Variation in Forest Floor Enzyme Activities among Different Forest Gap Positions in Pinus tabulaeformis Plantations
Studies on the influence of different gap positions on the enzyme activities of forest floor can provide the basis for accelerating nutrient cycling and forest regeneration, and enhancing the ecosystem services. A forest gap of 1-year age and area of 40~50 m2inPinus tabulaeformis plantations was selected in the Beijing mountainous areas. Forest floor samples (L and F layer) were collected at different gap positions, including gap center, gap edge, and under-canopy, and their chemical properties and enzyme activities were assessed, as well as the relationship between the chemical properties and enzyme activities were analyzed. The results showed that the concentrations of dissolved organic carbon, readily oxidized organic carbon, ammonium nitrogen, and nitrate nitrogen of the forest floor at the gap center were significantly higher than those at the gap edge and under-canopy; the total nitrogen concentration of the forest floor at the gap edge was significantly higher than that at the gap center and under-canopy; while there was no significant differences in pH value and total phosphorus concentration among different gap positions. Compared to under-canopy, the activities of α-glucosidase, β-glucosidase, β-N-acetylglucosaminidase, leucine aminopeptidase, acid phosphatase, polyphenol oxidase, and peroxidase at the gap center significantly increased by 26.75%, 31.29%, 32.17%, 53.41%, 11.24%, 8.19%, and 10.03%, respectively; at the gap edge, the corresponding individual enzyme activity significantly increased by 20.94%, 10.74%, 22.25%, 26.78%, 22.88%, 3.55%, and 20.32%, respectively; while no significant difference was found in the dehydrogenase activity among different gap positions. A two-way ANOVA demonstrated that forest floor layers have more significant effect on the chemical properties and enzyme activities of the forest floor than on the gap positions and interactions between them. Regression analysis indicated that the increase in dissolved organic carbon and ammonium nitrogen might enhance enzyme activities in the forest floor. In general, our study demonstrated that gap positions had a significant influence on the chemical properties and enzyme activities of the forest floor; thus, future studies on the role of forest floor layers should focus on the effect of forest gap on the chemical properties and enzyme activities of the forest floor.
国家科技期刊平台
NSTL
万方数据
维普
