Earth, fire, water, metal, and wood were considered the five basic elements or Wu Xing. The tree and the soil were juxtaposed in the Chinese mind as the embodiments of Yang and Yin, the eternal binary structure that balances the ever-shifting way of the universe, the Tao. Wood and earth were complimentary opposites; the light and dry above the dark and wet. Both had their power, energy, or Qi. Earth was the place of burial and the place of death, whereas the tree symbolized life and rebirth. This is a motif common to many cultures.
Wood was important because of its great value as a fuel and building material and because of its necessary harvesting to clear farmland. Forestry was of primary interest to the earliest agrarian-based Chinese kingdoms. Neolithic kings, the Wu Di, centralized Chinese political power and began to expand the frontiers of the mighty agrarian empire.
They climbed yon Mount Qing
Where the pines and the cypresses grew thick.
They cut them, they carried them,
Square hewed them upon the block.
The beams of pinewood stuck out far,
Mighty were the ranged pillars.
The hall was finished; all was hushed and still.
(The Book of Songs, 11th to 7th centuries BCE)
By the sixth century BCE wood had already become scarce in the north-east region of China. The early kingdoms fought with one another over access to timber, and with the people of the mountains and valleys beyond the central plains. The primeval Chinese forest was a mixture of deciduous and coniferous trees. The prized wood was fir, cypress, pine, oak, and ash, all good for building houses and boats.
By the end of the first millennium AD, timber was being imported to central China from hundreds of miles away. The utilitarian value of wood made the tree a venerated object. Not so the forest. For a thousand years the common Chinese had little knowledge or affinity for the mountainous woodlands, save as an area of mystery and danger. The forest was a place of demons, dragons, and barbarian tribes. Popular heroes were those who ventured there, to the periphery of the civilized world.
Mysteries of the Carpenter 