Improved tropical forest management for carbon retention.

PLoS Biology | www.plosbiology.org 1368 July 2008 | Volume 6 | Issue 7 | e166
Perspective
Negotiations leading up to an international climate change agreement to replace
the Kyoto Protocol in 2012 have
included consideration of reduced
emissions due to deforestation and
degradation (REDD). This option
has figured prominently in the “road
map” toward such an agreement that
was agreed upon during the 13th
Conference of Parties to the United
Nations Framework Convention
on Climate Change held in Bali in
December 2007 (http://www.unfccc.
int/). Most ongoing discussions of
REDD focus on tropical deforestation,
while the potential carbon saving
from reduced forest degradation is
mostly disregarded [1,2]. Given that
carbon losses due to degradation could
be of the same magnitude as those
from deforestation, this disregard is
worrisome [3,4]. We show here that
substantial reductions of global CO2
emissions can be achieved by improving
forest management in the tropics, and
argue that this cost-effective approach
to mitigation should be included in the
new climate change agreement.
Worldwide, a total area of 350
million hectares of tropical moist
forests is designated as production
forest [5], about a quarter of which is
managed by rural communities and
indigenous people [6]. These forests
are mainly exploited for timber, and
given growing timber demand and
increased forest access, logging is likely
to expand. Due to the high diversity
of natural forests and limited markets
for the timber of most tree species,
loggers usually harvest only one to
20 trees per hectare. Unfortunately,
for every tree logged in this selective
manner, some ten to 20 others are
severely damaged by untrained fellers
and machine operators working
without the aid of detailed maps or
supervision (Protocol S1). Numerous
studies have demonstrated that with
appropriate harvest planning of log
extraction paths, coupled with worker
training in directional felling, 50% or
more of this collateral damage can be
avoided (Protocol S1). Implementing
these basic reduced-impact logging
techniques, as we show below, could
substantially reduce global carbon
emissions from forest degradation.
We illustrate the carbon benefits of
improved forest management with a
large-scale, long-term study in Malaysia
(Protocol S1). In forests subjected to
conventional logging, carbon emissions
were over 100 tons per hectare (t ha−1)
(Figure 1). In contrast, where improved
harvesting practices were used, these
initial losses were much lower, mainly
due to reduced collateral damage. After
30 years, the typical period after which
loggers are allowed to return to an area
for the next harvest, carbon stocks in
forests with improved management
are predicted to be at least 30 t ha-1
higher than those in conventionally
logged forests [7], and are probably
much higher in practice. In a similar
study in Amazonian Brazil, where
forests are logged much less intensively
[8], the benefit of improved timber
harvesting practices was estimated to
be 7 t C ha−1. In both cases, improved
management reduced carbon emissions
by approximately 30%, relative to
conventional logging.
The potential global contribution of
improved tropical forest management
to carbon retention is substantial.
Using information on intensities and
intervals of logging, area of production
forest [5], and the above figures on
carbon loss, we estimated the global
consequences of improved tropical
forest management (Protocol S1). We
stress that this estimate is conservative,
insofar as we lacked information
to scale up the carbon-retention
effects of some practices in improved
forest management (improved road
planning, bridge construction, stream
protection). Also, our estimate of the
production forest area most likely
under-represents the actual area where
logging takes place.
Use of improved timber harvesting
practices in the tropical forests
designated for logging would retain
at least 0.16 gigatons of carbon per
year (Gt C y −1) (Figure 2). Most of the
emission reductions from improved
forestry will be from the more
intensively logged forests in Asia, where
emissions are largest. This reduced
annual rate of carbon emissions is
substantial. For comparison, the total
amount of carbon emitted due to
tropical deforestation is estimated
to be 1.5 Gt y −1 (or 20% of global
anthropogenic emissions [1]). Thus,
the potential for emission reductions
through improved forest management
is at least 10% of that obtainable by
curbing tropical deforestation.
Improved Tropical Forest Management
for Carbon Retention
Francis E. Putz*, Pieter A. Zuidema, Michelle A. Pinard, Rene G. A. Boot, Jeffrey A. Sayer, Douglas Sheil, Plinio Sist, Elias,
Jerome K. Vanclay
Citation: Putz FE, Zuidema PA, Pinard MA, Boot
RGA, Sayer JA, et al. (2008) Improved tropical forest
management for carbon retention. PLoS Biol 6(7):
e166. doi:10.1371/journal.pbio.0060166
Copyright: © 2008 Putz et al. This is an open-access
article distributed under the terms of the Creative
Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in
any medium, provided the original author and source
are credited.
Abbreviations: Gt C y −1, gigatons of carbon per year;
REDD, reduced emissions due to deforestation and
degradation; t C ha −1, tons of carbon per hectare
Francis E. Putz is with the University of Florida,
Gainesville, Florida, United States of America and
with Pieter A. Zuidema and Rene G. A. Boot at Utrecht
University, Utrecht, The Netherlands. Michelle A.
Pinard is with the University of Aberdeen, Aberdeen,
Scotland, United Kingdom. Jeffrey. A. Sayer is with
IUCN World Conservation Union, Gland, Switzerland.
Douglas Sheil is with the Center for International
Forestry Research, Bogor, Indonesia. Plinio Sist is with
CIRAD, the French Agricultural Research Centre for
International Development, Brasilia, Brazil. Elias is
with Bogor Agricultural University, Bogor, Indonesia.
Jerome K. Vanclay is with Southern Cross University,
Lismore, New South Wales, Australia.
* To whom correspondence should be addressed.
E-mail: fep@botany.ufl.edu
The Perspective section provides experts with a
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of broad interest.

PLoS Biology | www.plosbiology.org 1369 July 2008 | Volume 6 | Issue 7 | e166
Programs promoting global
reductions in carbon emissions through
improved forest management should
easily satisfy the United Nations
Framework Convention on Climate
Change criteria for biomass projects
(http://www.unfccc.int/). Given
that improved forest management is
currently practiced in less than 5% of
tropical forests [5], the additionality
criterion (i.e., the requirement that
the intervention have direct impacts
on carbon emissions relative to the
baseline) seems easily satisfied if carbon
policy-motivated interventions actually
result in changes in timber harvesting
practices. In regard to “permanence”
of the sequestered carbon (i.e., the
time period over which the carbon is
retained), the long intervals between
timber harvests in well-managed
forests guarantee that the benefits of
protecting trees from avoidable damage
are lasting. And, given that timber
harvests under improved management
continue at the same intensity and
with similar or even higher financial
yields as those with more destructive
conventional logging, there is little
threat of loggers employing their
destructive practices elsewhere and
hence causing “leakage” of the carbon
benefits (i.e., there is no incentive from
the intervention for participants to
increase carbon emissions elsewhere).
During the negotiations leading to
the Kyoto Protocol, improved forest
management practices were dropped
from consideration due to concerns
about the feasibility and costs of
monitoring. Since that time, numerous
field studies have demonstrated that
forest carbon stocks can be measured
with fair precision [8,9]. Of at least
equal importance are the rapid recent
improvements in remote sensing
methodologies, which should soon
make it feasible to directly estimate
forest carbon stocks from space
(Protocol S1) [4]. Furthermore, the
costs of monitoring forest carbon
stocks and fluxes, both on the ground
and through remote sensing, can be
shared by the responsible government
agencies, forest product certifiers,
and REDD credit programs. Clearly,
if REDD provides a true and strong
economic incentive to improve timber
harvesting in the tropics, it will be
cost-effective to solve any remaining
technical difficulties.
In addition to increased carbon
retention, there are important
other benefits from improving
forest management. For example,
minimizing canopy opening allows
forest flammability to decrease and
shade-requiring wildlife and plants to
continue to thrive. Also, future timber
yields are enhanced when fewer of
the valuable trees are damaged and
when careful planning of roads and
trails minimizes erosion and maintains
watershed functions. Finally, substantial
occupational health and safety benefits
can be achieved from training workers
in one of the world’s most dangerous
professions.
Incentives to retain more forest
carbon through improved management
would represent a big step toward
sustainability in the vast area of tropical
forests outside protected sites. Although
many details on measuring, monitoring,
and compensating carbon sequestering
by individuals, companies, communities,
and governments need to be sorted out,
reducing emissions of greenhouse gases
from tropical forest degradation should
be given a high priority in negotiations
leading up to the new climate change
agreement to be formulated in
Copenhagen in 2009. ◼
Supporting Information
Protocol S1.
Background Information on Reduced-
Impact Logging and Calculations of Carbon
Emissions
Found at doi:10.1371/journal.pbio.0060166.
sd001 (46 KB DOC).
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doi:10.1371/journal.pbio.0060166.g002
Figure 2. Annual Reductions in Global
Carbon Emissions that Would Result from
Adoption of Improved Tropical Forest
Management Practices (Protocol S1)
doi:10.1371/journal.pbio.0060166.g001
Figure 1. Substantial Reductions in Carbon
Loss from Improved Forest Management
at Scales of a Hectare of Malaysian Forest
(Protocol S1)