Options for monitoring and estimating historical carbon emissions from forest degradation in the context of REDD+

Measuring forest degradation and related forest carbon stock changes is more challenging than measuring deforestation since degradation implies changes in the structure of the forest and does not entail a change in land use, making it less easily detectable through remote sensing. Although we anticipate the use of the IPCC guidance under the United Framework Convention on Climate Change (UNFCCC), there is no one single method for monitoring forest degradation for the case of REDD+ policy. In this review paper we highlight that the choice depends upon a number of factors including the type of degradation, available historical data, capacities and resources, and the potentials and limitations of various measurement and monitoring approaches. Current degradation rates can be measured through field data (i.e. multi-date national forest inventories and permanent sample plot data, commercial forestry data sets, proxy data from domestic markets) and/or remote sensing data (i.e. direct mapping of canopy and forest structural changes or indirect mapping through modelling approaches), with the combination of techniques providing the best options. Developing countries frequently lack consistent historical field data for assessing past forest degradation, and so must rely more on remote sensing approaches mixed with current field assessments of carbon stock changes. Historical degradation estimates will have larger uncertainties as it will be difficult to determine their accuracy. However improving monitoring capacities for systematic forest degradation estimates today will help reduce uncertainties even for historical estimates

The climatic impacts of land surface change and carbon management, and the implications for climate-change mitigation policy

http://www.sciencedirect.com/science/journal/14693062Strategies to mitigate anthropogenic climate change recognize that carbon sequestration in the terrestrial biosphere can reduce the build-up of carbon dioxide in the Earth’s atmosphere. However, climate mitigation policies do not generally incorporate the effects of these changes in the land surface on the surface albedo, the fluxes of sensible and latent heat to the atmosphere, and the distribution of energy within the climate system. Changes in these components of the surface energy budget can affect the local, regional, and global climate. Given the goal of mitigating climate change, it is important to consider all of the effects of changes in terrestrial vegetation and to work toward a better understanding of the full climate system. Acknowledging the importance of land surface change as a component of climate change makes it more challenging to create a system of credits and debits wherein emission or sequestration of carbon in the biosphere is equated with emission of carbon from fossil fuels. Recognition of the complexity of human-caused changes in climate does not, however, weaken the importance of actions that would seek to minimize our disturbance of the Earth’s environmental system and that would reduce societal and ecological vulnerability to environmental change and variability

Sustainability of Leucaena leucocephala fallows in shifting cultivation on the Island of Mindoro, Philippines

Increasing human populations, declining crop yields and reductions in per capita arable land area suggest that shifting cultivation as traditionally practiced in much of the humid tropics is no longer a sustainable farming practice. The use of nitrogen-fixing trees such as Leucaena leucocephala (Lam. de Wit) (leucaena) as a fallow species may be an important strategy to maintain or improve crop yields in shifting cultivation where natural resources are rapidly declining. A series of experiments comparing leucaena and non-leucaena fallows was conducted on sites with fallows established between 1977 and 1992 on the Island of Mindoro, Philippines to determine the impacts of leucaena fallows on rice yields, soil nutrient status and the sustainability of production in shifting cultivation in the study area. Rice yields and yield components were measured on 10 shifting cultivation fields. One burning experiment and a series of chronosequence studies in fallows of 1-4 years of age were conducted. Informal interviews with farmers were also conducted to determine perceptions and social impacts of leucaena as a fallow crop. Moisture content-adjusted grain yields (@0.14 g H20/g dry matter) were 3.8 t ha"1 following leucaena fallows and 2.71 ha"1 following non-leucaena fallows for an average yield response of 42%. This difference appears to relate most closely to soil N accumulated during the fallow period and N added through seedling biomass applied as a surface mulch during the cropping period. N-fixation of leucaena and possibly the inhibition of nitrification of ammonium ions as demonstrated by higher NH4 + concentrations in soils under leucaena were associated with (and may explain) these differences. Higher N levels appear to delay crop maturity, as evidenced by higher grain moisture contents in the leucaena treatment. Available phosphorus levels are low, but do not appear to differ between fallow types, although the size of phosphorus pools in the biomass and litter varied with fallow type. Ca and Mg were not limiting in either fallow type, due to the large soil pool of these nutrients. Organic phosphorus inputs to the rice crop are higher in the leucaena fallows when leucaena wood removals from the site are low. The greatest potential threat to sustainability of crop production following leucaena fallows is charcoal making and the potential losses of P from the system. There appears to be little disadvantage to burning leucaena fallow fields prior to planting. The most significant advantages of burning appear to be increased P availability and reduced weeding costs, although no difference in grain yield due to burning was detected. Leucaena can increase sustainability of shifting cultivation through higher N and P contributions that result in grain yield increases. Additional increases in yield are probably attainable with the use of a minimum fallow age of 3-4 years, timely weed control and use of high-yielding, traditional rice varieties.Forestry, Faculty ofGraduat

Carbon monitoring costs and their effect on incentives to sequester carbon through forestry

Technically, land-use change and forestry (LUCF) projects have the potential of contributing significantly to mitigation of global warming, but many such projects may not be economically attractive at current estimates of carbon prices. Payments for greenhouse-gas emission offsets can make some projects attractive and hence stimulate the development of the forestry sector. However, the costs of participating in the carbon market may be too high to make it worthwhile. Forest carbon is in a sense a new commodity that must be measured to acceptable standards for the commodity to exist. This will require credible carbon-monitoring programs be in place. Carbon monitoring is subject to both fixed and variable costs and these will affect the profitability of projects - particularly small projects, those involving geographically dispersed parcels and those with high levels of heterogeneity. Monitoring schemes need to be designed to maximize efficiency. These issues are discussed at a general level and illustrated numerically based on a model of an 'Acacia mangium' plantation in South Sumatra, Indonesia. Using plausible assumptions we show that a project of this type can be economically attractive under a range of conditions and with variable monitoring costs as high as $1,500 per sampling plot, provided that the project is large enough to absorb fixed costs. Under the assumed fixed-monitoring costs and a discount rate of 15%, a 500-hectare project is shown not to be profitable from a carbon-sequestration standpoint, as a landholder would be better off not entering the carbon market and relying only on timber sales