| Yunnan pine (pinus yunnanersis Franch) is also called flying pine or livid pine. Yunnan pine forest is a kind of special forest type in southwestern China, and it is also the typical representative biotype in subtropical zones with aridity in western China. Its distribution areas are Yunnan ,Guizhou, Sichuan, Guangxi, and Tibet etc. The area in Yunnan province is about 5 million hm2,which occupies 52% of total national forest land and the timber volume is 300 million m3, which occupies 32% of timber volume in Yunnan province. The pine is an important industrial wood species of tree to make panels and also it is a main species of tree to produce rosin, which is a kind of industrial material. But 80% yunnan pine forests are pure forests with same age, its structure is simple and biodiversity is low, its stability is not good, its differentiation is serious and its density is irrational, so the forest land productivity cannot be used fully. Therefore, research on upgrading forest quality and land productivity and coordination of productive and ecological function of yunnan pine pure forest is one of main problems to be solved in Yunnan.By regarding Yipinglang forest farm which situated in middle Yunnan as research object, the study carries out some research works from different scales on management of yunnan pine forest as well as the problems of theory and technique about near-natural modification. The main research results are as follows:About acquiring datum:1)It needs quantity of work on wild investigation and collecting datum using normal method to acquire experimental datum. Not only much time and money would be expensed, there are much more problems on reliability of datum and updating of documents, such as low precision , large error, slow updating and inquiry. Aided by ArcGIS space analysis, the information of geographical factors can be acquired quickly and accurately through DEM.2)By the aid of Erdas and ArcGIS and national second-class resource investigation datum, a study of cooperation and usage of remote sensing and geographical information system are carried out. It is used to draw and evaluate habitat map of Yipinglang forest farm and to study quick collecting and storing of information about the research lands from macroscopical angle. It can be used to know the situation of ecological lands quickly and accurately and express the space relation of complicated habitats, so it can supply more clear information about habitat for forest protection and management in Yipinglang forest farm and it can also supply effective tools for forest landscape classification of yunnan pine more rationally.About landscape evaluation to yunnan pine forests in Yipinglang farm:1)According to the land usage type, the lands of Yipinglang forest farm are divided into 11 landscape types as forest land, sparse forest land, shrub land, unformed forest land, nursery land, barren land, cutover land, agricultural land, marshland, water area and others in the first grade. Furthermore, according to dominant trees and landscape ecological land factors( slope direction, slope degree, altitude and thickness of soil layers), second grade landscape are classified. The forest land are divided into 4 forest landscape types by TWINSPAN quantity classification method and then total 15 forest types are divided.2)The forest landscape series and laws are discovered by using internationally advanced TWINSPAN method to order 367 subcompartments in two directions according to indicated attribute and number of subcompartments. It shows that TWINSPAN not only can be used to class and order plant community types, but also it can be used to class and order forest landscape types. It has a certain indicated meaning to time and space grade of landscape series.3)The relation between predominant tree species that make forest landscape change with environmental factors is analyzed by using CCA typical corresponding analysis method. The results show that thickness and altitude are the main factors to affect the distribution of forest landscape and this is anastomosing with actual investigation.About management of yunnan pine forest stand:(1)The research results show that:1) the diameter structure distribution of pine forest in middle Yunnan reveals left bias, the figure belongs to single peak mountain figures and is more spiky than normal distribution;2)small diameter class trees are most, and with increasing of diameter, the number of trees are decreasing, when a certain diameter class appears, the decreasing rate is becoming slow and gradually stable. Through x2 fitting test, Weibull distribution function andβdistribution function can well describe the diameter distribution of natural and man-made yunnan pine forest and these two distribution function have great flexibility and good adaptability. Weibull distribution function is better thanβdistribution function and it can be used to predict the yield, wood production and valuate the effect of management to yunnan pine forest in middle Yunnan.2)The datum of sample lands and fitting results of yunnan pine forest in middle Yunnan reflect that the forest stand structure of this area is very irrational, so it is very urgent to reconstruct the stands according to the parameters of fitting distribution models and regulate the distribution of different diameter trees in the forest stand to increase the productivity and yield of the forest.3)The tree height growth model, diameter growth model, volume growth model and multi-type forest growth model are established by national second class forest resource investigative datum. The relations between tree height with age, diameter with age, volume with age are analyzed to supply evidence for calculating and simulating of yunnan pine forest growth.4)The developmental process of yunnan pine tree can be divided into 4 stages as preliminary stage of seedling, quick growth of tree height, quick growth of diameter and post growth of diameter. The growth law between tree height and diameter of every growth stage was analyzed and the key of tengding measures was proposed, which provided some basic data for yunnan pine forest management.5)The average timber volume of single tree is different in the stand, the time of predominant trees come to quick growth stage is earlier 5-8 years than that of average trees. The average timber volume of single tree can be 0.0034 m3 in 15th year after planting, it's 3.78 times of that average trees, so the difference is very great. The management system of object trees is one of key techniques in"near-natural"management, through above analysis, the object tree management can be regarded as the management of predominant trees, it's aim is to culture large diameter trees, so the fostering management should be continuous and disturbing trees and other trees should be used as needed. When the object trees come to the needed diameter and there are enough young trees in the lower layer of second generation, they can be choosed to be cropped.About near-natural modification in sustainable management of yunnan pine forest:1)The landscape programme of large scale in yunnan pine forest mainly focus on area distribution. According to succession laws and the principle of"fitting trees to lands", the regulation of landscapes to forest stands can be realized through near-natural forest developmental types design. Community habitat drawing is one kind of key ways to realize this managing technique. 2)The rational layout models of yunnan pine forest landscapes in research areas are brought forwarded. The developmental directions of yunnan pine forest landscapes in research areas are pointed out via near-natural programme design method. They are :1)the present ever-green soft and hard broad-leafed mingled forest landscapes in mountainous area should be kept and protected; 2)The landscape type of ever-green l broad-leafed forest, which is the local forest vegetation with belts , should be expanded;3)The managing situation of landscapes with stable ecology and high economic such as yunnan pine(pinus yunnanersis franch) forest, China Armand pine(Pinus armandi Franch) forest, Keteleeria evelyniana Mast forest should be improved. Regarding the community habitat blots of yunnan pine forest as objects, the layout area of forest landscape is regulated in this study.3)Two near-natural modification models of yunnan pine pure forest, which are managing model to the pure forest of yunnan pine and the managing model to single target tree in natural yunnan pine forest, are brought forwarded. The work procedures to modify yunnan pine forest to be near-natural are summarized. |
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