华北落叶松人工林目标树经营效果研究

为研究不同株数目标树经营（标准地设置为600 m²,每块标准地5株目标树记为T₅、每块标准地8株目标树记为T₈）对林分生长及林下草本层植物多样性的影响,以河北省木兰围场国有林场山湾子分场21年生华北落叶松人工林为研究对象,采用样地调查法,对目标树经营5年后的华北落叶松人工林生长及植物多样性变化进行比较分析。结果表明,目标树经营林分胸径年均生长量、平均单株材积年均生长量、蓄积年均生长量均高于CK,T₈、T₅胸径年均生长量分别是CK的1.7倍、1.5倍,T₈、T₅平均单株材积年均生长量分别是CK的1.5倍、1.2倍,T₈、T₅蓄积年均生长量分别是CK的1.3倍、1.1倍。用Forstat对径阶分布拟合,T₈径阶分布为正态分布拟合效果最好,呈现右偏,T₅径阶分布为Gamma分布拟合效果最好,呈现左偏;CK径阶分布为正态分布拟合效果最好,呈现左偏。T₅、T₈林分12 cm及以上径阶林木株数百分比分别比CK高9.02%、20.17%;目标树经营改变了草本层群落物种组成,促进草本层植物多样性提高。T8草本层优势度、均匀度、丰富度较好,Simpson指数、Shannon-Wiener指数、Pielou均匀度指数均表现为T₈>T₅>CK,而Margalef指数为T₈>CK>T₅。综合来看,目标树经营促进华北落叶松人工林林分生长并提高了草本层植物多样性,T₈经营效果更好。

Study on management effect of target trees in Larixprincipis rupprechtii plantation

In order to study the impact of different number of target trees(standard plot was set to 600 m2, 5 target trees in each standard plot were recorded as T5, and 8 target trees in each standard plot were recorded as T8) on forest growth and understory herbaceous plant diversity. The 21-year-old Larix principis-rupprechtii. plantation in the Shanwanzi branch of the Mulanweichang State-Owned Forest Farm in Hebei Province were used as the research object. The plot survey method was used to compare and analyze the growth and species diversity of Larix principis-rupprechtii plantation after the target trees were managed for 5 years. The results showed that the average annual growth of diameter at breast height, average annual growth of individual plant volume, average annual growth of volume of the target tree management forest were higher than that of CK, and average annual growth of diameter at breast height of T8 and T5 was 1.7 times and 1.5 times that of CK, respectively. The average annual volume growth of T8 and T5 per plant was 1.5 times and 1.2 times that of CK, respectively, and the average annual growth volume of T8 and T5 was 1.3 times and 1.1 times that of CK, respectively. Using Forstat to fit the diameter order distribution, the T8 diameter order distribution was the normal distribution with the best fitting effect, presenting a right deviation, the T5 diameter order distribution was the Gamma distribution with the best fitting effect, showing a left deviation, and the CK diameter order distribution was the normal distribution with the best fitting effect, showing a left deviation. The percentages of trees in T5 and T8 with a diameter of 12 cm and above was 9.02% and 20.17% higher than those of CK, respectively. The target tree management changed the species composition of the herb layer community and promoted the increase of herb layer plant diversity. The dominance, uniformity and richness of T8 herb layer were better. Simpson index, Shannon-Wiener index and Pielou uniformity index were all T8>T5>CK, and Margalef index was T8>CK>T5. On the whole, target tree management promoted the growth of Larix principis-rupprechtii plantation and increased the diversity of herbaceous plants, and the T8 management effect was better.