Deforestation Rate Calculator Formula

Understand the math behind the deforestation rate calculator. Each variable explained with a worked example.

Formulas Used

Average Annual Loss

annual_loss_ha = annual_loss

Annual Deforestation Rate

deforestation_rate = annual_rate_pct

Projected Forest in Future

projected_forest = current_forest_ha * pow(1 - annual_rate_pct / 100, projection_years)

Variables

VariableDescriptionDefault
initial_forest_haInitial Forest Area(hectares)500000
current_forest_haCurrent Forest Area(hectares)420000
years_elapsedYears Between Measurements(years)10
projection_yearsProjection Period(years)20
annual_lossDerived value= (initial_forest_ha - current_forest_ha) / years_elapsedcalculated
annual_rate_pctDerived value= (1 - pow(current_forest_ha / initial_forest_ha, 1 / years_elapsed)) * 100calculated

How It Works

Measuring Deforestation

Deforestation rate quantifies the speed at which forest cover is being lost, typically expressed as a percentage per year.

Formula

Annual Rate = 1 - (Current Area / Initial Area)^(1/years) x 100%

Projected Forest = Current Area x (1 - Rate)^(Projection Years)

This compound rate formula accounts for the shrinking base over time, giving a more accurate rate than simple division.

Worked Example

Forest cover dropped from 500,000 to 420,000 hectares over 10 years.

initial_forest_ha = 500000current_forest_ha = 420000years_elapsed = 10projection_years = 20
  1. 01Annual loss = (500,000 - 420,000) / 10 = 8,000 ha/year
  2. 02Compound rate = 1 - (420,000/500,000)^(1/10) = 1 - 0.9826 = 1.74%
  3. 03Projected forest in 20 years = 420,000 x (1 - 0.0174)^20 = 420,000 x 0.7046 = 295,932 ha

Ready to run the numbers?

Open Deforestation Rate Calculator