TITLE:
Change Point Analysis to Detect the Effect of Pruning Severity on Tree Growth
AUTHORS:
Yutaka Iguchi
KEYWORDS:
Regression Analysis, Crown Removal Limit, Tree Growth, Pretreatment, Abrupt Change
JOURNAL NAME:
Open Journal of Forestry,
Vol.14 No.1,
December
21,
2023
ABSTRACT: The effect of pruning severity on tree growth was analyzed by change
point detection using segmented regression. The present study applied this analysis
to a well-known published data set including diameter growth response, tree
age, pruning severity and pretreatment crown size. First, multiple regression
analysis was performed to assess the effect of tree age, pruning severity and
pretreatment crown size on diameter growth response. Next, segmented regression analysis was performed to assess the effect of pruning
severity on diameter growth response. The results of the multiple regression
showed that diameter growth response was significantly influenced by pruning
severity and pretreatment crown size. The results of the segmented regression
showed that in the whole data set, an abrupt change toward a decrease in
diameter growth response was detected at 25% of the live crown removed.
However, in the group of fully crowned and open-grown, diameter growth response
continuously decreased with increasing pruning severity with no significant
abrupt change, whereas in the group of 70% - 90%
live crown, diameter growth response did not significantly decrease up to the
break point (53% crown removed) and then abruptly decreased. This may be the
first study to show the numerical evaluation of the effect of pruning severity
on tree growth by change point analysis.