Effect of soil physical-chemical properties on the decay of standing Pinus koraiensis in Xiaoxing'an Mountains,northeast China

摘要

We selected 18 rotten and nine healthy postmature live standing Korean pine(Pinus koraiensis) to study the correlation between the degree of tree decay and soil physical–chemical properties in the Dialing Forest District of the Xiaoxing'an Mountains, China. One transverse section of each sample tree at 40–50 cm height above the ground was tested by Resistograph to determine the inner decay status. We collected soil samples around the root zones(6–20 cm depth) of each sample tree to test the soil physical–chemical indicators including moisture content, bulk density, total porosity, p H, organic matter content, total and hydrolyzed N contents, total and available P contents, total and available K contents, and C/N ratio. The degree of decay of postmature Korean pine live standing trees was significantly and positively correlated with the C/N ratio(R = 0.838, P<0.05), organic matter(R = 0.615, P = 0.007) and moisture content(R = 0.543,P = 0.020) of soil around the root. The contents of total N,hydrolyzed N and available P in the soil under healthy sample trees were significantly greater than those under decayed sample trees, and larger N and P contents might inhibit the decay fungi breeding in soils of p H 4.4–6.29.The optimum multiple regression equation for degree of tree decay on soil physical–chemical indicators showed that the linear correlations between the degree of decay and soil C/N ratio and p H were significant(P<0.01) and the correlation was high(R2= 0.778). Enhancement soil C/N ratio and p H could promote the decay of tree trunks.