Braving the Winter Cold

Our Passion for Pruning

Winter is on the way to the Twin Cities, which means some of us are holed up inside, protected from the elements. Although the landscape maintenance season is considered at a close, your trees can still use some attention. Winter in Minnesota is a great time to prune trees! Dormant season pruning is considered the best for tree health. This is especially true for those species most susceptible to insect and disease problems. Other benefits of dormant pruning include more visible branching structure and the protection that frozen ground creates for turf and other small plantings.

Without the leaves on the tree, field arborists can more clearly see the branching structure. Poor branching structure makes a tree more susceptible to failure in high load situations such as during heavy snow fall, ice storms, or windy days. These weak branch unions can be dealt with in winter when they are easily visible. This is true for both mature and small trees. Often times structural pruning done on small trees during the spring and summer creates holes in the canopy that can be unsightly, however pruning in the winter gives the tree a chance to fill in holes during spring leaf out. This makes the tree look more balanced and gives it a fuller canopy earlier in the season. In addition to being able to see structure, winter or dormant season pruning is better for the tree.

We can think of a tree’s system like we think of accounts at the bank. Leaves are the employees of the tree, creating opportunities for deposits. They make sugar, allowing the tree energy to grow, defend itself, and store energy for later use. These functions are like withdrawals. If the leaves are deposits, the roots are a savings account. Energy stored in the roots is used during spring to create new leaves for that season. When trees are shutting down, more of the energy created in the leaves goes into storage than into growth or other functions. By pruning after the leaves have fallen off, we maximize the energy the tree can send to its savings account, while still accomplishing our aesthetic and structural goals. This way we are minimizing the wasted energy in the tree.

Now the big question, without leaves on the tree, how do field arborists identify dead wood?

Sometimes identifying deadwood can be tricky. Sure, leaves can be a big clue, but as professionals we have other ways of knowing what must go, and what should stay. Branches without buds, bark that is falling off, and a lack of springiness are just a few clues we use to identify dead branches. In winter these branches can be removed, often times more efficiently than in spring or summer.

Another great reason to prune in the winter is that other plants can be better protected. Grass, hostas and other plantings can take a beating during spring and summer tree pruning. With snow cover and frozen ground these plants are cushioned from falling branches and constant foot traffic. Access gets better too. Our bucket trucks can safely be parked on frozen lawns with little or no worry about damaging the grass. Removals that otherwise would have to be climbed can be felled onto frozen lakes and ponds, making work much safer, and more efficient.

The cold weather of winter causes not only trees to go dormant, but insects and diseases are all shut down for the winter season. Some species of trees, such as oaks and elms, should only be pruned in the winter, because the insects that carry the oak wilt and Dutch elm disease fungi are not active at this time. When these undesirable insects are active, they are attracted to fresh pruning wounds; by pruning in the winter these wounds can begin to close before insect and disease activity reaches its peak. This reduces the risk of infecting these trees.

Even though it can be brutally cold the certified arborists at Rainbow Treecare love pruning in the winter. It is better for the trees, and as the professionals that are the liaison between trees and people, it is our pleasure to brave the cold for your trees. And if there are hot chocolate and cookies for us after a job well done, hey… life just doesn’t get any better!!

Jen Morgan joined our Rainbow Team in 2005 with a degree in Urban Forestry from Mid-State Technical College. Now working as one of our field arborists, you will likely find her up in a tree with a chainsaw in her hands.

 

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