The Study Of Fast-growing Large-diameter Timber Tomentosa Determination And Selection

In order to breed a Poplar varieties that fast-growing and suitable for the growth in Shaanxi Guanzhong,we study a Populus tomentosa plantation in Weihe test station of Northwest Agriculture and Forestry University,after measuring the tree height and DBH of each clones,then calculated individual volume.Lastly,using SPSS21.0 analysis each clones tree height,DBH and volume,then selected excellent clone and do stem analysis,The following is the result of this study:1.The growth of tested clones was difference with control group.2.In the tree height multiple comparison results,Only No.60 clones,No.77 clones,No.84 clones,No.66 clones,No.95 clones,No.75 clones,No.67 clones,No.69 clones and I-101 clones were significant differences at a significant level of 0.01;In the multiple comparisons of tree DBH,only No.85 clones,No.89 clones,No.84 clones and control were significant differences at a significant level of 0.01;In the multiple comparisons results of tree volume,only No.85 clones,No.89 clones,No.84 clones and control were significant differences at a significant level of 0.01.3.Lastly,the excellent clones we selected was No.85,No.89,No.84,and the No.85 clones was best.4.Using Populus tomentosa-85 clones do stem analysis that the fast growing period of tree height was 5 years to 10 years and 15 years to 25 years,the average growth and annual increment growth of tree height all reached the maximum value at 10 years,the maximum value of average growth was 1.09 m,and the maximum value of annual increment growth was 1.24 m.5.Using Populus tomentosa-85 clones do stem analysis that the fast growing period of tree DBH was 10 years to 15 years,and at 20 years the DBH reached 25.7cm;What's more,the average growth and annual increment growth of DBH all reached maximum value at 20 years,the maximum value of average growth was 1.25 cm,and the maximum value of annual increment growth was 2.18 cm.6.Using Populus tomentosa-85 clones do stem analysis that tree volume continued to grow during the year of measurement,and reached 0.7990m~3 at 28 years.What's more,the volume annual increment is more than the average growth in the measurement time,and did not intersect the trend,this shows that volume growth has not yet reached the number of mature age.7.So Populus tomentosa-85 clones very suitable for the environment in Guanzhong area and suitable for cultivation into large diameter timber.