Propriedades e utilização como lenha de árvores fixadores de N2

World deforestation and reforestation values are cited, and the increasing need for fuelwood tree plantings is noted. Tropical reforestation involves about 1 million hectares annually, of which less than 20% is believed to survive. Estimated tropical fuelwood needs alone, however, require 3 million hectares annually. Fuelwood remains the most cost-effective source of energy for rural poor, and charcoal demands are increasing worldwide. World deforestation is occurring primarily in the tropics (10-20 million ha/year), largely in relation to fuelwood demands (1,200 million m3/yr). The loss of newly planted forests to fire is stressed as a serious problem, notably for pine and eucalypt forests. It is suggested that over half the 650 known species of nitrogen-fixing trees (NFT) are suitable for fuelwood and charcoal, and many have wide present use. The fuelwood properties of 32 major NFT species are given, together with information on their uses and environmental constraints. Leucaena data are used to illustrate that tree age and density have little effect on calorific values, but have major influence on moisture content and specific gravity of the wood. It is stressed that calorific values should be quoted for the bone-dry wood, and then readjusted downward to reflect moisture in the wood as burned. The need is stressed for yield data from NFT biomass plantings at high densities, with appropriate controls of locally-important trees (including non-fixing trees, notably eucalyptus). Disadvantages are cited for monocultural plantings of single fuelwood species, and advantages suggested for mixed plantings of NFT species together with high-yielding trees that lack the ability to fix nitrogen.O trabalho salienta a extensão de devastação de florestas e do reflorestamento, bem como o aumento considerável da necessidade de plantações de árvores, para produção de lenha. O reflorestamento em áreas tropicais representa cerca de 1 milhão de hectares, anualmente, dos quais apenas 20% realmente sobrevivem. Entretanto, estimativas feitas sobre as necessidades de lenha mostram que são necessários 3 milhões de hectares, anualmente, somente para atender a essa finalidade. A lenha permanece como a fonte de energia mais importante no meio rural, e a demanda de carvão está crescendo em todo o mundo. As maiores devastações de florestas estão ocorrendo nos trópicos, onde 10-20 milhões de hectares por ano são cortados para atender principalmente a demanda por lenha (1.200 milhões m3/ano-1). A perda de novas florestas por queimada acidental é apontada como um problema sério, notadamente nos reflorestamentos de pinheiro e eucalipto. Mais da metade das 650 espécies conhecidas de árvores fixadoras de N2 são adequadas para a produção de lenha e carvão e muitas delas já são usadas no momento. As propriedades em termos de lenha de 32 das mais promissoras árvores fixadoras de N2 são apresentadas junto a informações sobre o uso e principais problemas de cultivo. Resultados obtidos com Leucaena são usados para ilustrar que a idade da árvore e a densidade têm pouco efeito sobre os valores caloríficos, mas têm grande influência sobre o teor de umidade e peso específico da madeira. É enfatizado que o valor calorífico deveria ser citado para a madeira completamente seca e, então, reajustado de modo a refletir o teor de umidade da madeira, quando queimada em condições normais. É apontada a necessidade de dados de produtividade de biomassa de leguminosa, em plantios de alta densidade, com apropriados controles de árvores não-fixadoras de N2, localmente importantes (provavelmente o eucalipto). As desvantagens das monoculturas de espécies produtoras de lenha e as vantagens de plantios mistos de árvores fixadoras de N2, junto a árvores de alta produtividade, mas incapazes de fixar N2, são discutidas

SDG 12: responsible consumption and production – potential benefits and impacts on forests and livelihoods

This chapter identifies and analyses the potential impacts and contributions of efforts to achieve SDG 12 Sustainable Consumption and Production (SCP) on forests and their conservation, sustainable management and use, as well as forest livelihoods. SCP has been part of the international policy discourse for more than four decades, but the uptake of SCP has not been smooth and has tended to be biased towards relatively weak measures. The inclusion of SCP in the SDG framework gives hope that SCP will receive stronger attention in the international efforts for sustainable development. Although SDG 12 targets or indicators make no direct reference to forests or forest communities, the chapter finds that SDG12 targets can contribute positively to forest protection and conservation efforts. The review of the SDG 12 targets does not point towards any direct trade-offs between achieving the SDG12 targets and protection of forest ecosystems, resources and livelihoods. SDG 12 can contribute to creating enabling conditions for advancing more responsible and sustainable supply of timber and other forest commodities, also linked to more responsible demand. To enhance forest conservation and livelihoods through SCP beyond 2030, an integrative SCP approach addressing systemic issues is needed

A review of methods to measure and monitor historical carbon emissions from forest degradation

In the absence of historical field data, developing countries can rely on consistent current ground data and remote sensing assessments

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

Consistent patterns of high alpha and low beta diversity in tropical parasitic and free-living protists

Tropical animals and plants are known to have high alpha diversity within forests, but low beta diversity between forests. By contrast, it is unknown if microbes inhabiting the same ecosystems exhibit similar biogeographic patterns. To evaluate the biogeographies of tropical protists, we used metabarcoding data of species sampled in the soils of three lowland Neotropical rainforests. Taxa-area and distance-decay relationships for three of the dominant protist taxa and their subtaxa were estimated at both the OTU- and hylogenetic-levels, with presence-absence and abundance based measures. These estimates were compared to null models. High local alpha and low regional beta diversity patterns were consistently found for both the parasitic Apicomplexa and the largely free-living Cercozoa and Ciliophora. Similar to animals and plants, the protists showed spatial structures between forests at the OTU- and phylogenetic-levels, and only at the phylogenetic level within forests. These results suggest that the biogeographies of macro- and micro-organismal eukaryotes in lowland Neotropical rainforests are partially structured by the same general processes. However, and unlike the animals and plants, the protist OTUs did not exhibit spatial structures within forests, which hinders our ability to estimate local and regional diversity of protists in tropical forests