Forest Monitoring
A forest number is a threshold, a release, a pixel area and a period before it is a forest.
Open forest data makes it easy to put a number on deforestation anywhere, and every number carries decisions that are easy to leave out. In one Rondônia window, 44% of the forest standing in 2000 was lost by 2024 — at a 30% canopy threshold, in release GFC-2024-v1.12, with each pixel weighted by its real area. Multiply pixels by the "30 m" 0.09 ha instead and the area is 19% too large there and 145% too large in Siberia. These guides start with what Global Forest Change measures, forest definitions, rates, fragmentation, land cover products and avoided deforestation; then read the Hansen tiles, compute loss by year and polygon, compare protected land with its surroundings, measure distance to roads, fragmentation and hotspots, compare products, add canopy height and detect new clearing with Sentinel-2 — with the fixes for thresholds, loss and gain, areas in degrees, resolution and trends across releases.
Step eight is where most published numbers are made: loss by year and polygon. Everything before it decides what the number means — threshold, release, pixel area — and the fixes at the end are the ways those decisions get lost between the table and the headline.
Start here
The cornerstone guide — the whole workflow end to end. Everything after it goes deeper into one part of it.
Step 1 Global Forest Change Explained hansen global forest change explained Begin the path →The full path, in order
The concepts underneath the work, then each task, then the errors that task produces. Work down, or jump to the step you need.
- Forest Definitions Explained forest definition canopy cover threshold 🧭 Concept
- Deforestation Rates Explained deforestation rate calculation explained 🧭 Concept
- Forest Fragmentation Explained forest fragmentation edge core explained 🧭 Concept
- Land Cover Products Explained land cover products worldcover dynamic world 🧭 Concept
- Avoided Deforestation Explained avoided deforestation baseline counterfactual 🧭 Concept
- How to Read Hansen Global Forest Change Data in Python read hansen gfc python ⚙️ How-To
- How to Calculate Forest Loss by Year for a Region in Python forest loss by year python ⚙️ How-To
- How to Compare Forest Loss Inside and Outside Protected Areas in Python forest loss protected areas python ⚙️ How-To
- How to Measure Deforestation Near Roads in Python deforestation distance to roads python ⚙️ How-To
- How to Measure Forest Fragmentation in Python forest fragmentation metrics python ⚙️ How-To
- How to Map Forest Loss Hotspots with H3 in Python forest loss hotspots h3 python ⚙️ How-To
- How to Compare Land Cover Products for Forest in Python compare land cover products forest python ⚙️ How-To
- How to Use Global Canopy Height Maps in Python global canopy height map python ⚙️ How-To
- How to Detect New Forest Clearing with Sentinel-2 in Python sentinel-2 forest clearing detection python ⚙️ How-To
- Forest Threshold Changes Everything forest area changes with canopy threshold 🔧 Fix
- Forest Loss and Gain Misread hansen loss gain net change wrong 🔧 Fix
- Forest Area Wrong in Degrees forest area wrong geographic crs pixels 🔧 Fix
- Fragmentation Metrics Change with Resolution fragmentation metrics resolution dependent 🔧 Fix
- Forest Loss Trend Not Comparable Over Time hansen forest loss trend not comparable 🔧 Fix
Topics this path covers
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