Remove less desirable species and trees that have poor form or are damaged. Do not eliminate all undesirable stems, only those touching the crowns of crop trees. Small understory trees are not significant competitors. Reduce stump sprout clumps to one or two stems when the sprouts are still less than three inches in diameter. Leave sprouts that are vigorous, straight and attached low on the stump. A forester can mark the trees to be removed in a thinning.