马尾松人工中龄林间伐与施肥效应

于宁乡、湘乡、道县选择18、19、21年生的马尾松人工中龄林,对其间伐与施肥效应进行研究,结果表明:间伐与施肥1年后,缩短了轮伐期1～4年。宁乡试验点胸径平均增长了2.26 cm,较对照的增长量大1.89 cm,平均增长率达15.44%;单株材积平均增长了0.023 2 m3,较对照的增长量大0.014 8 m3,平均增长率达19.72%;单位面积材积平均增长了0.267 5 m3/667 m2,较对照的增长量大0.256 1 m3/667 m2,平均增长率达2.82%;胸径增长量和单株材积增长量均以保留密度为50株/667 m2的处理最大,而单位面积材积增长量则以保留密度为70株/667 m2的处理最大。湘乡试验点的单株材积增长显著,平均增长率达62.65%;道县试验点的单位面积材积增长显著,平均增长率为5.29%。差异显著性检验结果是:密度、施肥方式和区组间的胸径增长量均存在极显著差异,同时,密度×施肥方式和施肥方式×区组对胸径增长的交互作用也达到了极显著;单株材积增长量在密度间的差异达到了极显著;单位面积材积增长量在施肥方式间的差异极显著。

Effect of thinning and fertilization on the middle-aged forest of Pinus massoniana plantation

The effect of thinning and fertilization on the middle-aged forest of 18,19,21-year-old Pinus massoniana plantation was studied,which was selected from Ningxiang County,Xiangxiang City and Dao County,respectively.The results showed that,after thinning and fertilization in one year,the rotation period was shorted 1 to 4 years.The average DBH growth of the treated in Ningxiang County testing area was greater than that of the control group 1.89 cm,which of the treated increased 2.26 cm,and average increaserate was 15.44%.The average individual volume growth of the treated was greater than that of the control group 0.014 8 m3,which of the treated increased 0.023 2 m3,and average increase rate was 19.72%.The average unit area volume growth of the treated was greater than that of the control group 0.256 1 m3/667 m2,which of the treated increased 0.267 5 m3/667 m2,and average increase rate was 2.82%.The results of thinning with different density showed that it was the maximum increase of the DBH and individual volume for reserving 50 strains per 667 m2,but the maximum increase of the unit area volume was for reserving 70 strains per 667 m2.There was extremly significant difference in the individual volume growth of Xiangxiang City testing area,and the average increase rate was 62.65%.There was extremly significant difference in the unit area volume growth of Dao County testing area,and the average increase rate was 5.29%.The results of variance analysis were found that there were extremely significant difference in the DBH growth among the different density,fertilization modes and blocks case,also the interaction of density with fertilization,and fertilization with block for DHB increase were found extremely significant difference.There were extremely significant difference in the individual volume growth among the different density.And there was significant difference in the unit area volume growth between the different fertilization modes.