| Pinus koraiensis-broadleaf mixed forests are typical zonality forests in the eastern part of China's northeast. However, owing to the long-term irrational exploitation and utilization, so far the primeval resources of Pinus koraiensis-broadleaf mixed forests have almost been used up. Consequently it is imminent to restore and develop Pinus koraiensis-broadleaf mixed forests. Being a dominant species in the Pinus koraiensis-broadleaf mixed forests and a key species in its ecology, studies on the technologies concerning the protection, restoration and enlarged propagation of Pinus koraiensis are of active significance in the restoration and development of Pinus koraiensis-broadleaf mixed forests. With individual young trees of Pinus koraiensis nurtured by means of preserving deciduous while planting coniferous as the object, through studies on various environmental factors that affect its growth, this study aims at a better understanding of the environment suitable for its growth understory. This paper also focuses on the conversion of the forest management into quantitative parameter to strengthen the applicability of the study result so as to accelerate the growth of the young trees of Pinus koaiensis.Investigations and studies have been made on the growth of Pinus koraiensis in different management periods (no released thinning and released thinning). It has been found that differences exist in thegrowth of the young trees of Pinus koraiensis, i.e., different environmental conditions are required in their different growth periods. Moreover, even in the same management period, some environmental factors have effects on the growth of the young trees of Pinus koraiensis to variant degrees, such as light condition, soil humus horizon thickness, direct sunniness, neighboring trees, tree species upstory, herbs and shrubs. Therefore, the standstructure regulation, the order which is to ameliorate the growth environment of the young trees of Pinus koraiensis, must be implemented timely and moderately in different growth periods by taking into consideration of the demands of the young trees understory on the growth environment.Besides, a series of external standstructure parameters have been taken in this study as the major quantitative indexes, such as opening degree, neighborhood comparison, mingling or neighborhood pattern. With a young tree of Pinus koraiensis as the reference tree and its 4 closest neighboring trees as the basic structure unit, analyses have been made on the relationship between its growth and surrounding mini-environment. The main conclusions of this study are as follows: 1 It is necessary for the growth of the young trees of Pinus koraiensis to be in a dominant or subdominant status. The stand structure parameter - the neighborhood comparison U quantifies the relationship between the reference tree and the neighboring trees. So using neighborhood comparison as the quantitative target, U=0.25 or U=0.Although the young tree of Pinus koraiensis can survive the shade in the secondary forests, its growth rate has been greatly affected, as it requires a given light condition for its normal growth. Opening degree is the relative light target of trees. Using opening degree as the quantitative target, the suitable2 opening degree for the young tree is K≥5.3 The young tree of Pinus koraiensis has a high demand on the soil horizon thickness. The humus horizon thickness over 20cm with good soil ventilation is most preferable for its growth. 4 The exposure of the top of the young tree of Pinus koraiensis in sunniness is favorable to its growth. Therefore it is necessary to ensure the direct sunniness in its top, especially from the east, northwest and middle as that favors its growth.5 The specie of the neighborhood trees and their locality relative to the young tree of Pinus koraiensis may have direct effect on its growth environment structure. Mingling(M), a way indicating the spatial distribution and isolation of species in the stands, describes the probability of the...
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