Table 2 Relative growth equations of different biomass components of the main tree species

10–12 years

Shrub layer

Loropetalum chinensis

W_L = 3.645D²H + 23.806

(R² = 0.906, p < 0.01)

W_B = 68.835e^0.063D²H

(R² = 0.936, p < 0.01)

W_S = 183.35e^0.042D²H

(R² = 0.997, p < 0.01)

W_R = 15.887D²H + 122.24

(R² = 0.925, p < 0.01)

Cunninghamia lanceolata

W_L = 99.654e^0.072D²

(R² = 0.848, p < 0.01)

W_B = 60.734e^0.063D²

(R² = 0.909, p < 0.01)

W_S = 696.51ln(D²) – 1275.5

(R² = 0.998, p < 0.01)

W_R = 283.41H – 207.98

(R² = 0.888, p < 0.01)

Quercus fabri

W_L = 93.995ln(H) + 67.777

(R² = 0.849, p < 0.01)

W_B = 96.326ln(D²H) + 71.774

(R² = 0.966, p < 0.01)

W_S = 14.646D²H + 199.63

(R² = 0.999, p < 0.01)

W_R = 223.55ln(D²H) + 20.502

(R² = 0.975, p < 0.01)

Vaccinium bracteatum

W_L = 37.689ln(D²H) + 67.245

(R² = 0.999, p < 0.01)

W_B = 94.287ln(D²H) + 70.024

(R² = 0.893, p < 0.01)

W_S = 28.751D²H + 93.238

(R² = 0.996, p < 0.01)

W_R = 16.979D²H + 552.98

(R² = 0.999, p < 0.01)

Litsea pungens

W_L = 21.396e^0.1003D²

(R² = 0.975, p < 0.01)

W_B = 89.889D²–315.730

(R² = 0.814, p < 0.01)

W_S = 234.54D² – 801.66

(R² = 0.823, p < 0.01)

W_R = 104.19e^0.1712D²

(R² = 0.932, p < 0.01)

Rhododendron mariesii

W_L = 128.49ln(H) – 27.847

(R² = 0.999, p < 0.010)

W_B = 108.19e^0.338 D²

(R² = 0.931, p < 0.01)

W_S = 79.85e^0.5883D²

(R² = 0.922, p < 0.01)

W_R = 139.92e^0.4106D²

(R² = 0.965, p < 0.01)

Eurya muricata

W_L = 82.87ln(D²H) + 63.537

(R² = 0.678, p < 0.01)

W_B = 279.77e^0.005D²H

(R² = 0.979, p < 0.01)

W_S = 25.363D²H – 165.85

(R² = 0.999, p < 0.01)

W_R = 52.678D²H – 774.93

(R² = 0.999, p < 0.01)

45–46 years

Tree layer

Pinus massoniana

W_L = 3.392D²H – 1098.5

(R² = 0.751, p < 0.01)

W_B = 9.725D²H – 3716.6

(R² = 0.833, p < 0.01)

W_S = 15.619D²H + 5983.8

(R² = 0.788, p < 0.01)

W_R = 2.7576D²H + 658.2

(R² = 0.870, p < 0.01)

Lithocarpus glaber

W_L = 1.5588D²H + 622.46

(R² = 0.997, p < 0.01)

W_B = 4.357D²H + 822.27

(R² = 0.971, p < 0.01)

W_S = 0.5041D²H + 2934.7

(R² = 0.954, p < 0.01)

W_R = 1.5011D²H + 878.59

(R² = 0.804, p < 0.01)

Loropetalum chinense

W_L = 17.088D²H – 434.52

(R² = 0.969, p < 0.01)

W_B = 25.141D²H – 513.19

(R² = 0.815, p < 0.01)

W_S = 42.117D²H – 467.12

(R² = 0.767, p < 0.01)

W_R = 13.951D²H – 115.53

(R² = 0.992, p < 0.01)

Cleyera japonica

W_L = 4.1278D²H + 2.936

(R² = 0.946, p < 0.01)

W_B = 4.744D²H + 122.5

(R² = 0.838, p < 0.01)

W_S = 32.98D²H – 1161

(R² = 0.840, p < 0.01)

W_R = 4.5443D²H + 106.77

(R² = 0.832, p < 0.01)

Camellia fraterna

W_L = 40.211ln(H) + 58.598

(R² = 0.844, p < 0.01)

W_B = 75.413ln(H) + 102.26

(R² = 0.867, p < 0.01)

W_S = 81.555H^0.7045

(R² = 0.828, p < 0.01)

W_R = 97.574ln(H) + 174.85

(R² = 0.809, p < 0.01)

Old growth forest

Tree layer

Cyclobalanopsis glauca (Ouyang et al. 2016)

ln W_L = 2750ln(D) – 5.394

(R² = 0.930, p < 0.01)

ln W_B = 2835ln(D) – 4.837

(R² = 0.943, p < 0.01)

ln W_S = 2358ln(D) – 1.915

(R² = 0.992, p < 0.01)

ln W_R = 2948ln(D) – 4.957

(R² = 0.980, p < 0.01)

Cunninghamia lanceolata

(Liu et al. 2010)

ln W_L = 1.4691ln(D) – 24,467

(R² = 0.663, p < 0.01)

ln W_B = 1.996ln(D) – 3.713

(R² = 0.779, p < 0.01)

ln W_S = 2.5835ln(D) – 3.353

(R² = 0.928, p < 0.01)

ln W_R = 2.053ln(D) – 3.167

(R² = 0.894, p < 0.01)

Deciduous broadleaf (Ouyang et al. 2016)

ln W_L = 2599ln(D) – 6.234

(R² = 0.739, p < 0.01)

ln W_B = 2691ln(D) – 4.724

(R² = 0.918, p < 0.01)

ln W_S = 2501ln(D) – 2.772

(R² = 0.962, p < 0.01)

ln W_R = 2282ln(D) – 3.272

(R² = 0.872, p < 0.01)

Evergreen broadleaf (Ouyang et al. 2016)

ln W_L = 2.013ln(D) – 3.760

(R² = 0.791, p < 0.01)

ln W_B = 2.375ln(D) – 3.406

(R² = 0.939, p < 0.01)

ln W_S = 2.419ln(D) – 2.428

(R² = 0.925, p < 0.01)

ln W_R = 2.343ln(D) – 3.329

(R² = 0.929, p < 0.01)