Nevada Statewide Greenhouse Gas Emissions Inventory and Projections, 1990 to 2030
Nevada Statewide Greenhouse Gas Emissions Inventory and Projections, 1990 to 2030
10. Land Use, Land Use Change, and Forestry
10.1 Overview
This section includes GHG emissions from land use, land use change, and forestry activities. Temperate
forests in the Northern hemisphere are in general CO2 sinks, as their net carbon flux balance (i.e., carbon
emissions minus carbon sequestration) is negative, hence actively contributing to offset anthropogenic
GHG emissions. The strength of these sinks, per unit of area, depends on many factors, such as forest
species composition, climate variability, and the occurrence of perturbations like wildfires and diseases.
Other natural ecosystem types (e.g., grasslands, shrublands, wetlands) also contribute to the overall
carbon flux balance, but the current scientific consensus is that they are, on average, close to carbon
neutral. The main approach adopted to estimate carbon (in the form of CO2) sequestration in forests
relies on estimating the magnitude of distinct carbon pools (i.e., the total amount of carbon found in
each pool, or stock, such as aboveground biomass, soil, roots, etc.) in the forest ecosystems and their
change through time (i.e. the net change of carbon in all pools of a forest, which is equated to carbon
flux between the forest ecosystem and the atmosphere, or other compartments of the biosphere). The
USDA-Forest Service collects, manages, analyzes and makes available such data through the Forest
Inventory and Analysis program (FIA). 37 In this respect, a positive change in overall carbon stocks per
unit of area of a forest indicates net carbon uptake (i.e., CO2) from the atmosphere. However, carbon
stocks can change as a result of land use change (i.e., cause an increase or decrease of forested areas),
or logging and wildfire events, which both decrease the amount of forest carbon stocks.
Land use and land use change only marginally contribute to GHG emissions in Nevada. Nevertheless,
wildfires and prescribed fires (wildland fires) can significantly contribute to the annual carbon balance of
the forests and other natural ecosystems. It is important to note that the carbon released by fires in
forests and other natural ecosystems is not accounted in the GHG inventory. This is because the loss of
carbon from forests is already accounted for by either the carbon-pool inventory approach (in forests),
or because it balances an equivalent amount of carbon previously sequestered through photosynthesis
(in other natural ecosystems). CH4 and N2O are also released during fires and they need to be included
in the GHG inventory as emissions.
The SIT provides methodologies and emission factors to estimate net GHG emissions from the forestry
sector. Historical data on the areas affected by fires in Nevada were obtained from the National
Interagency Fire Center (NIFC). 38
10.2 Historical Emissions
Forests in Nevada covered approximately 3,100,000 hectares in 200639, equivalent to 11% of Nevada's
land. Figure 10-1 shows land cover in Nevada, of note is Nevada's largely undeveloped state (nearly 85
percent of the State is federally owned).
37
http://www.fia.fs.fed.us/ (accessed September 2016).
38 http://www.nifc.gov/ (accessed September 2016).
43View entire presentation