Research Of Different Forest Management Regimes On Soil Properties And Carbon Storage Of Natural Secondary Forest In Northeasten China

The improvement of carbon storage and soil properties by optimizing forest management has been intensively investigated in recent years. The natural secondary Korean pine (Pinus koraiensis Sieb. et Zucc.) forests in Danqinghe Experimental Forestry Farm in Yilan County, Harbin, Heilongjiang Province were investigated. The effects of different forest management regimes, including extensive forest management (FM1), target tree-based forest management (FM2), adjustment and afforestation-based forest management (FM3), and nonintervention forest management (FM4), on soil properties and carbon storage were studied. Results showed:(1) The different forest management regimes in soil bulk density increased with the increasing soil depth, but soil water content and porosity decreased with increasing soil depth. The soil bulk density of FM1 is significantly higher than the other three forest management regimes, and its porosity is significantly lower than the others. The water content of FM2 is significantly higher than FM1、FM3.(2) The soil of four forest management regimes is strong acid, and their organic matter, total N, total P, total K, hydrolysable N, available P, available K is decreased with increasing soil depth. The soil PH of FM2 is highest in every soil layer. In 0-20cm soil layer, the organic matter of FM2 is significantly higher than the other three forest management regimes. In 20-40cm soil layer, the soil total N of FM2 is significantly higher than FM1、FM4. The soil total P of FM1、 FM2 and FM3 is significantly higher than FM4 in every soil layer. The soil total K of FM2 is highest in every soil layer, and is significantly higher than FM3 and FM4. The hydrolysable N of FM2 is highest in every soil layer, and is significantly higher than FM1 and FM3. The soil available P of FM3 is highest in every soil layer, and is significantly higher the others in 20-60cm soil layer. The soil available K of FM3 is significantly lower than FM2 and FM4 in every soil layer. In 0～60cm soil layer, the average organic matter, total N, total P, total K, hydrolysable N, available P and available K is highest.(3) Soil organic matter content showed a negative correlation with soil bulk density, but showed a very significantly positive correlation with soil porosity, total N, hydrolysable N, available K, and showed a positive correlation with soil water content and total P.(4) The carbon storage in the tree layer is as follows:FM2(112.92 t/ha)> FM4(85.91 t/ha)> FM3(80.09 t/ha)> FM1(76.97 t/ha). The carbon storage of every organ is as follows:trunk(56.00-85.22 t/ha)>root(11.70-15.50 t/ha)> branch(6.32-10.21 t/ha)>leaf(1.92-2.45 t/ha). The above-ground, underground and total carbon storage in shrub layer of FM4 is very significantly higher than the other three. The above-ground, underground and total carbon storage in herb layer of FM2 and FM4 and is very significantly higher than FM1 and FM3. There is no significantly difference among the four forest management regimes in carbon storage of litter layer. The distribution pattern of soil carbon storage was consistent with that of total carbon storage, i.e., FM2 (228.64 t/ha)> FM4 (205.36 t/ha)> FM1 (200.56 t/ha)> FM3 (182.54 t/ha).(5) The total carbon storage of four management regimes is as follows: FM2(344.02 t/ha)> FM4(294.75 t/ha)> FM1(279.42 t/ha)> FM3(264.51 t/ha). The distribution of total carbon storage is:soil layer(66.46%-71.78%)>tree layer(27.54%-32.82%)>litter layer(0.39%-0.53%)> shrub layer(0.16%-0.44%) >herb layer(0.03%-0.21%).Compared with the other three forest management regimes, FM2 had the highest water content and the highest contents of total potassium and available potassium of soil, which significantly improved soil property. We observed that the FM2 regime can improve the carbon storage of the forest and the physical and chemical properties of soil. This regime results in the most significant benefits for the sustainable management of the natural secondary Korean pine (P. koraiensis) forests in northeastern China.