Abstract: A field experiment of uncovered (control), covered single-layer and double-layer weeding cloth was conducted with randomized block design in Thuja sutchuenensis reintroduction experimental base of Mayun Forest Farm, Kaizhou District, Chongqing. We investigated the survival rate, height, ground diameter, crown width, canopy structure, vertical distribution of roots, biomass and its aboveground and belowground allocation, branch and leaf nutrient contents of T. sutchuenensis saplings as well as weed coverage. We examined the effects of weeding cloth on weed control and the growth and development of the saplings, aiming to provide scientific basis for the population maintenance of T. sutchuenensis at the initial stage of reintroduction. Our results showed that: (1) Weed coverage with single-layer and double-layer weeding cloth was 5% and 3%, respectively, and 87% for the control. (2) The survival rate of saplings covered with single-layer and double-layer weeding cloth was more than 95%, without significant difference between them. The survival rate of uncovered was only 65%, with significant difference between the uncovered and covered weeding cloth. (3) Most growth and canopy structure indices, aboveground and belowground biomass, root distribution depth of trees and nitrogen content in the branches and leaves of T. sutchuenensis saplings covered with single-layer and double-layer weeding cloth performed better than those of uncovered samplings. There were no significant differences between single-layer and double-layer. (4) The weed control effect and the promotion effect on the survival and growth of T. sutchuenensis saplings were correlated to the special structure and function of weeding cloth. In conclusion, the use of weeding cloth can effectively inhibit weed growth, improve the survival rate and growth of T. sutchuenensis, and reduce the cost of artificial weeding and tending at the initial stage of reintroduction. There was no significant difference in the impacts between single-layer and double-layer weeding cloth. Therefore, the ideal tending effect can be obtained by covering with single-layer weeding cloth.

Key words: Thuja sutchuenensis, weeding cloth, canopy structure, root distribution, biomass allocation