Effects Of Forest Thinning On Forest Environment Of Pinus Tabulaeformis And Quercus Aliena Var.acuteserrata Forest On The Southern Slope Of Qinling Mountains

Pine-oak forest, southern slope of the Qinling Mountains, was investigated andanalyzed to explore the impacts between stand and environmental factors under differentthinning intensities, diurnal variation, the relationships between stand, environmental factorsand the dominant factors, the main conclusions are as follows:(1) With the the increase of the intensity, stand average height, average diameter andshrub coverage of pine forest showed the increasing trend and are higher than former stand;however, the canopy density showed the opposite trend, namely, decreasing slowly with theincreasing thinning intensity and are lower than the former stand. The stand factors atdifferent thinning intensities showed a significant difference.The environmental factors in pine forest also make considerable significance with theincreasing thinning intensity. Light intensity and temperature showed an increasing trendthen dropping, and with the increase of the thinning intensity they increase instantly at thesame point, and are larger than the control samples in a day. Humidity in the pine forestdecreases at the first and then increases with the increase of the thinning intensity, it increasesthen suddenly declines at the same point, and is larger than the control samples in a day. CO2concentration showed a slightly falling trend then rising in a day, with the increase of thethinning intensity, CO2concentration rose in the pine forest in a day with the increasingthinning intensity at the same time in the forest, and are larger than the control samples. Windspeed showed no significance in a day but the difference was significant under the thinningintensity,.With the increasing thinning intensity, wind speed increases at the same time,and are larger than the control samples. In summary,thinning intensity factors, pine standtending and environmental factors showed a significant correlation.(2) With the the increase of the intensity, stand average height, average diameter andshrub coverage of oak forest in the southern slope of the Qinling Mountains have increasedand are higher than former stand; however, the canopy density decreases slowly with theincreasing thinning intensity and are lower than the former stand. The stand factors atdifferent thinning intensities showed a significant difference The environmental factors also make considerable significance with the increase of thethinning intensity in oak forest. Light intensity and temperature showed an increasing trendthen dropping, and with the increase thinning intensity they increase then increase at the sametime point, and are larger than the control samples in a day. Humidity in the pine forestdecreases at the first and then increases with increasing thinning intensity, and with theincrease thinning intensity, it increases then declines at the same time point, and is larger thanthe control samples in a day. CO2concentration showed a slightly falling trend then rising ina day, with the increase of the thinning intensity, CO2concentration rose in the pine forest ina day, CO2concentration increases Thinning intensity increased at the same time the forest,and are larger than the control samples. Wind speed showed no significance in a day but thedifference was significant under the thinning intensity,.With the increasing thinningintensity, wind speed increases at the same time, and are larger than the control samples. Insummary,thinning intensity factors, pine stand tending and environmental factors showed asignificant correlation.