[Microclimatic characteristics of different size gaps in Pinus koraiensis-dominated broadleaved mixed forests]

By the help of HOBO automatic weather stations, the microclimatic characteristics of different size forest gaps in Pinus koraiensis-dominated broadleaved mixed forests in Xiaoxing' an Mountains were studied during growth season, with closed forest and bare ground as the control. The results showed that the diurnal variation of illumination, ground temperature, and air temperature of the gaps and the controls, as well as the change trend of the microclimatic factors during growth season, all presented a single peak curve. The diurnal variation pattern of relative humidity of the gaps and the control was high-low-high, being higher in early morning and evening and lower at noon. The relative humidity during growth season also presented a single peak curve, and was the highest for closed forest, followed by small, medium, and large forest gaps, and bare ground. The amount and the times of precipitation tended to decrease with increasing forest canopy, and the precipitation amount in large gaps was about 1.4 times as much as that in small gaps. During growth season, the maximum wind speed above bare ground, large, medium, and small gaps, and closed forest was 3.34, 2.97, 2.87, 2.41 and 1.84 m x s(-1), respectively.