Ellis, P. W., Gopalakrishna, T., Goodman, R. C., Putz, F. E., Roopsind, A., Umunay, P. M., et al. (2019). Reduced-impact logging for climate change mitigation (RIL-C) can halve selective logging emissions from tropical forests. Forest Ecology and Management, 438, 176–18.
Abstract: We define two implementation levels for reduced-impact logging for climate mitigation (RIL-C) practices for felling, skidding, and hauling in dipterocarp forest concessions of East and North Kalimantan. Each implementation level reduces logging emissions by a consistent proportion below the business-as-usual emissions baseline, which varies with harvest intensity. Level 1 reflects the best recorded emissions performance for each type of practice. Level 2 is more ambitious but feasible based on workshop feedback from concession managers and forestry experts, and confirmed by a recent demonstration. At Level 1 emissions can be reduced by 33%, avoiding emissions of 64.9 +/- 22.2 MgCO2 per ha harvested, on average. At Level 2 emissions can be reduced by 46%, avoiding 88.6 +/- 22.7 MgCO2 ha(-1). The greatest emissions reductions derive from (i) not felling trees that will be left in the forest due to commercial defects, and (ii) use of long-line cable winching to avoid bulldozer impacts.
We also quantify the potential to avoid logging steep slopes and riparian habitats, while holding to our RIL-C accounting assumption that timber yields are maintained to avoid problems of leakage and product substitution. Logging damage to riparian areas < 50 m from perennial streams could be avoided by re-locating harvests to less sensitive areas that currently are not accessed due to lack of spatial planning. In all but the steepest concessions, all slopes > 40% could similarly be avoided. The combined areas of these sensitive habitats (steep slopes and riparian buffers) represented 16% of each cutting block on average.
Implementation of RIL-C practices would deliver 8% (Level 1) and 11% (Level 2) of Indonesia's pledged reductions to their forest reference emissions level as a nationally determined contribution to the Paris Climate Agreement In concert with RIL-C practices, 30% of logging concession areas could be permanently protected from logging and conversion to minimize impacts on biodiversity, soils, and water quality, thereby expanding Indonesia's protected areas by one third and achieving 93% of Indonesia's Aichi Target 11 (the effective conservation of at least 17% of lands). Both these Paris Climate Agreement and Aichi outcomes could be delivered with no reductions in timber yields and substantial improvements in worker safety and sustainability of the natural forest timber sector.
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Griscom, B., Ellis, P., & Putz, F. E. (2014). Carbon emissions performance of commercial logging in East Kalimantan, Indonesia. Glob Change Biol, 20(3), 923–937.
Abstract: Adoption of reduced-impact logging (RIL) methods could reduce CO2 emissions by 30–50% across at least 20% of
remaining tropical forests. We developed two cost effective and robust indices for comparing the climate benefits
(reduced CO2 emissions) due to RIL. The indices correct for variability in the volume of commercial timber among
concessions. We determined that a correction for variability in terrain slope was not needed. We found that conces-
sions certified by the Forest Stewardship Council (FSC, N = 3), when compared with noncertified concessions
(N = 6), did not have lower overall CO2 emissions from logging activity (felling, skidding, and hauling). On the other
hand, FSC certified concessions did have lower emissions from one type of logging impact (skidding), and we found
evidence of a range of improved practices using other field metrics. One explanation of these results may be that FSC
criteria and indicators, and associated RIL practices, were not designed to achieve overall emissions reductions. Also,
commonly used field metrics are not reliable proxies for overall logging emissions performance. Furthermore, the
simple distinction between certified and noncertified concessions does not fully represent the complex history of
investments in improved logging practices. To clarify the relationship between RIL and emissions reductions, we pro-
pose the more explicit term ‘RIL-C’ to refer to the subset of RIL practices that can be defined by quantified thresholds
and that result in measurable emissions reductions. If tropical forest certification is to be linked with CO2 emissions
reductions, certification standards need to explicitly require RIL-C practices.
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Griscom, B. W., Goodman, R. C., Burivalova, Z., & Putz, F. E. (2018). Carbon and Biodiversity Impacts of Intensive Versus Extensive Tropical Forestry. Conservation Letters, 11(1), e12362.
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Katabuchi, M., Wright, S. J., Swenson, N. G., Feeley, K. J., Condit, R., Hubbell, S. P., et al. (2017). Contrasting outcomes of species- and community-level analyses of the temporal consistency of functional composition. Ecology, 98(9), 2273–2280.
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Ndjondo, M., Gourlet-Fleury, S., Manlay, R. J., Engone Obiang, N., Ngomanda, A., Romero, C., et al. (2014). Opportunity costs of carbon sequestration in a forest concession in central Africa. Carbon Balance and Management, 9(1), 4.
Abstract: Background
A large proportion of the tropical rain forests of central Africa undergo periodic selective logging for timber harvesting. The REDD+ mechanism could promote less intensive logging if revenue from the additional carbon stored in the forest compensates financially for the reduced timber yield.
Results
Carbon stocks, and timber yields, and their associated values, were predicted at the scale of a forest concession in Gabon over a project scenario of 40 yr with reduced logging intensity. Considering that the timber contribution margin (i.e. the selling price of timber minus its production costs) varies between 10 and US$40 m −3, the minimum price of carbon that enables carbon revenues to compensate forgone timber benefits ranges between US$4.4 and US$25.9/tCO 2 depending on the management scenario implemented.
Conclusions
Where multiple suppliers of emission reductions compete in a REDD+ carbon market, tropical timber companies are likely to change their management practices only if very favourable conditions are met, namely if the timber contribution margin remains low enough and if alternative management practices and associated incentives are appropriately chosen.
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Pau, S., Detto, M., Kim, Y., & Still, C. J. (2018). Tropical forest temperature thresholds for gross primary productivity. Ecosphere, 9(7), e02311.
Abstract: Tropical forests are hyper-diverse and perform critical functions that regulate global climate, yet they are also threatened by rising temperatures. Canopy temperatures depart considerably from air temperatures, sometimes by as much as air temperatures are projected to increase by the end of this century; however, canopy temperatures are rarely measured or considered in climate change analyses. Our results from near-continuous thermal imaging of a well-studied tropical forest show that canopy temperatures reached a maximum of ~34°C, and exceeded maximum air temperatures by as much as 7°C. Comparing different canopy surfaces reveals that bark was the warmest, followed by a deciduous canopy, flowers, and coolest was an evergreen canopy. Differences among canopy surfaces were largest during afternoon hours, when the evergreen canopy cooled more rapidly than other canopy surfaces, presumably due to transpiration. Gross primary productivity (GPP), estimated from eddy covariance measurements, was more strongly associated with canopy temperatures than air temperatures or vapor pressure deficit. The rate of GPP increase with canopy temperatures slowed above ~28-29°C, but GPP continued to increase until ~31-32°C. Although future warming is projected to be greater in high-latitude regions, we show that tropical forest productivity is highly sensitive to small changes in temperature. Important biophysical and physiological characteristics captured by canopy temperatures allow more accurate predictions of GPP compared to commonly used air temperatures. Results suggest that as air temperatures continue to warm with climate change, canopy temperatures will increase at a ~40% higher rate, with uncertain but potentially large impacts on tropical forest productivity.
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Pau, S., Detto, M., Kim, Y., & Still, C. J. (2018). Tropical forest temperature thresholds for gross primary productivity. Ecosphere, 9(7), e02311.
Abstract: Tropical forests are hyper-diverse and perform critical functions that regulate global climate, yet they are also threatened by rising temperatures. Canopy temperatures depart considerably from air temperatures, sometimes by as much as air temperatures are projected to increase by the end of this century; however, canopy temperatures are rarely measured or considered in climate change analyses. Our results from near-continuous thermal imaging of a well-studied tropical forest show that canopy temperatures reached a maximum of similar to 34 degrees C, and exceeded maximum air temperatures by as much as 7 degrees C. Comparing different canopy surfaces reveals that bark was the warmest, followed by a deciduous canopy, flowers, and coolest was an evergreen canopy. Differences among canopy surfaces were largest during afternoon hours, when the evergreen canopy cooled more rapidly than other canopy surfaces, presumably due to transpiration. Gross primary productivity (GPP), estimated from eddy covariance measurements, was more strongly associated with canopy temperatures than air temperatures or vapor pressure deficit. The rate of GPP increase with canopy temperatures slowed above similar to 28-29 degrees C, but GPP continued to increase until similar to 31-32 degrees C. Although future warming is projected to be greater in high-latitude regions, we show that tropical forest productivity is highly sensitive to small changes in temperature. Important biophysical and physiological characteristics captured by canopy temperatures allow more accurate predictions of GPP compared to commonly used air temperatures. Results suggest that as air temperatures continue to warm with climate change, canopy temperatures will increase at a similar to 40% higher rate, with uncertain but potentially large impacts on tropical forest productivity.
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Rifai, S. W., West, T. A. P., & Putz, F. E. (2015). "Carbon Cowboys" could inflate REDD+ payments through positive measurement bias. Carbon Management, 6(3-4), 151–158.
Abstract: The United Nations Framework Convention on Climate Change (UNFCCC) guidelines aim for a maximum 10% uncertainty in forest biomass inventories, after which penalties accrue. Identification of this magnitude of error requires recognition of discrepancies in carbon stock estimates between project proponents and by Measurement, Reporting, and Verification (MRV) auditors for REDD+ (Reduced Emissions from Deforestation and Forest Degradation, plus the role of conservation, forest management and enhancement of carbon stocks). Given that carbon stocks might be intentionally overestimated by profiteers who would thereby benefit financially, it is important to know how those estimates might most expeditiously be inflated by systematic or random positive biases in measurements of tree diameter, height and wood density. We explore the differences in magnitudes of forest biomass estimate inflation that result from a scenario in which positive bias is added to a random selection of 1-20% of all trees, and a systematic Carbon Cowboy scenario in which 1-20% is added to the measurements of the largest trees. As expected, biases under the random scenario must be both highly frequent (>20% of trees) and large (>10%) to breach the UNFCCC 10% uncertainty threshold. In contrast, for the Carbon Cowboy scenario, a measurement bias in tree diameter as small as 10% reaches the same limit if added to the largest 5% of trees. A 10% upward bias achieves the same result if applied to the diameter, height and wood density of the largest 1% of trees. These findings suggest that MRV auditors of REDD+ projects should be especially vigilant about systematic measurement biases that involve large trees.
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Roopsind, A., Caughlin, T. T. van der H., P., Arets, E., & Putz, F. E. (2018). Trade-offs between carbon stocks and timber recovery in tropical forests are mediated by logging intensity. Global Change Biology, .
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Song, X., James Aaron, H., Brown, C., Cao, M., & Yang, J. (2017). Snow damage to the canopy facilitates alien weed invasion in a subtropical montane primary forest in southwestern China. Forest Ecology and Management, 391, 275–281.
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Xing, S., Bonebrake, T. C., Tang, C. C., Pickett, E. J., Cheng, W., Greenspan, S. E., et al. (2016). Cool habitats support darker and bigger butterflies in Australian tropical forests. Ecol Evol, 6(22), 8062–8074.
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