Evaluating the compatibility of American and Mexican national forest inventory dataThis article is part of a larger document. View the larger document here.
The international border region between the United States and Mexico represents a point of discontinuity in forest policy, land use management and resource utilization practices. These differences along with physical barriers which separate the two countries can interact to alter the structure and functioning of forest vegetation. One valuable source of information for analyzing potential effects of management on forest attributes is National Forest Inventory (NFI) data. Both Mexico and the United States have systematically designed NFI programs, the U.S. Forest Service Forest Inventory and Analysis (FIA) program and the Comisión Nacional Forestal (CONAFOR) Inventario Nacional Forestal y de Suelos (INFyS). However, data from NFIs are seldom harmonized with respect to reporting units, field procedures and estimation methods. Here we evaluate two important aspects of NFI data compatibility using seamless geospatial data. First, to gauge plot measurement and location accuracy we compared the elevations recorded in each countries NFI database with those taken from an independently derived digital elevation model (DEM). Second, basal area compatibility was determined by means of analysis of covariance (ANCOVA) using a seasonal time series of normalized difference vegetation index (NDVI) data from Landsat. The results showed that both countries have good location and measurement accuracy in relation to DEM elevations and in the majority of cases, statistically similar estimates of basal area per unit of NDVI. Despite finding a high level of plot data compatibility, our study uncovered key differences in inventory stratification between the two countries which prevented further statistical comparison of oak woodland stand densities. Suggestions for improving local and regional scale analysis compatibility of American and Mexican NFI data are provided.