The Amazon rainforest is a critical hotspot for bio-diversity, and plays an essential role in global carbon, water and energy fluxes and the earth's climate. Our ability to project the role of vegetation carbon feedbacks on future climate critically depends upon our understanding of this tropical ecosystem, its tolerance to...
We show that the vegetation canopy of the Amazon rainforest is
highly sensitive to changes in precipitation patterns and that
reduction in rainfall since 2000 has diminished vegetation greenness
across large parts of Amazonia. Large-scale directional
declines in vegetation greenness may indicate decreases in carbon
uptake and substantial changes in...
Developmental thresholds and thermal unit (degree
day) requirements for eggs, different larval instars,
pupal stage and preoviposition period were determined
for the obliquebanded leafroller (OBLR), Choristoneura
rosaceana (Harris). Separate thresholds and degree day
requirements were determined for males and females, but
differences between the sexes were not significant.
However, there...
Resolving the debate surrounding the nature and controls of seasonal variation in the structure and metabolism of Amazonian rainforests is critical to understanding their response to climate change. In situ studies have observed higher photosynthetic and evapotranspiration rates, increased litterfall and leaf flushing during the Sunlight-rich dry season. Satellite data...
Pigeonpea [Cajanus cajan (L.) Millsp.] seed stored in triple layer Purdue Improved Cowpea Storage (PICS) bags for eight months retained germination and seed integrity significantly better than seed stored in traditional gunny bags. PICS bags prevented major damage caused by bruchids (Callosobruchus maculatus F.), while grain stored in gunny bags...
The MODIS NBAR (M0D43B4) data space is explored in terms of biophysical variables with the objective of formulating a MODIS transformation relevant to global vegetation studies. The basic ideas of transform formulation were borrowed from the development of the TM Tasseled Cap transformation, but with differences in sampling strategy and...
Aniba rosaeodora commonly known as rosewood is a tree species of great socio-economic value in the Amazon because it is harvested for the extraction of its essential oil, which is used in the production of cosmetics. Since rosewood is a wild species included on the Convention on International Trade in...
Accurate estimates of forest aboveground biomass are needed to reduce uncertainties in the terrestrial carbon flux. The Geoscience Laser Altimeter System (GLAS) onboard the Ice, Cloud and land Elevation Satellite is now the first spaceborne lidar sensor that will provide global estimates of vegetation height. This study investigated the utility...
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Warren B. Cohen
Accurate estimates of forest aboveground biomass are needed to reduce
Human activities are causing profound changes to the global environment, yet the potential consequences of these changes on rising atmospheric carbon dioxide and climate change are not well understood. Improving our understanding of these processes requires an enhanced awareness of how global ecosystems are changing and how these changes affect...
The Earth’s surface is experiencing unprecedented change. Humanity’s growing population, expanding land-use footprint, and increasing global emissions of atmospheric greenhouse gases affect a vast number of species on Earth and the functioning of virtually all ecosystems. Given the vital interactions and feedbacks between the Earth’s land surface and climate, measurements...