Response Of Tree Rings To Different Planting Densities Based On The Data Of Resistograph

In this study,the Populus deltoids Bortr.cv.‘35' fast-growing and high-yielding forest of Dongtai Forest Farm was used as a research object.The Resistograph was used to perform nondestructive investigations on the trunks of poplars in both the west and the north directions,and conduct tree growth survey by the traditional increament borer was used at the west parallel position.By collating and analyzing the survey data,Main results of the study were as follows:1.Among all the 56 poplars,according to the age obtained by Resistograph,there are 3 plants which drilled from the north reduce 1 year,and 2 plants which drilled from the west reduce 1 year;the age obtained by the Resistograph is generally smaller at the tree which DBH large.The age determined by the increament borer is consistent with age in the forest archives.Using the Resistograph to determine the age of trees is more accurate and can be used instead of increament borer for tree age surveys.2.Among all the 56 poplars,perform T-test of the annual ring width data obtained by the increament borer,and which obtained by Resistograph;there are 54 groups where the difference is not significant.It shows that the annual ring width sequence obtained by the increament borer and Resistograph is basically the same,and the Resistograph can replace the increament borer for the determination of poplar growth.3.Among all the 56 poplars,T-test was performed on the data of annual ring widths obtained from Resistograph in the same tree in two directions.There were 10 significant differences and highly significant trees in both directions,accounting for 17.9%.In the survey of poplar growth,the use of the Resistograph in 2 directions can make the annual ring information more complete,and the information in 2 directions can be mutually confirmed and supplemented.4.In the 6-year-old and 9-year-old poplars,larger planting density will make the annual rings narrower.The poplars of 12 years,15 years and 18 years did not test the setting of planting density has an effect on the width of annual rings,may be affected by factors such as plot settings.5.The T-test was performed on the average annual resistance sequence obtained from the 56 groups of Resistograph in the same tree in two directions.There were 7 groups with significant differences.There were 2 groups with extremely significant differences.The average resistance sequence in 2 directions can confirm and supplement each other.6.The average resistance of poplar wood increases from the outside to the inside,and the average resistance value of the same year is about 80.The formation time of annual ring earlier,the greater the average resistance value of the annual rings.It is explained that after the formation of xylem,there is a process of material accumulation density increase.7.The higher the planting density in the two outer rings of the poplar trees in 6,9 and 12 years,the greater the average resistance in the annual rotation.Other years in the interior have not shown a similar relationship.In 15 years and 18 years,the annual rings of poplar trees did not show a similar relationship,which may be due to the influence of natural disasters and selective cutting of mature forest.8.By annual ring average resistance data and annual ring width data to estimate of breast height section average resistance,breast height section average resistance and age for regression analysis,the regression equation for y = 2.1927 + 114.72 x,the squared R = 0.7878,breast height section average resistance and positively related to the age.