What are they?
Secondary forests, or recovering forests, are those that were previously deforested and have grown back.
The area of secondary forests in the Amazon is estimated to be 850 million hectares. This figure corresponds to areas deforested between 1988 and 2023 that have grown back.
Most secondary vegetation in the Amazon are “young” – 90% are less than 29 years old. The recovery of secondary forests can take from two decades to centuries, depending on how much the forests have been disturbed, the types, their location, and other factors.
Ecosystem services provided by secondary forests
Even when damaged by deforestation or fire, secondary forests provide important ecosystem services. Globally, they remove up to 1.6 billion tons of carbon from the atmosphere each year.
During their recovery process, secondary forests remove carbon from the atmosphere at a faster rate than primary forests. Research conducted in South and Central American forests has shown that recovering forests accumulate carbon 11 times faster than primary forests.
“Secondary forests play an important role in mitigating the effects of climate change. Despite this, this type of vegetation is not protected at the federal level — not even by the Forest Code. Forests in their early stages of regeneration are more vulnerable to fire and other disturbances, requiring as much protection as primary forests,” says Celso Henrique Leite, a researcher at IPAM.
Furthermore, secondary forests protect primary forests from edge effects and deforestation, in addition to increasing connectivity between vegetation, allowing the exchange of seeds and animals between different forest areas.
Threats faced
Over a period of 35 years (1985 to 2019), most of the areas where secondary vegetation is concentrated in the Amazon were affected by deforestation and fire. This indicates a process of loss-recovery-loss that delays carbon accumulation, biodiversity recovery, and other ecosystem services necessary for its existence.
Between 1% and 2% of secondary forests in the Amazon burn each year, with 88% affected by fire in their first 20 years, when they store the most carbon. IPAM studies have shown that recovering forests, when affected by fire, take up to 29 years to recover.
Legislation and commitments for protection
In its NDC (Nationally Determined Contribution), Brazil committed to restoring 120,000 kilometers of forest by 2030, as part of its efforts to keep global temperatures below 1.5º.
Pará and Mato Grosso are the only states in the Legal Amazon with specific laws for the protection of secondary forests.
The specific legislation in Pará states that forests over 20 years old must be protected, and forests between 5 and 20 years old must be conserved, depending on their density.
The legislation in Pará progressed in 2015, as a result of a joint effort between the government and scientists. Previously, the law did not specify the age of the forests to be protected, making it difficult to enforce. If all the primary vegetation in the Amazon were protected by the Pará law, about 30% of it would be conserved.