| It is very important for scientific forestry management to understand and grasp the stand growth regulation and it’s relationship with topography factors. The objects of study in this paper are two typical forest types in Saihanba machine forest farm, i.e. Larix principis-rupprechtii mayr. artificial forest and Betula platyphylla Suk. secondary forest, and on the basis of collecting a large amount of temporary sample survey data, screened appropriate data, to find the optimal model and calculate the total growth of each growth index ( DBH, height, volume ) as well as their current annual increment, mean annual increment, growth rate, and the stem numbers and volume of all age stands represent. Compiled various stands growth table, and analyzed the growth process of each growth index and the reflection for all topography factors. The main study results are as follows:(1)the best fitting effect of average diameter, height and volume growth process is Logistic model in Larix principis-rupprechtii mayr. artificial forest stand, changes process of stem number along with age is parabolic equation best fitting, while in Betula platyphylla Suk. secondary forest stand, the best fitting effect is logarithmic equation for the growth process of average diameter and height, volume growth process is Richards equation best. Changes process of stem number along with age is parabolic equation best fitting as well. The correlation coefficient R of model fitting above is more than 0.9.(2) the growth process of Larix principis-rupprechtii mayr. artificial forest can be divided earlier slowly growing stage, fast-growing stage and later slowly growing stage. The mean annual increment of DBH is 0.46cm and at 20 years growing fast, while current annual increment is 0.8cm and fast-growing stage is 10~20 years. The mean annual increment of height is 0.38cm and at 20 years growing fast as well, current annual increment is 0.62m and fast-growing stage is first 20 years. The mean annual increment of volume is 0.00690m3 and at 30 years growing fast, it’s current annual increment up to 0.01185m3 and fast-growing stage is 10~30 years. So, in the fast-growing stage we should pay attention to the management of Larix principis-rupprechtii mayr. artificial forest, especially in 10 to 20 years, should strengthen water and nutrient management, adjustment stand density as well as moderately thinning to foster tall trees. (3) the stem numbers of Betula platyphylla Suk. secondary forest became less with the increase of age, from 4085 strains per hectare in 5 years dropped to 1087 strains per hectare in 50 years. The gradually volume increase and at 50 years is 136.38m3 per hectare. The mean annual increment of DBH is 0.30cm and at 10 years growing fast, while current annual increment is 0.75cm and fast-growing stage is first 10 years. The mean annual increment of height is 0.25m and it’s current annual increment would present gradually decrease at the begin of 5 years, after 25 years the current annual increment of height less than 0.2m. The mean annual increment of volume is 0.00183m3 and at 20 years growing fast, it’s current annual increment up to 0.00426m3. The Betula platyphylla Suk. secondary forest in this area lack of artificial management, if can appropriate to human interference will be to greatly improve it’s growing space of all stand factors.(4)the effects of altitude on the growing of average diameter, height and volume in Saihanba Larix principis-rupprechtii mayr. plantation stand are different. The effects for average DBH and volume is more significant and presents positive relation, while the influence to stand average height is small. Slope has less influence to the growth of Larix principis-rupprechtii mayr. plantation stand, especially to the stand average height. The changes of stand average height growth between sunny slope and shady slope are general consistent, slope is not the main factor for affecting the growth of Larix principis-rupprechtii mayr. plantation stand height. Locations have appreciable impact on the growth of average diameter, height and volume in Larix principis-rupprechtii mayr. plantation stand, and all represent that the increment of stand average diameter, height and volume of different slope widen differences following the increased age, the characteristics of downslope growing the best and the upslope worst, while the mesoslope growth moderately. So, all in all, location and altitude are the major topography factors to influence the growth of Larix principis-rupprechtii mayr. artificial forest in Saihanba, and slope has the least influence. The growth of stand average DBH and volume affected maximum by altitude, and then location, slope has minimum affection. But for stand average height, only affect the location is significant, while the affection of altitude and slop are tiny.(5)the effects of altitude, slop and location on stand growing of Betula platyphylla Suk. secondary forest in Saihanba are significant, and with the increasing of stand age present more obvious feature. The average DBH, height and volume of stand have negatively related with the altitude, the maximum difference of stand average DBH, height and volume are 1.9cm, 1.8m, 0.04607m3. Sunny slope is not suitable for Betula platyphylla Suk. secondary forest stand growth, few distribution and growing condition is very poor. Even if in shady slop and semi-shady slope, the stand growth also has bigger difference. The average DBH, height and volume of stand in shady slop all represent higher than semi-shady slop. The Betula platyphylla Suk. secondary forest stand growth response to the locations is: downslope growth is best, then is mesoslope, and upslope growth is worst. The influence of topography factors on stand growth in Saihanba Betula platyphylla Suk. secondary forest show that slop >location> altitude characteristic. |
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