Considerações sobre o sistema de classificação ecológica proposto por Holdridge

Resumo

In order to utilize efficiently environmental resources it is important to understand the ecological factors and their inter-actions. The definition of areas with specific ecological conditions is called ecological zoning.

A relatively recent system for classifying land based ecological regions has been proposed by Holdridge. This author has attempted to avoid subjectivity in defining ecological areas, by utilizing quantitative climatic data.

While this system is based principally on precipitation and bio-temperature, it also takes into consideration physiografic and edafic factors and phisiognomic characteristics of vegetation, and is considered to be of worlowide usefulness.

Using this system the initial category for division of the environment is called "life zone". Within a life zone one or more "associations" of plant may occur. In the identification of such on association physiognomic characteristics are funda- mental, and not the taxonomy of the plants involved.

The name of a life zone is accompanied by the name of the latitudinal regions, which are determined by use of apropriate tables and graphs.

The inclusion of a large range in temperature and precipitation within the limits of life zones is considered to be one of the imperfections of the system.

It is recognized, on the other hand, that this system has contributed inovations to the study of ecology, including the use of a logarithmic scale, introdution of the concept of biotemperature and of frost line or critical temperature line, and a practical method for determination of potential evapotranspiration.