Baltimore County’s Department of Environmental Protection and Sustainability is hosting its 10th biannual Big Trees Sale to encourage homeowners to plant trees in their yards. This year’s sale will take place on Oct. 18 from 9 a.m. to 2 p.m. at the Baltimore County Center for Maryland Agriculture and Farm Park, at 1114 Shawan Road in Cockeysville. The trees for sale are Maryland native species such as oaks and maples that need room to grow and take a long time to mature. Nearly 2,500 trees have been purchased through this program, the county said. The trees, which are 3 to 8 feet tall, cost $15 to $30. Only cash or checks will be accepted for payment. For more information, go to baltimorecountymd.gov/bigtrees.