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_lossAnnual Deforestation Rate
deforestation_rate = annual_rate_pctProjected Forest in Future
projected_forest = current_forest_ha * pow(1 - annual_rate_pct / 100, projection_years)Variables
| Variable | Description | Default |
|---|---|---|
initial_forest_ha | Initial Forest Area(hectares) | 500000 |
current_forest_ha | Current Forest Area(hectares) | 420000 |
years_elapsed | Years Between Measurements(years) | 10 |
projection_years | Projection Period(years) | 20 |
annual_loss | Derived value= (initial_forest_ha - current_forest_ha) / years_elapsed | calculated |
annual_rate_pct | Derived value= (1 - pow(current_forest_ha / initial_forest_ha, 1 / years_elapsed)) * 100 | calculated |
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.
- 01Annual loss = (500,000 - 420,000) / 10 = 8,000 ha/year
- 02Compound rate = 1 - (420,000/500,000)^(1/10) = 1 - 0.9826 = 1.74%
- 03Projected forest in 20 years = 420,000 x (1 - 0.0174)^20 = 420,000 x 0.7046 = 295,932 ha
Frequently Asked Questions
How much forest is lost globally each year?
About 10 million hectares of forest are lost per year (net), an area roughly the size of South Korea. Gross loss is higher, offset partially by regrowth and planting.
What drives deforestation?
Agriculture (especially cattle ranching and soy/palm oil) causes about 80% of deforestation. Logging, mining, and urban expansion account for the remainder.
Can deforested land recover?
Secondary forests can regrow if land is abandoned, taking 20-50 years for canopy closure. However, full biodiversity recovery may take centuries, and some degradation is irreversible.
Ready to run the numbers?
Open Deforestation Rate Calculator