As we look toward the winter months, there’s a lot happening with holiday shopping, family visits and community gatherings. Despite how busy life can get this time of year, it may be worthwhile to consider preparing your trees so they may better withstand the stresses placed on them from ice and snow (and the upcoming spring storm season).

Trees have the ability to endure weight and force from normal precipitation and winds combined with the pull of gravity. However, certain types of precipitation can place extreme loads on a tree, which magnifies the effects of winds and increases the likelihood of wood breakage. Some examples include accumulation of ice on branches, and heavy, wet snow (especially early or late in the season when deciduous trees have foliage). Density of twigs/foliage, length of a branch, and degree of lean also play a part in amplifying effects of snowfall and ice accumulation. When ice coats branches, they become stiff and lose their usual flexibility against the drag of the wind.

Structural defects in a tree reduce wood strength and make the tree more susceptible to breakage under excess weight of precipitation and force of winds. Defects may include wood decay and cavities, cracks, root problems, dead wood, broken limbs and narrow branch angles. Decayed, cracked and dead limbs are more likely to break than living, structurally sound branches. Limbs with a narrow fork may have bark trapped between the two branches, known as included bark. Because these limbs have a weak attachment, they are also more likely to fail. You can prune your trees when they are young and remove this defect to prevent branch failure problems later. If pruning your own trees, make sure to follow the “1/3 rule”: Remove no more than 1/3 of the canopy at one time. Similarly, remove no more than 1/3 of a single branch at once and always prune back to the junction of another branch that is at least 1/3 the diameter of the branch you are pruning.

Sometimes severity of defects results in a high risk situation that may warrant tree removal. Extensive decay in the trunk, heaving roots, or a crack that is visible on both sides of the trunk are just a few examples. The Urban Forestry Department recommends hiring an ISA Certified Arborist for tree risk assessments and pruning and removal needs. While some issues are small and can be managed by a tree owner with a hand/pole saw, contracting with a Certified Arborist ensures that one’s trees are cared for properly and safely. Whoever the tree worker may be, make sure that they are insured and steer clear of anyone who advertises “topping” (an extremely harmful, discouraged, size reduction practice). Find a Certified Arborist in your area here.

Following these guidelines may help to reduce the number of broken limbs you’re stuck cleaning up this season… or the number of trees that you have to replace.


Take a look at other topics in the December 2013 issue of Tree Mail