Seattle Public Utilities just sent the reminder – this is the last week for “free” composting of Christmas trees and other holiday greenery – either via curbside pickup, or transfer-station dropoff:

Remove all decorations, cut into sections 4-foot or less, and place trees or bundled greens next to your Food & Yard Waste cart on your regular collection day. Apartment residents may place up to two trees next to each Food & Yard waste cart at no charge. You can also drop off up to 3 trees less than 8 feet in length at a Transfer Station.

The “free” tree-cycling continues through Saturday (January 31). After that, you’ll have to chop up your tree so it fits in your yard/food-waste cart, or take it to the transfer station (South, in west South Park, is the closest)