Collect Earth is a free and open source software for land monitoring developed by the Food and Agriculture Organization of the United Nations (FAO). Built on Google desktop and cloud computing ...technologies, Collect Earth facilitates access to multiple freely available archives of satellite imagery, including archives with very high spatial resolution imagery (Google Earth, Bing Maps) and those with very high temporal resolution imagery (e.g., Google Earth Engine, Google Earth Engine Code Editor). Collectively, these archives offer free access to an unparalleled amount of information on current and past land dynamics for any location in the world. Collect Earth draws upon these archives and the synergies of imagery of multiple resolutions to enable an innovative method for land monitoring that we present here: augmented visual interpretation. In this study, we provide a full overview of Collect Earth's structure and functionality, and we present the methodology used to undertake land monitoring through augmented visual interpretation. To illustrate the application of the tool and its customization potential, an example of land monitoring in Papua New Guinea (PNG) is presented. The PNG example demonstrates that Collect Earth is a comprehensive and user-friendly tool for land monitoring and that it has the potential to be used to assess land use, land use change, natural disasters, sustainable management of scarce resources and ecosystem functioning. By enabling non-remote sensing experts to assess more than 100 sites per day, we believe that Collect Earth can be used to rapidly and sustainably build capacity for land monitoring and to substantively improve our collective understanding of the world's land use and land cover.
Humid tropical forests play a dominant role in the functioning of Earth but are under increasing threat from changes in land use and climate. How forest vulnerability varies across space and time and ...what level of stress forests can tolerate before facing a tipping point are poorly understood. Here, we develop a tropical forest vulnerability index (TFVI) to detect and evaluate the vulnerability of global tropical forests to threats across space and time. We show that climate change together with land-use change have slowed the recovery rate of forest carbon cycling. Temporal autocorrelation, as an indicator of this slow recovery, increases substantially for above-ground biomass, gross primary production, and evapotranspiration when climate stress reaches a critical level. Forests in the Americas exhibit extensive vulnerability to these stressors, while in Africa, forests show relative resilience to climate, and in Asia reveal more vulnerability to land use and fragmentation. TFVI can systematically track the response of tropical forests to multiple stressors and provide early-warning signals for regions undergoing critical transitions.
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•An index to track vulnerability of global rainforests to climate and land use•Four decades of satellite data show widespread vulnerability across the tropics•Response of rainforests to heat and drying varies across the continents•Early warning from the index can identify regions for conservation and restoration
Rainforests are being lost at an alarming rate due to deforestation and degradation. As these forests lose their intactness and diversity, their resilience to climate change declines and they become more vulnerable to droughts and wildfires. Here, we built a spatially explicit tropical forest vulnerability index (TFVI) based on observations of forest cover, carbon, and water fluxes to identify areas where rainforests are losing resilience to disturbance and are changing toward an irreversible state, a “tipping point.” Our findings show how and where tipping points may occur, either as a gradual downhill decline of ecosystem services or an abrupt change. We present TFVI as an index to monitor tropical forests and provide early-warning signals for regions that are in need of policies that simultaneously promote conservation and restoration to increase resilience and climate mitigation.
Rainforests take hundreds of years to be formed into a diverse and complex structure that is lush but fragile. The reason for their fragility is the difficulty to recover from disturbance. Using satellite observations, we show how increasing threats from large-scale deforestation and severe climate conditions over the past four decades have substantially impacted the ecological functions of these forests regionally, pushing them toward a critical point of no recovery and a dryer and less diverse state.
Around 76% of the 10,452 villages of Cambodia will still be without electricity in the year 2010. We examined the potential of biomass gasification fuelled by alternative resources of agricultural ...residues and woody biomass to increase rural power supply, using geographic and social economic databases provided by the Royal Government of Cambodia. About 77% of villages currently without electricity have sufficient land available for tree planting for electricity generation based on a requirement of 0.02
ha per household. Among 8008 villages with sufficient land, we assumed that those villages that had greater than 10% of households owning a television (powered by a battery or a generator) would have both a high electricity demand and a capacity to pay for electricity generation. Those 6418 villages were considered appropriate candidates for mini-grid installation by biomass gasification. This study demonstrated that while agricultural residues such as rice husks or cashew nut shells may have high energy potential, only tree farming or plantations would provide sufficient sustainable resources to supply a biomass gasification system. Cost per unit electricity generation by biomass gasification is less than diesel generation when the plant capacity factor exceeds 13%. In order to ensure long-term ecological sustainability as well as appropriate tree-farming technology for farmers, there is an urgent need for studies aimed at quantifying biomass production across multiple rotations and with different species across Cambodia.
Truncated abstract Globally, tropical rainforests are noted for their high biodiversity and key roles in carbon storage and influence on climate. Nevertheless, tropical deforestation in many parts of ...the world continues at an alarming rate. In Papua New Guinea (PNG), tropical rainforest is relatively well maintained, with about 70 % of the land area still covered by primary forest. However, PNG's native forests are coming under increasing pressure, particularly from selective logging for high quality timber. While the forests of PNG, and more broadly the entire New Guinea Island, are recognised as of high conservation and ecological significance, they remain grossly understudied with little knowledge of key ecosystem processes within lowland forests in particular. Such knowledge is urgently required if the impacts of logging and other land-use change are to be assessed and in order to develop sustainable management systems. This thesis investigated the impacts of logging on diversity and nutrient cycling in a lowland tropical rainforest growing on limestone soils in the area of the Mongi-Busiga Forest Management Agreement (FMA, which is a logging concession area), in northeastern PNG. These forests are on relatively young soils and provide a useful contrast to the majority of tropical forests. The research includes a four-year study of the recovery of diversity and structure after logging, and quantified forest structure, tree species diversity, forest biomass and productivity, and nutrient distribution and cycling. This thesis also examines the ecological sustainability of Eucalyptus deglupta plantations in Wasab, PNG as an alternative resource for timber and biomass energy. The thesis concludes with a discussion of long-term forest recovery and sustainable forest management in north-eastern PNG. Two adjacent one-hectare plots were established in lowland tropical rainforest at Mongi-Busiga FMA. One of these plots was subsequently selectively logged, one year after establishment. Before logging, the two one-hectare plots contained a total of 37 families, 70 genera and 110 tree species that were >5 cm in diameter at breast height. Mean basal area was 42.4 m2 ha-1. Two tree species, Madhuca leucodermis (Sapotaceae) and Pometia pinnata (Sapindaceae) accounted for ~60% of the total basal area. Gymnacranthera paniculata (Myristicaceae) was the most common species and accounted for 13% of individuals. ... This study concludes that the Mongi-Busiga forest has many unusual characteristics for a tropical forest, including relatively low diversity of tree species, high accumulation of P in the biomass, and N limitations, compared to other tropical rainforests. However, those extraordinary characteristics may be explained well by the underlying geology of young, marine-derived limestone. Sustainable management of the lowland tropical forests of PNG should consider the consequences of logging on nutrient cycling processes, with the possible significant removal of P from site with repeated logging, as well as the interactions between N and P in these systems. Establishment of Eucalyptus plantations on previously cleared land also has the potential to meet some of the timber and biomass energy requirements of northern PNG in ecologically sustainable manner.
This chapter evaluates life cycle CO2 (LCCO2) emissions by comparing biomass power plants with a coal power plant of the CO2 removal system. For the concrete investigation of the biomass life cycle ...analysis (LCA), the reforestation sites in Eastern Highland Province and Madang Province in Papua New Guinea (PNG) as model areas were selected.Then, Casuarina oligodon (C. oligodon) and Eucalyptus deglupta (E. deglupta), which are fast growing trees, were adopted as biomass materials. Especially, C. oligodon has the characteristics of nitrogen fixation from air. As the result, nitrogen fixation to soils is expected to mitigate LCCO2 emissions and direct and indirect energy input in the biomass LCA. The biomass energy system consists of two subsystems: the cultivation process and the energy conversion process. In the cultivation process, the nutrient circulation model in reforestation area was constructed. Nutrients losses by soil erosion are evaluated in this process. It is assumed that their nutrients are newly supplemented for the purpose of considering the sustainable forest management, and that they are equivalent to chemical fertilizer. In the energy conversion process, the Biomass Integrated Gasification Combined Cycle (BIGCC) in PNG was designed. On the basis of this study, it can be concluded that the biomass energy system, for example BIGCC system, can actualize the sequestration of CO2, that the improvement of the sequestration will be better by selecting C. oligodon, and that the system will be promising for developing countries as an environmentally friendly system or an alternative system to the fossil fuels in the future. As a future research subject, the continuous investigation about timber volume or nutrients circulation etc. in consideration of compound reforestation of C. oligodon will be important.
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