While deforestation may yield short-term economic gains, it has lasting impacts on climate change, biodiversity, and water systems. The age of political leaders is a key determinant of how these trade-offs are managed. We study closely contested elections in Brazil and show that when a young politician is in power there is less deforestation (p-value.000), lower greenhouse gas emissions (p-value.061), but higher local income (p-value.023). Results are partly explained by young mayors turning over the bureaucracy with younger public servants (p-value.043).