Folks, this April 2023 paper is full of interesting data. For example, this shows that some USFS regions are net CO2 emitters (positive numbers), while others are sinks (negative numbers). (Full title: “Greenhouse Gas Emissions and Removals From Forest Land, Woodlands, Urban Trees, and Harvested Wood Products in the United States, 1990–2021.)
2021 carbon stock changes (net flux) from forest land remaining forest land within the National Forest System (NFS) by NFS region and year (MMT CO2 Eq.):
| Alaska | -4 |
| Eastern | -11.5 |
| Intermountain | 11.5 |
| Northern | 0.9 |
| Pacific Northwest | -28.3 |
| Pacific Southwest | -5.7 |
| Rocky Mountain | 12.2 |
| Southern | -25.5 |
| Southwestern | 6.9 |
| Net emissions and removals | -43.5 |
Summary:
2021 Estimates at a Glance
Summary statistics for 2021 from the compilation of the forest land, woodlands, HWP, and urban trees in settlements in the U.S. EPA (2023) report:
• Economy-wide GHG emissions increased from 2020 to 2021 by more than 6.8 percent.
• Forest land, HWP, woodlands, and urban trees in settlements collectively offset more than 12.4 percent (785.0 MMT CO2 Eq.) of total GHG emissions or 15.6 percent of CO2 emissions in 2021.
• Private forest land accounts for nearly 84 percent (-493.9 MMT CO2 Eq.) of the estimated net sink strength in the conterminous 48 States and coastal Alaska in 2021.
• Land conversions to and from forest land continue to result in net emissions and/or transfers of carbon to other land uses (33.1 MMT CO2 Eq.).
• Soils store more than 55 percent of all the carbon in forest ecosystems, with small stock changes annually.
• Forest land area burned was nearly 1.7 million ha, and GHG emissions were among the highest reported over the time series from 1990 to 2021.
• Forest uptake averages 0.6 metric tons of carbon per hectare per year (MT C ha-1 yr-1), with live vegetation accounting for more than 83 percent (0.5 MT C ha-1 yr-1) of the uptake.
Perhaps I missed it but I could not find the emissions resulting from the decomposition & insect activity of dead wood left site after fire, wind, insect & disease mortality. As we see in the NW region, the fire removes a minor portion of the total forest vegetation, leaving the majority as “dead wood.” Trees that sequestered carbon for hundreds of years are reduced to a lump of rubble within 75 years, having release all of that once-stored carbon.
That is where devastating re-burns come in, ‘re-setting’ landscapes back for many decades, and possibly a century before forests get re-established. The many variables make new forest regeneration questionable.
Yes, dead trees do store carbon…. very temporarily.
Shows you what sound and consistent forest (forests are more than just trees) maintenance can do to help reduce the impacts of a changing climate, thereby reducing the negative impacts of disturbances, such as unplanned wildfires. Why then are we so adverse to addressing this national issue of the lack of forest maintenance?
Very respectfully,
Good data. I would like to see good data related to the difference over 100 years between no salvage after a stand replacement and salvage with a rapid reforests program in the PAacific NW
John, I don’t know if this fits, but at one time post St. Helens there was neighboring FS and private land that were treated differently. I don’t remember about salvage, but I remember the private was planted and maybe the FS wasn’t? Since the eruption was in 1980, we’d have at least 40 years of data.. maybe someone has looked at that for carbon?
That is correct, Sharon. Weyerhaeuser replanted their lands impacted by the 1980 eruption. The federal/Forest Service land became a National Monument. The difference was pretty striking when I took a trip to Coldwater Ridge several years ago and could provide an interesting study if the monument and non-monument sites are comparable in terms of slope, aspect, elevation, soils and other factors that affect vegetation growth. I was impressed by the amount of cottonwood and willow in the Monument.