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ABSTRACT
Rapid changes in vegetation over short distances, high species diversity, and fragmented landscape challenge the implementation of the Forest Service's Forest Inventory and Analysis (FIA) program on Puerto Rico. Applying the hexagonal FIA grid as used on the continental United States,the Forest Service is installing a new forest sampling and monitoring framework that incorporates previous inventory plots and has an expanded scope. However, an adequate description of Puerto Rico's diverse tropical forests requires additional sampling; the solution is to intensify the base systematic sampling grid. Ultimately, this framework can be used to monitor all vegetation and cover types on the island, plus fauna, soils, and air and water quality-in short, to create a comprehensive, long-term natural resources inventory and monitoring network.
Keywords: FIA; international forestry
The Forestry Research Act (McSweeney-McNary) of 1928 required the USDA Forest Service to -make and keep current a comprehensive inventory and analysis of the present and prospective conditions and requirements for the renewable resources of the forest and rangelands of the United States and cooperate with the appropriate officials of each State, territory, or possession of the United States" (Resources Planning Act of 1974, PL 93-378). The Forest Service is therefore responsible for inventorying not only the forests of the continental United States, Alaska, and Hawaii but also the islands of Guam, the Republic of the Marshall Islands, American Samoa, the Commonwealth of the Northern Marianas, the Federated States of Micronesia, Palau, the US Virgin Islands, and Puerto Rico.
Under direction of the Agriculture Research, Extension, and Education Reform Act of 1998, the USDA Forest Service's Forest Inventory and Analysis (FIA) program has developed a nationally standardized sampling scheme and a core set of plot-level inventory and monitoring variables. However, these national protocols do not always lend themselves to work on tropical islands, leading to concerns about the effectiveness and utility of the national sample design and variable sets for these areas (Willits et al. 2000).
The challenges to adapting the FIA program's current methodology to the forests of Puerto Rico are three:
1. Maintaining continuity with previous inventories to capture long-term tree growth information and 20 years of land-use change, and incorporating forest health monitoring (FIA Phase 3) pilot study plots.
2. Expanding inventory scope to...