Most structural timber species now used in the North China's rural areas are poplar, willow, elm etc, which are fast growing trees but whose woods are very susceptible to biological deterioration.

The exposure used in this practice is not intended to simulate the deterioration caused by localized weather phenomena such as atmospheric pollution, biological attack, and saltwater exposure.

The paper expounds the organism and methods of the amendment of aquatic ecosystem with biological control technique based on the deterioration of the Dalangdian Reservoir water environment.