Investigation On The Empty Rot Status And Root Distribution Of Ancient Sophora Japonica In Guanzhong Of Shaanxi Province

In this paper,we investigated the current status of empty rot and root distribution of ancient Sophora japonica of different diameters at breast height in Guanzhong,Shaanxi using TRU tree radar non-destructive testing technique,the aim is to understand the ancient Sophora japonica empty rot rule,root distribution characteristics and its health,to provide a strong theoretical basis for the protection and management of the Sophora japonica,rejuvenation and reinforcement and safety hazard investigation.A total of 40 ancient Sophora japonica sample trees of different diameter classes were selected according to the diameter at breast height,and the results of tree radar scanning were used to analyze the current status of the ancient Sophora japonica and to classify the ancient Sophora japonica empty rot class;the relationship between the ancient Sophora japonica empty rot and diameter at breast height,trunk height,and the empty rot rule of the ancient Sophora japonica trunk was studied;the distribution characteristics of the ancient Sophora japonica root system and the effects of diameter at breast height,tree height,crown breadth,and empty rot rate on the distribution of the ancient Sophora japonica root system were analyzed.The main conclusions are as follows:1、The results showed that all the 40 ancient Sophora japonica tested had different degrees of empty rot.the overall average empty rot rate of the ancient Sophora japonica was 30.38%,which belonged to grade 3 empty rot.among the 40 ancient Sophora japonica,5 ancient Sophora japonica trees with grade 1 empty rot,accounting for 12.5% of the total;11 ancient Sophora japonica trees with grade 2empty rot,accounting for 27.5% of the total;12 ancient Sophora japonica trees with grade 3 empty rot,accounting for 30% of the total,and 9 ancient Sophora japonica trees with grade 4 empty rot,accounting for 22.5% of the total;3 ancient Sophora japonica trees with grade 5 empty rot,accounting for 7.5% of the total.2、The proportion of molding hole,sapwood rot and whole empty rot increased with the increase of DBH,and the proportion of primeval rot and benign parts decreased with the increase of DBH.There is a close relationship between the trunk height and the empty rot of ancient Sophora japonica Among the five detection heights,the empty rot of 60 cm from the ground was the largest,and the empty rot of 180 cm from the ground was the smallest.3、Through the research on the empty rot rule of ancient Sophora japonica,it is found that the empty rot of ancient Sophora japonica begins to appear when the DBH is about 50 cm,the early type of empty rot is mainly primeval rot,sapwood rot begins to appear when the DBH is about 70 cm,and the ancient Sophora japonica trunk appears molding hole when the DBH about 80 cm,and grows rapidly,becoming the main type of trunk empty rot.When the DBH is 130 cm,the empty rot rate of Sophora japonica reaches about 40%,and the trunk empty rot of the Sophora japonica transforms from grade 3 to grade 4.Therefore,in the protection of Sophora japonica,it is necessary to pay special attention to the health status of Sophora japonica whose DBH is more than 130 cm.The higher the trunk height,the larger the proportion of benign part and the smaller the empty rot rate.4、The distribution characteristics of ancient Sophora japonica roots are as follows: in the vertical direction,the roots are mainly distributed in 40-80 cm of 0-1m depth range.In the horizontal direction,the root density of 0-1m detection range was the largest,followed by 1-2m detection range,and the root density of 2-3m detection range was the smallest.The roots of Sophora japonica were mainly distributed in the0-100 cm depth range of 0-1m level.In addition,the growth of roots is closely related to the health of trees.The crown of trees with relatively developed roots and high density grows well,and the branches and leaves are luxuriant;The ancient Sophora tree with relatively weak root growth and low density has smaller crown,sparse branches and leaves,more dead branches and poor ability to absorb water and nutrients.5、Through the analysis of the relationship between the root distribution and the trunk empty rot,DBH,tree height,crown breadth,etc.it is concluded that the main factor affecting the root distribution of the ancient Sophora japonica is DBH,and the trunk empty rot,tree height,crown breadth have little correlation with the root system of the ancient Sophora japonica.