Forest Plot Expansion Calculator
Expand observed tree counts by sampled hectares and combine unequal plot areas correctly.
What would you like to do next?
Combine plot counts through sampled area
List a plot identifier, its area in hectares and observed tree count. The calculator displays density for every valid row and derives the combined result by dividing total observed trees by total sampled hectares. This area-weighted method avoids treating a small plot and a large plot as equally influential.
Review inclusion probability before extrapolation
Simple area expansion does not correct non-random placement, inaccessible plots, boundary handling, detection error, stratification or unequal selection probability. Confirm plot geometry and tree inclusion in the field record. Use a sampling estimator suited to the design when reporting uncertainty or expanding to a management area.
Frequently asked questions
How are unequal plots combined?
Total observed trees are divided by total sampled hectares.
Are zero-area plots included?
They remain visible but contribute no sampled area.
Does this calculate confidence intervals?
No. It produces a simple area expansion only.