A Synopsis of the Vegetation of Thailand

Abstract

Although there has been active botanical collecting in Thailand throughout most of the 20th century and the inception of the Flora of Thailand project in 1970, there has never been a thorough, competent, and reliable classification of its vegetation. There have been numerous attempts to interpret Thailand’s vegetation, ranging from preliminary to primitive, but none is suitable. The first regional classification was done by Kurz in 1877 for British Burma. This system is still the best and most detailed scheme since Kurz was a very competent forester and botanist. Much of Kurz’s work has been adopted for Thailand, but with vastly inferior credibility and accuracy. This trend has been especially prevalent since the 1950’s when the Thai Royal Forest Department began to obscure and otherwise confuse the issue.
The basic problem with understanding Thai vegetation is the fact that a holistic (i.e. total or comprehensive) approach has never been done. Most classifications have been based on one or two criteria, viz., trees and rainfall. What is needed is a thorough survey including climate (especially rainfall), elevation, all vascular plants in all habitats, bedrock, and ecological information (especially transects) by a skilled team of plant taxonomists, plant ecologists, and other professionals (climatologists, agronomists, hydrologists). All surveys must be field checked, since relying soley on satellite imagery or aerial photographs is not conclusive enough.
Thailand has a monsoonal (seasonal) climate with a dry + hot season lasting from 4-6 weeks in the peninsula and 3-4 months in the north and north-east. The hottest and driest months are April-May, while August has the most rain. Frost often occurs in the northern mountains from December to February. During the past century the forest cover of Thailand has been reduced to 15%, most of which is in the north.