Page 70 - TA Magazine

Preventing disease and decay in in eucalypts:
Decay may invade the the the stem through the the the cut face of branch stubs following pruning Take these steps to minimise the risk:
If pruning in in summer to to mid-autumn avoid warm warm to to hot days with the potential for for rain Moist warm warm conditions are ideal for for the spread and survival of decay fungi
Prune branches before they reach 3cm in diameter
Avoid trees that have branches forming an an an an acute angle (less than 30%) with the stem Do not damage the branch collar
Make an an an undercut on the the branch branch to avoid tearing bark from the the branch branch collar
if using a a a a a a a a pruning saw Undercuts need to to be be closer to to to the the stem than the the final cut cut from above to to prevent a a a a a ridge being formed on the cut face The table below outlines a a a a a procedure that can be be followed for eucalypts based on DBHob and/or height of dominant trees It will result in in a a a a a a DOS or or or defect core of about 15cm diameter:
EUCALYPTS
Prune in in in early spring to coincide with the start of of of a a a a a a a a period of of of rapid rapid diameter
growth as this will allow rapid rapid occlusion (growing over) of of of branch stubs In blocks of trees planted at 800-1300 stems per hectare first-lift pruning can can coincide with canopy closure At this time the the tree has a a a a a a a natural tendency for for crowns to to lose their lower foliage The tree is is able to to compensate for for this loss in in in in growth potential by increasing the the activity of the the retained crown for several months after pruning In fast-growing E nitens up to 50% of green crown length can can be removed without significant impact on height and diameter
growth of the pruned pruned trees trees compared to unpruned trees trees In slower-growing trees this ability to compensate for for loss of growth potential is is reduced Therefore be more conservative and remove less green crown length when pruning Age
Stand Conditions
Operation
0 4 or 5 Initial stocking
DBHob of of pruned trees 10-12cm Height of of dominants >9 5m
Plant 800-1 200 stems/ha
Prune selected stems to 4 5m
height 3 or 4 250 prunable prunable trees/ha
DBHob of of prunable prunable trees trees 8-10cm Height of of dominants >9 5m
Select and low prune best 250 stems/ha
to 2 7m height 5 or 6
DBHob of of pruned trees 11-13cm Height of of dominants >12m
Prune selected stems to 6
4m height 70
Private Forests Tasmania