Mobilizing expert knowledge of tree growth with the PLANTGRO and INFER systems

PLANTGRO can provide estimates of plant and tree growth under a wide range of conditions by evaluating responses to some environmental variables ranging from day length to soil pH and determining the limiting factor. Although intended only to indicate the suitability of a given sitespecies combination, empirical trials suggest that the suitability index provides a reasonable indication of growth potential, offering correlations with height growth as high as 80%. PLANTGRO can be calibrated for new situations by providing appropriate soil, climate and species files. These can be compiled from plot-based data, casual observations, or expert knowledge. INFER is an expert system which complements PLANTGRO by providing an objective framework to elucidate plant growth details from casual observations. Together, INFER and PLANTGRO offer an effective way to provide initial growth estimates for species-site combinations not covered by plot data or other models. PLANTGRO is available from the first author, and INFER and many PLANTGRO files for forest trees may be accessed on the internet at http://www.cgiar.org/cifor/research/tropis/plantgro.html