Woods Hole Research Center

2011

The papers highlighted in this annotated bibliography offer recent research findings relevant to the negotiations and policy discussions underway at COP17. For a complete list of WHRC peer-reviewed literature, and where permitted, access to the full articles, visit www.whrc.org/resources/publications.

Beck, P.S.A., S.J. Goetz, M. Mack, H. Alexander, Y. Jin, and J.T. Randerson. 2011. The impacts and implications of an intensifying fire regime on Alaskan boreal forest composition and albedo. Global Change Biology doi:10.1111/j.1365-2486.2011.02412.x

Climate warming and drying are modifying the fire dynamics of many boreal forests, moving them towards a regime with a higher frequency of extreme fire years characterized by large burns of high severity. Plot-scale studies indicate that increased burn severity favors the recruitment of deciduous trees in the initial years following fire. Consequently, a set of biophysical effects of burn severity on postfire boreal successional trajectories at decadal timescales have been hypothesized. Prominent among these are a greater cover of deciduous tree species in intermediately aged stands after more severe burning, with associated implications for carbon and energy balances. Here we investigate whether the current vegetation composition of interior Alaska supports this hypothesis.  Our results show that since the 1950s, more severely burned areas in interior Alaska have produced a vegetation cohort that is characterized by greater deciduous biomass. We discuss the importance of this shift in vegetation composition due to climate-induced changes in fire severity for carbon sequestration in forest biomass and surface reflectance (albedo), among other feedbacks to climate.

Cattaneo, A. 2011. Robust design of multiscale programs. Environment and Development Economics. doi:10.1017/S1355770X11000040

A framework is provided for structuring programs aimed at reducing emissions from deforestation and forest degradation (REDD). Crediting reference levels and the coordination among different implementing entities at multiple geographic scales are discussed. A crediting reference level has an error component if it differs from the business-as-usual (BAU) without REDD. Both the BAU emissions and the impact of REDD actions are uncertain, implying that participating in REDD entails stakeholder risk, the distribution of which depends on REDD program design. To categorize REDD architectures we define scale-neutrality whereby, for a given REDD design, crediting relative to the reference level at a given scale is not affected by errors in reference levels at scales below it. Sufficient conditions are derived for scale-neutrality to hold. A Brazilian Amazon example is provided, comparing potential REDD architectures, and highlighting how a cap-and-trade approach may match the environmental outcome obtainable with perfect foresight of the BAU emissions.

Coe, M.T., E.M. Latrubesse, M.E Ferreira, and M.L. Amsler. 2011. The effects of deforestation and climate variability on the streamflow of the Araguaia River, Brazil. Biogeochemistry DOI: 10.1007/s10533-011-9582-2

Deforestation changes the hydrological, geomorphological, and biochemical states of streams by decreasing evapotranspiration on the land surface and increasing runoff, river discharge, erosion and sediment fluxes from the land surface. Deforestation has removed about 55% of the native vegetation and significantly altered the hydrological and morphological characteristics of an 82,632 km2 watershed of the Araguaia River in east-central Brazil. Observed discharge increased by 25% from the 1970s to the 1990s and computer simulations suggest that about 2/3 of the increase is from deforestation, the remaining 1/3 from climate variability. Changes of this scale are likely occurring throughout the 2,000,000 km2 savannah region of central Brazil.

Davidson, E.A, P.A. Lefebvre, P.M. Brando, D. Ray, S.E. Trumbore, L.A. Solórzano, J.N. Ferreira, M.M. da C. Bustamante, and D.C. Nepstad. 2011. Carbon inputs and water uptake in deep soils of an eastern Amazon forest. Forest Science 57:51-58.

Rooting depth affects soil profiles of water uptake and carbon inputs. Here we explore the importance of deep roots in a mature tropical forest of eastern Amazonia, where a throughfall exclusion experiment was conducted to test the resilience of the forest to experimentally induced drought. We hypothesized that soil water depletion occurred below the depth previously measured by sensors in 11-m-deep soil pits and that only a small root biomass is necessary to affect water uptake and the isotopic signature of soil CO2. A noninvasive electrical profiling method demonstrated greater depletion of soil water in the 11–18 m depth increment in the exclusion plot compared with the control plot by the end of the 3rd year of the experiment. A fine root biomass of only 0.1 g/cm3 measured at 3–6 m was sufficient for soil water drawdown and for imparting an isotopic signature of modern soil 14CO2 in both plots. A soil 13CO2 profile indicated drought stress in the exclusion plot. Fine root  inputs of organic C to deep soils are small with respect to the carbon dynamics of the forest, but the deep rooting habit clearly affects the ecosystem water balance and profiles of soil CO2.

Galford, G.L., J.M. Melillo, D.W. Kicklighter, J.F. Mustard, T.W. Cronin, C.E.P. Cerri, and C.C. Cerri. 2011. Historical carbon emissions and uptake from the agricultural frontier of the Brazilian Amazon. Ecological Applications 21(3):750-763. doi: 10.1890/09-1957.1

Tropical ecosystems play a large and complex role in the global carbon cycle. Clearing of natural ecosystems for agriculture leads to large pulses of CO2 to the atmosphere from terrestrial biomass. Concurrently, the remaining intact ecosystems, especially tropical forests, may be sequestering a large amount of carbon from the atmosphere in response to global environmental changes including climate changes and an increase in atmospheric CO2. Here we use an approach that integrates census-based historical land use reconstructions, remote-sensing-based contemporary land use change analyses, and simulation modeling of terrestrial biogeochemistry to estimate the net carbon balance over the period 1901–2006 for the state of Mato Grosso, Brazil, which is one of the most rapidly changing agricultural frontiers in the world. By the end of this period, we estimate that of the state's 925 225 km2, 221 092 km2 have been converted to pastures and 89 533 km2 have been converted to croplands, with forest-to-pasture conversions being the dominant land use trajectory but with recent transitions to croplands increasing rapidly in the last decade. These conversions have led to a cumulative release of 4.8 Pg C to the atmosphere, with 80% from forest clearing and 20% from the clearing of cerrado. Over the same period, we estimate that the residual undisturbed ecosystems accumulated 0.3 Pg C in response to CO2 fertilization. Therefore, the net emissions of carbon from Mato Grosso over this period were 4.5 Pg C. Net carbon emissions from Mato Grosso since 2000 averaged 146 Tg C/yr, on the order of Brazil's fossil fuel emissions during this period. These emissions were associated with the expansion of croplands to grow soybeans. While alternative management regimes in croplands, including tillage, fertilization, and cropping patterns promote carbon storage in ecosystems, they remain a small portion of the net carbon balance for the region. This detailed accounting of a region's carbon balance is the type of foundation analysis needed by the new United Nations Collaborative Programmme for Reducing Emissions from Deforestation and Forest Degradation (REDD).

Goetz, S.J., and R.O. Dubayah. 2011. Advances in remote sensing technology and implications for measuring and monitoring forest carbon stocks and change. Carbon Management 2:231-244. doi: 10.4155/cmt.11.18.

Forest monitoring using satellite imagery has advanced tremendously over the past few decades, to the point that these datasets now inform international policy agreements, notably those associated with emissions of CO2 into the atmosphere from deforestation and other types of land-use change. However, satellite technological advances require time to move towards a state of operational readiness for monitoring and reporting; for example, in the case of forest cover and associated carbon stock (biomass) and their changes through time. In this article, we provide an overview of the current status of forest monitoring using satellites and we explore new technologies that are already revolutionizing the way that forest carbon is measured. In particular, we focus on the capabilities of light detection and ranging (LiDAR), noting the opportunities and also the challenges that arise in moving technologies from those flown on aircraft to earth orbiting satellites. We discuss these capabilities in the context of next-generation earth observation missions and international reporting requirements for reducing emissions from deforestation and forest degradation under the United Nations Framework Convention on Climate Change.

Goetz, S.J., H.E. Epstein, U. Bhatt, G.J. Jia, J.O. Kaplan, H. Lischke, Q. Yu, A. Bunn, A. Lloyd, D. Alcaraz, P.S.A. Beck, J. Comiso, M.K. Raynolds, and D.A. Walker. 2011. Recent changes in Arctic vegetation: satellite observations and simulation model predictions. In Eurasian Arctic Land Cover and Land Use in a Changing Climate, ed. G. Gutman and A. Reissell, 9-36. Amsterdam: Springer-Verlag.

This chapter provides an overview of observed changes in vegetation productivity in Arctic tundra and boreal forest ecosystems over the past 3 decades, based on satellite remote sensing and other observational records, and relates these to climate variables and sea ice conditions. The emerging patterns and relationships are often complex but clearly reveal a contrast in the response of the tundra and boreal biomes to recent climate change, with the tundra showing increases and undisturbed boreal forests mostly reductions in productivity. The possible reasons for this divergence are discussed and the consequences of continued climate warming for the vegetation in the Arctic region assessed using ecosystem models, both at the biome-scale and at high spatial resolution focussing on plant functional types in the tundra and the tundra-forest ecotones.

Greenglass, N. and R.A. Houghton. 2011. Towards results-based REDD+ mechanisms. Carbon Management 2 (5): 513-515. doi: 10.4155/cmt.11.53

The need for additional guidance on forest monitoring systems and reference emission levels/reference levels in the near term is critical to the long-term success of REDD+ at the global scale. This observation in no way diminishes the importance of work on the remaining policy, methodological and technical elements, but is rather a response to the accelerating pace of REDD+ activities in developing countries and the most time-sensitive gaps in guidance. Robust and thorough guidance is needed to ensure that the rapid development of national REDD+ frameworks currently underway follows a path that will result in an effective, efficient and equitable mechanism at the global scale.

Hansen, A.J., C.R. Davis, N. Piekielek, J. Gross, D.M. Theobald, S. Goetz, F. Melton, and R. DeFries. 2011. Delineating the Ecosystems Containing Protected Areas for Monitoring and Management. BioScience 61:363-373. doi: 10.1525/bio.2011.61.5.5

Park managers realized more than 130 years ago that protected areas are often subsets of larger ecosystems and are vulnerable to change in the unprotected portions of the ecosystem. We illustrate the need to delineate protected area–centered ecosystems (PACEs) by using comprehensive scientific methods to map and analyze land-use change within PACEs around 13 US national park units. The resulting PACEs were on average 6.7 times larger than the parks in upper watersheds and 44.6 times larger than those in middle watersheds. The sizes of these PACEs clearly emphasized the long-term reliance of park biodiversity on surrounding landscapes. PACEs in the eastern United States were dominated by private lands with high rates of land development, suggesting that they offer the greatest challenge for management. Delineating PACEs more broadly will facilitate monitoring, condition assessment, and conservation of the large number of protected areas worldwide that are being degraded by human activities in the areas that surround them.

Masek, J.G., W.B. Cohen, D. Leckie, M.A. Wulder, R. Vargas, B. de Jong, S. Healey, B. Law, R. Birdsey, R.A. Houghton, D. Mildrexler, S. Goward, and W.B. Smith. 2011. Recent rates of forest harvest and conversion in North America. Journal of Geophysical Research 116, G00K03, doi:10.1029/2010JG001471.

Incorporating ecological disturbance into biogeochemical models is critical for estimating current and future carbon stocks and fluxes. In particular, anthropogenic disturbances, such as forest conversion and wood harvest, strongly affect forest carbon dynamics within North America. This paper summarizes recent (2000–2008) rates of extraction, including both conversion and harvest, derived from national forest inventories for North America (the United States, Canada, and Mexico). During the 2000s, 6.1 million ha/yr were affected by harvest, another 1.0 million ha/yr were converted to other land uses through gross deforestation, and 0.4 million ha/yr were degraded. Thus about 1.0% of North America’s forests experienced some form of anthropogenic disturbance each year. However, due to harvest recovery, afforestation, and reforestation, the total forest area on the continent has been roughly stable during the decade. On average, about 110 m3 of roundwood volume was extracted per hectare harvested across the continent. Patterns of extraction vary among the three countries, with U.S. and Canadian activity dominated by partial and clear‐cut harvest, respectively, and activity in Mexico dominated by conversion (deforestation) for agriculture. Temporal trends in harvest and clearing may be affected by economic variables, technology, and forest policy decisions. While overall rates of extraction appear fairly stable in all three countries since the 1980s, harvest within the United States has shifted toward the southern United States and away from the Pacific Northwest.

McKinley, D.C., M.G. Ryan, R.A. Birdsey, C.P. Giardina, M.E. Harmon, L.S. Heath, R.A. Houghton, R.B. Jackson, J.F. Morrison, B.C. Murray, D.E. Pataki, and K.E. Skog. 2011. A synthesis of current knowledge on forests and carbon storage in the United States. Ecological Applications 21: 1902-1924.

Using forests to mitigate climate change has gained much interest in science and policy discussions. We examine the evidence for carbon benefits, environmental and monetary costs, risks and tradeoffs for a variety of activities in three general strategies: 1) land-use change to increase forest area (afforestation) and avoid deforestation; 2) carbon management in existing forests; and 3) the use of wood as biomass energy, in place of other building materials, or in wood products for carbon storage. We found that many strategies can increase forest sector carbon mitigation above the current 162-256 Tg C/yr, and that many strategies have co-benefits such as biodiversity, water, and economic opportunities. Each strategy also has tradeoffs, risks, and uncertainties including possible leakage, permanence, disturbances, and climate change effects. Because ~60% of the carbon lost through deforestation and harvesting from 1700-1935 has not yet been recovered and because some strategies store carbon in forest products or use biomass energy, the biological potential for forest sector carbon mitigation is large. Several studies suggest that using these strategies could offset as much as 10-20% of current U.S. fossil-fuel emissions. To obtain such large offsets in the U.S. would require a combination of afforesting up to one-third of crop or pasture land, using the equivalent of about one-half of the gross annual forest growth for biomass energy, or implementing more intensive management to increase forest growth on one-third of forest land. Such large offsets would require substantial tradeoffs, such as lower agricultural production and non-carbon ecosystem services from forests. The effectiveness of activities could be diluted by negative leakage effects and increasing disturbance regimes.

Pan, Y., R.A. Birdsey, J. Fang, R. Houghton, P.E. Kauppi, W.A. Kurz, O.L. Phillips, A. Shvidenko, S.L. Lewis, J.G. Canadell, P. Ciais, R.B. Jackson, S.W. Pacala, A.D. McGuire, S. Piao, A. Rautiainen, S. Sitch, and D. Hayes. 2011. A large and persistent carbon sink in the world’s forests. Science 333:988-993.

The terrestrial carbon sink has been large in recent decades, but its size and location remain uncertain. Using forest inventory data and long-term ecosystem carbon studies, we estimate a total forest sink of 2.4 ± 0.4 petagrams of carbon per year (Pg C year–1) globally for 1990 to 2007. We also estimate a source of 1.3 ± 0.7 Pg C year–1 from tropical land-use change, consisting of a gross tropical deforestation emission of 2.9 ± 0.5 Pg C year–1 partially compensated by a carbon sink in tropical forest regrowth of 1.6 ± 0.5 Pg C year–1. Together, the fluxes comprise a net global forest sink of 1.1 ± 0.8 Pg C year–1, with tropical estimates having the largest uncertainties. Our total forest sink estimate is equivalent in magnitude to the terrestrial sink deduced from fossil fuel emissions and land-use change sources minus ocean and atmospheric sinks.

Richter, D. deB., and R.A. Houghton. 2011. Gross CO2 fluxes from land-use change: implications for reducing global emissions and increasing sinks. Carbon Management 2(1):41-47.

The role of land use in the global carbon cycle involves both CO2 sources (e.g., as forest land is converted to agricultural uses) and CO2 sinks (as vegetation regrows following land disturbance). While land-use change contributions to the carbon cycle have been mainly evaluated using net emissions of CO2, we estimated gross emissions and gross sinks of CO2 from land-use change via global and regional simulations with a widely used carbon cycle model. Gross fluxes are large; for example, the gross CO2 sources from land-use change amount to 4.3 PgC year-1 or more than 55% of emissions from fossil fuel combustion and cement manufacture. The airborne fraction is therefore estimated to be approximately 34% of total CO2 emissions (i.e., fossil fuel plus land-use). Since land-use conversions and abandonment differ regionally, gross sources and sinks provide strong support for extensive land protection and land-use management strategies to reduce atmospheric CO2.

Salimon, Cleber I., F.E. Putz, L. Menezes-Filho, A. Anderson, M. Silveira, I.F. Brown, and L.C. Oliveira. 2011. Estimating state-wide biomass carbon stocks for a REDD plan in Acre, Brazil. Forest Ecology and Management. doi: 10.1016/j.foreco.2011.04.025

As in many other developing countries, the state government of Acre, Brazil, is developing a program for compensating forest holders (such as communities of rubber tappers and indigenous peoples as well as small, medium and large private land holders) reducing their emission of atmospheric heat-trapping gases by not deforesting. We describe and then apply to Acre a method for estimating carbon stocks by land cover type. We then compare the results of our simple method, which is based on vegetation mapping and ground-based samples, with other more technically demanding methods based on remote sensing. We estimated total biomass carbon stocks by multiplying the measured above-ground biomass of trees >10 cm DBH in each of 18 forest types and published estimates for non-forest areas, as determined by measurement of 44 plots throughout the state (ranging from 1 to 10 ha each), by land-cover area estimated using a geographical information system. State-wide, we estimated average above-ground biomass in forested areas to be 246 ± 90 Mg ha?1; dense forest showed highest (322 ± 20 Mg ha?1) and oligotrophic dwarf forest (campinarana) the lowest biomass (20 ± 30 Mg ha?1). The two most widespread forest types in Acre, open canopy forests dominated by either palms and bamboo (for which ground-based data are scant), support an estimated 246 ± 44 and 224 ± 50 Mg ha?1 of above-ground biomass, respectively. We calculate the total above-ground biomass of the 163,000 km2 State of Acre to be 3.6 ± 0.8 Pg (non-forest biomass included). This estimate is very similar to two others generated using much more technologically demanding methods, but all three methods, regardless of sophistication, suffer from lack of field data.