Global climate change is having greater effects on plants throughout the world, and central Texas is not immune to the changes. As average temps climb higher, we are seeing a shift in the natural range of some species. We are also seeing increased severity of storms, paradoxically during both warm and cold weather. In the last half decade we have seen two of the greatest winter storms we’ve seen in at least 50 years. The result of those storms was not only abnormal amounts of freeze damage, but abnormal amounts of snow and ice breakage as well. Add to this an increase in the severity of the typical wind storms we see in spring and the likelihood of even more damage to trees in the future is high.
What should be done when branch ends break on trees, whether it be due to snow, ice, or wind? Should they be left alone? Should they be cut right below the damage area? Or should they be completely removed? It may surprise you to learn that there is not a great amount of research that specifically compares tree response to the first two options. But there are many true experts out there who have recommendations based on their experience. The problem is, all of these highly qualified experts do not agree. However, most of them seem to come down one on side.
First, some basic information. How a tree responds to such breakage depends on several different factors, species being a key one. Fortunately, many if not most of our large shade trees in central Texas will respond to branch breakage in winter or spring with vigorous sprouting at the break site. Live oaks are particularly vigorous in their response. This is a good thing, as it keeps the remaining part of the branch alive. If the branch is particularly large and is completely removed soon after breaking, its removal will likely result in decay entering the tree sometime after the removal cut is made, even if the cut is made in accordance with recommended arboricultural standards. This will almost certainly happen on a species that does not have good decay resistance. It will also leave a large “hole” in the canopy, which greatly affects how a tree responds to high winds. So preserving as much of a broken branch as possible is recommended by all experts.
So that leaves us with the first two options: leaving the broken end alone, or cleanly cutting the damaged part off. If the branch end is still connected (Fig. 1), then there is only one answer: the damaged part must be cut off, since for safety reasons the broken part cannot be left, and in most species it will die anyway. In this case, we would cut back to completely undamaged wood (Fig. 2). This article is mostly intended to discuss dealing with recent damage. If the break occurred some time ago and new sprouts have emerged, which action to take will vary depending on the specific situation.
Fig. 1
Fig. 2
If the branch end has completely broken off (is not still connected at all) most experts recommend cleanly cutting off the jagged end (as in the first scenario). I agree with this approach. Those that recommend leaving the damaged area alone argue that “mother nature knows best” and that the increased circumference of the wound provides more opportunity for sprouts to emerge. Those like myself who recommend removing the damaged end argue that the increased surface area of the break is more likely to result in decay, and that even if there would be more sprouting, these sprouts would be less likely to develop into strong branches if they have emerged from spindly splinters of wood. Fig. 3 is an example of resprouting from a damaged end, and Fig. 4 and example of resprouting from a cut end.
Fig. 3
Fig . 4
If the tree does not respond with new growth within about 15 months, it is most likely dead (in most central TX species). At this point, the entire branch should be removed, for safety purposes as well as for tree wound response. As with any pruning cut, especially a large one, this must be done in a precise way to avoid further injury to the tree.
As always, my recommendation for all your trees, damaged or not, is to contact me for a consultation. (Five one two) 301 8700.