Effects Of Thinning On The Typical Ecological Forest On Mountainous Area Of Northern Hebei Province

The ecological forest plays an important role in maintaining and improving the ecological environment,and in the protection of biodiversity. As an important forest distribution area in Hebei Province, Mountainous area of Northern Hebei Province has large area of ecological non-commercial forest,and has a special location and plays an important role in soil and water conservation, and water conservation for the Beijing and tianjin areas. At present, the restriction of the relevant policy of ecological forest led to most of the ecological forest management in the state of loss, which led to the local ecological forest growth decline, and ecological benefits and social benefits had suppressed. Therefore, the management of ecological forest is proceed to protection strictly or should be required management measures,and the management measures in place to the ecological function is a problem to be solved at present. This study selected several typical ecological forest in Mountainous area of northern Hebei Province as the research object,and set up the control plots before tending thinning. In thinning stands we set up the same area and same number plots. Analysis and discussion the effect of thinning on the northern Hebei mountain typical ecological forest in the growth of forest,and forest vegetation changes and microclimate. To provide the ecological basis for local forest construction, and operation and management. The main conclusions include the following aspects:1) Thinning had promoted the growth of DBH.On the average level,the mean annual DBH growth in thinning stands was 1.79 times that of in thinning stands.Thinning had made the stand diameter distribution closer to normal distribution. The growth of individual volume in thinning stands larger than unthinning stands,the most significant increased 10 times. The crown growth amount in thinning stands is obviously higher than unthinning stands. Effects of thinning on the stand volume growth and the total volume is not obvious.2) Thinning had increased the number of understory herbaceous species, but the impact on the number of shrub species is not obvious.The richness index of understory herb in thinning stands had increased,but the species evenness and diversity did not improve. Thinning had promoted the richness index and evenness index of understory shrub. Thinning significantly increased the biomass of understory vegetation. The understory herbaceous biomass increased by 205.95%,and the shrub leaf biomass increased by 246.89%,and the branch biomass of shrub increased by 344.41%. Thinning make forest litter accumulation and water-holding capacity decreased.3) Thinning has a significant effect on stand microclimate. The light intensity in the thinning forests was markedly higher than the un-thinning forests,and the former is 4-5 times than the latter.The topsoil temperature of thinning forest was markedly higher than that of un-thinning forests and the difference between the thinning area and un-thinning area decreases gradually with the increase of the deep of soil and disappear in the soil depth of 15 cm.There was no distinct difference in air temperature between the thinning forest and un-thinning forest. The diurnal course of air relative humidity was like “V”, there are no markedly difference between the thinning forest and un-thinning forest.