Research

Research has been the cornerstone of the Institute's program since its inception. Early research focused on reforestation, plantation forestry, tropical species identification, forest inventory methods, endangered species, and carbon sequestration. Currently, the Institute’s research programs are focused on forest ecology, disturbance ecology, ecosystem functions and services, urban ecology, watershed dynamics, migratory species, climate change, and policy science to better understand the effect of natural and human-induced pressures on tropical forests and the landscapes in which they are found. Our research provides key information on forest structure and function, land cover change, and governance to inform the development of sustainable land use practices and policy. Research will continue to focus on the Luquillo Experimental Forest and its Bisley Long-term Ecological Research watersheds, the San Juan Urban Long Term Research Area, the Guánica Biosphere Reserve, various novel secondary forests, and other ecosystems in Puerto Rico; the Estate Thomas Experimental Forest in St. Croix U.S. Virgin Islands; the Brazilian Amazon; and throughout the Western Hemisphere in collaboration with partners in the region.

• Network Science - Collaborative

• Forest Inventory and Analysis

The U.S. Forest Service inventories the forests of the United States and its territories. For Puerto Rico and the U.S. Virgin Islands, the inventory and related research are funded and managed jointly by the Institute and the Southern Research Station’s Forest Inventory and Analysis (FIA) Program. The field crew includes employees of both the Institute and the Southern Research Station, and they conduct the inventory out of the Institute’s Headquarters in Río Piedras, Puerto Rico. The Institute’s Chemistry Laboratory dries, processes, and analyzes all soil and litter samples. Maps of land cover and forest types for the region, which Institute scientists have produced with Landsat satellite imagery, help to refine the FIA forest cover estimates that come from the plot data. These maps also estimate the areas of forest and land-cover types with limited extent, like mangroves, which are not well-represented by the inventory plots given the systematic inventory design. The Institute also contributes to setting priorities for the inventory and its design, and it maintains a species taxonomy database for the inventory.

The goal of the Institute investment in the Caribbean FIA Program is forest ecology research in four main areas: stand dynamics and diversity; land-cover and climate change; methods for remote sensing and mapping of forest attributes; and biogeochemical cycling. Research on stand dynamics and diversity investigates controls on tree species richness and diversity (succession, competition, productivity, dispersal, and functional traits) from stand to landscape scales, and on the structuring of the tree species communities that regrow after large-scale clearing. Remote sensing and mapping research develops and tests approaches for mapping forest attributes through integrating Caribbean Forest Inventory and Analysis Program data with remotely sensed data, particularly multispectral and hyperspectral imagery and lidar, and through modeling of future climate and land-use scenarios. Example forest attributes that the Institute is mapping or modeling in this way include forest structure, growth, phenology and leaf traits, productivity, species composition and diversity, species distributions, nutrient cycling, and other attributes. The Institute also plans to project potential changes in forest attributes, such as the distributions of tree species, forest types, and ecological zones that may occur with climate change. Research considers the influence of current and historical landscape structure, including forest fragmentation, on stand dynamics, structure, wildlife habitat, element cycling, diversity, and species composition. Another goal is to evaluate the combined impacts in these landscapes of land-use and land-cover changes and global climate change in the context of existing protected areas and reserves.

IITF Contact: Eileen Helmer, ehelmer@fs.fed.us

• Luquillo Long Term Ecological Research

The goal of Luquillo Long Term Ecological Research (LTER) (LUQ) is to understand how forest and stream ecosystems, and the services that they support, are changing in Puerto Rico, thereby providing guidance for management of change in the tropics. We focus on understanding the key role of disturbance in determining ecosystem functions, processes, and their services. In the first phases of LUQ (1988–2006), degrees and mechanisms of resistance and resilience were studied, especially after the passage of hurricanes. This background led to more recent work on response to human disturbance and climate change, both likely to cause long-term, directional change in ecosystems and services. The LUQ also identified ecosystem trends over its 23 years of existence (Peters et al. 2012) and synthesized results in several books. Major achievements included leading the establishment of the National Ecological Observatory Network (NEON), Critical Zone Observatory (CZO), Integrative Graduate Education and Research Traineeship (IGERT), and San Juan Urban Long Term Research Areas-Exploratory (ULTRA-Ex) programs in Puerto Rico, thereby creating a broad, strong synergy toward sustainability science in the tropics. Over the years, LUQ has also given a commanding perspective on tropical ecology, resulting in numerous synthetic works. A site-synthesis book (Brokaw et al. 2012), for example, contains chapters whose content ranges from theory to management and reflects the benefit of long-term research toward understanding resistance and resilience of tropical systems in a changing disturbance regime. This research program also contributed to syntheses of LTER Network contributions (Robertson et al. 2011) and long-term trends (Peters et al. 2011).

IITF Contact: Grizelle González, ggonzalez@fs.fed.us

• The National Ecological Observatory

The Institute is a major collaborator of the National Ecological Observatory Network (NEON). NEON has been under development for many years, but recently $434 million in construction funding was provided to the program by the National Science Foundation. NEON will be the first continental ecological research platform and promises to change the way ecological research is accomplished. Data will be collected on biodiversity, disease and pathogens, nutrients, water, pollutants, and greenhouse gases at more than 60 sites spread from Alaska and Hawaii across the United States to Puerto Rico. A very ambitious crow flying to the four corners of the network would cover more than 14,000 miles. The sites in Puerto Rico will be the southern and eastern-most in the network. Unique features of the NEON program are that it will use a single protocol to collect all data sets nationwide, rather than different instruments or protocols from site to site as other research networks have done. The data collected will also be freely available to scientists and the public in near-real time; since no one owns the data, they will be available for everyone. Having vast amounts of baseline data available will allow scientists to design studies that build from that platform, without having the costs and efforts needed to collect baseline data. NEON will also provide the first truly standardized continental network of research sites dedicated to being able to describe and forecast ecological trends at such a large scale.

Puerto Rico was chosen to represent the Atlantic Neotropical domain after the Institute, academic, and other scientists and educators came together to inform NEON on the advantages and opportunities of using the island as an observational site. Guánica Forest will be the core “wildland” site for the Observatory and will anchor a land use gradient that includes the Lajas Agricultural Experiment Station, an urban forest in Ponce, and stream sites near San Germán and Adjuntas. Sampling and instrumentation are planned to remain in Guánica for 30 years and in the other sites for 5–10 years. Installation of equipment is projected to begin in 2012–13. Geotechnical, environmental assessment, and permitting work are already completed or currently underway, as is planning for specific locations for instrument arrays. Local scientists are facilitating permitting, science decisions, and site access for the central NEON staff. More information on the NEON project can be found at www.neonic.org

IITF Contact: Skip Van Bloem, svanbloem@fs.fed.us

• San Juan ULTRA-Ex: Understanding the Socio-Ecology, Sustainability, and Future of the City

The city of San Juan has been selected as part of a national initiative for interdisciplinary scientific research in cities, the Urban Long Term Research Areas-Exploratory (ULTRA-Ex). A collaborative program between the National Science Foundation, the Puerto Rican Conservation Foundation, and the Forest Service, the ULTRA-Ex seeks to address how an increasingly urban landscape affects natural and human communities. With more than half of the world’s population already living in cities, it is crucial that we develop scientific knowledge that contributes to the long-term quality of life and environmental health, or the sustainability, of cities. San Juan ULTRA-Ex scientists seek a holistic understanding of how environmental, social, and economic factors interact in the city of San Juan as a socio-ecological system—the perspective that cities are products of human-nature interactions. This approach will help us understand what aspects of the city are more vulnerable to local and global risks, such as extensive development, climate change, and global economic changes, among others.

With a focus on San Juan’s urban watershed, the Río Piedras River Watershed, we have multiple ongoing projects that address various aspects of the socio-ecology of the urban watershed, including: hydrology; urban forests and biodiversity; soil nutrients; water quality and ecology; riparian restoration; environmental history of the watershed; flooding risks; residents’ perceptions and behavior towards sea-level rise, yard practices, and streams; decision-makers’ perspectives, knowledge, and roles in governing the urban environment; land use and land cover change; and energy use. These projects are linked through a common network of sampling points across the watershed that was selected to meet both social and ecological criteria (Fig. 6).

Our scientists collect both quantitative and qualitative data within the same sampling points and use diverse ecological and social methods, such as vegetation and water quality sampling, questionnaires and interviews (see photo) and modeling approaches. This integrated network allows us also to examine the watershed from various scales including spatial scales (i.e., household and river scale, to community and watershed scale), as well as temporal (i.e., historical, contemporary, and future visions and scenarios). In this process we have had the contribution of numerous graduate and undergraduate students from a diverse set of disciplines.

More than an interdisciplinary scientific effort, San Juan ULTRA-Ex seeks transdisciplinarity where, through the engagement of non-science stakeholders (city managers, communities, NGOs, and other social groups) in different phases of the research process, we hope to provide policy-relevant knowledge to city planners and administrators. We have engaged approximately 32 different organizations and community leaders through various stages of research, including framing problems and questions, providing feedback and critique to products, and participating in mapping workshops to develop land use scenarios. We have also developed the San Juan ULTRA-Ex Web Database and Mapping Portal as a tool to facilitate collaboration among our researchers and partners by making data, documents, events, and other information, accessible. Overall, our objective is to put science at the service of city residents to collectively work toward improving life in our cities. For more information please visit our website –www.sanjuanultra.org – or contact Tischa A. Muñoz-Erickson at sanjuanultra@gmail.com.

IITF Contact: Ariel E. Lugo, alugo@fs.fed.us

• Luquillo Critical Zone Observetory

The “Critical Zone” is defined as the outer layer of the Earth that directly sustains human life. It extends from the lower atmosphere into the underlying bedrock and includes all the physical, chemical and biological processes that shape and transform the Earth’s surface. The Luquillo Critical Zone Observatory (LCZO) is one of six National Science Foundation-supported observatories designed to provide an integrated platform for collaborative studies that will provide the scientific basis for the long-term management of critical zones.

How critical zone processes, water balances, and mass fluxes differ in landscapes with contrasting bedrock lithology but similar climatic and environmental histories is the overarching focus of the LCZO. Our infrastructure, sampling strategy, and data management system are designed to use the natural laboratory of northeastern Puerto Rico as a platform whereby collaborators can quantify and contrast how critical zone processes differ in watersheds underlain by quartzdiorite and volcaniclastic bedrock. The two main study watersheds, the Río Mameyes and the Río Blanco, drain the Luquillo Experimental Forest (Fig. 1, earlier) and have similar climates and environmental histories but differing lithology. The Mameyes watershed is primarily underlain by volcaniclastic bedrock that weathers to produce clay-dominated soils and boulders. The Río Blanco watershed is underlain by quartzdiorite, which weathers into a saprolite composed of sand and large corestones. These differences in weathering patterns have a profound influence on forest composition, landslide frequency, chemical weathering, and the morphology of streams and hillslopes. LCZO research is based around seven broad hypotheses that address the following main questions:

• How are soil carbon, redox, and nutrient cycling coupled and decoupled from lithology, landscape position, and climate?
• How does weathering vary with regolith thickness and landscape position?
• How does lithology influence sediment supply and the residence time and routing of water and solutes across the landscapes?
• How do the morphology, biogeochemistry, and vegetation of riparian zones vary with lithology, climate, and basin size?
• How does basin lithology influence depositional environments and stratigraphic resolution of the coastal and fluvial sediments?

The LCZO is supported by a $4.4 million, 5-year grant from the Earth Science Division of the National Science Foundation. It also receives additional technical and infrastructure support from the U.S. Geological Survey-Water, Energy, and Biogeochemical Budget Program, and the Institute. The principal researchers and students involved in the LCZO are from the University of Pennsylvania, Pennsylvania State University, the University of California at Berkeley, the University of New Hampshire, Brown University, the University of Puerto Rico, the U.S. Geological Survey, and the Institute. The Observatory also provides facilities for collaborators from a host of U.S. and international research institutions and works closely with the Luquillo Long Term Ecological Research Program. In the first 2 years of existence, more than 40 individuals have actively participated in LCZO research.

For additional information, data, and publications, see the LCZO web site http://www.sas.upenn.edu/lczo or contact: Luquillo-CZO@sas.upenn.edu: Luquillo Critical Zone Observatory, Department of Earth and Environmental Science,240 South 33rd Street, Philadelphia, PA 19104-6316, University of Pennsylvania

IITF Contact: Ariel L. Lugo, alugo@fs.fed.us

• Caribbean Landscape Conservation Cooperative

The Institute has been working with a number of other Federal and local agencies to establish a Caribbean Landscape Conservation Cooperative (CLCC), which was initiated this year as part of a national network of 22 landscape conservation cooperatives. Landscape conservation cooperatives are applied conservation science partnerships among State and Federal agencies, regional organizations, tribes, non-governmental organizations, universities and other entities within a geographic area. They are designed to provide science to inform resource management decisions in an integrated fashion across landscapes—at a broader scale than any individual partner’s responsibility. Landscape conservation cooperatives consider landscape-scale stressors including climate change, habitat fragmentation, urban sprawl, invasive species, and water availability in order to assess the conservation status of species and habitats and provide a vision for sustainable landscapes under future scenarios. The Caribbean Landscape Conservation Cooperative includes the Puerto Rican archipelago and the U.S. Virgin Islands (Fig. 7), and recognizes the connectivity of these islands with the greater Caribbean and the continental regions through shared species, habitats, and conservation opportunities and goals. The purpose of the CLCC is to provide a regional context to conduct conservation planning and management at different scales, from decisions on site management to understanding the implications of management actions regionally, nationally and globally. It is a platform for partners to integrate information, perform regional assessments of conservation status, assess future scenarios, and collaborate in applied conservation science. The CLCC mission is providing science and technology for conservation planning and action – addressing the need to restore and sustain natural resources in Caribbean land and seascapes.

Collaborating Institutions: U.S. Fish and Wildlife Service, U.S. Geological Survey, National Oceanic and Atmospheric Administration, and Puerto Rico Department of Natural and Environmental Resources

IITF Contact: William A. Gould, wgould@fs.fed.us





• Research Highlights By Scientists

• Tropical Ecosystem Dynamics
1. Characterization of lichen communities along an elevation gradient in Puerto Rico

While studies of lichens in Puerto Rico have been historically discontinuous, the lichen biota is probably among the best known in the region. Recent work has shown that there are about 1,181 documented lichen species in Puerto Rico, while another effort suggests that there actually could be as many as 1,600 species. This indicates that at least 26 percent of our lichen species is yet to be discovered. Furthermore, since only one work has explored the interaction between lichens and environmental conditions in Puerto Rico, ecological dynamics of lichens in these ecosystems are still mostly unknown. To address these issues, we are carrying out a comprehensive survey of lichen species occurrence and abundance in a series of plots established along an elevation gradient of eight forest types in northeastern Puerto Rico. We expect to see differences in the composition and structure of lichen communities among these forest types with differences in environmental conditions such as precipitation, and temperature as factors explaining most of the variation observed between these communities. While the study is ongoing, we have already developed an extensive collection of photographs showing the diversity of lichens at these forests. Other expected outcomes include a compilation of methods and guidelines for long-term monitoring of forest health using lichens as indicators, and increased interest in the study of lichens of Puerto Rico and their potential use as bioindicators of the environment.

Collaborating Institutions: USFS International Institute of Tropical Forestry - Research and State and Private Forestry, University of Puerto Rico, Río Piedras Campus (Dr. Eugenio Santiago-Valentín)

IITF Contacts: Joel A. Mercado, jmercado@fs.fed.us; and William A. Gould, wgould@fs.fed.us

2. Disturbance ecology in the Bisley Experimental Watersheds

Vegetation dynamics under the canopy. Hurricanes strongly influence short-term patterns of plant community structure, composition, and abundance, and are a major contributor to the maintenance of plant diversity in many forests. Previous research in the Bisley Experimental Watersheds had focused on the immediate and long-term effects of hurricane disturbance on tree species composition, number of species, and diversity, while far less attention has been given to other types of vegetation that dominate under the canopy. Yet the non-tree understory community is where the majority of plant species reside. With measurements from a unique 20-year dataset, the response and recovery of forest herbs, shrubs, and vines were tracked through multiple storms, hurricanes, and droughts. Changes in number of species, ground cover, biomass, and diversity of the non-tree community were analyzed following Hurricane Hugo (1989) and Hurricane Georges (1998) in a mature secondary subtropical wet forest of the Bisley Experimental Watersheds. Our results demonstrate that hurricanes caused an immediate, but transient, increase in overall number of species, ground cover, and diversity. Over the 20-year study period, the non-tree community exhibited pronounced and persistent changes in composition, including a dramatic increase in abundance and number of fern and vine species and a decrease in forbs and shrubs. In the 2010 census, the understory composition and relative abundance of understory vegetation was significantly altered from previous censuses, as proportions of shrubs, herbs, ferns, and vines had drastically changed. Currently, the ferns and vines combined are 75 and 90 percent of total understory ground cover and biomass, respectively (compared to 35 to 45 percent 20 years ago ). These results for the non-tree community contrast sharply with previous studies from the Bisley Experimental Watersheds that considered the same study period and area, but found that hurricanes rarely altered dominant tree species composition over the long-term. These results suggest that the role of hurricane disturbance in structuring plant diversity may be even more important than previously thought, particularly as the non-tree community contains most of the vascular plant species in tropical forests.

Collaborating Institutions: Northern Research Station; University of Pennsylvania

Leaf litter dynamics in headwater streams. Leaf litter that falls from the forest into streams is broken down into smaller particles. This broken-down leaf litter is then transported downstream in varying amounts and with different nutrient composition, to be consumed by native aquatic fauna. Leaf litter in streams is also known as coarse particulate organic matter (CPOM), and it is the basic energy source of forested headwater streams. Analysis of 18 years of data from the Bisley Experimental Watersheds showed there were various annual peaks in the quantity of CPOM exported instead of the single annual export pulse observed in temperate deciduous systems. The variation in the quantity and quality of exported material depended on traits of particular events (storms, hurricanes), season, and the successional status of forests. The quality (chemical composition) of exports varies temporally, with proportion of carbon to nitrogen (low quality for consumers) being highest in the driest months and lowest (high quality for consumers)during rainy months. These results signal that more attention should be given to changes in precipitation seasonality in the tropics. Changes in rainfall patterns could not only affect the timing of new leaf and flower production and stream discharge, but also increase the seasonal range in quality of organic matter exports to reach streams. Changes in the quality of organic matter resources in streams can potentially alter ecosystem processes and aquatic food webs.

In terms of quantity, median daily exports were similar before and after hurricane Hugo (September 18, 1989). However, after 16 years of forest succession following this hurricane, the moderate and high stream flows still exported less CPOM than what was exported in the 2 years prior to the hurricane. Median daily amounts of CPOM export had been observed to occur following hurricanes, but it seems that several decades are required for high storm flow exports to return to pre-disturbance conditions. Thus, the state of development of vegetation in the watershed limits how much material can be exported during a storm independently of the steepness of hillsides or amount of stream runoff. The synergy between hurricane intensity and frequency and level of vegetation maturity defines the long-term pattern of high CPOM exports in these watersheds. Forested headwaters continuously provide leaf litter and retention structures such as fallen logs and branches, and these can create and maintain pools along with natural litter traps that facilitate processing of organic matter in headwaters. Our observations in these forested watersheds have shown that most of the leaf litter that reaches these streams is processed in place and only very small amounts (0.024 percent) are exported. However, headwaters under non-forested land cover conditions may not be able to retain and process large percentages of leaf litter inputs, and this in turn can affect water quality and resource availability for aquatic ecosystems downstream.

IITF Contact: Tamara Heartsill Scalley, theartsill@fs.fed.us

3. Long-term forest dynamics in the Caribbean: assessment of long-term forest dynamics in the Caribbean

Recent discussions during regional Caribbean foresters meetings highlighted a need for a regional workshop to synthesize results on regional forest dynamics from individual studies in permanent forest plots across the Caribbean. The main question to be addressed by the workshop is the detection of change in forest stands as a result of environmental change, particularly hurricane effects and climate change. Specific targets of inquiry are changes in: (1) stem or biomass turnover, (2) tree growth rates, (3) structural attributes, and (4) species composition. Our challenge is to have all collaborators at the same starting point before the workshop. From our initial contacts, the conditions of permanent-plot data sets in the region vary substantially, from data in file cabinets to data sets with metadata in database programs, and thus our pre-workshop work has begun. The range of permanent plot descriptions, based on the participants’ metadata provided, will be our first available product. The next steps in pre-workshop activities are the development of a Webpage and initial permanent plot site description products for sharing among the group. We expect to host a workshop aimed at synthesizing data in mid 2013.

Collaborating Institutions: The Puerto Rico Conservation Foundation http://www.caribbeanforesters.org/, and others

Contact: Tamara Heartsill Scalley, theartsill@fs.fed.us

4. Forest dynamics

Three studies were carried out in the Luquillo Experimental Forest to explore forest structural and species site relationships. The first used plots on ridge, slope, and ravine topography within the lower montane rain forest of the Espíritu Santo and Mameyes watersheds between 350 and 570 meters elevation (Weaver 2010a). Canopy height in the upper Espíritu Santo watershed (leeward of the El Yunque to Mt. Britton ridge) was greater than in the Mameyes watershed (windward of the ridge); moreover, canopy height tended to decline from ridge to slope to ravine topography for sampling sites in both watersheds. Within both watersheds, total aboveground biomass was greater on ridges than in ravines, and stem density decreased from ridges and slopes to ravines. Prestoea montana (R. Grah.) Nichols and Dacryodes excelsa Vahl accounted for about 30 percent of the 1,400 stems and 69 species that were tallied. Correspondence analysis showed that species abundances for 37 species with = 6 occurrences (94 percent of all stems), varied by watershed and topographic position. Moreover, the Mameyes plots contained some tree species associated with forest types at higher elevation. Hurricanes affect the Luquillo Experimental Forest with sufficient frequency to maintain all forest types in various stages of recovery. Forest composition at any site is a function of environmental gradients, major climatic events, and tree species attributes.

The second study was in elfin forest at the summits of the Luquillo Experimental Forest above 880 meters in elevation, where tree cover was explored by aspect and topographic positions (Weaver 2010b). Mean stem density for all topographic positions decreased from ridge to ravine, whereas the opposite was true for canopy height . Biomass was greater on ridges and slopes than in ravines, regardless of aspect. Tabebuia rigida Urban was the most abundant species, accounting for 23 percent of the 3,620 stems encountered. Eugenia borinquensis was the best distributed, occurring on 90 percent of the plots. One-half of the 42 recorded species accounted for less than 2 percent of all stems. Climatic, edaphic, and physiological factors account for elfin forest, which is adapted to survive under rigorous environmental conditions. Elfin forest provides numerous benefits, including critical habitat for many endemic flora and fauna, valuable water supplies, panoramic vistas, and recreational opportunities.

The last study was in the El Toro Wilderness, which was designated by Congress in 2005. El Toro occupies 36 percent of the Luquillo Experimental Forest and is the only tropical wilderness managed by the U.S. Department of Agriculture. The wilderness extends from 370 to 1074 meters in elevation and is occupied by four forest types that are characteristic of mountainous Caribbean islands: lower montane rain forest, montane rain forest, palm brake, and elfin forest (Weaver 2011). The Luquillo Experimental Forest contains: 225 tree species with 45 endemic to Puerto Rico and several to the Luquillo Experimental Forest alone; 150 species of ferns, 79 species of orchids, 11 native bats, 100 birds, 19 native reptiles, 14 native amphibians, and 6 fish species. Most of these species are also present within the wilderness. The Luquillo Experimental Forest is surrounded by a dense human population and is under multipurpose management. Future activities in El Toro will involve the demarcation of wilderness boundaries, determination of wildlife habitats, and long-term monitoring. El Toro provides visitors with solitude, an uncommon resource elsewhere on the island.

IITF Contact: Peter L. Weaver, pweaver@fs.fed.us

5. Dry forest research in southwestern Puerto Rico

Recent research in Guánica Forest and the surrounding area has focused on determining how native species respond to wildfires and on techniques that can be used to help re-establish native species in degraded areas. In their native state, Puerto Rican dry forests do not have natural ignition sources and appropriate ground-level fuel structure to carry wildfires across the landscape. However, the island’s agriculture history has resulted in the introduction of a vast number of pasture-grass species that provide excellent fuel for fires in the dry season. This fuel, combined with careless or malicious human activities that provide sparks, results in wildfires that threaten native tree species. Our research has shown experimentally that peak fire temperatures from 150 to 300°C will kill a majority of saplings. Lower temperatures (i.e., lower than 150°C) kill saplings when fires occur in the afternoon, presumably because the morning dew has evaporated by then and does not absorb the heat from a wildfire. In areas where we did controlled burns, about 75 percent of the saplings incurred temperatures above 300°C. In experimental plots where we planted native saplings, fires from controlled burns killed about 65 percent of the saplings (representing 13 native species and Leucaena leucocephala, an introduced species) and subsequent summer drought killed additional saplings, resulting in total mortality of 96 percent. Of the 13 native species that we planted, Bursera simaruba (almácigo or turpentine tree) and Erythoxylon areolatum (indio) had the best combination of growth and survival after fires. The conclusion is that reforestation projects that attempt to re-establish trees in grass-dominated locations either need to prevent fire or reduce grass cover, both requirements can be costly or labor-intensive.

One species that had acceptable post-fire survival and growth rates was Leucaena leucocephala, a species brought to Puerto Rico more than 200 years ago. We planted saplings of native species using Leucaena as a “nurse tree” and prevented the occurrence of fire. Survival of native saplings under Leucaena was not different than when planted in open areas, but growth of saplings under Leucaena was 50 percent higher. Thus, Leucaena did show a nurse tree effect. Previous work had established that Leucaena canopies suppressed grass biomass and density, and protected native saplings planted in Leucaena stands by reducing fire effects (Santiago et al. 2008). Because of the time and expense required to control grass and fire, it may be a better strategy to establish a more fire-resilient forest dominated by Leucaena and then underplant native species once canopy cover is established.

IITF Contact: Skip Van Bloem, svanbloem@fs.fed.us

6. Caribbean vegetation mapping: Tropical forest associations and land cover for Trinidad and Tobago mapped from multiseason, multidecade, gap-filled Landsat.

Drawing upon field plots labeled as to forest assemblage, field data collected by foresters from the Trinidad and Tobago Forestry Division, and unique historical work by J.S. Beard (1944, 1946), investigators teamed up to produce the most detailed maps of wetlands, forest types, and land cover that have ever been available for conservation and management in Trinidad and Tobago (Figs. 8 and 9). Unlike most previous work, in which tropical forests were mapped only to physiognomic class (e.g., evergreen, deciduous, montane, etc.), the Institute and collaborators have shown for the first time that old tropical forests can be mapped to the level of species assemblage with gap-filled Landsat imagery. In gap-filled imagery, image gaps from clouds or scan-line failure are filled with imagery taken on various dates.

Earlier maps of Trinidad and Tobago show forest types for public lands only. No previous maps detailed forest types and land cover. The team learned that many forest associations are identifiable in the multiseason, fine resolution view of forest canopies that is viewable on Google Earth. Decision tree classification models of forest habitats were 59 to 99 percent accurate for individual classes, based on a randomly-selected 10 percent of reference pixels. Accuracy improved when ~20-year-old gap-filled images representing late dry season phenology, including drought phenology, supplemented recent gap-filled imagery from the early dry season. The synthetic multiseason imagery that they produced from these old dry-season images significantly improved model predictions by 14 to 21 percent for deciduous, 7 to 36 percent for semi-evergreen, and 3 to 11 percent for seasonal evergreen associations; and by 5 to 6 percent for secondary forest. The team also established that Tobago’s “xerophytic rain forest” is associated with ultramaphic geology. Like the State Forests of Susúa and Maricao in Puerto Rico, which also have ultramaphic geology and serpentine substrates, this forest type exhibits more xerophytic features, including more sclerophyllous leaves than other forests with just as much rainfall.

In addition to digital data for land cover and forest type, the project designed and printed 45 cartographic products for Trinidad and Tobago, including island-wide maps as well as 41 maps at 1:25,000-scale that correspond to the topographic maps for the country. These maps show and label land cover and forest type, roads, rivers, towns, topography, forest and wildlife reserves, and management boundaries. The GIS data for roads and topographic contours required considerable development work. The project also included a month of hands-on training in remote sensing and GIS for two staff members from the Trinidad and Tobago Forestry Division.

Collaborating Institutions: Colorado State University, Trinidad and Tobago Forestry Division, and Fanning Software Consulting

IITF Contact: Eileen Helmer, ehelmer@fs.fed.us

• Global Change
• Biodiversity
• 1. Avian diversity among agroscapes in Nicaragua’s northern highlands.

Nicaragua’s highland forests are threatened by continual wood extraction and encroaching agriculture. Nicaraguan students and I used fixed-width point counts to characterize bird assemblages in agro forestry systems under five land uses. Overall species richness and abundance were higher in coffee plantations and forest fallows, whereas disturbance-sensitive species were more abundant in secondary and riparian forest (Fig. 10). Species and foraging guilds characteristic of closed-canopy forest were found in coffee plantations, but only at points near forest remnants. To conserve and manage agroscapes as well as natural habitat, land stewards should maintain woodland strips and hedgerows bordering streams, remnant forest tracts and an arboreal component, including over- and understory, within the landscape matrix.

IITF Contact: Wayne Arendt, warendt@fs.fed.us

• 2. New species and notes on distributions of Nicaragua’s avifauna.

Nicaragua’s avifauna may be the least understood in Mesoamerica because the ecology, life history, and distribution of most species remain little known. However, in the plast decade local and international biologists have made several important contributions to Nicaraguan bird distribution, including more than 90 new species recorded and noteworthy range extensions for the country. We recently reported (Sandoval and Arendt 2011) the first records of striated heron (Butorides striata) and brown-capped tyrannulet (Ornithion brunneicapillus) from Nicaragua and range extensions and abundance of 29 additional species in the Atlantic Region and the Paso del Istmo Biological Corridor.

IITF Contact: Wayne Arendt, warendt@fs.fed.us

• Laying patterns of the pearly-eyed thrasher in the Luquillo Experimental Forest.

Temporal aspects of egg deposition are important factors governing avian reproductive success. I documented hourly egg-laying patterns of the pearly-eyed thrasher (1979 to 2000). The first eggs laid each day were in the early morning (median 06:42 a.m.) and almost half of the eggs were laid by 7:23 a.m. Many times, however, the last two eggs of a clutch were laid later in the morning and some not until mid afternoon (2:29 p.m.), thus extending egg laying to 8 hours. Delayed laying of the last eggs in a clutch may be an adaptive strategy triggering brood reduction to ensure survival of older and more robust siblings during periods of physiological stress and food shortages. A delay in the hatching of younger siblings, even by just a few hours, results in a growth and development advantage of older nestlings. Consequently, their survivability is increased over that of the younger, under-developed, and less fit siblings when resources are scant (Arendt 2011).

IITF Contact: Wayne Arendt, warendt@fs.fed.us

• Collapse of a winter resident bird community in the Guánica Dry Forest.

Most North American migrants spend the non-breeding season in Mexico, the Caribbean, and Central America. The declines in migrant-bird population may first become apparent on the wintering grounds, where they occur in high concentrations. Collaborators and I documented an approximately 40-year decrease in both abundance and diversity of winter-resident birds, with a precipitous decline recorded during the past decade. Constant-effort mist-netting captures only about one-third as many birds as it did 20 years ago. Statistical modeling confirms a population decline and predicts local extirpation by 2033. Species richness estimates also decreased during our study, with average species richness estimated at 12.3 species during 1991 to 2001, but only 7.6 species during 2007 to 2011 (Fig. 11).

Populations of the three most common species that historically constituted 75 percent of winter resident captures are declining dramatically (Fig. 12). Black-and-white warbler (Mniotilta varia) declined from more than 250 birds in 1991 to fewer than 50 birds for the past 4 years. American redstart (Setophaga ruticilla) averaged 150 to 200 birds during 1990 to 2004, but since 2005 has been fewer than100 birds; and ovenbird (Seiurus aurocapilla) also declined. It is critical that we accelerate on-the-ground conservation for migrant as well as resident birds and support research that attempts to understand these declines.

Collaborating Institution: University of Missouri

IITF Contact: Wayne Arendt, warendt@fs.fed.us

• Avian studies and research opportunities in the Luquillo Experimental Forest.

In commemoration of 100 years of avian research in U.S. Forest Service experimental forests, a special symposium was held at the American Ornithologists Union meeting in Philadelphia, PA, in August 2009. As a result of this symposium, participants were invited to submit manuscripts reviewing avian studies from their respective experimental forests to be considered for publication in a special section on avian studies in Forest Ecology and Management. As a result of this invitation, Joe Wunderle and Wayne Arendt submitted a manuscript reviewing avian studies from the Luquillo Experimental Forest (LEF), which was recently published (Wunderle and Arendt 2011). In their review, Wunderle and Arendt emphasized avian studies with management implications and noted opportunities for future studies, especially those that would help managers respond to local and global changes, which may affect the forest’s ecosystems and avifauna.

As one of the most active ecological research sites in the Neotropics, the Luquillo Experimental Forest has a rich history of ecological studies on which to base future avian studies. As is typical of an island ecosystem, the Luquillo Experimental Forest has low avian species richness, as represented by only 23 bird species that breed in the forest and another 76 species, mostly migrants, that are known to occur. The role of birds in the food web of the lower elevation tabonuco forest has been especially well-studied as part of a larger investigation of the rainforest’s food web. The forest is noted for its remarkably high densities of Anolis lizards and Eleutherodactylus frogs, which may depress insect and spider densities, thereby contributing to the forest’s low species richness and densities of most insectivorous birds. The endangered Puerto Rican parrot has become the symbol of the forest, in part, because it has been the focus of intensive long-term research and management efforts, which have stimulated research on other associated species. The spin-off studies from the parrot recovery effort are many, including long-term studies of the pearly-eyed thrasher and botfly parasitism. Given the high frequency of hurricane disturbance to the Luquillo Experimental Forest and studies providing a baseline for comparisons, research has provided substantial contributions to an understanding of hurricane effects on forest ecosystems including bird populations and their resources. Censuses conducted over a 20- to 30-year period have documented disturbing population declines in sharp-shinned and broad-winged hawks and the elfin-woods warbler in the forest. These and other studies are summarized in Wunderle and Arendt’s (2011) review of more than 150 publications pertaining to avian studies from the Luquillo Experimental Forest, which will be a useful reference for others interested in conducting research at this site.

IITF Contact: Joseph M. Wunderle, Jr., jwunderlejr@fs.fed.us

• Winter ecology of the endangered Kirtland’s warbler.

Field work on the winter ecology of the endangered Kirtland’s warbler and its habitat continued for the ninth winter (November 2010 to May 2011) on the island of Eleuthera, The Bahamas. The Kirtland’s warbler ranks as one of North America’s rarest songbirds and has been the focus of an intensive state and federal recovery effort on its North American breeding grounds. Yet despite these efforts little was known of the nonbreeding biology of the species and its habitat requirements and potential conservation needs on its wintering grounds in the Bahamas. At the request of the Kirtland’s Warbler Recovery Team, the Institute wildlife program has focused much of its research on the winter ecology of this species. This work currently focuses on: (1) elucidating factors controlling the occurrence of Kirtland’s warbler habitat on the island of Eleuthera, The Bahamas, and (2) examining effective means of creating, enhancing, or managing Kirtland’s warbler habitat in disturbed areas.

Research findings to date indicate that Kirtland’s warblers require early successional habitats, derived mostly from anthropogenic disturbance, and therefore habitat disturbance is required to produce winter habitat for the warbler. Thus the challenge for wintering grounds conservation is the need to work with private landowners (given limited public lands) and the requirement for re-occurring habitat disturbance to produce Kirtland’s warbler habitat. To addresses these challenges the research program now focuses on answering the question: How can we tweak re-occurring habitat disturbances for the benefit of the Kirtland’s warbler in a cost-effective manner on private lands? Re-occurring disturbances are typical of areas where brush is controlled for the maintenance of utility corridors, boundary lines, fire breaks, and rights-of-ways, and these areas are also known to provide habitat for the Kirtland’s warbler. Therefore, the research goal is to devise management strategies that allow maintenance of Kirtland’s warbler fruit plants in these managed sites without compromising the original management objectives of the landowner.

Collaborating Institutions: The Nature Conservancy-Michigan and Bahamas programs, Bahamas National Trust, Southern Forest Research Station (Athens, GA), and Forest Products Laboratory (Madison, WI)

Contact: Joseph M. Wunderle, Jr., jwunderlejr@fs.fed.us

• Changing Climate
• Tropical forest carbon balance in a warmer world.

Tropical forests are likely to experience a significant and permanent increase in temperature over the next 2 decades. Given the importance of tropical forests to the global carbon budget, understanding the potential for these forests to adapt to an unprecedented temperature regime is critical to our ability to accurately predict feedbacks to future climate. In response to a recognized need to understand the tropical forest response to increased temperatures, the International Institute of Tropical Forestry is leading a collaborative effort to develop a whole-forest warming experiment in Puerto Rico. This experiment will enable us to determine the resilience and adaptability of tropical forests to increasing temperatures and will provide valuable insight into mechanisms controlling the uptake and storage of carbon in these systems.

In October 2010, the Institute hosted a 3-day workshop that involved 10 scientists from university and government institutions to discuss the development of a whole-forest warming experiment in Puerto Rico. This collaborative effort led to the production of an expansive literature review of the response of tropical forests to increased temperature (currently in review for publication in Biological Reviews). The institute’s scientists and collaborators also led an organized oral session at the 96th annual Ecological Society of America Meeting in Austin, TX, USA, August 2011, titled “From Leaf to Biosphere: The Effects of a Warming Climate on Tropical Rain Forests.” This session was one of just three selected to develop a meeting report for publication in the journal New Phytologist.

The U.S. Forest Service awarded the Institute funds to begin development of a full-scale prototype for the warming experiment. Equipment to begin production of the prototype is ordered and we anticipate construction will begin in 2012. This will be the first tropical forest warming experiment and the first experiment to warm at the whole-forest-scale for any forested ecosystem.

Collaborating Institutions: University of California-Berkeley; Michigan Technological University; U.S. Geological Survey, UT; Lawrence Berkeley National Laboratory; USDA-Agricultural Research Service, AZ; Environmental Improvement Systems Inc., PR; Brookhaven National Laboratory, NY; Oak Ridge National Laboratory, TN; California State University-San Marcos; University of Puerto Rico; and The Puerto Rico Conservation Foundation

Contacts: Tana Wood, tana@berkeley.edu and Ariel E. Lugo, alugo@fs.fed.us

• Assessing the carbon balance of a non-native forest stand in the karst region of Puerto Rico.

In the face of a rapidly changing world, understanding the functional role of non-native species is critical to the development of effective forest management strategies. We are investigating the net carbon balance of a forest stand dominated by the introduced species, Castilla elastica. As part of this assessment, we installed an automated soil respiration system in February 2011, to evaluate soil respiration with high temporal resolution. This research builds on the master’s research of Jessica Fonseca Da Silva and the work of high school students during the Puerto Rico Math and Science Partnership program of the National Science Foundation. The results of the combined research program established a baseline of forest structure and carbon dynamics in replicated long-term plots. Studies are conducted at the privately owned El Tallonal Reserve, where two canopy towers and climate stations are available for the carbon balance research. Results from this study will provide information on net soil carbon loss from this forest with high temporal resolution.

Collaborating Institutions: University of California-Berkeley; Citizens for the Karst; The Puerto Rico Conservation Foundation; and University of Puerto Rico-Río Piedras

Contacts: Tana Wood, tana@berkeley.edu and Ariel E. Lugo, alugo@fs.fed.us

• Preserving the nighttime environment for future generations in Puerto Rico.

Preserving dark skies and the nighttime environment has recently become a focus of researchers studying the effects of light pollution in Puerto Rico. In Puerto Rico, which spends an estimated $3,700 million annually on electricity for its 3.7 million residents, artificial illumination is the main cause of light pollution. Light pollution not only makes it more difficult to see the stars, but it also adversely affects sensitive nocturnal species and increases energy costs and carbon emissions. Expansion of the San Juan Metro Area and other urban corridors is encroaching on upland and protected areas, causing a marked decrease in night sky quality. Currently, scientists from the Institute are monitoring artificial light pollution in Puerto Rico by customizing nighttime remote sensing imagery and map products for local use and directly monitoring nighttime lightscape conditions in the field for research, policy, and mitigation. On the periphery of the El Yunque National Forest, the only tropical rainforest in the National Forest System, light pollution is obvious at uphill locations. Numerous community outreach presentations have been offered to educate children and adults about ecological and astronomical effects of light pollution in Puerto Rico, especially in the vicinity of the El Yunque National Forest. Light pollution also greatly diminishes the visibility of the island’s three main bioluminescent water bodies where high concentrations of bioluminescent microorganisms make the bays glow. Since 2006, the Forest Service has worked with the Conservation Trust of Puerto Rico Light Pollution Task Force to implement a light pollution management strategic plan for the Bioluminescent Lagoon Demonstration Project at Las Cabezas de San Juan Nature Reserve in Fajardo, Puerto Rico. The task force and management plan aim to safeguard the resources in the Reserve and to protect local economic revenues derived from tourists visiting these globally unique locations.

Collaborating Institutions: Conservation Trust of Puerto Rico, Sociedad de Radioastronomía del Caribe, and University of Puerto Rico-Humacao

IITF Contact: Olga M. Ramos González, oramos@fs.fed.us

• Effects of experimental warming and snow manipulation in Alaskan tundra.

Increases in global air temperatures are predicted to increase vascular plant productivity in the Arctic through temperature effects on key ecosystem processes such as soil microbial respiration, organic matter decomposition, and nutrient availability. However, little is known about the effect that increasing precipitation or the interaction of warming and precipitation may have on tundra ecosystems. We established a long-term experimental study to shed more light on these interactions (Mercado Díaz 2011). The study involved manipulating snow depths and warming plots of tundra vegetation, and comparing growth and composition of vegetation with control plots. Two common Alaskan Arctic ecosystem types were manipulated, dry heath and moist-acidic tussock tundra. These sites have been exposed to warming and snow manipulations since 1994 and responses have been measured periodically. Changes in snow regimes had the largest effects on vegetation. Most common changes associated with increasing snow depths included increases in canopy height and shrub abundance and decreases in species diversity and lichen cover. Increases in air temperature had few measurable effects on vegetation; however, differences between control and warmed plots were more noticeable over time in terms of the abundance of shrubs at the moist site. Responses of vegetation in terms of canopy height and total vegetation cover varied over time within and between ecosystem types, suggesting diverging long-term responses of ecosystems within this tundra region to climate change (Figs. 15 and 16).

Collaborating Institutions: University of Puerto Rico, The Puerto Rico Conservation Foundation, and Florida International University

IITF Contacts: William A. Gould, wgould@fs.fed.us; and Joel A. Mercado, jmercado@fs.fed.us

• Biodiversity Assessment and Conservation
• Mapping protected natural areas of Puerto Rico.

Conservation of natural resources is a balance of protection, managed use, restoration, and sustainable development. Effective planning and management of protected areas for biodiversity conservation integrates local, regional, and global concerns with scientific research assessing the extent and status of protected areas. We have developed a map that portrays 115 terrestrial and marine protected areas—public and private lands designated for biodiversity conservation—in Puerto Rico (Gould et al. 2011). The commonwealth of Puerto Rico owns and manages the greatest area of protected lands (58 percent), followed by the Federal government (28 percent) and non-governmental organizations or other private entities (14 percent). Eight percent of the island has some degree of legal protection for conservation, while nearly 92 percent of the island has no biodiversity protection. Protected areas are concentrated on the high peaks of the Central and Luquillo Mountains, the wetlands of the coastal plains, and the lesser islands and cays of the Puerto Rican Archipelago. These areas are relatively well-protected. Under-protected areas include non-wetlands of the coastal plain, the karst limestone hills in northwestern Puerto Rico, and the coastal hills and lower slopes—which form an important hydrological and ecological link between the upper mountains, the coastal wetlands, and the near shore marine areas. The map we developed is a product of the Puerto Rico Gap Analysis Project, supported by the Institute and the United States Geological Survey National Gap Analysis Program. The information was primarily gathered through interviews with protected area management officials and through literature review. The map is part of the Forest Service Research Map (RMAP) series recently developed at the Institute.

Collaborating Institutions: University of Puerto Rico, The Conservation Trust of Puerto Rico, The Puerto Rico Department of Natural and Environmental Resources, and The USGS National Gap Analysis Program

IITF Contact: William A. Gould, wgould@fs.fed.us

• Integrated Gap Analysis Project—modeling and mapping sea turtle distributions.

The Integrated Gap Analysis Project for Puerto Rico and the U.S. Virgin Islands is evaluating the conservation status of 237 animal species and habitats in order to identify “gaps” in conservation. Sea turtles, including the hawksbill (Eretmochelys imbricata), green (Chelonia mydas), and leatherback (Dermochelys coriacea), were prioritized in this analysis because of their endangered or critically endangered status (IUCN 2010) and essential ecological role in marine ecosystems. We developed a comprehensive set of databases including natural history information, local species distribution, potential habitat identification, and conservation status of sea turtles in the region. We have developed habitat suitability models and mapped predicted distributions for different turtle activities and parts of the life cycle, such as nesting and feeding activities, and juvenile or adult distributions (Fig. 18).

Collaborating Institutions: U.S. Geological Survey, and Puerto Rico Department of Natural and Environmental Resources

IITF Contact: William A. Gould, wgould@fs.fed.us

• Working Lands
• Advancing tropical forest management through governmental and non-governmental forest policies.

Tropical forests are increasingly valued for the goods and services that they provide at local to global levels, yet they continue to be degraded and lost at alarming rates. Governmental forest regulation and non-governmental forest certification are policy approaches used throughout the tropics to promote and advance forest sustainability, but they are often criticized for failing to curtail continuing rates of tropical forest degradation and loss. Regulation generally encompasses guidelines, rules, and/or restrictions on forest use and extraction. Certification is a fairly new, non-governmental market-driven policy tool that aims to promote sound forest management through market-based incentives. With collaborator Fred Cubbage, I analyzed the effectiveness of governmental forest regulation and non-governmental forest certification in Costa Rica, Guatemala, and Nicaragua. We found that sufficient human, financial, and technical resources and capacity are fundamental for adequate implementation of both policy approaches, but in most tropical settings, resources and capacity are often substantially limited, particularly for governmental forest regulation. The findings also show that innovative arrangements for promoting, verifying, and enforcing regulatory compliance can compensate for limited governmental resources and processes. In particular, forest sustainability was enhanced where combinations of policy tools and actors beyond the traditional command-and-control approach were used to promote forest sustainability, including economic incentives for sustainable forest management, technical assistance for forest owners and managers, development and participation of private-sector forest ‘stewards,’ and support for sustainable forest management from nongovernmental organizations. The results also shed light on the mitigating effects of local-level inducements and constraints to governmental and non-governmental forest policy adoption and compliance, such as forest size and composition, management resources and capacity, and attitudes toward forest policy and implementers. Overall, the research and its results help policy- and decision-makers as well as forest owners and users by identifying key factors to consider in developing and implementing policies to promote sustainable forest management in the tropics.

Collaborating Institution: North Carolina State University

IITF Contact: Kathleen McGinley, kmcginley@fs.fed.us

• Integrating research, education, and traditional knowledge in ecology: a case study of biocomplexity in Arctic ecosystems.

Integrating research and education is a fundamental goal of institutions and agencies supporting science because of the benefits to society of a more informed population. The value of engaging public interest in ecological research is to maintain support for and integrate science in solutions to environmental problems. For environmental scientists there can be some costs to developing programs that address broader impacts. For example, while there is a call for environmental scientists to broaden their activities to engage in outreach (i.e., have broader impact), there are few venues or incentives to report on these activities in ways that would enhance an environmental scientist’s research career. Publishing examples of successful integration in environmental research journals can help researchers and institutions evolve better mechanisms to achieve goals beneficial to society, including improved public understanding of science, greater diversity of research and stakeholders, and better application of current scientifically based information to managing environmental issues. In that spirit, we present as an example an effort that integrates an interdisciplinary research project investigating the interactions of climate, vegetation, and permafrost in the study Biocomplexity of Arctic Tundra Ecosystems with a university field course, Arctic Field Ecology, and with indigenous Inuit students and elders (Gould et al. 2010). The integration allowed university students and native community members to participate with the research team, drawn by the opportunity to gain education and experience. This participation has had synergistic benefits with the research agenda and diversified the pool of stakeholders involved in the research.

Collaborating Institutions: Kitikmeot Inuit Association, University of Alaska-Fairbanks

IITF Contacts: William A. Gould, wgould@fs.fed.us; and Grizelle González, ggonzalez@fs.fed.us

• Sustainable management of big-leaf mahogany in the Brazilian Amazon.

Big-leaf mahogany is by far the most valuable timber species in seasonally dry forests across the southern rim of the Amazon Basin, but much of it is unsustainably managed. Our research supports sustainable management through better understanding of mahogany life history and population dynamics in natural forests. Local economies and livelihoods will benefit from forest industries invested in active management of long-term timber production from standing forests.

The Mahogany Project seeks to understand what makes big-leaf mahogany ‘tick’ in natural forests across southern Brazilian Amazonia by monitoring vital rates for all stages of its life cycle, from seeds to senescent adults, across temporal and spatial scales relevant to each life phase. With steady support from the IITF since 1995, the Mahogany Project has addressed a long list of basic and applied research questions, as demonstrated by more than 30 mahogany-related scientific articles and book chapters published to date. Project researchers have contributed directly to Brazilian national forest policy through participation in working groups and seminars to revise and improve industry harvest practices. Based on 16 years (1995 to 2010) of annual censuses of more than 600 trees and many thousands of seedlings and saplings scattered across nearly 5,000 hectares of forest, project researchers have developed demographic models that simulate both short- and long-term population responses to forest management practices such as minimum diameter felling limits, commercial tree retention rates, and vine cutting. One of these, the Big-Leaf Mahogany Growth and Yield Model, is a highly interactive and user-friendly computer application that can be operated on-line at www.swietking.org or downloaded with complete instructions for use on office or home computers. The model can be run based on pre-installed example populations from project sites in southeast and southwest Amazonia, or forest managers can upload data from actual management sites. Transforming unsustainable harvest practices into sustainable management systems through better understanding of mahogany life history and population dynamics in natural forests will benefit local economies and livelihoods as forest industries invest in long-term timber production from standing forests under active management.

Collaborating Institutions: ISCIENCES, Middlebury College, HJ Andrews Experimental Forest, Oregon State University, Instituto Floresta Tropical–IFT (Brazil), ESALQ / Universidade de São Paulo (Brazil)

Contact: James Grogan, Instituto Floresta Tropical–IFT, Brazil, and Yale University School of Forestry and Environmental Studies, Connecticut. jgrogan@swietking.org.




• Silvics of Tropical Forest Trees

• Scientists' Biosketches