Ice storms are uncommon in South Carolina, but they can be very damaging to trees since ice is much heavier than snow. The result can be widespread power outages and tree damage from minor to devastating. Ice accumulations of ¾ inch can seriously damage some timber types and age classes, especially when accompanied by wind. Trees can be uprooted, broken or bent over.
Not all forests are the same when it comes to ice storms. Young pines and recently thinned pines are very susceptible. Young pines do not have trunks large and strong enough to support a crown covered with ice. Trees bent more than 60 degrees from vertical likely will not straighten themselves. They should be removed and the stand replanted. Pine trees in older stands can support each other during an ice storm, but in recently thinned pine stands, the remaining trees may be too far apart to provide adequate support. The result can be broken or uprooted trees.
Hardwoods are more tolerant of ice due to the lack of leaves. However, in urban conditions, both hardwoods and pines are susceptible to ice because they are often individual trees rather than part of forest. Hardwoods losing 50% of their crown may remain standing and survive, but their productivity will be reduced and they are more susceptible to insects and disease. Severely damaged hardwood stands can be harvested and allowed to sprout from roots and stumps, but the species composition will need to be controlled to prevent light-seeded, sun-loving trees like sweetgum or red maple from dominating the new stand. Hardwood trees with structural damage to the trunk, such as splits and large wounds, should be removed.
After an ice storm, your forest needs to be assessed to determine the extent of damage and any actions you should take. If you are familiar with basic forestry and can safely enter the forest, you may be able to inspect your forest, but utilizing a professional forester is the best option. Do not go near powerlines that may be on the ground or close to the ground. If there is minimal damage, no action should be taken. In a severely damaged stand, consider harvesting individual trees that likely will not recover or clearcut the stand. You may want to consider the wildlife value of a tree before removing it. Even a damaged tree can be beneficial for wildlife by providing dens and places to forage. The trees will need to be monitored for several years after the storm to detect decline and insect and disease that could invade weakened trees.
Continue to practice forestry that matches your goals and avoid removing too many trees unless necessary. The management choices after any storm should be linked to your management goals. Depending on the type and severity of damage, you may need to alter or change your goals. If you do not have management goals or a management plan, this may be a good time to work with a forestry professional to write a plan. If you need to harvest damaged timber, the timing will be influenced by the severity of the damage and how quickly the trees or wood will lose value. You also need to consider the market. After a widespread disaster, the market may be flooded with wood which lowers the price for the wood. You may be able to increase profits by harvesting when prices are higher. Standing damaged trees do not need to be harvested immediately because it may take some time for them to succumb to ice damage. An alternative to a tradition logging job is to hire someone with a portable sawmill to cut the trees into boards for specialty wood markets. If the storm results in a federal disaster designation, there may be money available with clean-up, site prep, regeneration and reducing fuel to prevent wildfire. A forestry professional can help with obtaining disaster relief funds and determining the best time and method of harvest.
In any case, a well-managed forest may be less susceptible to ice damage. Trees that have well-developed crowns and straight trunk tend to receive less ice damage. Well spaced trees that have been thinned regularly allows for a well-developed crown that is less likely to receive severe damage. However, thinning to a wide spacing can make the remaining trees more vulnerable because their neighbors are not close enough to offer support. Similarly, trees that are not leaning and receive enough sunlight are more likely to develop full crowns with stronger branches. A professional forester and management plan will help make this happen.
Additional Resources
https://kytimberdamage.mgcafe.uky.edu/files/caring_for_trees_damaged_by_ice-Updated.pdf
https://treesforever.org/wp-content/uploads/2021/07/Ice-Damaged-Trees.pdf
https://kytimberdamage.mgcafe.uky.edu/files/forfs09-03-Updated.pdf
https://extension.oregonstate.edu/catalog/em-9671-why-some-trees-can-stand-ice-storms
Author
Robert Carter, Cooperative Extension, Area Forestry and Wildlife Agent
Clemson University Cooperative Extension Service offers its programs to people of all ages, regardless of race, color, religion, national origin, disability, political beliefs, sex, marital or family status and is an equal opportunity employer.
