Saturday is Earth Day, and hundreds of volunteers gathered at Tifft Nature Preserve in Buffalo on Thursday to plant trees.

The new trees will help replace the existing canopy that is slowly diminishing.

The preserve says eastern cottonwood trees were the first to colonize the area. But now, they are approaching the end of their lifespans.

They say, because of wildlife, most new trees on the reserve are planted by humans.

"New trees are not coming in, and the reason for that is largely an overabundant population of deer,” preserve steward at Tifft Nature Preserve Zach Goodrich said. “We have so many deer here that they eat every single new tree that starts to grow, every new seedling. And we also have a number of very problematic, invasive species that unfortunately crowd out space where other new trees could grow as well."

Organizers say there are plenty of other opportunities to volunteer at Tifft year-round if you missed Thursday’s event.

To find other volunteer opportunities, you can visit Tifft.org.