Teak (Tectona grandis Linn. f) and Edaphic Factors Affecting the Regeneration of Woody Species and Their Functional Traits in Economic Forest Plantation, Northern Thailand
Table 4
Mean ± standard deviation (SD) of soil variables including sand, silt, clay, organic matter (OM), nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg) contents.
Soil
10-year-old
20-year-old
30-year-old
40-year-old
Old-growth forest
Sig
Sand (%)
47.43 ± 19.11a
29.63 ± 6.15bc
42.53 ± 9.73ab
27.73 ± 4.30c
45.93 ± 6.19a
Silt (%)
21.15 ± 5.84
24.95 ± 2.37
23.95 ± 7.25
23.15 ± 1.68
21.85 ± 1.47
NS
Clay (%)
31.42 ± 13.43b
45.42 ± 5.87a
33.52 ± 5.53b
49.12 ± 4.07a
32.22 ± 5.32b
pH
5.89 ± 0.42b
5.97 ± 0.28b
5.78 ± 0.22b
6.57 ± 0.23a
5.89 ± 0.23b
OM (%)
3.21 ± 1.19b
4.97 ± 0.83a
3.55 ± 0.72b
6.02 ± 0.85a
4.91 ± 1.44a
N (%)
0.13 ± 0.04c
0.23 ± 0.04b
0.16 ± 0.03c
0.29 ± 0.03a
0.24 ± 0.05b
P (mg kg−1)
4.33 ± 1.58
4.79 ± 1.50
4.48 ± 1.60
8.73 ± 8.90
3.54 ± 1.16
NS
K (mg kg−1)
80.57 ± 37.12b
77.83 ± 13.33b
117.01 ± 38.79ab
101.82 ± 27.08ab
144.39 ± 47.82a
Ca (mg kg−1)
570.79 ± 393.55b
867.96 ± 266.09b
520.24 ± 165.98b
1476.6 ± 498.46a
642.86 ± 191.59b
Mg (mg kg−1)
170.3 ± 80.82c
289.16 ± 81.36b
196.86 ± 70.11c
473.28 ± 71.01a
194.27 ± 41.95c
Measurements in teak plantations and old-growth forest sites in Khun Mae Khum Mee plantation. Different lowercase letters within a row indicate significantly different means by Tukey’s test (one-way ANOVA test, ;n = 50). ; NS = nonsignificant.