Spatial modeling using the Holdridge life zone system in Puerto Rico

The Holdridge system has been widely used for classifying global ecology types and is now used for predicting climate change. In this dissertation, a mathematical approach to the Holdridge model and an automatic life zone map generating system is presented. This presentation uses an Avenue script to generate a point life zone, so users do not have to deal with the Holdridge diagram, which uses logarithm base of 2. In the past, transitional life zones were not included when producing life zone maps. In this case study of Puerto Rico, transitional life zones have been included. Based on 30 years (1970–2000) of climate data, the Holdridge model defined 31 life zones that considered transitional zones, including 12 non-transitional and 19 transitional life zones.; Criticisms of the Holdridge system are various, but these criticisms do not assess the Holdridge model itself. The Holdridge model was evaluated by using new life zone maps. The hidden errors or fallacies, such as topographic disorder and the mixing of latitude zones, became apparent when an updated Puerto Rico life zone map was produced. Potential modifications of the Holdridge model and its factors have been developed. The modified Holdridge model adopted the Holdridge model concepts without considering the hexagon boundaries. There is no evidence that Holdridge (1959) developed his potential evapotranspiration formula (PE = 58.93 X Biotemperature) from empirical data or a theoretical argument; it only appears to be a geometric coincidence to arrive at the coefficient 58.93.; The climate has changed for Puerto Rico when the updated map compared to a 30-year old life zone map based on climate data for years 1931–1970 (Ewel and Whitmore 1973). Ewel and Whitmore only defined 6 subtropical life zones in Puerto Rico. More recently, based on 30 years of climate data (years 1971–2000), the Holdridge model defined 14 life zones without considering transitional life zones. Puerto Rico became a mixture of tropical and subtropical latitudes. The humidity provinces extended from rain forest, wet forest, and moist forest to dry forest, very dry forest and even desert. Seventy-five percent of the areas shifted from wetter life zones to dryer life zones. The diversity of life zones has increased. Climate change could be established as the cause for the shifting of these life zones. (Abstract shortened by UMI.)...