Structural Characteristics of Pinus taiwanensis Plantation in Siming Mountain of Ningbo

In November 2021, a 100×100 m permanent sample plot was established for tally in Pinus taiwanensis plantation planted in 1969 in Ningbo Forest Farm, Siming Mountain, Zhejiang province. Structure characteristics of plantation and dominant tree species were analyzed by spatial structure index and diameter distribution. The spatial structure index included uniform angle index (W), aggregation index (R), dominance index (U), differentiation index (T), mingling index (M) and competition index (CH). The result demonstrated that distribution pattern of the stand (W=0.513, R=0.846) was aggregated, so as that of Cerasus. serrulata (W=0.529, R=0.846), that of P. taiwanensis (W=0.507, R=1.060) random distribution, that of Cryptomeria fortunei (W=0.419, R=1.506) uniform distribution. The dominance index of the stand (U=0.486, T=0.420), of C. serrulata (U=0.419, T=0.408) and of C. fortunei (U=0.423, T=0.376) showed medium tree size, while that of P. taiwanensis (U=0.080, T=0.627) showed tree size advantage. Mingling of the stand (M=0.746), of P. taiwanensis (M=0.882) and of C. serrulata (M=0.780) showed strong mingling, but that of C. fortunei (M=0.009) weak mingling. The competition index was ordered by the stand (CH=68.006) > C. serrulata (CH=28.868) > P. taiwanensis (CH=5.104)>C . fortunei (CH=1.791). It concluded that the stand with aggregated distribution, medium tree size, high species mingling, indicating stable community structure.