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混交林能改善林内的各种生态因子,为林木生长创造良好的环境条件,从而促进林木生长。在我省马尾松分布在高温、干热、土壤贫瘠的浅丘和深丘地区,进行杉木、马尾松混交林营造试验;同时调查观测该区内马尾松天然下种形成的杉木、马尾松混交林,并与该区的杉木纯林进行对比分析。杉木、马尾松人工混交林3—5年郁闭,林内直射光比杉木小13.1—27.3％,夏季高温季节气温比杉木纯林低2.2—2.4℃,湿度大5.0—10.0％。混交林内每年单位面积上的枯枝落叶量比杉木纯林高1—2倍,土壤中有机质含量大13.7—17.3％,孔隙度大5.0—7.4％,速效性氮高0.47—2.27毫克/100克,磷高0.59—0.60PPM,钾高2.28—3.78毫克/100克。混交林分比纯林提早1—2年郁闭,间伐期可提前3—4年。第一次间伐,每亩可出小径材0.3—0.5立方米。20年生的混交林分比杉木纯林每亩蓄积量大1.1—1.3倍,且大径材占42.3％,杉木纯林仅占14.5％。 试验和实地调查结果均证明,营造杉木、马尾松混交林,不仅促进了杉木的速生,而且改善林地的生态条件,减少病虫害的危害和蔓延,对扩大我省杉木的栽植范围,提高林分的经济效益,为我省混交林的营造提供依据。
Mixed forest can improve various ecological factors in the forest, creating good environmental conditions for forest growth, thus promoting the growth of trees. In our province, masson pine and Pinus massoniana mixed forest were set up in Masson pine and Pinus massoniana distributed in high temperature, dry and hot, poor soil conditions. At the same time, we observed the natural distribution of Pinus massoniana and Pinus massoniana mixed forest , And compared with the pure fir forest in this area. Cunninghamia lanceolata and Pinus massoniana mixed forest 3-5 years canopy, the direct light in the forest 13.1-27.3% smaller than the fir, summer high temperature season than the fir pure forest low 2.2-2.4 ℃, humidity 5.0-10.0%. The annual amount of litter per unit area in mixed forest was 1-2 times higher than that in pure Chinese fir plantation, the content of organic matter in soil was 13.7-17.3%, the porosity was 5.0-7.4%, the available nitrogen was 0.47-2.27 mg / 100g Phosphorus 0.59-0.60PPM, Potassium 2.28-3.78 mg / 100g. Mixed forest than 1-2 years earlier than the pure forest canopy, thinning period of 3-4 years ahead of schedule. The first thinning, a small amount of material per mu 0.3-0.5 cubic meters. The 20-year-old mixed forest is 1.1-1.3 times larger than the pure forest per acre, with the large-diameter timber accounting for 42.3% and the pure Chinese fir forest only accounting for 14.5%. Both the experiment and the field survey prove that it is not only promoting the fast growing of Chinese fir and the mixed masson pine, but also improving the ecological conditions of the forest and reducing the harm and spread of pests and diseases. It is of great importance to expand the planting range of Chinese fir and improve the stand Economic benefits, provide the basis for the construction of mixed forest in our province.