You know how to handle the cold season, but is winter tree care on your radar?
By this point in the winter season, many of us feel like we’ve got it all figured out. We’ve worked out the snow removal kinks, have all our firewood in, and know how to keep our family and animals cozy and safe. But what about winter tree care? Has that crossed your mind?
If you’re like most people, unless you’re dealing with broken limbs, probably not.
So, what does winter tree care involve? Thankfully, there’s not much to it, but these few key points are important.
Root protection The first consideration for roots is insulation. In the Sandpoint area, this is usually not a problem. We get enough snow to insulate roots from cold temperatures. However, it’s still not a bad idea to mulch around the base of your trees for added protection. After the snow melts, get ready for next winter by spreading a two-to-four-inch layer of mulch around the base of your tree, under the canopy. Just be sure to keep mulch away from the trunk.
The other consideration for roots that is an issue in Sandpoint is the use of road salt. This can cause discoloration of foliage in evergreens and bark dieback in all trees. In the long term, it can lead to systemic issues caused by the preponderance of salt in the soil. Several options exist to remediate this issue:
Use calcium chloride instead of sodium chloride. It’s more expensive but less harmful to plants. And when you consider the cost of a hazard tree removal, it may be more cost effective in the end.
Furthermore, you can mix your road salt with sand for added traction and to lessen the amount of salt used.
Extra watering of roadside trees can dilute the amount of salt present on the trees and in the soil.
Finally, apply gypsum in late fall, before snow comes, to protect roots.
Trunk protection Especially on young trees, thin bark is a vulnerability. Deer can do damage by rubbing their antlers on the trunk. Rodents can tunnel through the snow and chew the bark. And even temperature swings can do damage, warming the trunk on a sunny day, only to freeze hard at night, damaging a vascular system that got excited about spring. An easy winter tree care solution to these problems is to wrap the trunks—from the base to the lowest branches—with plastic tree guard. This is especially important for young maple, ash, linden, locust, dogwood, cherry, birch, and crabapple trees.
Branch protection The best protection for branches is maintenance pruning. This ensures that broken and diseased branches are removed before the snow does it for you. At this point in the season, though, proactive care can include gently removing snow from drooping branches to prevent them from breaking. Do this with a broom rather than by shaking the limb so as not to harm the branch. Also, try to keep from piling snow against your tree, trapping low branches in the process. And finally, if you notice ice covering your tree, leave it. Let it melt and then inspect for damage. Trying to remove ice yourself will likely cause more harm.
With these few tips in mind, your tree should easily weather the winter. Come spring, if you notice any damage from the cold season, call us. We’re happy to assess your tree’s health and suggest any corrective action it might require.
Just how cold does it have to get to kill those pests?
Many of us like to look for silver linings, and the shining hope of a frigid winter is that overwintering insects suffered more than we did. If there are fewer harmful creepy-crawlers this summer, then maybe that chilly February was worth it.
I can’t speak to how the yellow jackets fared (hopefully poorly), but I do know that our problematic bark beetles—specifically the fir engraver and Douglas fir engraver—took it all in stride. February was hardly a blip on the radar for their sleeping larval selves. It was not cold enough to cause beetle die-off. Thus, expect more browning firs in the months and years to come.
When it comes to winter, beetle larvae are way tougher than we are. They use snow around the base of a tree and the tree’s bark as insulation. The larvae excrete all their stomach contents so the liquid won’t freeze up. Then they fold over on themselves and generate a kind of internal antifreeze. Finally, they wait, able to withstand temperatures of up to -40 degrees.
February’s chill didn’t even come close to that.
This is the characteristic “mining” pattern the Douglas-fir engraver beetle larvae makes when eating the tree’s inner bark. Each beetle has a pattern all its own. Image courtesy of Wayne Brewer, Auburn University, Bugwood.org.
The best hope for temperature-related beetle die-off is to have a hard freeze—below zero—very early or very late in the season. Like in October or now, in March or April. If the freeze comes early, the beetles won’t have yet generated enough antifreeze in their systems to survive; and if the freeze comes late, the larvae will have already woken up with the warmer weather and shed their defenses. However, even in these scenarios, beetles can always fly in from areas that didn’t get as cold.
Thus, it seems, the beetles—and their detrimental effects—are with us for at least another year.
So, in the absence of such beetle die-off, what is a landowner to do? First, keep an eye on the health of your trees. Beetles are opportunists. They’ll go for stressed trees whose defenses are down, and then they’ll spread from there. Cull the diseased trees from your forest to limit infestation opportunities. And while you’re at it, just thin your forest in general. Trees living in competition with one another for light and nutrients don’t have the necessary resources to fend off beetle attacks. Give your trees the room they need to thrive. Finally, if you do have beetle-kill on your property, remove it.
To learn more about beetles, check out these Forest Service documents on the fir engraver and the Douglas-fir engraver beetles. Also, our last post was about bark beetles in North Idaho. Finally, don’t hesitate to give us a call if you have any questions about the health of your trees.
This winter, there seems to be a pattern of one serious cold snap per month, and it looks like March will be no exception. Forecasts are calling for temperatures around zero degrees this weekend. Our home is about 600 feet higher in elevation than town-proper, meaning that the mercury dips lower for us. In December, we had a reading of -10, and one January morning found us at -16 degrees. Brrrrr!
During these cold snaps, we’ve also noticed strange popping noises emanating from the otherwise silent forest around our home. The sounds have been akin to that of a golf ball striking a hard surface, but certainly no one is playing a round in the dark amongst the hemlock and cedar.
It turns out, the trees are making the noise.
As everyone knows, when water freezes, it expands – including the water content in trees. Thankfully, sap is not pure water; it contains sugar, which acts as antifreeze. The higher the sugar content, the lower the freezing point. This protects the trees from the ravages of Old Man Winter. However, there comes a point when the sugary sap must finally succumb to the frigid temperatures…and it does so with a POP!
This is the sound of a rupture. In most cases, these ruptures are harmless to trees, and come spring and early summer (when trees do most of their growing), they will compartmentalize the wound. Some ruptures are more difficult to heal around, though. This can create two problems for a tree (along with the tree owner who has structures nearby): One is that a rupture that leads to an open wound allows pathogens to enter, thus compromising the health, stability, and longevity of the tree. The other problem is that the rupture may have generated cracks in the trunk of the tree, weakening it structurally. With a strong wind or a heavy snow, the tree could come down.
Native trees have many defense mechanisms for cold, and even with a little popping this winter, they should be just fine come spring. If you’d like to learn more about what trees do at a cellular level to survive cold, the Science Questions With Surprising Answers site has a good explanation. And if you have concerns about a specific tree exhibiting cracks or ruptured bark, don’t hesitate to contact us for a risk assessment.
In the meantime, stay warm!
This winter, there seems to be a pattern of one serious cold snap per month, and it looks like March will be no exception. Forecasts are calling for temperatures around zero degrees this weekend. Our home is about 600 feet higher in elevation than town-proper, meaning that the mercury dips lower for us. In December, we had a reading of -10, and one January morning found us at -16 degrees. Brrrrr!