Table 2.
Change of inorganic compounds in the wood during burial period (unit: %)

	Na	Fe	S
PC	-	0.016	0.013
P3	1.467	0.011	0.293
P6	1.819	0.021	0.282
OC	0.014	0.018	0.012
O3	0.834	0.068	0.127
O6	03.889	0.013	0.169
Seawater	0.951	-	0.007
Mud in the study	0.515	2.007	-

PC: Korean red pine for control, OC: sawtooth oak for control, P3: Korean red pine after 3 months, P6: Korean red pine after 6 months, O3: sawtooth oak after 3 months, O6: sawtooth oak after 3 months.