It’s been almost two years since we planted some 175-200 cm sugar maple saplings on the Farm. An arborist will recommend that you wait at least 2-3 years before attempting any pruning but we knew a few of these trees could use our help.
Most deciduous trees and shrubs should be pruned when they are dormant, preferably in the early spring just before growth starts. Maples are an exception to the dormant pruning rule and should be pruned when actively growing in mid-summer. When pruned in early-spring, maples ‘bleed’ excessive amounts of sap. Pruning should not be done too late in the fall either, as wounds will not have time to heal before winter.
Sugar maple sapling, 200-250 cm, shortly after it was planted mid-May 2018. Note uniform branching structure and single, dominant terminal shoot.
Without some guidance, young maples can start to branch out in the wrong direction. Newly planted trees soak up the sun, moisture and nutrients as they regenerate new roots to strengthen and nourish the tree. They often need help finding their way during their formative years.
It’s almost two years later and this young maple needs some pruning. Note the multiple leaders at the top of the tree and imbalance of new growth on the right side of the tree compared to the left. Selective pruning will correct these conditions as shown in the tree below.
We did some light pruning during a recent tree inspection. The goal was to encourage the tree’s leader to grow by trimming competing branches. We began by removing any dead (leafless) or damaged branches. These were few and far between. We prefer to use bypass shears when pruning.
A few trees had many strong branches but lacked a central guiding leader. For these trees, we selected the strongest central branch to be the new leader and shortened the remaining co-dominant branches. Where experienced suggested doing so, a few of the larger competing branches were completely removed as we pruned to reestablish a single, dominant leader. Any new branches that were found growing on the lower parts of the trunk were also removed.
If there were multiple leaders at the top of a tree, we selected the strongest, best of the group and either reduced the competing leaders by 1/3 their length or completely removed them (if doing so did not remove an excessive amount of leaves).
We limited pruning of these young maples to what was essential and made a note to revisit these trees after the leaves fall in October.
Elsewhere on the farm, we pruned several 60-70 mm caliper trees by removing or shortening branches that had an irregular growth habit. We removed the parts of any branches that were growing toward the center of the tree’s crown or downwards in any fashion and removed the smaller of any branches that rubbed against one another.
We reduced the length of many of the lower branches that will not be part of the permanent canopy of the larger canopy trees. A few we removed completely. We will continue to do this selective pruning as the tree grows. This raises the tree’s canopy (crown) providing clearance under the tree.
Removal of a competing branch within the crown of a young caliper tree. We prefer to use bypass shears for our pruning work.
We reduced the length of most of the lower branches that will not be part of the permanent canopy of these trees. A few, we removed completely. We will continue to do this selective pruning annually as the trees grow, raising the canopy (crown) until there is at least 1.8- 2.1 m of clear trunk under the canopy.
We did not apply any tree pruning paint or wound dressing to the cuts. Using these products hinder the maple’s natural heeling process.
- Carl Mansfield, Arboreal Consultant, Maple Leaves Forever