PT  - JOURNAL ARTICLE
AU  - Edward F. Gilman
TI  - Pruning Severity and Crown Position Influence Aspect Ratio Change
AID  - 10.48044/jauf.2015.008
DP  - 2015 Mar 01
TA  - Arboriculture & Urban Forestry (AUF)
PG  - 69--74
VI  - 41
IP  - 2
4099  - http://auf.isa-arbor.com/content/41/2/69.short
4100  - http://auf.isa-arbor.com/content/41/2/69.full
AB  - Growth on one branch is suppressed in proportion to pruning severity, resulting in a predictable reduction in branch:trunk diameter (aspect) ratio. However, little is known about response to pruning multiple branches. Several of the largest branches on live oak (15.3 cm trunk diameter) were pruned with four severities (0%, 25%, 50%, and 75%), then branch, nearby stem, and trunk diameter were measured for five subsequent years. Rate of trunk diameter increase five years after pruning was greatest for trees pruned with the 25% severity. Aspect ratio on all three pruned and measured branches decreased with time after pruning, pruning severity, and increasing height in the crown. Mean aspect ratio ceased declining between three and five years after pruning. The decrease in aspect ratio over time and with increasing severity on pruned branches was less pronounced in the lower crown than in the upper crown. Smaller change in aspect ratio on pruned branches in the lower crown suggests that when structurally pruning trees, branches in the lower crown may require a higher pruning severity to effect the same change in aspect ratio as upper branches.