The Grounded Gardener: The value of your trees can shed light in tough situations

What's it worth to you, that big oak, pine or cedar that you rest up against on a summer afternoon? There may be more to your trees than you think: Besides providing memories, shade and a racecourse for squirrels, you may be able to put a dollar figure on that tree.

"In the property appraisal community," says arborist Scott Baker, with Tree Solutions, "the landscape accounts for 10 to 20 percent of the total property value."

Although it's a complex and often subjective process, understanding the basic elements of tree valuation will help you manage your current and future trees.

For example, putting a monetary value on a tree might aid you with an insurance claim if the tree is damaged. It could help settle legal disputes, or its loss could be claimed on your federal taxes.

Knowing the potential worth of a tree can guide you in planning and planting a new one. How do you find out what your trees are worth?

Considerations in tree valuation are both objective and subjective, so the best first decision is to hire a knowledgeable and experienced appraiser, just as you would drag that lamp you think might be a Tiffany to the "Antiques Roadshow" specialists to see what it's worth.

For trees on your property, that's probably a certified consulting arborist, but you also may find the right person to carry out landscape valuations in the nursery industry.

The arborist follows a set of guidelines to determine a tree's worth. The guidelines, set up by the International Society of Arboriculture, focus on four interdependent aspects of the tree -- size, species, condition and location.

First, size. It's obvious, even to us laypeople, that a really big oak tree should be worth more than a really small maple. But an oak and a maple of almost equal size have other factors that would tip the scales toward one or the other.

The tree's species is closely linked with its size in valuing its worth. Baker and other arborists have developed a list of the most commonly planted trees in our region; that, along with weight and size considerations, can give them a rating. But subjectivity plays a role.

"The whole process is complicated," Baker says, "because the appraiser can argue against or for the species rating."

Adding weight to the value of a tree is its condition. An arborist takes into consideration all parts of the tree from roots to tip. Damage from pests and diseases may detract from its condition; a tree that has been topped or poorly pruned will not be assessed in top condition.

The location of the tree can make a difference in its value. Location refers to its place in your garden, which then affects the condition of the tree. Too near the house or hanging over the fence, so that branches have been lopped off? Too much shade so that its foliage is sparse?

Location also refers to your property, and this can lead to more subjectivity. "A tree in an Olmsted-designed garden will be worth more than a tree in the woods," Baker points out. Just as your property is partially valued by its neighborhood, so is your tree.

Arborists who assign a value to a tree may be doing it after the fact, on a tree damaged by a weather- or human-related incident. This can complicate things when it comes to replacement value. "If someone runs over a cutleaf maple," Baker says, "and the replacement tree of the same size is $30,000 -- it may be that the casualty tree wasn't worth that much."

Disputes about the value of trees can lead to legal cases, but homeowners can do a lot toward avoiding such disputes by following these guidelines offered by Baker: