Urban forestry strategies and new Brazilian policy aim to combat extreme heat

Researchers and policymakers are developing strategies to protect urban trees and enhance city resilience against extreme climate events. Scientific studies highlight that mature trees provide significant cooling benefits, reducing temperatures under their canopies by up to 3 °C through shade and evapotranspiration. Preserving a single mature tree is considered a priority, as it would take approximately 400 saplings to replicate its environmental benefits.

To ensure survival, experts recommend specific irrigation techniques and soil compositions to allow root expansion in compacted urban environments. Urban planning is also shifting toward greater biodiversity to prevent pest devastation, following the 10-20-30 rule, which suggests limiting species, genera, and botanical families to specific percentages within a forest.

In Brazil, a proposal for a National Urban Arborization and Thermal Resilience Policy has been introduced. The initiative aims to establish mandatory tree coverage targets, particularly in large cities and vulnerable neighborhoods, to combat heat islands. The policy focuses on creating urban shade infrastructure near schools and health centers, while providing federal incentives for municipalities that meet preservation and planting goals.