Test of sound frequency treatment in timber and the hypothesis of trees’ sound principle.

To explore application of acoustic wave technology in forestry production, we used acoustic frequency generator of plant to carry out a number of nursery and woodland tests on different plant species during the year 2013 and 2014. The results showed that the acoustic wave can promote the growth of trees. It increases the height of Pinus tabulaeformis and Platycladus orientalis seedlings by 32.4% and 49.7%, respectively, and improves the volume growth of Cunninghamia lanceolata forest by 2.16 times, compared to the control. It can also promote the breeding of Rhizobium legume species and the amount of nodule volume of Robinia pseudoacacia seedlings is 7.1 times that of the control group. Besides, sonic wave can also enhance vigor, improve the capacity of pest-resistance of trees and increase the effects of chemical control. The results have shown that there is a wide range of promotion prospects about sonic technology in the forestry production. Nevertheless, questions such as how the trees sound, and why the sonic wave can enhance the photosynthetic rate of trees and promote the growth of trees still remain unclear. We come up with a hypothesis to explain these issues. Based on the sound principles, the sound of trees comes from the vibration of water passing through the xylem vessels and tracheids. Transpirational pull is not only the driving force of water flowing of trees, but also the main driver of vocalization of trees.