Those who join the National Arbor Day Foundation during March will receive 10 free shade trees.

Varieties include red oak, weeping willow, sugar maple, green ash, thornless and honey locust, pin oak, river birch, tuliptree, silver maple and red maple. Six- to 12-inch trees will be shipped postpaid at the right time for planting between now and May 31, with planting instructions.To become a member, send a $10 membership contribution to Shade Trees, National Arbor Day Foundation, 100 Arbor Ave., Nebraska City, Neb. 68410, by March 31.