Climate change may cut US forest inventory by a fifth this century


Date:
February 1, 2023
Source:
North Carolina State University
Summary:
A study found that under more severe climate warming scenarios,
the inventory of trees used for timber in the continental United
States could decline by as much as 23% by 2100. The largest
inventory losses would occur in two of the leading timber regions
in the U.S., which are both in the South.


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FULL STORY ==========================================================================
A study led by a North Carolina State University researcher found that
under more severe climate warming scenarios, the inventory of trees used
for timber in the continental United States could decline by as much
as 23% by 2100. The largest inventory losses would occur in two of the
leading timber regions in the U.S., which are both in the South.


========================================================================== Researchers say their findings show modest impacts on forest product
prices through the end of the century, but suggest bigger impacts in
terms of storing carbon in U.S. forests. Two-thirds of U.S. forests are classified as timberlands.

"We already see some inventory decline at baseline in our analysis, but relative to that, you could lose, additionally, as much as 23% of the U.S.

forest inventory," said the study's lead author Justin Baker, associate professor of forestry and environmental resources at North Carolina State University. "That's a pretty dramatic change in standing forests."
In the study, which is published in Forest Policy and Economics,
researchers used computer modeling to project how 94 individual tree
species in the continental United States will grow under six climate
warming scenarios through 2100. They also considered the impact of two different economic scenarios on demand growth for forestry products. The researchers compared their outcomes for forest inventory, harvest, prices
and carbon sequestration to scenarios with no climate change. Researchers
said their methods could provide a more nuanced picture of the future
forest sector under high-impact climate change scenarios compared to
other models.

"Many past studies show a pretty optimistic picture for forests under
climate change because they see a big boost in forest growth from
additional carbon dioxide in the atmosphere," Baker said. "The effect
that carbon dioxide has on photosynthesis in some of those models tends
to outweigh the losses you see from precipitation and temperature induced changes in forest productivity and tree mortality. We have a model that
is specific to individual tree species, and that allows us to better
understand how climate factors influence growth rates and mortality." Researchers found that in certain regions trees would grow more slowly
in higher temperatures, and die faster. Combined with increasing harvest
levels and greater development pressures, that led to declines in the
total tree inventory. They projected the largest losses would be in the Southeast and South-Central regions, which are two of the three most
productive timber supply regions in the U.S. Those regions could see tree inventories shrink by as much as 40% by 2095 compared to one of their
baseline scenarios. Due to declines in pine products, the researchers
projected softwood lumber prices could increase as much as 32% by 2050.

"We found pretty high levels of sensitivity to warming and precipitation changes for productive pine species in the South, especially when climate change is combined with high forest product demand growth," Baker said.

However, the researchers projected gains in tree supplies in the Rocky
Mountain and Pacific Southwest regions, driven by higher rates of death
of certain trees that lead to larger harvests initially, followed by
the growth of more heat- tolerant species.

"These are regions losing a lot of inventory right now due to pests and
fire disturbance," Baker said. "What you're seeing is a higher level
of replacement with climate adaptive species like juniper, which are
more tolerant to future growing conditions." Combining the effects
from all the regions, researchers projected total losses of U.S. tree
inventory of 3 to 23% compared to baseline. They projected losses in
carbon sequestration in most scenarios, and estimated the value of lost
carbon stored in U.S. forests up to $5.5 billion per year.

They found the economic impact of climate change on the overall
U.S. forest products industry value could range from a loss of as much as
$2.6 billion per year -- representing 2.5% of the value of the industry --
or a gain in value of more than $200 million per year.

"We saw that the markets could be more resilient than the forests
themselves," Baker said. "Your market effects may seem modest in terms of
the effect it has on the consumers and producers, but those impacts are
small compared to the carbon sequestration value that forests provide
on an annual basis." Researchers say more studies are needed to bring
the future of U.S. forestry into sharper focus.

"We don't know a lot about how disturbance-related mortality or loss
in tree productivity is going to bear out across the landscape as
temperatures get warmer," Baker said. "We did our best to address
a couple pieces of the puzzle with temperature and precipitation
changes, and interactions between climate and market demand, but a
lot more work needs to be done to get a good handle on climate change
and forestry." The study, "Projecting U.S. Forest Management, Market,
and Carbon Sequestration Responses to a High-Impact Climate Scenario,"
was published online in Forest Policy and Economics.Co-authors included
George Van Houtven, Jennifer Phelan, Gregory Latta, Christopher M. Clark,
Kemen Austin, Olakunle Sodiya, Sara B.

Ohrel, John Buckley, Lauren E. Gentile and Jeremy Martinich. The study
was funded by the U.S. Environmental Protection Agency under contract No.

68HERH19D0030. The views and opinions expressed in this paper are those
of the authors alone and do not necessarily state or reflect those of
the EPA, and no official endorsement should be inferred.

* RELATED_TOPICS
o Plants_&_Animals
# Trees # Nature # Endangered_Animals
o Earth_&_Climate
# Forest # Global_Warming # Climate
o Science_&_Society
# Environmental_Policies # Resource_Shortage #
Ocean_Policy
* RELATED_TERMS
o Logging o Taiga o Forestry o Climate_change_mitigation o
Consensus_of_scientists_regarding_global_warming o Climate o
Conifers o Global_warming_controversy

========================================================================== Story Source: Materials provided
by North_Carolina_State_University. Original written by Laura
Oleniacz. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Justin S. Baker, George Van Houtven, Jennifer Phelan, Gregory Latta,
Christopher M. Clark, Kemen G. Austin, Olakunle E. Sodiya,
Sara B. Ohrel, John Buckley, Lauren E. Gentile, Jeremy
Martinich. Projecting U.S. forest management, market,
and carbon sequestration responses to a high-impact climate
scenario. Forest Policy and Economics, 2023; 147: 102898 DOI:
10.1016/j.forpol.2022.102898 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2023/02/230201134216.htm

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