Studies On Tending Technique Of Scenic Forest Of Yong And Half—Mature Planted Pinus Tabulaeformis And Platycladus Orientals In Beijing

As the suburban transportation developed, outdoor recreational activities get popular in recent years. Nowadays, the suburban landscape forests become an important recreational space for Beijing residents. To meet the recreational demand of public, increasing the quality of landscape forests becomes the key part of forest management in Beijing. The Beijing landscape forests are mainly composed of Pinus tabulaeformis and Platycadus orientalis. By virtue of a field investigation and SBE (Scenic Beauty Estimation) method, combined with the landscape spatial pattern analysis in landscape ecology, we evaluated the quality of landscape forests in 4 scales-individual tree, in-forest landscape, color patches of in-forest landscape and the forest accessibility. Meantime, the techniques in forest classification and tending were established in fundamentally through combination effects of pruning and thinning tending of the Pinus tabulaeformis and Platycadus orientalis. The main research contents are as follows:The main indicators influencing the quality traits of individual P tabulaeformis and P orientalis were selected by correlation analysis. The relationship between the quality traits of individual tree and SBE grade result showed that parameter of Pinus tabulaeformis and Platycadus orientalis including crown volume, annual average increment of DBH, annual average increment of crown width, crown length ratio, stretch degree of crown, the ratio of death crown length to total crown length, were changed in linear trend with the changes of SBE grades. For Pinus tabulaeformis, the annual average increment of tree height, the ratio of DBH to tree height and straightness of trunk, were changed non-linear with the SBE grades. So does the annual average increment of tree height for Platycadus orientalis. Factor analysis was then introduced to construct 4 factors, which include tree crown morphology, harmony between trunk and crown, tree growth and trunk form. Following, all of these 4 factors were used to establish the quadratic curve model to reflect the relationship between SBE grades and quality traits for single trees.Study on the effects of stand structure P tabulaeformis and P orientalis on in-forest scenic beauty and accessibility suggested that with the increasing of perspective distance, average branch height, average diameter at breast height, undergrowth coverage, shrub coverage and herb coverage, the quality traits of in-forest landscape was also enhanced; With the increasing of stock density, the quality traits of in-forest landscape was reduced; With the increasing of shrub height, the quality traits of individual Pinus tabulaeformis in-forest landscape was reduced, but the quality traits of Platycadus orientalis in-forest landscape was enhanced; In-forest accessibility was increased with the increasing of perspective distance and average branch height, and it was decreased with the increasing of stock density, average diameter at breast height, shrub coverage and height; There was no obvious effects of herb coverage on accessibility. The main factors that influencing color patch of in-forest landscape of Pinus tabulaeformis and Platycadus orientalis were selected by correlation analysis. Then the effects of stand structure consisted by different stand densities, herb coverage, and trunk shape on color patch index were analyzed. Ultimately, the stand structures with the color index of the largest and smallest were determined.Study on effects of various tending on in-forest landscape showed that different pruning and thinning intensities were positive relationship with SBE value of in-forest Pinus tabulaeformis and Platycadus orientalis. The larger of the thinning intensity is, the greater of the net growth of average diameter at breast height, crown and tree height are. Then the accessibility model and in-forest landscape model based on the color plaque index were established. According to contribution of indicators on the accessibility model, the range of best in-forest accessibility control indicators were proposed.The main results of tenging technology for Pinus tabulaeformis and Platycadus orientalis were as follows:for Pinus tabulaeformins, depend on morphological and growth potential indicators, the types for single tree could be divided into 3 classes and 6 sub-classes. Class one was named as key trees of in-stand landscape (Ⅰ), which could be divided into quality upgrade trees of in-stand landscape (Ⅰ1) and framework trees of in-stand landscape (Ⅰ2). Class two was named as beneficial trees of in-stand landscape (Ⅱ), which could be divided into adjuvant trees of in-stand landscape (Ⅱ1) and potential trees of in-stand landscape(Ⅱ2). Class three was named as harmful trees of in-stand landscape (Ⅲ), which could be divided into harmful trees of in-stand landscape (Ⅲ1) and destructive trees of in-stand landscape (Ⅲ2). For Platycadus orientalis, the types for single tree could be divided into 3 classes and 5 sub-classes by means of the same method of classification. Compared with Pinus tabulaeformins, the 3 classes were completely same, and the first 5 sub-classes were included, only the last one — destructive trees of in-stand landscape (Ⅲ2) was not covered. Then the prediction model for various levels of forest trees was established. According to results of forests classification, pruning belongs to beneficial trees of in-stand landscape. Depending on studies on pruning and scenic beauty, the ratio of average tree height and crown length were ascertained as following:for Pinus tabulaeformis with strong, medium and weak pruning, the values are 0.36,0.42 and 0.56, respectively; for Platycadus orientali, these three values are 0.72,0.68 and 0.54, respectively. Shaping forest belongs to key trees of in-stand landscape while thinning forest is part of the harmful trees of in-stand landscape. The reasonable density table was also build through study the relationship between single tree’s DBH and crown. Finally, the tending technology on single tree and stand for Pinus tabulaeformis and Platycadus orientalis were proposed according to tree’s classification and reasonable density table.