Effects of Soil Compaction and Relative Light Intensity on Survival and Growth Performance of Planted Shorea macrophylla (de Vriese) in Riparian Forest along Kayan Ulu River, Sarawak, Malaysia

Table 3

Comparison of soil penetration resistance at 0-100 cm depth in plot aged 20 years (SPD96), plot aged 19 years (SPD97), plot aged 18 years (SPD98), and plot aged 17 years (SPD99).

	Soil Penetration Resistance (J cm^-1)
Depth (cm)	0-10	10-20	20-30	30-40	40-50	50-60	60-70	70-80	80-90	90-100
Study Sites
SPD96	2.5 ± 0.1a	4.3 ± 0.2ns	5.7 ± 0.4a	6.9 ± 0.7ns	8.6 ± 0.7ns	11.3 ± 0.9ns	14.7 ± 2.2ns	19.3 ± 3.0ns	21.1 ± 3.1ns	24.7 ± 3.6ns
SPD97	2.5 ± 0.2a	4.3 ± 0.4ns	6.6 ± 0.4ab	8.3 ± 0.4ns	9.5 ± 0.4ns	11.4 ± 0.5ns	13.7 ± 0.8ns	15.7 ± 1.1ns	18.0 ± 1.4ns	21.6 ± 1.8ns
SPD98	3.7 ± 0.4b	5.3 ± 0.6ns	7.8 ± 0.5b	8.6 ± 0.5ns	9.0 ± 0.6ns	10.0 ± 0.8ns	11.3 ± 1.0ns	13.2 ± 1.8ns	16.2 ± 1.9ns	20.4 ± 2.6ns
SPD99	3.4 ± 0.3ab	5.3 ± 0.2ns	7.1 ± 0.4ab	8.7 ± 0.5ns	10.3 ± 0.7ns	11.4 ± 0.9ns	14.9 ± 1.3ns	18.7 ± 1.6ns	23.7 ± 2.2ns	29.8 ± 3.2ns

Means ± standard error: values in the same column followed by different letters indicate significant differences among sites at P < 0.05 using Tukey’s test; ns: no significant differences.