Early Effects of Thinning and Topdressing on Changes of Timber Assortment Structure in Middleaged Cunninghamia lanceolate
To construct the efficient cultivation technology system of Cunninghamia lanceolate diameter timber in the Nanling mountain area,and improve the yield and quality of large diameter timber of C.lanceolate in the Nanling mountain area,the orthogonal design was used to carry out the thinning and fertilization experi-ment of C.lanceolate middle-aged forest,and the stand growth was carried out after 3 years.T-test analysis results showed that the unit area accumulation of T-3(After thinning,the density was 1 500 plants per hm2,with each plant being fertilized with 200 g urea and 600 g calcium superphosphate)and T-6(The density after thinning was 1 200 plants per hm2,with each plant being fertilized with 200 g)reached significant(P<0.05)and extremely significant difference(P<0.01)before and after treatment,respectively.The optimal DBH-height growth model fitting was y=3.783 8x0.472 7.The results of growth analysis of different timber assortment structures showed that before and after treatment,timber assortment structures showed a decreasing trend of small diameter timber,and an increasing trend of medium diameter timber and large diameter timber.Orthogo-nal test analysis showed that the density control and topdressing effect had an effect on the timber assortment structures of C.lanceolate middle age forest.The optimal combination of factors for increasing the yield of large diameter timber was A3 B3 C2,that is,the minimum density(900 plants per hm2),the amount of urea(200 g per plant),and the medium level of calcium superphosphate(300 g per plant),which is the most conducive to increase the yield of large diameter timber.The best combination of factors to increase the output of large diame-ter timber was A3 B3 C1,that is,the minimum density(900 plants per hm2),the amount of urea(200 g per plant),and the minimum level of calcium superphosphate(0 g per plant).
Cunninghamia lanceolatemiddle age forestcultivation for large diameter timberdensity controlfertilization control
NETL
NSTL
万方数据
