The Cora Hartshorn Arboretum in Short Hills organizes ongoing classes and special events. Go to www.hartshornarboretum.org for information.

Stay warm with Hot Chocolate Hike Weekend, Dec. 17 and 18. Hike times are 11 a.m., 1 p.m. and 3 p.m. Take a break from the holiday rush and in for a guided hike on the Arboretum’s grounds, and finish up in the historic Stone House with a cup of hot cocoa by the fireplace.

For more information, call 973-376-3587.