SELECTION OF SUPERIOR TREES OF JUGLANS MANDSHURICA IN EASTERN LIAONING AND EFFECTS OF ENVIRONMENTAL FACTORS ON ITS GROWTH Zhou3, Yuchun Yang', Chunping Jifeng Deng1,2'*

In order to determine the optimal provenance of Juglans mandshurica, the selection criteria of superior trees suitable for J. mandshurica wood purpose forest in Liaoning region were formulated. In this paper, the absolute growth method was used to select superior trees from six provenances of J. mandshurica natural forests distributed along Changbai mountain range in eastern Liaoning. The quantitative characteristics of the candidate superior trees were measured and the correlation between the growth of I mandshurica from different provenances and environmental factors was analyzed. The results indicated that: (1) the tree age of J. mandshurica natural forest was estimated to be 30-80a by using the outer 7 cm, and the tree age was divided into 5 age classes. the quantitative indexes of different age classes were determined by taking the average annual growth of the tree height (H) and diameter at breast height (DBH) plus half of its standard deviation as the baseline standard to select 24 superior trees; A scoring method was used to select the selected superior trees, and 14 superior trees were finally selected, with a selection rate of 6.93%. Among the six provenances of J. mandshurica, the highest selection rate of Qingyuan superior trees was 11.43%, which was the best provenance. While, Dandong did not select superior trees. (2) Xinbin provenance has the largest annual growth of H and DBH, Qingyuan provenance has the largest average of H, DBH, height under living branches, central diameter and crown width from north to south. Slope was significantly positively correlated with height under living branches, but not with DBH and tree height. The tree height of J J. mandshurica at different slopes was significantly different, and the tree height and overall growth at the middle slope position were better. The central diameter of different slope and direction was significantly different, and the central diameter and overall growth of the southern slope were better. (3) The average annual temperature in environmental factors has a very significant negative correlation with tree height and a significant negative correlation with height under living branches. The average annual precipitation has a significant negative correlation with DBH. The highest air temperature has a very significant negative correlation with the annual growth of DBH and a significant negative correlation with the height -diameter ratio. The selection rate of J. mandshurica superior trees was significantly negatively correlated with the average annual temperature of the seed source. The results of this study are of practical significance for further understanding the variation law of J. mandshurica geographic provenance and rational utilization of precious resources ofJ. mandshurica, accelerating the construction of ecological environment and breeding fine varieties of high-quality timber species.

Automated summary

By formulating selection criteria for Juglans mandshurica trees in Liaoning region and analyzing the correlation between growth and environmental factors, the study concluded that Qingyuan provenance had the highest selection rate, while Xinbin provenance showed the largest growth advantage.