The fast growth of willow trees and the ease of planting these common wetlands trees make the willow one of the best choices for renewable biofuel. Coppicing--cutting back trees nearly to the ground--causes some species like willow to regrow dense clusters of thin shoots rather than a trunk. The willow tree in its coppiced form actually lives longer than a full-size tree. Coppiced fields of willow provide several harvests, spaced 2 to 4 years apart, before beginning a gradual decline. Small farmers may be more interested in coppicing to produce willow basketry and other craftwork than in growing the tree for biofuel.
Select a well-drained fertile planting site--old pasture land is ideal. Spray the site with herbicide the year before planting willow, and plow the site deeply in the fall. Leave the soil broken over the winter to allow clods to soften, and cultivate again in spring.
Cut willow whips from willow trees any time from December through March while trees are dormant. Divide the branches into 8- to 10-inch lengths with the first bud about half an inch from the end of the cutting. Choose branches at least 1/2 inch in diameter.
Lay out the field in a double row pattern--two rows together with a wider space between each pair of rows. Space the paired rows 2 1/2 feet apart, with 5 feet between the double rows.
Drive the base--the larger end--of the cutting into the ground, spacing the cuttings 2 feet apart in the row. Leave at least two willow buds above ground level.
Cut willow whips back the first winter after planting. Top-prune the whips to 2 or 3 inches above the top of the first cutting to stimulate more whip formation in the second year of growth.