Treesearch

Although tropical forests account for only a fraction of the planet's terrestrial surface, they exchange more carbon dioxide with the atmosphere than any other biome on Earth, and thus play a disproportionate role in the global climate. In the next 20 years, the tropics will experience unprecedented warming, yet there is exceedingly high uncertainty about their potential responses to this imminent climatic change. Here, we prioritize research approaches given both funding and logistical constraints in order to resolve major uncertainties about how tropical forests function and also to...

To better accomplish their mission of an informed public, environmental education organizations often exchange ideas, share financing, and distribute overhead through collaboration. Yet it remains to be seen whether benefits of these collaborations extend to the public. We examine two possible benefits: the ability of the organizations to act as representatives of the public interest, and equitable access to environmental educational materials. We model patterns of public access to water-related education across organizations using two surveys in metropolitan Phoenix, AZ. This enables the...

Gap phase dynamics are the dominant mode of forest turnover in tropical forests. However, gap processes are infrequently studied at the landscape scale. Airborne lidar data offer detailed information on three-dimensional forest structure, providing a means to characterize fine-scale (1 m) processes in tropical forests over large areas. Lidar-based estimates of forest structure (top down) differ from traditional field measurements (bottom up), and necessitate clear-cut definitions unencumbered by the wisdom of a field observer. We offer a new definition of a forest gap that is driven by...

The high species richness of tropical forests has long been recognized, yet there remains substantial uncertainty regarding the actual number of tropical tree species. Using a pantropical tree inventory database from closed canopy forests, consisting of 657,630 trees belonging to 11,371 species, we use a fitted value of Fishers alpha and an approximate pantropical stem total to estimate the minimum number of tropical forest tree species to fall between ~40,000 and ~53,000, i.e., at the high end of previous estimates. Contrary to common assumption, the Indo-Pacific region was found to be as...

Ecologists are increasingly tackling questions that require significant infrastucture, large experiments, networks of observations, and complex data and computation. Key hypotheses in ecology increasingly require more investment, and larger data sets to be tested than can be collected by a single investigator’s or s group of investigator’s labs, sustained for longer than a typical grant. Largescale projects are expensive, so their scientific return on the investment has to justify the opportunity cost-the science foregone because resources were expended on a large project rather than...

This report contains the results of analyses conducted at the chemistry laboratory of the International Institute of Tropical Forestry in Puerto Rico from 1981 to 2000. The data set includes 109,177 plant analyses and 70,729 soil analyses. We report vegetation chemical data by plant part, species, life zone, soil order, geology, or parent material. Soil data are reported by depth, soil order, geology or parent material, and life zone. These data are summarized to facilitate interpretation and highlight the mean and range of values obtained.

Element uptake from substrate and resorption capacity of nutrients before leaf shedding are frequently species-specific and difficult to determine in natural settings. We sampled populations of Rhizophora mangle (salt-excluding species) and Laguncularia racemosa (salt-secreting species) in a coastal lagoon in the upper section of the Maracaibo strait in western Venezuela to estimate accumulation and resorption of mineral elements. Leaves collected fortnightly during 4 months within the rainy season were stratified as young, adult, old, and senescent. We measured changes in concentration of...

The southernmost presence of Rhizophora mangle in the western Atlantic coast occurs in coastal wetlands between 27 and 28ºS in the State of Santa Catarina, Brazil. We selected mangrove communities at the estuary of Rio Tavares, Florianopolis, and Sonho Beach, Palhosa, for measurement of photosynthetic performance and intrinsic water use efficiency of R. mangle and coexisting individuals of Avicennia schaueriana and Laguncularia racemosa, during the spring season. We used gas exchange techniques and isotopic signatures of C and N to estimate instantaneous water use and carboxylation...

Background: Carbon stocks and fluxes in tropical forests remain large sources of uncertainty in the global carbon budget. Airborne lidar remote sensing is a powerful tool for estimating aboveground biomass, provided that lidar measurements penetrate dense forest vegetation to generate accurate estimates of surface topography and canopy heights. Tropical forest areas with complex topography present a challenge for lidar remote sensing. Results: We compared digital terrain models (DTM) derived from airborne lidar data from a mountainous region of the Atlantic Forest in Brazil to 35 ground...