The Impact Of Different Management Measures On The Structure And Growth Of Larix Principis-rupprechtii

The mountainous area of northern Hebei Province is the important ecological barrier of annulus Beijing ferry , it is also the important birthplace of Luanhe River Basin.But due to the frequent interference of the human, in areas of forest vegetation is severely degraded, the existing natural forest are mainly secondary forest . Since the founding of new China, a large area of Larix pricipis have been created in the mountainous area of northern Hebei Province.But because of the high density of the early planting and the management which lack of scientific theoretical guidance and research, extensive and experiential management style led to the currentLarix pricipis forest into single structure low function and slow-growing forest, Therefore, finding sustainable management for Larix principis-rupprechtii plantation has become the important task. In order to promote theLarix pricipis plantation renovation and change the forest structure, restore the shrub and grass vegetation, improve the vegetation under the forest biodiversity and the water conservation function, promoting ecological system function, it is important to find the technological innovation, according to which the North ChinaLarix pricipis inefficient forest to explore the establishment of sustainable management of the technical system.In this article taking the 39 years old Larix principis-rupprechtii artifical pure forest as the research objection, rearch the growth and changes in the structure after it has taken a different management measures. The experiment mainly comprises prohibition area and no prohibition area. There are totally five management mearsues in the prohibition area, which are ribbon clearcut, cluster shape selective cutting, artificial promoting regeneration and the introduction of shrub, the no prohibition area served as controls. After four years of natural recovery, Analysis the effect of different management measures on the forest diameter distribution structure, the growth of the wood and artificial introduction, and undergrowth plant diversity change. The results are as follows:(1)The investigation of the management measures on experimental stand diameter class distribution shows that: The diameter distribution of Larix principis-rupprechtii plantation is a peak mountain shape curve , the stand average diameter ( ?d ) is a peak point, the medium diameter of the tree is the majority, the number of the too large or small number is gradually reduced. The curve is approximate symmetry, basically conforms to the pure forest of diameter structure. There is some changes after four years’management measures. Each point of the curve move to right uniformly. Found to fit them for the path-order more stands application the Weibull distribution fit a good effect. Different management measures has little effect on the stand diameter distribution.(2) Different management measures has obvious effect on the original stand’diameter growth and volume growth , but there is no obvious regularity effect on the growth of tree height. For the implemented management measures, the results show that, the prohibition is beneficial to improve the Larix pricipis’DBH increment, the height growth, volume growth and canopy density. While no prohibition areas, Larix principis-rupprechtii has no change in growth basically. Compared the stand in 2007with 2011,it shows that: with several measures, the Larix pricipis DBH growth, tree height, the total of volume and canopy density are increased; But all the growth of the average and annual DBH and height and volume increment of Larix principis tree. There is both a rising and downward trend. This suggests the difference effects of the measures. The stand Which take artificial promotion update and introduction of shrub measures is in good condition of growth. It shows that the two measures of stand has a beneficial effect on the growth.(3)There in a investigation of the introduction trees, it includes Chinese pine, Birch, Larix pricipis, Spruce, Pinus sylvestris and Mongolia oak, the ivestigation shows that before the survey of 2011 August ,the preservation of each species is more than 90%. The difference of tree’biological and ecological characteristics, leading to its growth discordance. Spruce, Mongolia oak and Pinus sylvestris grow slowly, Birch grows fast, the growth rate of Chinese pine and the Larix pricipis is between them. The average height of the Chinese pine is more than 130cm, and the average height of the Birch is more than 200cm. The average height of Larix pricipis, Pinus sylvestris, Spruce and Hippophae rhmnoides is 100cm, 79cm, 74cm and 167cm. In short, it is helpful for raising economic benefits to planting trees in the canopy. After 3 years, the Chinese pine can be sold as green seedlings, to get economic benefits. Clearcutting and cluster shape selective cutting has a great influence on the growth of the artificial introduced trees of the several management measures, it promotes the growth of the seedlings.(4) Different management measures have different effects on the change of undergrowth plant diversity. The undergrowth vegetation species diversity index of Simpson index, Pielou evenness index and species richness index are all improved after the management measures take in to implementation. The species and individual numbers of forest plants have been improved significantly. The measure which has the biggest changes on the spieces is the introduction of shrub. And this may because the experimental area is in the lower slope of stand and canopy density, which is suitable for plant growth. Because the ribbon clearcut transformation and cluster shape selective cutting have changed the forest environment at a large extent, so the two measures’effects on vegetation diversity are most apparent.Research on the Larix principis-rupprechtii plantation which takes management measures, after analysis of the change of the stand diameter structure, growth status and understory vegetation diversity, different measures according to different effects, find the suitable for the growth of plantation management measures and provide theoretical basis and experimental evidence for the transformation of low quality of Larix low yield forest are the purpose of the study.