Formation of forest ecosystems caused by the dominant influence of environmental factors on the formation and development of communities in forest ecosystems. The grouping is based on understanding the formation of a climax forest, the community of which occur during late succession. Understanding relating to the adaptation climax vegetation cover in terms of overall physiological, morphological, terms of growth, and growth form, so that extreme conditions of climate and soil will lead to adaptation effects trees and other vegetation to be real. This will affect the structure of forest ecosystems (forest formations).
Based on the environmental factors that have a dominant influence on the structure of communities or forest ecosystems, forest ecosystems will be grouped into two formations, namely the climatic formation and edaphic formations. Climatic formation is also called climatic climax formations, whereas edaphic formations called edaphic climax formations. Understanding of each formation is as follows.
1. Climatic formation is the formation of forests that in its formation is strongly influenced by climatic elements, such as temperature, humidity, light intensity, and wind. Forest ecosystems that belong to the climatic formations, namely the tropical rain forest, monsoon forest, and forest peat (Santoso, 1996; Directorate General of Forestry, 1976). According to Schimper, forest ecosystems which belong to the climatic formations, for example tropical rainforest, monsoon forest, savanna forest, thorn forest, subtropical rain forests, temperate rain forests, coniferous forests, and montane forests. According to Davy, the forests which belong to the climatic formation is the tropical rain forest, spring rain forest, monsoon forest, mountains or forests temperate forests, coniferous forests, bamboo forests or forest woody Gramineae, and Alpine forest .
2. Edaphic forest formations are formations which in its formation is strongly influenced by soil conditions, such as physical properties, chemical properties, and biological properties of soil, and soil moisture. Forest ecosystem that is included in edaphic formations, for example swamp forest, brackish, and coastal forests. Schimper, mentions that the forests belong to the climatic formations include forest edges, swamp forests, coastal forests and mangrove forests. According to Davy which belong to the group of edaphic formations, namely the riparian forest, swamp forest, mangrove forest, beach forest, dry evergreen forest, savannah forest, palm forest or palm forest, and thorn forests. Riparian forest (riparian forest) is considered as a subtype of tropical rain forests, while forest palm (nipha forest) is often regarded as konsosiasi of brackish forest or swamp forest; depend on factors edaphic.