CGIAR Research Program on Forests, Trees and Agroforestry - Plan of Work and Budget 2020

There were no significant changes in 2019 to FTA’s theory of change1. FTA plans all its work on the basis of its operational priorities. These, in turn, focusresearch towards major development demands and knowledge gaps, orienting FTA towards the implementation of the SDGs and other global commitments. Three operational priorities were added in 2020 (see list in Appendix 1) to better delineate pre-existing research areas addressing development bottlenecks needing dedicated investment and visibility: smallholder tree-crop commodities, tree seeds and seedlings delivery systems, and foresight. FTA organized in 2019, at the request of its ISC, a joint ISC-FTA workshop on impact assessment methods for the program. Based on the outcomes of this workshop FTA will, inter alia, revisit in 2020 its impact pathways and end of programme outcomes, and if need be, corresponding adjustments to the ToC of FTA and/or of its FPs will be made

Tropical forest degradation in the context of climate change: increasing role and research challenges. [K-2215-01]

While developed countries in temperate regions faced their forest transition about 100 years ago or more, “tropical forest rich” nations still largely depend on forest resources or land clearing for their development. Hence, tropical forests are retreating at an alarming rate from advancing cash crops, such as oil palm, soybean, or cattle ranching. Beside tropical deforestation, tropical forest degradation resulting mostly from human-induced causes (e.g. predatory or illegal logging, non-timber forest product extraction, fuel wood extraction) significantly contributes to greenhouse gas emissions and loss of biodiversity. If deforestation is an obvious ecosystem change, forest degradation is more difficult to discern and quantify. Degraded forests have become a major component of today's tropical landscapes, representing up to 50 % of all tropical forests. For example, almost half of standing primary tropical forests, up to 400 million ha, are designated by national forest services for timber production. The portion of tropical forests managed for timber extraction, hereafter referred to as “managed forests”, will therefore play key roles in the trade-off between provision of goods and maintenance of carbon stocks, biodiversity, and other services. However, so far, most of our understanding of tropical forest arise from studies carried out in old-growth undisturbed forests, or secondary forests (i.e. regrowth forests) while the ecology of degraded forests at the regional and continental scale remains poorly studied and their role to mitigate climate change still very poorly known. However, understanding the functions played by degraded forests in providing goods and environmental services in the context of climate change is crucial. We will first discuss the complex concept of forest degradation in the tropics and then define degraded forests. We will show their importance in providing timber while maintaining high levels of biodiversity and carbon stocks. We will further demonstrate that implementation of sustainable forest management can promote long term provision of ecosystem services. Finally, the potential of tropical degraded forests in mitigating climate change will be discussed along with future research challenges on this issue. (Texte intégral

Environmental Degradation and the Legal Imperatives of Improvement: Forest Policy in Western Australia from European Settlement to 1918

The Australian forests have experienced deforestation since European settlement in 1788. According to Bradshaw, Australia has lost nearly 40% of its forests and the remaining forest is highly fragmented and degraded. In Western Australia (WA), Australia’s only biodiversity hotspot, forests cover approximately 16% or 21.0 million hectares. In the southwest and central parts of the state these forests are significantly cutover and degraded. In some instances, particularly in the wheatbelt, the local cutover has been complete. For example, in the Avon Botanical District (the central part of the wheatbelt) over 93% of the original vegetation and 97% of the woodlands were removed. William Wallace, an officer of the Forest Department, estimated that between 1829 and 1920, 1 million acres of forest was cut. The Forests Department Annual 1921 Report lamented: [S]eventy five years of practically uncontrolled cutting, and entirely uncontrolled burning have reduced this national asset to such a condition that only a negligible quantity of sound young trees is growing to the acre on the portion that has been cutover. Today the only significant forests that remain in Western Australia are the Jarrah, Karri and Wandoo forests. However, these forests have been significantly degraded and contain approximately 30% of their original forest cover

Information Forests

We describe Information Forests, an approach to classification that generalizes Random Forests by replacing the splitting criterion of non-leaf nodes from a discriminative one -- based on the entropy of the label distribution -- to a generative one -- based on maximizing the information divergence between the class-conditional distributions in the resulting partitions. The basic idea consists of deferring classification until a measure of "classification confidence" is sufficiently high, and instead breaking down the data so as to maximize this measure. In an alternative interpretation, Information Forests attempt to partition the data into subsets that are "as informative as possible" for the purpose of the task, which is to classify the data. Classification confidence, or informative content of the subsets, is quantified by the Information Divergence. Our approach relates to active learning, semi-supervised learning, mixed generative/discriminative learning.Comment: Proceedings of the Information Theory and Applications (ITA) Workshop, 2/7/201

Estimating above ground net biomass change in tropical and subtropical forests: refinement of IPCC default values using forest plot data

As countries advance in greenhouse gas (GHG) accounting for climate change mitigation, consistent estimates of above ground biomass (AGB) net change are needed for the tropics and subtropics. Countries with limited forest monitoring capabilities rely on 2006 IPCC default AGB net change values, which are averages per ecological zone, per continent. These previous defaults come from single studies, provide no uncertainty indications, and aggregate old secondary forests and old-growth forests. In this study, we update these default values using forest plot data. In comparison with previous estimates, new values include data published from 2006 onwards, are derived from multiple sites per global ecological zone, provide measures of variation, and divide forests >20 years old into older secondary forests and old-growth forests. We compiled 176 AGB chronosequences in secondary forests and AGB net change rates from 536 permanent plots in old-growth and managed or logged forests. In this dataset, across all continents and ecozones, AGB net change rates in younger secondary forests (go years) are higher than rates in older secondary (>20 years and ≤100 years) forests and managed or logged forests, which in turn are higher than rates in old-growth forests (> 100 years). Data availability is highest for North and South America, followed by Asia then Africa. We provide a rigorous and traceable refinement of the IPCC 2006 AGB net change default rates, identify which areas in the tropics and subtropics require more research on AGB change, and reflect on possibilities for improvement as more data becomes available

The Distribution of Lianas and Their Change in Abundance in Temperate Forests Over the Past 45 Years

Lianas (woody vines) are an important and dynamic component of many forests throughout the world, and increases in CO2, mean winter temperature, and forest fragmentation may promote their growth and proliferation in temperate forests. In this study, we used a 45‐year data set to test the hypothesis that lianas have increased in abundance and basal area in the interiors of 14 deciduous temperate forests in Wisconsin (USA) since 1959. We also censused woody plants along a gradient from the forest edge to the interior in seven of these forests to test the hypothesis that the abundance of lianas declines significantly with increasing distance from the forest edge. We found that lianas did not increase in abundance within the interiors of temperate forests in Wisconsin over the last 45 years. However, relative and absolute liana abundance decreased sharply with increasing distance from forest edges. Our findings suggest that forest fragmentation, not climate change, may be increasing the abundance of lianas in northern deciduous temperate forests, and that lianas may further increase in abundance if the severity of forest fragmentation intensifies

Can we set a global threshold age to define mature forests?

Globally, mature forests appear to be increasing in biomass density (BD). There is disagreement whether these increases are the result of increases in atmospheric CO2 concentrations or a legacy effect of previous land-use. Recently, it was suggested that a threshold of 450 years should be used to define mature forests and that many forests increasing in BD may be younger than this. However, the study making these suggestions failed to account for the interactions between forest age and climate. Here we revisit the issue to identify: (1) how climate and forest age control global forest BD and (2) whether we can set a threshold age for mature forests. Using data from previously published studies we modelled the impacts of forest age and climate on BD using linear mixed effects models. We examined the potential biases in the dataset by comparing how representative it was of global mature forests in terms of its distribution, the climate space it occupied, and the ages of the forests used. BD increased with forest age, mean annual temperature and annual precipitation. Importantly, the effect of forest age increased with increasing temperature, but the effect of precipitation decreased with increasing temperatures. The dataset was biased towards northern hemisphere forests in relatively dry, cold climates. The dataset was also clearly biased towards forests <250 years of age. Our analysis suggests that there is not a single threshold age for forest maturity. Since climate interacts with forest age to determine BD, a threshold age at which they reach equilibrium can only be determined locally. We caution against using BD as the only determinant of forest maturity since this ignores forest biodiversity and tree size structure which may take longer to recover. Future research should address the utility and cost-effectiveness of different methods for determining whether forests should be classified as mature