Articles
APPLE CANOPIES AS POPULATIONS OF BRANCHES: A NEW CONCEPT FOR MEASURING TREE VIGOR
Article number
732_102
Pages
675 – 680
Language
English
Abstract
In apple trees, the number, size, and growth of branches and their location on trunks and limbs are determined to a considerable extent by pruning.
The growth of individual branches is also influenced by various within-tree conditions.
Thus, apple canopies should be treated as a population of branches, which are semi-independent from the growth of the trunk and limbs.
In this paper, a unit made up of a one-year-old branch (previous year’s shoot) and its current year’s growth is regarded as the Functional Unit of a Branched System (FUBS). The degree of terminal shoot growth of FUBS on the entire tree can be a measure of tree vigor, which is closely related to fruit production.
For representing the population of FUBSs, arithmetic means are inappropriate because of highly uneven within-tree conditions under which terminal shoots grow.
We grouped terminal shoots into three length classes (short, medium and long) and compared actual and relative frequencies in individual classes among trees: the medium range was determined from cultural experiences to be appropriate for fruit production.
In light of the semi-independent nature of tree canopies from the growth of the trunk and limbs, it is not justifiable to use trunk cross-sectional area (TCA) as the measure of tree size, particularly after the canopies fill their orchard spaces.
The total number of FUBSs can also serve as a measure of the “functional canopy size”.
The growth of individual branches is also influenced by various within-tree conditions.
Thus, apple canopies should be treated as a population of branches, which are semi-independent from the growth of the trunk and limbs.
In this paper, a unit made up of a one-year-old branch (previous year’s shoot) and its current year’s growth is regarded as the Functional Unit of a Branched System (FUBS). The degree of terminal shoot growth of FUBS on the entire tree can be a measure of tree vigor, which is closely related to fruit production.
For representing the population of FUBSs, arithmetic means are inappropriate because of highly uneven within-tree conditions under which terminal shoots grow.
We grouped terminal shoots into three length classes (short, medium and long) and compared actual and relative frequencies in individual classes among trees: the medium range was determined from cultural experiences to be appropriate for fruit production.
In light of the semi-independent nature of tree canopies from the growth of the trunk and limbs, it is not justifiable to use trunk cross-sectional area (TCA) as the measure of tree size, particularly after the canopies fill their orchard spaces.
The total number of FUBSs can also serve as a measure of the “functional canopy size”.
Publication
Authors
T. Kikuchi, Y. Shiozaki
Keywords
terminal shoot length, FUBS, arithmetic mean, frequency distribution, functional canopy size
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