| In this paper,the natural secondary forest of Quercus mongolica in eastern Liaoning Province was selected as the research object.The long-term density test forest(middle-age forest)of Quercus mongolica in Caohekou area of Benxi County was selected,with 6 density gradients(control area of 2041 plants/hm~2,1475 plants/hm~2).Weakness zone,moderate area of972 plants/hm~2 and intensity zone of 967/hm~2,extremely strong zone of 670 plants/hm~2 and super-strong zone of 550 plants/hm~2);newly established Quercus mongolica density test forest in Qingyuan County Age forest),three density gradients(900 plants/hm~2,720 plants/hm~2 and 600 plants/hm~2);and Quercus mongolica natural secondary forests of different ages and densities in 7 state-owned forest farms in Qingyuan County,Fushun,Liaoning.The effects of different density stands on the growth of Quercus mongolica(tree height,DBH,live branch height and crown width)were carried out.The diversity of forests under different forest stands,understory vegetation intensity,understory temperature,understory temperature,The effects of humidity under the forest,soil properties under the forest and ground temperature were also studied.The relationship between the number and type of Quercus mongolica mites and the number and species of the ramblings of the Quercus mongolica were studied by different forest density and forest age.The aim of this study is to cultivate high-quality Quercus mongolica alfalfa large warp timber,increase the economic benefits of Quercus mongolica,and provide scientific references and data for improving the forest resources in Northeast China and improving the utilization of forest land.The results of this pilot study are as follows:1.The average tree height,average DBH,average height of the live branches and crown width of the Quercus mongolica natural secondary forests treated with 1.6 stands were significantly different(P<0.05).The average tree height of Quercus mongolica will show a parabolic trend with the decrease of the density of Quercus mongolica.It does not increase with the decrease of forest density.When the density of forest stands is reduced to a certain value,the Quercus mongolica The average tree height tends to be stable.When the forest density is too low,some of the higher trees are more likely to be damaged due to the decline in natural disaster resistance.Among the 6 density treatments,the density of 550 plants/hm~2 was the best stand density for the high growth of Quercus mongolica.The average tree height of Quercus mongolica reached 19.68 m,which was higher than the total average height of the Inner Quercus mongolica alfalfa.It should be about 3.06 m higher.With the decrease of density,the average DBH of Quercus mongolica showed a significant growth trend.The average DBH of the minimum test density of 550 plants/hm~2 stands was 15.81 cm larger than the average DBH of the maximum test density of 2041 plants/hm~2,which was nearly increased.Doubled.With the change of density,the trend of high variation under living branches is disorderly,and there is a big difference in the height of living branches between similar density forests.Therefore,although the density of different Quercus mongolica forests is higher than that of Quercus mongolica Difference,but there is no certain law to be found,so this experiment temporarily determined that the forest density of Quercus mongolica is not the main factor affecting the height of the live branches or the direct relationship between the density of the stand and the height of the live branches.The crown amplitude showed a gradual upward trend with the decrease of the density of Quercus mongolica forest.This conclusion is similar to the average breast diameter study.Considering the volume of accumulation,the accumulation of Quercus mongolica under the density of 972 plants/hm~2 is46.41m3/hm~2,with an average growth rate of 4.82.The accumulation of Quercus mongolica under the density of 550 plants/hm~2 is 36.13m3/hm~2,with an average growth rate of4.06.Therefore,based on the cumulative growth and the growth of individual trees,we can determine that the density of 550 plants/hm~2 is the highest forest yield density for the cultivation of high-quality large-yield Quercus mongolica alfalfa,and the density of 972plants/hm~2 is more suitable for cultivation.Quercus mongolica medium diameter wood.2.Through the investigation of light intensity,temperature and humidity,ground temperature,soil properties and vegetation types of three density stands,the Simpson diversity index of understory vegetation in the medium density group(720 plants/hm~2)was 0.9432.The Shannon-Wiener diversity index is 3.2208 and the Alatalo uniformity index is 0.9710,which is significantly higher than the high density group(900 plants/hm~2)and the low density group(600 plants/hm~2),which means the medium density group.The vegetation diversity of the stand was the best,and the light utilization rate of the middle density group was also significantly higher than the other two stand density groups.In the results of this study,there is no significant difference in the temperature of the forest,the humidity in the forest,and the temperature under the forest.The water content and N content of the soil increase,although the forest density increases,the specific data show that The increase between the two is not much different.Therefore,the under-forest environment with medium-density stands(720plants/hm~2)is the best.3.Correlation analysis was carried out on the number,angle and lateral branch thickness of Quercus variabilis in different forest stands of three forest ages(young forest,middle-aged forest and near-mature forest):the number of forest side branches with the change of forest density There are no obvious changes in the factors such as diameter,growth angle and life and death,but the above indicators have different differences among different forest ages.The total amount of side branches,the amount of live branches and the number of dead branches in young forests were higher than those in middle-aged and near-mature forests,but there was no significant difference between middle-aged and near-mature forests.The thickness of the lateral branches between the forest ages is not much different,but the young and young forests of the live and dead branches are slightly smaller than the middle and near mature forests.The anatomical observation of the different lateral branches of the thrifty found that the thrift produced by the native branches penetrated into the forest core,and the thrift produced by the sprouting branches only extended to the annual ring of the starting year of the lateral branches,so the branches of the original branches were more than those produced by the sprouting branches.Thrift has a greater impact on the quality of wood.Whether it is a native branch or a sprouting branch,the thrift produced by the necrotic collaterals often causes the growth of forest trees due to the accumulation of rain or the invasion of pests and diseases,which not only reduces the economic value of the forest but also affects the growth of the entire forest. |
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