Tree Value Calculator
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Tree Value Calculator
Tree Value Calculator: The Trunk Formula Method
Our free Tree Value Calculator can help you estimate the replacement value of a particular tree based on its size, species, and other factors. The calculator uses the Trunk Formula Method found in the Guide for Plant Appraisal, Ninth Edition, published by the International Society of Arboriculture. The Trunk Formula Method is used to calculate the replacement value of large trees by calculating the per-square-inch cost of a smaller available replacement tree from a nursery and extrapolating that per-square-inch cost to the total volume of the large tree being valued in the appraisal.
Finding the basal area of a tree from stump diameter
The size/volume of the tree being appraised is calculated by using the equation π (i.e., pi or 3.14) x radius squared (r²). The formula essentially treats the tree as a cylinder in order to roughly approximate its volume.
The key to applying the Trunk Formula Method is determining the diameter of the tree in question. The diameter is traditionally measured at “breast height,” defined as 4.5 feet off the ground (thus, the measurement is referred to as “diameter at breast height,” or “DBH”).
If the tree being appraised was cut down by a neighbor or some other person in a timber trespass, measurement of the stump’s diameter will be a relatively straightforward exercise of simply laying a tape measure over the stump and recording the diameter in inches. Although the measurement may be lower than breast height depending on the height of the cut, the formula should still provide a fair approximation of value.
If the tree being appraised is still standing, diameter will need to be calculated based on the tree’s circumference. Wrap a tape measure around the trunk of the tree at breast height and then divide that circumference figure by pi (3.14). That will provide the diameter at breast height for use in the Tree Value Calculator.
Data used by the calculator
The calculator utilizes data published by the New England chapter of the International Society of Arboriculture. The NE-ISA website provides “cost per square inch” of various common New England trees, as well as “species ratings” associated with said trees. Those values are used in the calculator. Data for other regions may differ.
The Trunk Formula Method makes further adjustments based on a tree’s condition and location. These factors are somewhat subjective and are determined by the discretion of the arborist making the tree appraisal. Some guidance and assumptions are included below.
Disclaimers
This calculator is offered as a tool for homeowners who have had their trees removed, cut down, or otherwise destroyed. It provides only a rough estimate of replacement/restoration value according to one valuation method and is provided “as is” without any warranties. Different valuation methods may be appropriate depending on the circumstances of the case and the law of your jurisdiction. For example, a licensed arborist with an appraisal certification may be recommended for more accurate valuations or for litigation purposes. If you are considering bringing a legal claim for a timber trespass, your attorney should be able to arrange for an arborist or other professional to value your trees.
Condition: The formula assigns a “Condition” percentage based on the health and structure of the tree being valued. The below table provides a rough description of the respective Condition ratings in the calculator.
| Condition | Tree Structure | Tree Health |
|---|---|---|
| Excellent | Root plate undisturbed and clear of any obstructions. Root flare has normal development. No visible trunk defects or cavities. Branch spacing/structure and attachments are free of any defects. | Perfect specimen with excellent form and vigor, well-balanced crown. Trunk is sound and solid. No apparent pest problems. Normal to exceeding shoot length on new growth. Leaf size and color normal. Exceptional life expectancy for the species. |
| Good | Root plate appears normal; only minor damage may be found. Possible signs of root dysfunction around trunk flare. Minor trunk defects from previous injury, with good closure; less than 25% of bark section missing. Good branch habit, minor dieback with some signs of previous pruning. Codominant stem formation may be present. Minor corrections required. | Imperfect canopy density in few parts of the tree, 10% or less, lacking natural symmetry. Less than half normal growth rate and minor deficiency in leaf development. Few pest issues or damage, controllable. Normal branch and stem development with healthy growth. Typical life expectancy for the species. |
| Fair | Root plate reveals previous damage or disturbance and dysfunctional roots may be visible around the main stem. Evidence of trunk damage or cavities with decay or defects present. Less than 30% of bark sections missing on the trunk. Codominant stems are present. Branching habit and attachments indicate poor pruning or damage, which requires moderate corrections. | Crown decline and dieback up to 30% of the canopy. Overall poor symmetry. Leaf color somewhat chlorotic with smaller leaves. Shoot extensions indicate some stunting and stressed growing conditions. Obvious signs of pest problems contributing to lesser condition. Some decay areas found in the main stem and branches. Below average life expectancy. |
| Poor | Root plate disturbance and defects indicate major damage with girdling roots around the trunk flare. Trunk reveals more than 50% of bark section missing. Branch structure has poor attachments, with several structurally important dead or broken. Canopy reveals signs of severe damage or topping, with major corrective actions required. | Lacking full crown, more than 50% decline and dieback, especially affecting larger branches. Stunting obvious with little evidence of growth on smaller stems. Leaf size and color reveal overall stress in the plant. Insect or disease infestation may be severe. Extensive decay or hollow. Life expectancy is low. |
Location: The formula assigns a “Location” percentage based on, among other things, the type of property (residential, commercial, etc.) that the tree is on and its placement on that property. The below table provides a rough description of the respective Location ratings used by the calculator.
| Location Rating | Site Position | Site Placement |
|---|---|---|
| Excellent | Arboretum Well-maintained residential area Historical district Designated parks and recreation areas |
Specimen trees in a functional landscape design Single, sentimental, historic or specimen tree Outstanding aesthetic value in the landscape |
| Good | Suburban residential areas Golf course School/corporate campus Green spaces/memorials Cemetery Scenic parkways |
Considerable element in the landscape for design, quality or function Plants in a windbreak, screen or other integral planting Planting allows maximum functional benefits |
| Fair | City streets/boulevards Rural residential areas Urban streets Industrial/commercial areas |
Well-spaced planting site Tree installation in planting pits or lawn strips Mass, unplanned plantings on a site |
| Poor | Streets/roadways in rural areas Woodlots, managed Freeways/interstates Countryside, naturally occurring woodlands Woodlots, unmanaged |
Trees with utility interaction Improper spacing with infrastructure conflicts Species with fruit or leaf litter issues Invasive species |
Assumptions used by calculator: the calculator assumes the largest commonly available replacement tree is a sapling with a 2.5” diameter. It assumes that the approximated Installation Cost of the replacement tree (purchase price plus installation) is $1,500. Data from NE-ISA is current as of January 2024. Tree unit costs may vary in different regions.
Sources: ISA-NH website; International Society of Arboriculture, Guide for Plant Appraisal (9th ed.) For an explanation of why we use the 9th edition rather than the 10th edition, click here; Tables sourced from the Purdue Extension Program.
