Google and a research group map the world's forests by type

Google DeepMind and the World Resources Institute have released ForTy, a free map that sorts the world's land into six types, including primary forest, planted forest and tree crops like oil palm and cocoa. It is built to help companies show their goods are not tied to deforestation. It is also far from perfect.

What changed

Most satellite maps show only whether trees are growing in a place. ForTy, short for Forest Typology, tries to say what kind of forest it is. It covers land as it stood in 2020, at 10-meter detail. The authors say it is the first global map of its kind. Earlier datasets, including one from the European Commission, cover only parts of the world.

The six classes are primary forest, naturally regenerating forest, planted forest, plantation forest, tree crops and other land.

Why the EU cares

The EU Regulation on Deforestation-free Products bans goods linked to forests cleared or degraded after December 31, 2020. That includes goods grown after primary forest was turned into a plantation. Oil palm and cocoa farms count as farmland, so companies need to know how a site was used in 2020. ForTy offers that reference point.

How well it works

Two experts reviewed each of 8,190 random sites. The map was right 90.2 percent of the time. The authors warn that this score gets a big lift from the easy "other land" class.

• It found 89 percent of confirmed primary forests.
• It found only about half of tree crops and planted forests.
• It found 60 percent of plantations.
• About a third of areas labeled planted forest were wrong.

These weak spots sit on the boundaries that matter most for the EU rules. Still, ForTy beat European Commission maps made for those rules on the same test data. It scored 90.9 percent on forest types, against 87.8 percent.

The big picture

The researchers estimate the world has about 4.1 billion hectares of forest. About 2 billion hectares of that is primary forest. Planted forests cover about 250 million hectares, and tree crops nearly 200 million, mostly in Asia.

Regional errors remain. The map overestimates primary forest in Asia by about 200 million hectares, largely in Russia. In Africa it misses about 94 million hectares of forest.

What happens next

The map is free to use under a CC BY 4.0 license, including in Google Earth Engine. It has confidence scores so users can set their own thresholds. It has no separate class yet for open woodlands, which the EU treats separately. The researchers say future versions should add one.