The part and form of the flora in this area are affect by environmental factors such as rainfall, humidity, slope aspects and winds. Yushan National Park’ s topographical nature is unique, with more than thirty mountains exceeding 3,000 meters in elevation. More than two thirds of the area is above 2,000 meters. The elevational difference is more than 3,600 meters with valleys, cliffs and wind gaps. The climate is diverse and unstable, with warm, temperate, and frigid zones. The flora therefore is extremely diverse. Although the area of the park accounts for merely 3% of the total area of the island, it contains more than half of the native plant species of Taiwan. Vegetation covers vary from subtropical to alpine.
The plant communities that have reached a state of equilibrium can be divided into alpine tundra and forests. Grasslands, pine forests, and Formosan Alder forests are secondary plant covers that are still developing after suffering from fires or logging.
Alpine tundra is distributed in the Yushan massif, as well as areas in the Central Mountain Range that are 3,600 meters above sea level, such as Mabolasi Mountain, Xiuguluan Mountain and Guan Mountain. Winter snow lasts for more than four months out of the year in these areas. High winds, thin layers of rocky soil, and extreme temperatures are challenging conditions for plant life. Alpine plants have developed unique mechanisms in order to survive the harsh environment. Woody plants are grown close to the ground while perennial herbaceous plants utilize roots and rhizomes to survive the winters and spread out through mosses and lichens.
Beneath the alpine plants are the forests, which are the treasure coves of the national park. The growth of the forests is dependent upon environmental factors such as soil, rainfall and temperature. Precipitation is abundant within the national park, even during the dry seasons. With high humidity, a large area of forests is formed. There are five vegetation zones in the park in order of decreasing elevation: subalpine coniferous forest, cold temperate mountain coniferous forest, warm temperate mountain coniferous forest, warm temperate rainforest and tropical rainforest.