Table 1. Mean tree characteristics of each thinning treatment under P. tabulaeformis plantation at establishment: Control (number of trees left equals the average natural density after self-thinning; 2700 trees ha–1), light (1925 trees ha–1), moderate (1325 trees ha–1) and heavy thinning (1125 trees ha–1).
Thinning intensity DBH (cm) Total tree height (m) Height under first live branch (m) Tree canopy width (m)
EW a) NS b)
Control 11.38 6.94 3.17 3.09 2.84
Light 12.18 7.69 3.38 3.16 3.15
Moderate 13.08 8.60 4.93 3.20 3.01
Heavy 11.75 6.81 3.18 3.00 3.75
a) EW = average tree canopy width at east-west direction.
b) NS = average tree canopy width at north-south direction.
Table 2. Influence of the initial litter N concentration (low N and high N concentration in litter) and thinning intensities (Control, number of trees left equals the average natural density after self-thinning, 2700 trees ha–1; light, 1925 trees ha–1; moderate, 1325 trees ha–1; heavy thinning, 1125 trees ha–1) on litter decomposition rate (expressed as percentage mass loss of the original 50-g sample after one year), N accumulation value, and net release value after one year.
Sources of variation Mass loss rate N accumulation value N net release value
Mean square P Mean square P Mean square P
Initial litter N concentration (I) 71.595 <0.001 0.039 <0.001 0.037 <0.001
Thinning intensities (T) 8.529 0.001 0.003 0.003 0.003 <0.001
I×T 7.434 0.002 0.002 0.009 0.001 <0.001
Error 0.925   <0.001   <0.001  
P = significance value.
Table 3. One year decomposition rate (expressed as percentage mass loss of the original 50-g sample after one year) of different initial N concentration litter (litter with low N concentration and litter with high N concentration) affected by the four thinning treatment intensities (Control, number of trees left equals the average natural density after self-thinning, 2700 trees ha–1; light, 1925 trees ha–1; moderate, 1325 trees ha–1; heavy thinning, 1125 trees ha–1). Within each litter type different letters in the same column indicate statistically significant differences according to Duncan’s multiple range test at the 0.05 level.
Thinning intensity Mass loss rate (%) of LN a) Mass loss rate (%) of HN b)
Control 20.57 ± 1.56a 26.39 ± 0.90b
Light 22.74 ± 0.75b 23.27 ± 0.72a
Moderate 23.89 ± 0.87b 27.10 ± 0.84b
Heavy 22.87 ± 0.84b 27.13 ± 0.97b
a) LN = litter with low N concentration.
b) HN = litter with high N concentration.
1

Fig. 1. N concentration changes over time of LN (litter with low N concentration) and HN (litter with high N concentration) decomposition under Control (a) (number of trees left equals the average natural density after self-thinning, 2700 trees ha–1), Light (b) (1925 trees ha–1), Moderate (c) (1325 trees ha–1) and Heavy (d) (1125 trees ha–1) thinning treatment during one year.

2

Fig. 2. N accumulation (a) and net release (b) value of per-g LN (litter with low N concentration) and HN (litter with high N concentration) as affected by four thinning treatments (Control, number of trees left equals the average natural density after self-thinning, 2700 trees ha–1; light, 1925 trees ha–1; moderate, 1325 trees ha–1; heavy thinning, 1125 trees ha–1). Within each litter type different letters indicate statistically significant differences according to Duncan’s multiple range test at the 0.05 level.