Effects of different densities on growth,soil physicochemical properties and microorganisms of long-period management Cunninghamia lanceolata forest
[Objective]Cunninghamia lanceolata is one of the most important fast-growing timber species in southern China.Long-period management of Cunninghamia lanceolata is a new management mode that takes into account the high-value large-diameter timber production and long-period maintenance of soil strength.This paper investigates the effects of different densities on the growth and soil of long-period management of Cunninghamia lanceolata forests,in order to determine the reasonable management density of long-period management of Cunninghamia lanceolata plantation forests,and to provide a basis for sustainable management of Cunninghamia lanceolata plantation forests.[Method]A 40-year-old fir plantation forest in Lanshan County,Yongzhou City,Hunan Province,which had been logged at 30 years of age,was used as the study object,and four densities were set at the time of inter-harvesting(A:750 plants/hm2,B:825 plants/hm2,C:900 plants/hm2,and D:1 050 plants/hm2),to analyze the effects of densities on the growth of the forest stand and the physicochemical properties of the soil through the investigation of the sample plots and the testing of the soil samples.[Result]The average DBH,tree height,number of large diameter timber plants and stock volume of fir forests all showed a tendency of increasing and then decreasing with increasing stand density,and were highest at density B.The soil nutrients were affected by the density of fir forests,and the soil nutrients were affected by the density of Cunninghamia lanceolata forests.Soil nutrients were significantly affected by changes in stand density,showing a trend of increasing and then decreasing with increasing density,mostly reaching a maximum at density B.Soil nutrients in the 40-60 cm soil layer were more closely related to the growth of cedar.The average diameter at breast height was positively correlated with soil nitrogen and potassium;the total accumulation was positively correlated with phosphorus content,and the number of large-diameter Cunninghamia lanceolata plants and accumulation were both positively correlated with soil nitrogen and potassium.The diversity index and OTU number of the soil bacterial community increased with increasing density,and the diversity index and OTU number of the fungal community decreased.The effect of total phosphorus content on the community structure of fungi was significant,and the effect of total potassium content on the community structure of fungi was highly significant.[Conclusion]It can be summarized that density B(825 plants/hm2)is the most suitable density for long-period large-diameter timber management in Cunninghamia lanceolata forests.Long-period management of Cunninghamia lanceolata is conducive to the cultivation of large-diameter timber and the maintenance of good bacterial community structure,which promotes the accumulation of soil organic matter and nutrients,and is conducive to the sustainable management and stable development of Cunninghamia lanceolata forests.
stand densitystand growthsoil physicochemical propertiessoil microorganisms
万方数据
维普
