Tree Care calculators

Tools for arborists and tree crews: trunk-formula appraisal, green log weights by species, and rigging shock loads.

• Log Weight Calculator by SpeciesA green white oak log 20 inches across and 8 feet long weighs roughly 1,100 pounds; weight is volume times the green density for the species.
• Rigging Shock Load CalculatorPeak force from a dropped load is F = W + √(W² + 2·W·h·k), where h is the free-fall distance and k the rope stiffness; even a short drop can load a line several times the weight.
• Tree Appraisal Calculator (Trunk Formula Technique)The trunk formula scales a nursery tree's cost by trunk area, so value = trunk area × unit nursery cost per square inch, less depreciation for condition and limitations, plus added costs.