Tree reach calculator

How the reach is worked out

A tree that fails at the base pivots and lands roughly its own height away, so the first test is height against distance. Measure the distance along the ground from the center of the trunk to the nearest part of the target: the eave, the deck, the car, the property line.

The tool then adds two safety margins from OSHA’s tree-care guide Falls and Falling Object Hazards (HB-3731, June 2014): ground workers keep at least 2× the tree’s height away from a felling, and at least 1.5× when the tree is felled with a rope [1]. Those are worker rules, not a forecast, but they show how much room a whole falling tree claims. Trunks bounce and roll, tops snap off, and limbs throw.

A lean toward the target or ground that drops toward it doesn’t make the tree longer, but it sets the likely direction and lets logs roll. The tool flags both and adds nothing to the numbers.

How to estimate height

Stick method. Find a stick as long as the distance from your eye to your fist at arm’s length. Hold it upright at arm’s length and walk back until the stick covers the tree from base to top. Your distance from the trunk is about the tree’s height [2]. Pace it or use a tape.

Shadow method. On a sunny day, measure your own shadow and the tree’s shadow at the same moment. Tree height = tree shadow × (your height ÷ your shadow). If you are 6 ft tall with a 4-ft shadow and the tree’s shadow is 40 ft, the tree is about 60 ft. It needs flat ground and a clear shadow tip, which rules out most Northwest winter days.

Estimates from the ground are rough on tall conifers, so treat a result within a few feet of the line as “can reach.” The American Forests measuring handbook gives stick variations, including one where you add your eye height to the distance [3].

What to do with the answer

• It can reach. That alone isn’t a reason to remove a healthy tree. Run the tree risk checklist; if it shows warning signs, book a tree risk assessment.
• If it comes out. A tree that can reach a building is usually dismantled in sections or lifted out by crane; see large tree removal and crane tree removal. Within 10 ft of a structure the cost calculator applies a ×1.25 multiplier. Modeled estimate, not quotes (method).
• The neighbor’s tree. Who pays if it falls depends on state law: Oregon, Washington.
• Wires in the way. Don’t measure near lines; see tree removal near power lines.