| This study selected in Guangxi state-owned Daguishan forest six row breakout 10 years Machilus pauhoi Kanenira plantation(2500 plants/hm2)and 3 years of Machilus pauhoi Kanenira and adorable Eucalyptus mixed forest as the research object,based on the investigation of different thinning intensity(0%,20%,30%,40%)of the 12 plots based on different thinning intensity under the variety of the forest growth and soil nutrient properties,find out the reasonable thinning intensity do efficient cultivation pattern.Based on 18 standard plots under two modes of mixture of Machilus Nana,eucalyptus and Machilus,the forest growth and soil physical and chemical properties in various places were investigated and analyzed in detail.The feasibility of mixing the shavings and Eucalyptus was discussed,which provided a basis for the transformation of pure plantation of Eucalyptus.The main conclusions are as follows:(1)Thinning significantly promoted the growth of Machilus pauhoi Kanenira height and DBH,height and DBH with thinning intensity increases first and then reduces the thinning intensity of 30%,Machilus pauhoi Kanenira height and DBH growth fastest;branch height increased with thinning intensity decreased gradually,were increased after reduced,combined with the experimental found crown Machilus pauhoi Kanenira thinning intensity under 30%growth reached a reasonable threshold;the number of sprouting will increase with the increase of thinning intensity,average height and average the bud sprouting size will gradually increase first reduction under the effects of thinning on the average diameter of the base obviously,the number of sprouting on the second,the influence of the coppice height minimum,remaining number of comprehensive analysis of Machilus pauhoi Kanenira forest rational was 1750 plants/hm2.(2)The soil total nitrogen,total phosphorus and soil organic matter in the thinning shavings were increased with the increase of thinning intensity,and then decreased and then decreased.The accumulation of 30%was the most and the thinning of 40%was the lowest,soil total potassium will gradually reduce the trend.Comprehensive see effects of thinning on Soil nutrients showed effects on total nitrogen,total phosphorus effect,organic matter content is third and the effect on soil total potassium is smallest,and the greatest impact on available phosphorus of soil available nutrients,available potassium,ammonium nitrogen least effect.(3)Analysis of different forest components,with a slope of Machilus pauhoi Kanenira growth of pure forest under the mode of Machilus pauhoi Kanenira height,ground diameter is better than that of Eucalyptus-Machilus pauhoi Kanenira mixed forest model;in the same species composition,different slope performance in pure forest slope>mode on the downhill slope>,mixed forest in slope>>uphill downhill.The ground diameter pure forest is downhill>upslope>middle slope,and the mixed forest is downslope>middle slope>upslope.Mixed forest branch height in the same slope position is generally higher than that of pure forest,forest distribution of two kinds of mode under branch height is all downhill uphill slope>>;crown in pure forest is greater than the mixed forest,mixed forest canopy:upper slope>>in the downhill slope,and the pure forest showed that the middle slope>>uphill downhill.(4)The same slope mixed forest soil total nitrogen,total phosphorus was slightly higher than that of pure forest,mixed forest soil total nitrogen,total phosphorus content with slope position from top to bottom gradually increased,and the pure forest mode increased first and then decreased;soil total potassium showed the same slope under pure forest was higher than that of mixed,mixed forest of the slope a difference is not large,pure forest>>uphill downhill slope;the content of organic matter is higher than that of pure forest mixed,two modes are gradually increased,the content of most downhill.The pure forest of ammonium nitrogen and available potassium in the same slope position was generally higher than that of mixed forest,potassium ammonium nitrogen and mixed pure forest with the slope increases from top to bottom and then decreased,available potassium ammonium nitrogen and pure forest mixed forest increased;available phosphorus showed mixed forest mode in the same slope is higher than that of pure forest pattern,and the trend was gradually increased with slope position.In conclusion,under the 30%thinning intensity,the growth of Machilus Nana forest is the best,and the soil fertility condition is the best.The comprehensive condition is the best,which is suitable for the cutting intensity of Machilus parlour forest.The forest pattern and downhill position are more suitable for the growth of shavings and the retention of soil fertility. |
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