Topographic complexities of Taiwan's terrains and climatic variability have together produced an environment that is warm and moist, giving rise to a many varieties of vegetation classes. Based on the influence of climate, humidity, and altitude, forests can be classified as tropical forests, sub-tropical forests, temperate forests, and alpine forests. Taiwan's forests retain a diversity in tree species, including zelkova (Zelkova serrata), Formosa michelia (Michelia compressa), camphor tree (Cinnamomum micranthum), Formosan Ash (Fraxinus formosana), Formosan red cypress (Chamaecyparis formosensis), Taiwan cypress (Chamaecyparis obtusa) and Taiwan hemlock (Tsuga chinensis), among which cypresses especially enjoy world-wide celebrity for their antiquity and beauty. On the other hand, species such as cryptomeria (Cryptomeria japonica), China fir (Cunninghamia lanceolata), Taiwania (Taiwania cryptomerioides), cypress, and Taiwan acacia (Acacia confusa) are popular components of plantations.
Favorable habitats allow for specific tree species to gather into respective forest types by means of gradual colonization. The forest types of Taiwan can be generalized as follows:
- Spruce-fir type: The major member species of this type are spruce and fir. Spruces are found usually in higher altitude and as pure stands. The average altitudinal distribution is 2,500m or above, which delineates regions that are not easily accessible.
- Hemlock type: This forest type, which is one of the most significant conifer forest types, is distributed between 2,000~3,000m above sea level and usually mixed with firs at higher elevation and with pines or temperate hardwoods at lower elevation.
- Cypress type: Being one of the most valuable resources in Taiwan, this type of forest is found 1,500~2,000m above sea level as either pure stands or mixed stands of Formosan red cypress and Taiwan cypress.
- Pine type: Distributed between 300~2800m above sea level, this type of forest is the most accessible of all conifers on the island. The Taiwan red pine (Pinus taiwanensis) has a wide range of adaptive habitats, thus evolving to be the most abundantly distributed species within this type.
- Other conifer type: All conifers are native with the exception of cryptomeria and China fir being exotic species and existing as even-aged, pure plantations. Native conifers usually exist as mixed with hardwoods or other conifer species, whereas pure stands are rare.
- Conifer-hardwood mixed type:This type is distributed between temperate hardwood zone and conifer zone. Elevation ranges from 1,500~2,000m above sea level.
- Hardwood type: Distributed from sea level to an elevation of 2,000m, this type of forest is readily accessible due to its lower locality than that of the conifers. The major species of this type are members of the taxonomic families, Lauracaceae and Fagaceae.
- Bamboo type:This forest type is commonly spread throughout the island; however, large pure stands are found only in the central part of the island at intermediate altitudes. Ma Bamboos (Sinocalamus latiflorus) are found at elevation below 1,300m; Makino Bamboos (Phyllostachys makionoi) are found from 100~1000m; Moso Bamboos (Phyllostachys edulis) are found between 1,000~1,600m.