连香树人工林林分结构及生长规律研究

Study on stand structure and growth law of plantation of Cercidiphyllum japonicum

以8年生连香树人工林为研究对象,设置临时样地3块,实测样地林木的胸径、树高、分枝高、冠幅等,并于每样地选择平均木及胸径最大的优势木各1株,按1 m区分段法做树干解析,研究连香树人工林林分结构及生长规律。结果表明:8年生连香树人工林胸径呈典型正态分布,树高分布曲线为接近平均树高的株数最多的不对称单峰曲线。林分平均胸径5.15 cm,胸径年均生长量0.64 cm·a^(-1);平均树高6.94 m,树高年均生长量0.87 m·a^(-1);单位面积蓄积量23.0110 m^(3)·hm^(-2),单位面积年均蓄积量2.8764 m^(3)·hm^(-2)a^(-1)。平均木胸径、胸径年均生长量持续增长,在8年生时分别达到4.48 cm及0.56 cm·a^(-1);胸径连年生长量的波动性较年均生长量的大。树高年均生长量的波动性较连年生长量的小,平均木在6年生后,优势木在4年生后树高年均生长量急剧下降。材积总生长量、年均生长量及连年生长量均持续增长,在8年生时分别达到0.006275 m^(3)、0.000784 m^(3)·a^(-1)及0.002513 m^(3)·a^(-1),材积年均生长量与连年生长量曲线明显分离。优势木胸高形数于6年生后稳定在0.44左右。

Taking the 8-year-old Cercidiphyllum japonicum plantation as the research object,three temporary sample plots were set up to measure the DBH,height,branch height,and crown width,of the trees in the samle plots.The one dominant tree with the largest DBH and one average tree were selected in each sample plot.The structure and growing behavior of C.japonicum as plantation were studied by analyzing the trunks according to the 1m section.The results showed that the DBH structure of 8-year-old artificial forest of C.japonicum presented a typical normal distribution,and the height distribution was an asymmetric unimodal curve with the highest number of trees close to the average height.The average DBH of the stand was 5.15 cm,and the annual growth of DBH was 0.64 cm·a^(-1);The average height was 6.94 m,and the annual growth of height was 0.87 m·a^(-1);The storage volume per hectare was 23.0110 m^(3)·hm^(-2),and the average annual storagevolume per hectare was 2.8764 m^(3)·hm^(-2)a^(-1).The average DBH and average annual growth of DBH were increased continuously,reaching 4.48 cm and 0.56 cm·a^(-1)at the age of 8 years,respectively;The fluctuation of continuous annual growth was higher than that of annual growth.The fluctuation of annual growth of height was lower than that of successive years;The annual growth of height decreases sharply after the average wood was 6 years old and the dominant wood was 4 years old.The total volume growth,the average volume growth and the continuous annual growth have continued to grow,reaching 0.006275 m^(3),0.000784 m^(3)·a^(-1)and 0.002513 m^(3)·a^(-1),at age of 8 years,respectively.The curve of the average volume growth and the continuous annual growth was obviously separated.The breast height form factor of dominant wood were stable at about 0.44 after 6 years old.