Table 1 Topics and keywords with topic modelling analysis

Division Abbreviation Unit Definition
Tree height H m It refers to the vertical distance from the surface to the top of the tree, excluding coating paper. However, for tropical and subtropical trees such as Cycas revoluta Thunb. and palms, the vertical height of the stem is the height of the tree.
With of crown W m It refers to the diameter of the crown of a tree, and the crown of an oval tree is the width of the crown of the tree, divided by the sum of the widths of the shortest and the longest centered on the crown axis of the largest layer.
Diameter at breast height B cm It refers to the diameter of the stem at a height of 1.2m from the ground. However, in the case of a tree with two or more split stems, it is as follows.
Diameter at root collar R cm It refers to the diameter of the stem in contact with the ground surface of the cultivation area before trees are excavated. In the case of a tree that has the property of splitting the stem into several branches below the height of the chest, it is indicated by the root diameter instead of the chest height.
Stem length L m It is the maximum length of a tree crown. In particular, the length of the tree crown is applied when the tree crown is a tree that has the characteristic of growing horizontally or a shaped tree crown.