立地因子对半天然杉阔混交林生长的影响

Effects of Site Factors on the Growth of Semi-natural Mixed Forest of Chinese fir and Broad-leaved Trees

为高质量培育杉木Cunninghamia lanceolata速生丰产大径材和檫树Sassafras tzumu珍贵用材,精准提升森林经营成效,以13~14 a生半天然杉阔混交林为研究对象,分析不同坡向、坡位、立地等级对其生长的影响。结果表明,3个坡向杉木胸径、树高和材积生长量表现为阴坡>半阴坡>半阳坡,不同坡向间差异极显著(P<0.01);木荷Schima superba和檫树的胸径、树高、材积生长量表现为半阳坡>半阴坡>阴坡,不同坡向间木荷生长差异不显著,檫树胸径、材积生长差异极显著(P<0.01)。3个坡位杉木、檫树的胸径、树高、材积生长量表现为下部>中部>上部,杉木胸径、树高、材积生长差异均为极显著(P<0.01);檫树胸径、树高生长差异显著(P<0.05),材积生长差异极显著(P<0.01);木荷胸径、树高、材积生长差异不显著。2个立地级杉木、木荷、檫树胸径、树高和材积生长量表现为Ⅰ立地级>Ⅱ立地级,杉木树高生长差异显著(P<0.05),胸径、材积生长差异极显著(P<0.01);木荷胸径、材积生长差异不显著,树高生长差异显著(P<0.05);檫树胸径、树高、材积生长差异极显著(P<0.01)。在一代杉木林阴坡、山坡下部、Ⅰ立地级条件下,连栽杉木混生天然檫树林分中,13~14 a生杉木平均树高12.4~13.9 m、平均胸径14.0~14.8 cm、蓄积量201.45~248.90 m^(3)·hm^(-2)、年均蓄积生长量15.50~19.15 m^(3)·hm^(-2),达到速生丰产林大径材指标。

To cultivate the fast-growing and high-yielding large-diameter timber of Cunninghamia lanceolata and the precious timber of Sassafras tzumu with high quality,and accurately improve the effectiveness of forest management.This paper took the 13-14-year-old semi-natural mixed forest of Chinese fir and broadleaved trees as the research object,and analyzed the effects of different slope directions,slope positions and site classes on its DBH,tree height and volume growth.The results showed that the growth of DBH,tree height,and volume of C.lanceolata in three slope directions were shady slope>semi-shady slope>semi-sunny slope,and the difference between different slope directions was extremely significant(P<0.01).The DBH,tree height,and volume growth of Schima superba and S.tzumu showed semi-sunny slope>semi-shady slope>shady slope.There was no significant difference in the growth of S.superba among different slope directions,and the difference of DBH and volume growth of S.tzumu were significantly different(P<0.01).The growth of DBH,tree height and volume of C.lanceolata and S.tzumu at three slope positions was lower>middle>upper,and the difference of DBH,tree height and volume growth of C.lanceolata was extremely significant(P<0.01).The growth of DBH and tree height of S.tzumu was significantly different(P<0.05),and the volume growth was significantly different(P<0.01).There was no significant difference in DBH,tree height and volume growth of S.superba.The growth of DBH,tree height and volume of C.lanceolata,S.superba and S.tzumu at two site levels wasⅠsite level>Ⅱsite level.The difference of height growth of C.lanceolata was significant(P<0.05),and the difference of DBH and volume growth was extremely significant(P<0.01).There was no significant difference in DBH and volume growth of S.superba,but a significant difference in tree height growth(P<0.05).There were significant differences in DBH,tree height and volume growth of S.tzumu(P<0.01).Under the conditions of shady slope,lower slope and site I of the first-generation of C.lanceolata forest,the average tree height of 13-14-year-old C.lanceolata was 12.4-13.9 m,the average DBH was 14.0-14.8 cm,the volume was 201.45-248.90 m^(3)·hm^(-2),and the average annual volume growth was 15.50-19.15 m^(3)·hm^(-2),which reached the large diameter timber index of fastgrowing and high-yield forest.