U.S. President Joe Biden chose Friday — Earth Day — to sign an executive order to protect some of the country’s largest and oldest trees.

“We’ve reached the point where the crisis on the environment has become so obvious, with the notable exception of the former president, that we really have an opportunity to do things we couldn’t have done two, five, 10 years ago,” Biden said.

The order, which the president signed during a visit to Washington state, will require the Forest Service, Bureau of Land Management and National Park Service to identify threats to older trees, such as wildfire and climate change, and develop policies to safeguard them.

Old trees are an ally in fighting climate change because they absorb large amounts of carbon dioxide, which contributes to global warming. Scientists say redwood forests are among the world’s most efficient means of removing and storing carbon dioxide. Thousands of U.S. redwoods have been destroyed in recent years.

Biden’s order requires federal land managers to define and count mature and old-growth forests nationwide within a year.

The measure is a safeguard designed to protest U.S. forests that have been decimated by fires, drought and blight in recent years.