The weather in the winter takes its toll on trees due to storms, ice, and rapid fluctuations in temperature. Winter is a stressful time even in species native to colder regions in North America. This is acutely true for exposed and isolated residential trees, and some of this stress is unavoidable.
But there are things to minimize the damage caused by winter stress.
Cold stress appears in many forms. The rapid variations between daytime and nighttime temperatures often leads to stress between the outer and inner wood leading to cracks. These cracks are called frost cracking or southwest injury, the side of the tree receiving the most sunlight.
Unfortunately, there is little to do to prevent frost cracking. Often the tree can repair itself, though the cracked area remains vulnerable. Further, cracking at the same place can cause major damage. Young trees and palms and other tropical trees may benefit from wrapping the bark as part of a fall maintenance routine.
A sudden early front on late growth is another impactful cold stress. Late season tree growth is vulnerable because it has not had the same amount of established growth to prepare for cold. The cell walls on the new tips of branches often rupture when ice crystals form and die off in the following season.
This situation is avoidable if you do not prune until the tree has gone dormant in the fall. Pruning too soon encourages new growth and increases the risk of frost damage. Additionally, avoid using fertilizers with high amounts of quick-release nitrogen.
Periodic droughts during the winter are problematic for trees, especially evergreens. When a tree loses more water than it can absorb from frozen ground it dries out. It is often critical in the early spring when the ground stays frozen as the sun warms the rest of the tree. Windy conditions also add to the problem.
While there is no real way to combat winter drought, putting down a thick layer of mulch around the base of the tree before winter arrives is helpful. The mulch acts as a temperature barrier for the roots, while slowing down moisture loss and runoff.
Branches are more vulnerable to breakage during the winter, especially for deciduous trees. The wood hardens and becomes somewhat more brittle and susceptible to wind damage. Further, the problem of ice and snow accumulation affects both deciduous trees and evergreens alike.
Good fall tree maintenance is the key to minimizing branch breakage. Pruning weak and vulnerable branches can make the entire tree less susceptible. Removing one limb of a pair sharing a deep "V" crotch is another method to alleviate branch breakage. Arborist Now are the premier tree care experts in the greater San Francisco Bay area. Contact us to help for winter tree care services.
Rodents foraging for food target trees during the winter. The two major offenders are mice and rabbits both of which chew bark and can girdle trees. Squirrels are possible problems.
Leave a space between the mulch and the trunk of a tree and check frequently to guard against mice. You main consider setting out bait if mice are a problem but be sure to follow directions very carefully. Wire mesh enclosures deter rabbits and commercial paint-on repellants are available.
Winter Preparation Checklist
- When adding new trees, purchase only those species native to your area's hardiness zone. Trees native to areas even one zone milder than yours might experience significant stresses during your region's winters.
- Maintain good tree upkeep throughout the year. Strong healthy trees will always have an easier time than weak and damaged ones.
- Inspect your trees every year at the end of the spring and treat any damage found.
- Only prune trees have entered dormancy after the risk of new growth when preparing for winter.
- Apply a good fall fertilizer that promotes root growth over leaf growth.
- Put down a layer of mulch around the base of your trees to moderate temperature fluctuations and moisture loss. Be sure to leave a space between the mulch and the trunk of the tree to discourage mice.
- Check occasionally during the cold season for signs of rodent damage. Use bait, enclosures, or repellents, as necessary.
Ready to take that next step for your tree healthcare in Oakland with Arborist Now? Give us a call today, or reach out to us on our contact page to initiate the next step. We look forward to helping your trees and landscape thrive.