Healthy, mature trees increase the value of a property and provide many benefits to the homeowner. But if they’re not properly maintained, tree health can decline and removal may be necessary, which can be expensive. By learning to identify some of the most common health and structural issues of mature trees and knowing when and how to involve a certified arborist, you can help your sellers earn top dollar and your buyers benefit from their new investment.
Data from the International Society of Arboriculture as well as the U.S. Forest Service shows that a home with mature, handsome trees sells faster and for a higher price than a similar property without trees. And according to University of Washington researcher Kathleen Wolf, Ph.D., wooded lots sell for more than those in a divided-up field. Most buyers instinctively like trees, for good reason. Trees in residential areas provide a wealth of benefits to the homeowner:
- Trees improve residents’ health. Asthma, obesity, anxiety and depression rates are lower in well-treed neighborhoods, according to research published by the International Journal of Environmental Research and Public Health (IJERPH). Plus, an American Journal of Preventive Medicine article found that when neighborhoods lose trees, residents suffer significantly greater deaths from cardiovascular disease.
- The presence of trees is associated with lower crime, according to the IJERPH.
Treed neighborhoods stay cooler on a hot summer day. Arbor Day Foundation research found that well-placed trees can reduce cooling costs by up to 35%.
- Trees remove pollutants from the air and intercept the impact of rain, reducing stormwater runoff and erosion.
- Trees provide privacy, block unwanted views and bring natural beauty to a property.
Trees on a residential property are an asset for the seller and the buyer. But what if a tree on a property for sale isn’t looking so good? What signs do you need to be concerned about? Can these problems be fixed? What do you do if the buyer asks about emerald ash borer or oak wilt? And who can you go to for help?
Signs a tree needs help
Trees are resilient by nature. However, if several sources of stress are stacked on top of each other, a tree can start to decline, lose limbs and eventually die. But if we recognize a tree is at risk and can remove some of the stress, a tree can often recover.
Some signs of stress are relatively easy to identify. Other signs are impossible to spot without specialized knowledge and equipment.
Familiarize yourself with the most common signs of stress, but keep in mind that only an expert will be able to identify certain issues. When checking trees on a property, pay special attention to large trees near the home and outbuildings. If these trees fail, they could cause damage or injury.
Check the canopy for these signs of stress
- Lots of small branches growing from the trunk or large branches (see photo 1).
- Dead branches in the canopy.
- Leaves that are yellowish in summer, except for specialty trees that are bred for yellow leaves.
- Leaves that are dying, tattered, chewed up, deformed, hanging dead on the tree or missing.
- The tree is “topped” (see photo 2).
Check the trunk and base for these signs of stress
- The root flare is buried: the trunk rises straight up from the ground (see photo 3), the tree is surrounded by a “tree well,” or there is a “mulch volcano” around the trunk (see photo 5).
- Splits or cracks, especially if there are fungal conks or shelves growing out of the tree (see photo 6).
- Scarring or open wounds at the base of the trunk from string trimmers or lawnmowers.
While these signs of stress vary in seriousness, many conditions can be treated by a good arborist and the tree returned to health. For example, big, old silver maples naturally shed branches that are less productive, and they need to be groomed every few years to prevent these branches from coming down in storms. Leaves may be tattered because of a short-term or preventable issue such as herbicide exposure or leaf-feeding insects. An oak with yellow leaves may be suffering from chlorosis and returned to health by acidifying the soil beneath its canopy and mulching out to the drip line.
Some types of stress will be more expensive to correct or may require the removal of a tree that has become hazardous. “Topped” trees, trees whose root systems have been buried more than two feet, trees with long vertical splits, or significant internal decay are examples of conditions that are more difficult or impossible to correct.
Insect and disease issues Wisconsin REALTORS® need to know
There are a few insects and diseases of trees you should be familiar with as they can affect home sales. The public is aware of them and may ask questions during negotiations.
Emerald Ash Borer (EAB)
EAB girdles green, white and black ash under the bark, killing the tree within a few years. REALTORS® should become familiar with ash trees because they must be treated with an insecticide to prevent infestation by EAB or they will need to be removed soon. An ash tree with dying branches and a thinning canopy is too far gone for successful treatment and should be removed as soon as possible. As decline progresses, ash trees become fragile and dangerous.
According to Jeremy Kane, certified arborist and executive director of the Urban Tree Alliance in Madison, “ash trees with advanced emerald ash borer infestation quickly lose their structural weight-bearing capacity. Total decline can happen in a single growing season. This means branch failure becomes imminent in a matter of months and hazards for both homeowners and arborists working on them increase quickly. Removing an infested ash while it is still alive can significantly reduce risks and potential costs.” The increase in cost is substantial; removing a declining tree may cost twice as much as removing a healthy ash, and removing a dead tree may cost three times as much.
Emerald Ash Border resources
Oak wilt
Oak wilt is a serious but preventable threat to oaks. It is a disease often associated with homes and new building. Infection requires a wound made between April and mid-July and the presence of spore-bearing fungal mats of oak wilt. Building construction provides many opportunities for accidental wounding, and even a nail hole can be enough to allow infection. Oak wilt is often accidentally introduced to a new area when infected firewood is transported to a property. Once oak wilt is introduced, it can spread quickly to nearby oak trees. A red oak cannot be saved after symptoms develop, but an arborist may be able to successfully treat a white oak.
Oak wilt resources
Gypsy moth
This insect is established across the eastern two-thirds of Wisconsin, but it is not noticeable most years. However, gypsy moth populations may have a temporary, large increase, or an “outbreak,” in an area about every 10 years. Caterpillars can be a nuisance during an outbreak as they strip the leaves off their favorite trees. Oaks, lindens and birch take the most damage, but other trees may also be fed on. While a healthy tree growing in a forest can recover from even complete defoliation, trees around our homes are rarely in peak health and will benefit from protection with pesticides or egg mass removal. Watch for gypsy moth egg masses on the trunks and undersides of large branches of oaks between the months of August and April. If you see some, you should consult with a certified arborist to assess the population and recommend treatments to reduce the population of the pest at that property.
Gypsy moth resources
- Gypsy moth management options: gypsymoth.wi.gov
- Insects that may be confused with gypsy moth (note: gypsy moth do not make nests or silken tents):
What can an arborist do for REALTORS®?
Let’s assume you’ve looked over the trees on a property and the oak in the front yard has a lot of shoots coming off the trunk and some dying branches. You now know those can indicate a health problem, but it is a large tree that adds a lot of character to the property and shades the house from the heat of the summer afternoon sun. It’s a valuable tree. Can this tree be saved, or is it a hazard that should be removed? And how much will the options cost?
This is the sort of situation where you should call in the certified arborist with whom you have a business relationship to assess the tree and give their recommendation and a cost estimate. An arborist can often significantly extend the productive life of a tree. Unless a tree is untreatable and becoming hazardous, extending a tree’s life is usually a better option than removal. Mature trees are irreplaceable; they provide many more benefits to the homeowner than newly planted trees. There is also a direct cost benefit. Treatments to extend the life of a tree are typically much less expensive than removing a tree near a house.
Whether or not a tree appears healthy, buyers should seriously consider hiring a certified arborist to inspect any large tree that could harm people or property if it fails. Only an expert will be able to identify all potential health and structural issues that may affect a tree.
Mark Pinkalla, ISA-certified arborist and president of First Choice Tree Care, recommends that every home inspection include a tree inspection by a certified arborist. “I frequently get requests from new homeowners to identify and evaluate the trees in the yard, only to discover that a tree that ‘looked fine’ to everyone involved in the home sale is indeed not fine. The cost of having a certified arborist look at the trees is usually a fraction of the cost of removing one large ‘not fine’ tree.”
You will also want to be prepared to call in an arborist in less-common situations, such as when a tree topples over midway through the sale of a property. A certified arborist can help estimate the value of a tree and cost of removal if an adjustment needs to be made to the selling price.
How to choose an arborist
Certified arborists are tree care professionals and businesspeople like you. They are most commonly found in urban areas, where individual trees have high value. There are many in Wisconsin’s southeastern counties, the Fox Valley and near larger communities around the state. Some arborists will also service properties distant from their home office. Certified arborists can be in high demand at certain times of the year and after storms, so it’s good to develop an ongoing relationship with one so they will make time for you when your need is urgent.
Here are some tips for choosing a qualified arborist:
- Choose an ISA-certified arborist. This credential is given to those who have passed comprehensive tree care exams.
- Look for membership in professional organizations such as the International Society of Arboriculture (ISA), the Tree Care Industry Association (TCIA) or the American Society of Consulting Arborists (ASCA).
- Ask for proof of insurance and confirm with the insurance company.
- Ask for references and check them.
To find an ISA-certified arborist in Wisconsin, visit the Wisconsin Arborist Association website at www.waa-isa.org/find-certified-arborist. If you need less common services such as a valuation of a tree, tree protection on development sites or expert witness testimony, check the DNR list of urban forestry consultants at dnr.wisconsin.gov/sites/default/files/topic/UrbanForests/UrbanForestryConsultantsDirectory2021.pdf.
Mature trees add a lot to the value of a home. With the help of a certified arborist, you can maximize their contribution and minimize their expense for both the seller and buyer.
Resources and additional reading
Wisconsin resources
Additional reading
Andrea Diss-Torrance is Invasive Forest Insects Program Coordinator for the Wisconsin Department of Natural Resources. Patricia Lindquist is Urban Forestry Communications Specialist for the Wisconsin Department of Natural Resources.