This user's guide describes a top pruner (figure 1) the Missoula Technology and Development Center developed for the U.S. Department of Agriculture, Forest Service's Lucky Peak Nursery in Boise, ID. Trees such as western larch grow tall in the greenhouse before they are ready to be planted. Top pruning (cutting the tops off of plants) controls shoot height, ensures that all trees are about the same size, decreases shoot-to-root ratio (important because the tree has to have enough root to provide water for the leaves and stems), increases stem diameter, and makes it easier to handle seedlings during transplanting and outplanting.

Figure 1—Key components of the top pruner.