Botanical theory holds that the growth of plants is not only related to themselves, but also related to the surrounding environment. Especially sunlight has a great influence on the growth of plants. Although most of the ultraviolet rays in the sun are absorbed by the ozone layer, only a small part reaches the ground, especially in mountainous areas. Because ultraviolet rays can inhibit the elongation of plant stems, many alpine plants are short.

Secondly, the altitude of the top of the mountain is relatively high, and the temperature decreases with the increase of altitude. Because low temperature is not conducive to the growth and development of plants, and shorter plants are conducive to heat preservation; Alpine soil is loose, the terrain is steep, the nutrients in the soil are easily washed away by rain, the soil is barren, and the growth and development of plants are affected because they can not get enough nutrients; In addition, the wind in the mountains is particularly strong, and in order to prevent the wind from blowing down, the stems of plants tend to be shorter.