The Study Of Growth Characteristics And Density Regulation Of Eucalyptus Coppice

In this paper,the eucalyptus artificial forest were used as the experimental subjects which planted in the Guangxi Naning arboretum.The effects of different germination methods on the tree height,DBH and volume of the eucalyptus artificial forest were studied.The main results are as follows:1.The seasonal differences of DBH,tree height and stock growth in eucalyptus plantations in different regions were significantly significant(p<0.01).The DBH,tree height and stock growth of eucalypt plantations increased gradually with monthly changes.Large,the peak of breast diameter,tree height and accumulation in each region mainly appeared from June to August,and the trough appeared in November,December and January.2.The effects of harvesting months on the growth of coppice stem in different regions were significantly different(p<0.01).There was no significant difference in the growth of coppice stem in different regions(p>0.05).The growth of 6-month-old germinating bars was rapid in the germinating forests felled in January-June,but poor in July-December.The height growth of germinating tree was the lowest in September,It was suggested that the best felling month was February-June.3.Different numbers of coppice stems per stump have different effects on the survival rate of coppice.① The initial density is 111 plants a unit area:the fewer the number of germinations,the easier the germination strips will survive.After half years of the first time cutting coppice,the average preservation rate of the coppice was 72.59%,and the difference in the preservation rate of the buds in different ways was not significant(p>0.05).After the second cutting coppice,the average preservation rate of coppice in each plot was 87.96%(compared with the second removal).②The initial density was 83 plants a unit of area:The average preservation rate of stump was 89.23%;the average preservation rate of the coppice was 76.45%after half years of the first time cutting coppice;the overall preservation rate was 84.02%after the second time cutting coppice,higher than the first time.4.Different stem number per stump can affect the tree growth.After 1 year of treating,the tree height of treatment 1 was significantly better than other treatments.After the second remove stem,the high growth of the treatment 2 and the treatment 3 trees increased significantly,and the difference in tree height growth became smaller,but it was still best to retain 2 stems per stump.The results of variance analysis showed that the effects of different retention methods on tree height growth were significantly different(p<0.05).5.The coefficient of variation of DBH of the two initial planting densities decreased with the increase of the number of remaining germination,and the average DBH growth was the best with 2 stems per stump.The initial value density of 83 plants a unit of area had different significant effects on the growth of DBH(p<0.01),and the initial density was 111 plants a unit of area(p>0.05)6.The average single plant volume of the two initial densities was the best(0.05 m3)with 2 stems per stump.The initial density of 83 plants per mu had different significant effects on the average single-soil volume(P<0.01),while the initial density was 111 plants per mu(p>0.05).