomass levels than private forests, where periodic grazing and harvesting are more common (Spies et al. 1994;Turner et al. 1996;Hudiburg et al. 2009;Heath et al. 2011). ...
Sustainable management of complex social-ecological systems depends on understanding the effects of different drivers of change, but disentangling these effects poses a challenge. We provide a framework for quantifying the relative contributions of different components of a social-ecological system to the system’s outcomes, using forest fires in the western United States as a model. Specifically, we examine the difference in wildfire probability in similar forests under different management regimes (federally managed vs. privately owned) in eleven western states from 1989–2016 and compare the magnitude of the management effect to the effect of climate variables. We find a greater probability of wildfires in federally managed forests than in privately owned forests, with a 127% increase in the absolute difference between the two management regimes over the 28 year time period. However, in 1989, federally managed forests were 2.67 times more likely to burn than privately owned forests, but in 2016, they were only 1.52 times more likely to burn. Finally, we find that the effect of the different management regimes is greater than the marginal (one-unit change) effect of most climate variables. Our results indicate that projections of future fire probability must account for both climate and management variables, while our methodology provides a framework for quantitatively comparing different drivers of change in complex social-ecological systems.
... The Carbon Storage model calculates the quantity of carbon stored (metric tons) in each pixel within the study area based on a table used as input data containing the carbon stored in each land cover class (Table A1 in Appendix A). We estimated the carbon stored above-and belowground using a variety of sources (Brown et al. 1999;Heath et al. 2011;Jerath et al. 2016;Olson et al. 2006;Pan et al. 2011; The Intergovernmental Panel on Climate Change (IPCC) 2006; Timilsina et al. 2013). Since the NLCD layer is limited in land cover classes and does not differentiate species and forest stand age, we used average numbers that best represent the study area. ...
The Upper Chattahoochee Watershed supplies most of the drinking water to the Atlanta Metropolitan Area, a region with one of the fastest urban growth rates in the United States. Smart conservation planning is necessary to conciliate urban development and the provision of critical ecosystem services (ESs) such as water quality, carbon storage, and wildlife habitat. We employed optimization models to compare the value of the ESs provided by alternative allocations of land parcels for conservation. We adopted boundary penalties to determine the trade-offs of choosing higher connectivity among parcels regarding economic values provided by carbon storage, wildlife habitat, and water quality. We used InVEST models to quantify and map ESs and value transfer to assign economic values to them. We set low and high ESs economic value bounds and discounted their values to perpetuity using 3% and 7% discount rates. Our results indicate that incorporating boundary penalties results in solutions with larger, fewer, and more connected parcels but yields lower economic benefits than unconstrained models. However, these differences are relatively small (between 2.6% and 7.3% loss in economic value). Additional transaction costs of purchasing more parcels and improving ecological networks provided by larger forest patches might justify the selection of solutions with higher connectivity. Decision-makers can use the developed models for estimating the economic cost of selecting connected parcels for conservation purposes at the landscape level.
... The annual land-to-ocean flux of dissolved organic carbon (DOC) from Southeast Alaskan watersheds is massive, and currently equates to ~ 20% the flux from the entire contiguous United States due to the high DOC yield (Edwards et al. 2021). Further, soil and tree biomass in the NPCTR contain substantial carbon stocks (Buma et al. 2016;Heath et al. 2011;McNicol et al. 2019) and temperate rainforests such as the NPCTR have the highest carbon density of any forest ecosystem (Keith et al. 2009), providing sizable and varied carbon sources for DOM leaching. Southeast Alaskan landscapes experience substantial precipitation, with precipitation intensity projected to increase with climate change, potentially influencing the magnitude of DOM fluxes to the productive coastal ocean (Bidlack et al. 2021;Lader et al. 2020;Nash et al. 2018). ...
To investigate how source and processing control the composition of “terrestrial” dissolved organic matter (DOM), we combine soil and tree leachates, tree DOM, laboratory bioincubations, and ultrahigh resolution Fourier-transform ion cyclotron resonance mass spectrometry in three common landscape types (upland forest, forested wetland, and poor fen) of Southeast Alaska’s temperate rainforest. Tree (Tsuga heterophylla and Picea sitchensis) needles and bark and soil layers from each site were leached, and tree stemflow and throughfall collected to examine DOM sources. Dissolved organic carbon concentrations were as high as 167 mg CL⁻¹ for tree DOM, suggesting tree DOM fluxes may be substantial given the hypermaritime climate of the region. Condensed aromatics contributed as much as 38% relative abundance of spruce and hemlock bark leachates suggesting coniferous trees are potential sources of condensed aromatics to surface waters. Soil leachates showed soil wetness dictates DOM composition and processing, with wetland soils producing more aromatic formulae and allowing the preservation of traditionally biolabile, aliphatic formulae. Biodegradation impacted soil and tree DOM differently, and though the majority of source-specific marker formulae were consumed for all sources, some marker formulae persisted. Tree DOM was highly biolabile (> 50%) and showed compositional convergence where processing homogenized DOM from different tree sources. In contrast, wetland and upland soil leachate DOM composition diverged and processing diversified DOM from different soil sources during bioincubations. Increasing precipitation intensity predicted with climate change in Southeast Alaska will increase tree leaching and soil DOM flushing, tightening linkages between terrestrial sources and DOM export to the coastal ocean.
... Case information provides an important basis to establish the strategies for climate change mitigation as well as sustainable wood utilization towards a sustainable society. Case studies have been conducted to estimate the amount of carbon stored in HWPs at the Tier 2 level [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. The literature indicates that there is empirical research on HWP carbon stock accounting using the Tier 3 method in Japan [20], Ireland [21], UK [22], Portugal [23], Australia [24], the Czech Republic, and Lithuania [25,26]. ...
Many countries, including South Korea, decided to suspend the inclusion of harvested wood products in their Nationally Determined Contributions, as part of the carbon inventory, in 2016. The inclusion of harvested wood products in the national greenhouse gases inventory must ensure the accuracy of carbon accounting and its conformity with the policy direction. The method used for harvested wood product carbon accounting can influence the accuracy of carbon account value, as well as policy direction based on greenhouse gas accounting. This research evaluated the utilization of domestic wood resources in South Korea in terms of carbon storage impacts from the perspective of the cascading use of wood products. The study also compared the two accounting methods (Tier 2 and Tier 3) of carbon storage for the period from 1970 to 2080, assuming the current pattern of wood resource utilization for the next sixty years. The results show that the current utilization of domestic wood resources is inefficient in terms of climate change mitigation. The analysis shows that there is a significant difference between the Tier 2 and Tier 3 methods in carbon storage effects, and the amount of harvested wood products carbon stock calculated by the Tier 2 method was found to be approximately double that of Tier 3. This result implies that there is a possibility of overestimating the carbon storage of harvested wood products when using the Tier 2 method in the case of net timber-importing countries, such as South Korea. The study can provide guidance for designing timber resource management from the perspective of the cascading use of wood products in order to contribute to sustainable development goals, including climate change mitigation.
... Therefore, any such stock change may also include effects of land use change. Because remeasurement data from permanent inventory plots are now widely available, we calculate change in aboveground live tree carbon stock by aggregating change on only those inventory plots that remain forested over the time-1 to time-2 remeasurement interval, which avoids incorporating effects of land use change as in some past stock-change approaches (e.g., [19,20]). Most states in the conterminous US have a large number of such remeasured continuous-forest plots useful to characterize forest types, age classes, ownerships, and management practices, as well as removals and disturbances. ...
... They also found the lowest carbon densities in the Rocky Mountain region, which agrees with our findings. Earlier estimates of forest carbon stock in the National Forest System [19] summarized by National Forest region generally agree, with highest aboveground live tree carbon densities in forests of southeast coastal Alaska (not considered here), and the Pacific Northwest and Pacific Southwest regions of the National Forest System. Heath et al. [19] also report the lowest carbon densities in the Southwestern and Intermountain regions (generally corresponding to Rocky Mountain South although not an exact match). ...
... Earlier estimates of forest carbon stock in the National Forest System [19] summarized by National Forest region generally agree, with highest aboveground live tree carbon densities in forests of southeast coastal Alaska (not considered here), and the Pacific Northwest and Pacific Southwest regions of the National Forest System. Heath et al. [19] also report the lowest carbon densities in the Southwestern and Intermountain regions (generally corresponding to Rocky Mountain South although not an exact match). Harris et al. [24] used a combination of FIA data and remote sensing methods to examine forest carbon stock and change across the US with a focus on disturbance; mapped carbon densities agree with values reported here. ...
Background
With the introduction of the Trillion Trees Initiative and similar programs, forests’ ability to absorb carbon dioxide is increasingly in the spotlight. Many states have mandates to develop climate action plans, of which forest carbon is an important component, and planners need current information on forest carbon stocks and rates of change at relevant spatial scales. To this end, we examine rates of average annual change in live aboveground tree carbon in different forest type groups and provide state-wide and regional summaries of current live tree carbon stock and rates of change for the forests of the conterminous United States. Forest carbon summaries are presented in a format designed to meet the needs of managers, policymakers, and others requiring current estimates of aboveground live tree carbon at state and regional scales.
Results
Regional average aboveground live tree carbon stocks (represented on a per area basis) are generally between 40 and 75 tC/ha but range from 12.8 tC/ha in the Great Plains to 130 tC/ha in the Pacific Northwest West (west-side of Cascades). Regional average annual change in live aboveground tree carbon varies from a low of − 0.18 mtC/ha/y in the Rocky Mountain South to a high value of 1.74 mtC/ha/y in Pacific Northwest West. For individual states, carbon per unit area varies widely, from a low of 11.9 tC/ha in Nevada to a high of 96.4 tC/ha in Washington, with half the states falling between 50 and 75 tC/ha. Rates of average annual change in live aboveground tree carbon vary from a high of 1.82 tC/ha/y in Mississippi to a low of − 0.47 tC/ha/y in Colorado.
Conclusions
Aboveground live tree carbon stocks and rates of average annual change vary by forest type within regions. While softwood forest types currently exhibit a higher rate of increase in the amount of carbon in aboveground live tree biomass, the current standing stock of carbon per unit area does not consistently follow this pattern. For this reason, we recommend computing and considering both measures -standing stock and average annual change—of carbon storage. The relative importance of each component will depend on management and policy objectives and the time frame related to those objectives. Harvesting and natural disturbance also affect forest carbon stock and change and may need to be considered if developing projections of potential carbon storage.
... Although inventory methods are evolving and new approaches may help reduce costs and provide additional information on C cycle components at a smaller spatial scale [17], these new approaches are not currently applicable to individual landowners. Understanding the challenges and opportunities associated with establishing a reliable C baseline for landowners will have significant implications for management policies and practices, and for detecting change in C stocks in the future [18]. ...
... The ability to compare our biomass and C estimates between SRS in 2001 and other forest landscapes of similar scale in the region are limited. Data from the US National Forest have been published for the USA [18]. The C density we calculated for 2001 (174.4 ...
... Various changes in the manner in which the national biomass estimator equations were developed for the species groups by Chonacky et al. [36] account for these differences. The relative increase in the softwood biomass we observed, was also found when the updated equation predictions were compared to the original Jenkin's equations at the regional level [18]. The differences between the hardwood and softwood C estimates using different methods will be important in detecting the total aboveground tree C changes in the future as the relative species composition within the landscape changes. ...
Establishing reliable carbon baselines for landowners desiring to sustain carbon sequestration and identify opportunities to mitigate land management impacts on carbon balance is important; however, national and regional assessments are not designed to support individual landowners. Such baselines become increasingly valuable when landowners convert land use, change management, or when disturbance occurs. We used forest inventories to quantify carbon stocks, estimate annual carbon fluxes, and determine net biome production (NBP) over a 50-year period coinciding with a massive afforestation effort across ~80,000 ha of land in the South Carolina Coastal Plain. Forested land increased from 48,714 ha to 73,824 ha between 1951 and 2001. Total forest biomass increased from 1.73–3.03 Gg to 17.8–18.3 Gg, corresponding to biomass density increases from 35.6–62.2 Mg ha−1 to 231.4–240.0 Mg ha−1. Harvesting removed 1340.3 Gg C between 1955 and 2001, but annual removals were variable. Fire consumed 527.1 Gg C between 1952 and 2001. Carbon exported by streams was <0.5% of total export. Carbon from roots and other harvested material that remained in-use or in landfills comprised 49.3% of total harvested carbon. Mineral soil carbon accounted for 41.6 to 50% of 2001 carbon stocks when considering depths of 1.0 or 1.5 m, respectively, and was disproportionately concentrated in wetlands. Moreover, we identified a soil carbon deficit of 19–20 Mg C ha−1, suggesting opportunities for future soil carbon sequestration in post-agricultural soils. Our results provide a robust baseline for this site that can be used to understand how land conversion, forest management, and disturbance impacts carbon balance of this landscape and highlight the value of these baseline data for other sites. Our work also identifies the need to manage forests for multiple purposes, especially promotion of soil carbon accumulation in low-density pine savannas that are managed for red-cockaded woodpeckers and therefore demand low aboveground carbon stocks.
... The forest inventory data together with sets of carbon conversion factors or models provide estimates of plot-level carbon, which are aggregated as needed for estimation and reporting. These forest carbon estimates are similarly applied to other national reports (USDA 2016) or regional analyses ( Heath et al. 2011, Ogle et al. 2015, Hoover and Smith 2017. In turn, summaries such as U.S. EPA (2018) or USDA (2016) are often the sources for subsequent additional analyses. ...
... The Forest Service is continually improving this process of obtaining carbon estimates from forest inventory (e.g., see Domke et al. 2016Domke et al. , 2017. One result of these updates is that on average over 98% of ecosystem carbon on forest plots is estimated according to different conversion factors or models today (U.S. EPA 2018) relative to similar scope summaries from almost a decade ago (U.S. EPA 2010, Heath et al. 2011). However, all such estimates and changes are documented, and incremental differences, or step changes, in stand level carbon stocks are generally small (Heath 2012, Domke et al. 2016. ...
... In order to provide some perspective on changes in carbon reporting arising from updates in the conversion process, we informally summarize additional representative sets of carbon estimates (in addition to current as described here) that reflect updates over several years (approximately an 8-yr interval). A second set of carbon conversion factors applied to a specific inventory at a somewhat similar scope (as this report) is the summary of Forest Service forest lands of Heath et al. (2011), which also corresponds to forest carbon as reported in U.S. EPA (2010). The third set of estimates is from fields currently populated in the tree and forest condition tables of the FIADB, which represents a mix of both current and older carbon conversions. ...
Forest land in the United States offsets more than 11% of total domestic greenhouse gas emissions each year through growth of live woody biomass and accumulation of carbon in trees, dead organic matter, and harvested wood products. Forest lands owned and managed by various agencies of the U.S. government cover 77 million hectares, which is 29% of U.S. forest land and an estimated 33%, or 17.2 Pg C, of forest carbon stocks. Here, we summarize forest inventory‐based estimates of forest carbon stocks and indications of carbon stock change on forest lands managed by agencies within the U.S. federal government. Within the conterminous USA, the proportion of forest land that is federally owned is higher in the West representing two‐thirds of forest carbon stocks; in the East, federal lands represent 9% of forest carbon. The majority of federal forests and forest carbon are managed by the U.S. Forest Service (13.8 Pg C), but 20% of federal forest carbon stocks, or 3.5 Pg C, are managed by other federal agencies (e.g., National Park Service, Bureau of Land Management). We also briefly review some broad characteristics of the forest inventory that affect forest carbon reported for the USA as included in greenhouse gas inventories such as for United Nations Framework Convention on Climate Change reporting.
... The climatic changes taking place in high latitudes impact stores and overall C dynamics (Goetz et al., 2007). Coastal Alaska is a vast region in the northern latitudes of the northern hemisphere with forest area of 6.2 million ha (Barrett and Christensen, 2011) which has been of interest due to large C stores in live and dead biomass and in soils (Birdsey and Heath, 1995;Heath et al., 2011;Goodale et al., 2002). ...
Forests provide significant long-term carbon (C) storage, but have the potential to increase future C emissions with a changing climate. Aboveground biomass, C stores, and the effect of disturbance were examined using forest inventory data collected across all ownerships on 6.2 million ha in Coastal Alaska. We modelled six C pools using empirical data, estimated two others using the literature, and quantified estimate uncertainty. The average (±SE) aboveground live (218.9 ± 4.6 Mg/ha) and log (28.1 ± 1.8 Mg/ha) biomass in the Alaskan Temperate ecoregion were among the lowest in the Pacific Northwest, whereas snag biomass (30.5 ± 1.0 Mg/ha) was among the highest. In the Alaskan Boreal ecoregion, on the Kenai Peninsula, coarse woody debris (CWD) biomass comprised almost 50% of the regional average of aboveground woody biomass (76.7 ± 3.8 Mg/ha) with bark beetle damaged stands containing 82% of the total CWD biomass. In contrast, in the Temperate ecoregion, CWD comprised 20% of the regional aboveground woody average (277.5 ± 5.4 Mg/ha) with 76% of total CWD biomass in undisturbed stands. Total C stores estimates in Coastal Alaska forests ranged between 1523.6 and 1892.8 Tg with the highest contribution from soils. The largest potential reductions in uncertainty are related to the tree and soils C pools. Disturbance determined total biomass amounts in the system and controlled the ratio between live and dead biomass pools and thus has the ability to shift forest stands into a C source to the atmosphere.
