identify potential hazards before the storm
Many factors play into how strong a tree is and how well it will withstand the high winds and icy loads of winter including tree species, overall structure, and health of the tree. But what are some things you can look for to determine if your trees will be safe this winter?
Look for the Obvious First
Dead Limbs - Removing dead limbs should be a no-brainer right? Well, yeah, but.... dead limbs can be deceiving. Do you ever notice that some dead limbs just seem to stick around? Why is that? Well, being dead, they no longer carry the weight of a live limb since they no longer hold water (water weighs a lot!). When a tree limb dies, it dries up and becomes hard and rigid. Think of a 2 x 4 from the lumber yard... very hard to break. Yeah! At least temporarily, a dead limb may have a net gain on strength compared to a live limb. But sooner or later all dead limbs come down so it is a good idea to remove dead limbs. Plus it just looks so much better too.
Trees with Lean - Trees with lean can easily uproot during winter storms especially if the soil is already saturated with water. What makes matters worse are combined factors that contribute to a tree failure such as decay in the root system or girdling roots that make the tree less stable.
Look for the Not so obvious
Cracks or Splits - Trees sometimes develop cracks or splits from previous severe weather events. A branch is damaged but not to the point of falling or even killing the branch. Limbs with cracks and splits may seem to continue to grow like normal but it will never be as strong as it was before the damage occurred. Both types of injury allow for decay to entrer into the tissue where decay fungi will eventually weaken the limb. These types of injuries also make great starter houses for carpenter ants which eventually further weakens the tree. The defect to the lower right was not detectable from the ground.
Narrow Crotches - Tree stems or branches with narrow crotches are dangerous because the holding wood is shared so-to-speak and the narrower the crotch angle, the less support there is to go around. Some crotches contain included bark this can be particularly dangerous since the tree grows against itself eventually causing a crack or stem failure. When the stems arising from the crotch are similar in diameter we call them co-dominant stems. Co-dominant stems with V-shaped unions are inherently weaker than stems with U-Shaped unions.