James E. Smith

• US Forest Service

Background Forests are significant terrestrial biomes for carbon storage, and annual carbon accumulation of forest biomass contributes offsets affecting net greenhouse gases in the atmosphere. The immediate loss of stored carbon through fire on forest lands reduces the annual offsets provided by forests. As such, the United States reporting include...

Forest inventory data are useful for determining forest stand structure, growth, and change. Among the information collected on forest inventory plots by the USDA Forest Service Forest Inventory and Analysis Program, attributes characterizing various types of disturbance provide researchers a means of selecting plots specifically affected by distur...

Supplementary tables from Hoover and Smith 2023, reformatted for easier use and with several values corrected.

Background Sequestration of carbon on forest land is a common and practical component within many climate action plans developed by state or municipal governments. Initial planning often identifies the general magnitude of sequestration expected given the scope of the project. Because age plays a key role in forest carbon dynamics, we summarize bot...

As a signatory to the United Nations Framework Convention on Climate Change (UNFCCC), the United States has reported an inventory of greenhouse gas (GHG) emissions and removals by sector, as defined by the Intergovernmental Panel on Climate Change (IPCC), since the mid-1990s (U.S. EPA 2023). In 2021, United States net GHG emissions increased by mor...

This Resource Update provides an overview of the status and trends of GHG emissions and removals from forest land, woodlands in the grassland category, HWP, and urban trees in settlements in the United States from 1990 to 2020. The estimates for the United States summarized here are based on the compilation reported in the "Land Use, Land-Use Chang...

Downed woody material (DWM) is a unique part of the forest carbon cycle serving as a pool between living biomass and subsequent atmospheric emission or transference to other forest pools. Thus, DWM is an individually defined pool in national greenhouse gas inventories. The diversity of DWM carbon drivers (e.g., decay, tree mortality, or wildfire) a...

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 ch...

Figure 1.-Estimated annual emissions and removals by carbon pool for forest land remaining forest land in each of the conterminous 49 States in 2019 (MMT CO 2 Eq.). Note that points and uncertainties represented by confidence intervals (95 percent) reflect net flux for all carbon pools in each State. Negative estimates indicate net C uptake (i.e.,...

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...

Land use and management activities have a substantial impact on carbon stocks and associated greenhouse gas emissions and removals. However, it is challenging to discriminate between anthropogenic and non-anthropogenic sources and sinks from land. To address this problem, the Intergovernmental Panel on Climate Change developed a managed land proxy...

Assessments of forest carbon are available via multiple alternate tools or applications and are in use to address various regulatory and reporting requirements. The various approaches to making such estimates may or may not be entirely comparable. Knowing how the estimates produced by some commonly used approaches vary across forest types and regio...

The focus on forest carbon estimation accompanying the implementation of increased regulatory and reporting requirements is fostering the development of numerous tools and methods to facilitate carbon estimation. One such well-established mechanism is via the Forest Vegetation Simulator (FVS), a growth and yield modeling system used by public and p...

Background: In 2014, Chojnacky et al. published a revised set of biomass equations for trees of temperate US forests, expanding on an existing equation set (published in 2003 by Jenkins et al.), both of which were developed from published equations using a meta-analytical approach. Given the similarities in the approach to developing the equations...

The Silences of the Archives, the Reknown of the Story. The Martin Guerre affair has been told many times since Jean de Coras and Guillaume Lesueur published their stories in 1561. It is in many ways a perfect intrigue with uncanny resemblance, persuasive deception and a surprizing end when the two Martin stood face to face, memory to memory, befor...

Background/Question/Methods International negotiations for a new global treaty to limit greenhouse gases are based in part on understanding the current and potential role of forest offsets. The US Forest Inventory and Analysis (FIA) data have been recognized as valuable data sources for estimating forest carbon stocks and changes. In this study, w...

Most nations have ratified the United Nations Framework Convention on Climate Change, and are mandated to report National Greenhouse Gas Inventories, including the land use, land use change and forestry sector when it is significant. Participating countries commonly use data from national forest inventories as a basis for their forest-related emiss...

Quantifying forest carbon changes associated with growth and major disturbances is important for management of greenhouse gas emissions related to forests. Regional-level approaches with improved local growth data may refine estimates obtained using coarser resolution information. This study integrates remote-sensing-derived land cover change produ...

The inventory and monitoring of coarse woody debris (CWD) carbon (C) stocks is an essential component of any comprehensive National Greenhouse Gas Inventory (NGHGI). Due to the expense and difficulty associated with conducting field inventories of CWD pools, CWD C stocks are often modeled as a function of more commonly measured stand attributes suc...

The documented role of United States forests in sequestering carbon, the relatively low cost of forest-based mitigation, and the many co-benefits of increasing forest carbon stocks all contribute to the ongoing trend in the establishment of forest-based carbon offset projects. We present a broad analysis of forest inventory data using site quality...

Background/Question/Methods As signatories to the United Nation Framework Convention on Climate Change, the US has been estimating standing and down dead tree carbon (C) stocks using a model based on live tree attributes. The USDA Forest Service began sampling forest detrital components nation-wide in 1999. With comprehensive field data now availa...

Background/Question/Methods Forest ecosystem carbon flux has been monitored by the Intergovernmental Panel on Climate Change (IPCC) since 1990 – the base year for which all subsequent IPCC reports reference. In the United States, estimates of forest carbon flux are obtained from data collected and maintained by the USDA Forest Service, Forest Inv...

Forest ecosystems are the largest terrestrial carbon sink on earth and their management has been recognized as a relatively cost-effective strategy for offsetting greenhouse gas emissions. Forest carbon stocks in the U.S. are estimated using data from the USDA Forest Service, Forest Inventory and Analysis (FIA) program. In an attempt to balance acc...

Until recently, standing dead tree biomass and carbon (C) has been estimated as a function of live tree growing stock volume in the U.S. Forest Service, Forest Inventory and Analysis (FIA) Program. Traditional estimates of standing dead tree biomass/C attributes were based on merchantability standards that did not reflect density reductions or stru...

The U.S. Forest Service, Forest Inventory and Analysis Program made a transition from state-by-state periodic forest inventories—with reporting standards largely tailored to regional requirements—to a nationally consistent, annual inventory tailored to large-scale strategic requirements. Lack of measurements on all forest land during the periodic i...

We examined spatial patterns of changes in forest area and nonsoil carbon (C) dynamics affected by land use/cover change (LUC) and harvests in 24 northern states of the United States using an integrated methodology combining remote sensing and ground inventory data between 1992 and 2001. We used the Retrofit Change Product from the Multi-Resolution...

The Forest Inventory and Analysis (FIA) program of the U.S. Department of Agriculture Forest Service is charged with the responsibility of monitoring forest ecosystem attributes, such as carbon (C) stocks, across the U.S. Given the role of both natural and anthropocentric disturbance on forest C stocks across a range of spatial scales and intensity...

Standing dead tree biomass equations and example calculations. This file presents equations necessary to estimate above and belowground SDT biomass and C stocks and provides example calculations for reference [25,26].

Standing dead trees are one component of forest ecosystem dead wood carbon (C) pools, whose national stock is estimated by the U.S. as required by the United Nations Framework Convention on Climate Change. Historically, standing dead tree C has been estimated as a function of live tree growing stock volume in the U.S.'s National Greenhouse Gas Inve...

Land-use change and forestry is the major category featuring carbon sequestration in the annual US Greenhouse Gas Inventory, required by the United Nations Framework Convention on Climate Change. We describe the National Greenhouse Gas Inventory and present the sources of our data and methods and the most recent results. Forests and forest products...

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...

We estimated forest area and carbon changes in the conterminous United States using a remote sensing based land cover change map, forest fire data from the Monitoring Trends in Burn Severity program, and forest growth and harvest data from the USDA Forest Service, Forest Inventory and Analysis Program. Natural and human-associated disturbances redu...

The full text of this article is available in the pdf provided.

Background/Question/Methods Both climate and human disturbances affect forest carbon dynamics but human-introduced disturbances may have greater impact than climate does over shorter time scales (e.g., years, decades). Thus, an integrated analysis including all major components of human-introduced disturbances on forest carbon dynamics are necess...

A greenhouse gas and carbon accounting profile was developed for the U.S. forest products industry value chain for 1990 and 2004-2005 by examining net atmospheric fluxes of CO(2) and other greenhouse gases (GHGs) using a variety of methods and data sources. Major GHG emission sources include direct and indirect (from purchased electricity generatio...

Reviews of each nation's annual greenhouse gas inventory submissions including forestland are part of the ongoing reporting process of the United Nations Framework Convention on Climate Change. Goals of these reviews include improving quality and consistency within and among reports. One method of facilitating comparisons is the use of a standard i...

We quantified the scaling effects on forest area estimates for the conterminous USA using regression analysis and the National Land Cover Dataset 30 m satellite‐derived maps in 2001 and 1992. The original data were aggregated to: (1) broad cover types (forest vs. non‐forest); and (2) coarser resolutions (1 km and 10 km). Standard errors of the mode...

The official U.S. forest carbon inventories (U.S. EPA 2008) have relied on tree biomass estimates that utilize diameter based prediction equations from Jenkins and others (2003), coupled with U.S. Forest Service, Forest Inventory and Analysis (FIA) sample tree measurements and forest area estimates. However, these biomass prediction equations are n...

Maine (ME), New Hampshire (NH), and Vermont (VT) are three of the four most heavily forested states in the United States. In these states, we examined how land- use change, at the Anderson Level I classification, affected regional forest carbon using the 30-m Multi-Resolution Land Characteristics Consortium 1992/2001 Retrofit Land Cover Change prod...

Concerns over the effect of greenhouse gases and consequent international agreements and regional/national programs have spurred the need for comprehensive assessments of forest ecosystem carbon stocks. Down and dead woody (DDW) materials are a substantial component of forest carbon stocks; however, few surveys of DDW carbon stocks have been conduc...

We developed matrices representing historical area transitions between forest and other land uses. We projected future transitions on the basis of historical transitions and econometric model results. These matrices were used to drive a model of changes in soil and forest floor carbon stocks. Our model predicted net carbon emission from 1900 until...

Forest inventory data supplemented with data from intensive research sites and models were used to estimate carbon stocks and sequestration rates in U.S. forests, including effects of land use change. Data on the production of wood products and emission from decomposition were used to estimate carbon stocks and sequestration rates in wood products...

We modeled the effects of afforestation and deforestation on carbon cycling in forest floor and soil from 1900 to 2050 throughout 13 states in the southern United States. The model uses historical data on gross (two-way) transitions between forest, pasture, plowed agriculture, and urban lands along with equations describing changes in carbon over m...

The hazards associated with pathogens in land-applied animal and human wastes have long been recognized. Management of these risks requires an understanding of sources, concentrations, and removal by processes that may be used to treat the wastes; survival in the environment; and exposure to sensitive populations. The major sources are animal feedi...

Carbon sequestration through forest growth provides a low-cost approach for meeting state and national goals to reduce net accumulations of atmospheric carbon dioxide. Total forest ecosystem carbon stocks include "pools" in live trees, standing dead trees, understory vegetation, down dead wood, forest floor, and soil. Determining the level of carbo...

A method is suggested for estimating additions to carbon stored in harvested wood products (HWP) and for evaluating uncertainty. The method uses data on HWP production and trade from several decades and tracks annual additions to pools of HWP in use, removals from use, additions to solid waste disposal sites (SWDS), and decay from SWDS. The method...

A method is suggested for estimating additions to carbon stored in harvested wood products (HWP) and for evaluating uncertainty. The method uses data on HWP production and trade from several decades and tracks annual additions to pools of HWP in use, removals from use, additions to solid waste disposal sites (SWDS), and decay from SWDS. The method...

Approximately 37% of forestlands in the conterminous United States are publicly owned; they represent a substantial area of potential carbon sequestration in US forests and in forest products. However, large areas of public forestlands traditionally have been less intensively inventoried than privately owned forests. Thus, less information is avail...

Department of Agriculture (USDA), is dedicated to the principle of multiple use management of the Nation's forest resources for sustained yields of wood, water, forage, wildlife, and recreation. Through forestry research, cooperation with the States and private forest owners, and management of the National Forests and National Grasslands, it strive...

Abstract—Forest, agricultural, rangeland, wetland, and urban landscapes have different rates of carbon (C) sequestration and total C sequestration potential under alternative management,options. Future changes,in the proportion and spatial distribution of land use could increase or decrease the capacity of areas tosequest er,C in terrestrial ecosys...

Uncertainty is an important consideration for both developers and users of environmental simulation models. Establishing quantitative estimates of uncertainty for deterministic models can be difficult when the underlying bases for such information are scarce. We demonstrate an application of probabilistic uncertainty analysis that provides for refi...

Estimates of uncertainty are presented for projections of forest carbon inventory and average annual net carbon flux on private timberland in the US using the model FORCARB. Uncertainty in carbon inventory was approximately ±9% (2000 million metric tons) of the estimated median in the year 2000, rising to 11% (2800 million metric tons) in projectio...

Most models of the potential effects of climate change on forest growth have produced deterministic predictions. However, there are large uncertainties in data on regional forest condition, estimates of future climate, and quantitative relationships between environmental conditions and forest growth rate. We constructed a new model to analyze these...

Synthesizing probable effects of climate change on such large, complex ecological systems as forests is not readily achieved through experimental manipulation. Therefore, numerical models and assessments based on “expert opinion” are often the bases for projections of future climate effects. The essential goal of each of these two processes is the...

Currently, assessments of how environmental stresses such as tropospheric ozone affect forests employ point estimates of factors such as ozone dose and species sensitivity. However, there is substantial regional heterogeneity in such factors. Hence, we have developed an approach for incorporating probabilistic analysis in estimating ecological risk...

We present a simple model to analyze uncertainty in predicted effects of tropospheric ozone on loblolly pine stands in southeastern USA. Assessment of pollution stress on an ecosystem requires the intergration of many, possibly disparate, datasets to produce a quality-estimate of the information provided for resource management and policy formulati...

Increasing photosynthetic photon flux density (PPFD) received during development from 5.5 to 31.2 mol m(-2) d(-1) resulted in greater leaf and mesophyll cell surface areas in cotton (Gossypium hirsutum L.). The relationships between the amounts of these surface areas and potential CO2 assimilation by these leaves were evaluated. Leaf area (epiderma...

Increasing photosynthetic photon flux density (PPFD) received during development from 5.5 to 31.2 mol m⁻² d⁻¹ resulted in greater leaf and mesophyll cell surface areas in cotton (Gossypium hirsutum L.). The relationships between the amounts of these surface areas and potential CO2 assimilation by these leaves were evaluated. Leaf area (epidermal su...

Alternanthera philoxeroides, alligator weed, was grown at five different NaCl concentrations to determine the effect of salinity on factors related to the net rate of CO(2) uptake (P(n)). Over the range of 0 to 400 millimolar NaCl, P(n) declined 51%. Stomatal conductance declined in parallel with P(n) and as a result there was no reduction in inter...

The report summarizes presentations at a workshop jointly sponsored by the Interdisciplinary Climate Systems Section of the National Center for Atmospheric Research and the Northern Global Change Research Program of the USDA Forest Service. This year`s title was Moving from Equilibrium to Transient GCMs (general circulation models): Linking Physiol...

Standing dead trees in forests of the United States serve as wildlife habitat, a fuel loading component, and carbon stocks. Although standing dead trees are a vital component of forest ecosystems, information regarding this resource across the Nation is lacking. The first annual inventory of standing dead trees across the United States was initiate...