The eastern mountainous region of northeastern China is the hometown of Korean pine. Under natural conditions, there are many species of broad-leaved trees associated with Pinus koraiensis during its entire growth and development, forming a coniferous and broad-leaved mixed forest. With the development and utilization of forest resources in forest areas, Korean pine forests have been reduced in a large area, and the consumption of forest resources is very large. In order to restore forest resources as soon as possible, although the growth of introduced larch and poplar species is rapid and the forest is fast, it is not conducive to The full use of forestland productivity and the restoration of ecological communities will also lead to deterioration of soil conditions in the forest land and reduce forest productivity. Based on the characteristics of Pinus koraiensis, Populus Euphratica, and Populus davidiana and their growth patterns, a broad-leaved Korean pine broad-leaved mixed forest is formed, which not only accords with the current direction of forestry development for building mixed forests, but also helps restore the areas in the eastern mountainous regions of northeastern China. Climax community. Its main advantage is to obtain reasonable forest structure that conforms to natural laws through human activities. In the past 20 years, a large amount of poplar wood was obtained and a Korean pine forest was formed. I. Characteristics of Pinus koraiensis and Populus simonii and their growth patterns Second, the theory of analysis of mixed poplar and Korean pine Third, poplar and Korean pine mixed way and density Fourth, the analysis of operating results Medical Imaging,U Arm System,Mobile Patient Table,Compact Dr System MinFound Medical Systems Co., Ltd , https://www.minfoundmed.com
The biological characteristics and growth laws of tree species are the main theoretical basis for the establishment of mixed forests. The main characteristics of the two tree species are briefly described as follows:
Korean pine is one of the main tree species in the eastern mountainous region of northeastern China. It is the main component of the climax community that constitutes this region. It prefers well-drained, moist, fertile dark brown soil. It grows slowly in its young stage and has strong resistance to negative. Certain shades, as the age increases, the resistance to negative gradually weakens, the requirement for light gradually strengthens, and the growth rate increases. It grows best when it has a certain degree of canopy and its size is properly adjusted.
Daqing Populus is a native tree species in the northeastern region. It is hardy, humid, and well-watered. It drains well in the middle and lower abdomen of the mountain. It grows best in deep and fertile soil, and it does not tolerate shading. It must have sufficient light. The growth peak of Populus euphratica comes early, and the highest growth rate is 10 years ago. The annual growth amount exceeds 1 meter, and it gradually decreases after 10 years. The growth of DBH grows fastest in 6-15 years, and the annual growth can reach 1cm or more, and then decline year after year. A round of Lang Lang only about 25 years.
Seen from the characteristics of tree species, the early fast-growing tree species of Populus euphratica can be matured within 20-25 years, and its tree height, breast diameter, and volume can reach the peak, which can be used for harvesting. The growth of young Korean pine is slow. With age, 20 After the year, the amount of growth rapidly increased. Mixing the two can complement each other and achieve greater benefits.
From an ecological point of view, both tree species prefer to grow in fertile, moist, well-drained areas of the soil, and are often associated with growth. Poplars are happy and cedar trees need shade. Therefore, the formation of mixed forests in the early stages of regeneration can not only meet their own ecological habits, but also avoid competition. When the growth rate of Pinus koraiensis was accelerated and the demand for light was strengthened, it was exactly during the harvesting period of Daqing Populus, which just felled and the canopy closure was adjusted so that Pinus koraiensis was liberated. Due to the difference in the fast-growing period between the two tree species, especially the growth of the first 10 years of Korean pine is particularly slow, the demand for nutrients is less, and neither will have adverse effects on nutrient requirements.
According to the production and operation conditions, under the same site conditions, the growth conditions of Populus euphratica in pure and mixed forests are similar, and in the case of the same conditions, the Korean pine has a slightly lower mixed height in terms of tree height and DBH, but no big difference. It can be seen that if the timely and reasonable adjustment of the density of Populus alba, it will not only affect the growth of Korean pine, but also can receive the effect of double harvest of Korean pine and poplar.
In short, the mixing of Korean pine and poplar is feasible both theoretically and practically.
Determining the method and density of mixing should be considered mainly from the ecological habits, growth patterns, forest management measures, rotation, and product specifications of tree species. It is necessary to create a good ecological environment to facilitate the growth of trees while fully utilizing them. Woodland productivity is also conducive to the conduct and management of various production operations.
According to the ecological habits and growth laws of tree species, it is not appropriate to adopt the method of mixing ribbons or agglomerates, because these two methods are not conducive to the side shade of Korean pine, so that the Korean pine is in full light, and is not conducive to the management To implement the measures, we should adopt the method of mixing between the rows, that is, plant the cedar trees on the intersection of the adjacent four poplar crosses. In order to improve the preservation rate, the planting method of the vegetative group should be adopted, and the methods of planting poplar seedlings and korean pine once and planting them once should be adopted. In this way, korean pine trees are basically shaded laterally, and poplar trees occupy space quickly due to their rapid growth. Into the fast-growing period.
According to the requirements of wood species and the characteristics of tree species, poplar plantation should adopt a row spacing of 3m x 3m or 6m x 6m, poor growth of dense trees, early closure of vegetation, low value of thinning materials; Without being closed down, the area per unit area will be low during a certain period of time, and a large number of natural hardwood trees will be mixed, which will be detrimental to the management.
From the aspect of wood material, the poplar grows rapidly, the trunk is straight, and the growth period is short. About 200 cubic meters of wood per hectare can be obtained in about 20 years. At the same time, due to the effect of poplars, the phenomenon of easy bifurcation of the Korean pine plantation can be changed, and the quality of Korean pine can be improved.
From the aspect of ecological benefits, while harvesting poplars, Korean pine trees that have been growing for more than 20 years are equivalent to shortening the cultivation period of Korean pine and giving full play to the productivity of forest land. At the same time, due to the cover of vegetation, soil erosion is prevented, and a regional climax community in the eastern mountainous region of northeastern China, the Korean pine broad-leaved forest, can be formed.