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Forestry in 2013 found that greenhouse gases
from a power plant fired by wood from New
England forests would outrank emissions
from a similar coal-fired power plant for
nearly half a century.
The bottom line for climate can shift
depending on how far into the future
researchers peer. The EPA panel on which
Abt and Khanna sit has endorsed a long
view. In its latest draft, the group recommends doing carbon accounting over a
100-year timeframe, based on research
suggesting that it takes that long for the
planet to feel the full impact of cumulative
greenhouse gas emissions. Such long tallies
give new forests plenty of time to mature
and recapture carbon, making wood appear
closer to carbon neutral.
But some scientists object that such long
timescales gloss over the risk that the near-term spike in emissions produced by large-scale wood burning will cause damage that
can’t be undone. “If we melt Arctic ice in the
next 20 years, that’s not going to come back,”
says William Schlesinger, a biogeochemist
and president emeritus at the Cary Institute
of Ecosystem Studies in Millbrook, New York,
who sits on EPA’s Science Advisory Board.
Such issues suggest policymakers should
proceed with caution, says Sami Yassa, a
forestry scientist with NRDC in Kittery,
Maine. “Our belief,” he says, “is that these
uncertainties need to be resolved in favor of
avoiding damage” to today’s forests.
Meanwhile, Abt and some other researchers are pursuing modeling approaches that
attempt to take into account the important
role that economics and human behavior
play in shaping future forests. At one extreme, logged forest might be converted
into farmland or housing lots, never getting
a chance to regrow and soak up carbon.
Or a booming pellet trade could have the
opposite effect: encouraging farmers to plant
trees where crops or pasture grasses once
grew, amplifying the carbon benefits.
One study using Abt’s approach has of-
fered a counterintuitive conclusion: that an
expansion of the southeast’s pellet industry
might offer a net benefit, in terms of car-
bon, in the long run. That’s because it could
prompt landowners to plant more trees, lead-
ing to more carbon storage. And shipping
pine pellets to Europe to produce electricity
can make both economic and environmental
sense, Abt and Khanna concluded in a 2015
study in Environmental Research Letters.
Compared with coal, wood fuel cut carbon
emissions by 74% to 85% when they took
into account the entire life cycle of both fuels,
including emissions from production and
transportation, and possible land-use shifts.
The point, Abt says, is that “you can’t just tell
a biological story. My thesis is that ignoring
markets gives you more of a wrong answer.”
That’s a view seconded by Tommy Norris,
a North Carolina timber supplier in Rocky
Point. His company, Tri-State Land & Tim-
ber LLC, bought the rights to log the Duplin
County site. Demand for wood, he says, cre-
ates incentives for landowners to manage
forests for the long term, and can prevent
them from being converted to other uses.
“If you don’t have markets,” he says, “people
are just going to ignore their forests.”
ROUGHLY 160 KILOMETERS NORTHEAST of the
logging site, NC State ecologist Asko
Noormets is investigating what he believes is
another important—and often overlooked—
part of the wood fuel puzzle. It’s right be-
neath his feet. Under loblolly pines on a
plantation owned by timber giant Weyer-
haeuser, Noormets crouches next to a white
plastic pipe embedded in the forest floor. A
motor whines as a mechanism drops a small
plastic dome over the end of the pipe, and a
sensor takes a deep breath of the CO2 inside,
rising from the soil.
The measurements, taken every 30 min-
utes for the last 11 years, have Noormets
worried. They suggest that logging, whether
for biofuels or lumber, is eating away at the
carbon stored beneath the forest floor. Every
square meter of this forest is losing roughly
125 grams of carbon annually into the atmos-
phere, the data suggest. Over time, he pre-
dicts, logging could wear this fertile, peat-
based soil down to the sandy layer below,
releasing much of its carbon and destroying
its long-term productivity.
When he has looked at emissions from
other managed forests around the world, he’s
found similarly elevated rates of soil carbon
loss. Noormets isn’t certain what’s driving
the losses, but he suspects that by disturb-
ing the soil, logging alters the activity of soil
microbes that release CO2.
The soft-spoken scientist tends toward
technical jargon. But he says that when he
first saw the numbers a few years ago, “I was
Economist Bob Abt has been examining the economic
and ecological implications of wood fuels. P H
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