Sapling and Poletimber Stands
Competition among trees eliminates poor quality and low-vigor trees throughout the life of a stand. In sapling and poletimber stands, focus your management on identifying potential crop trees and encouraging their growth. Typical objectives are to:
- Improve species composition.
- Control stand density.
- Improve tree quality.
- Increase tree growth rate.
- Harvest trees before they die.
Weeding is the practice of removing undesirable tree species that take up valuable growing space. Culling is the removal of trees that have no commercial value because of poor form, damage, or other physical defects. Thinning involves selectively cutting trees of a desirable species to give the remaining trees more growing space. Pruning removes limbs to straighten saplings or to allow knot-free wood to develop on poletimber trees. These practices collectively are called timber stand improvement (TSI). In TSI, your first step is to pick the objective, then determine which trees should be left in the stand and how to maximize their growth and potential.
For general woodland health:
- Retain tree species best suited for your site.
- Retain a diversity of tree species to protect biodiversity as a hedge against serious pest problems.
- Remove trees with insect and disease problems.
- Remove trees with severe damage to bark or crowns.
- Thin the stand to sustain vigorous growth on the best trees, thereby helping them resist insects, diseases, and weather extremes.
- Remove invasive, exotic species that may take over the stand and suppress the regeneration and growth of desirable native species.
If timber production is your goal, determine what products you wish to grow (for example, fuelwood, pulpwood, sawtimber, or veneer), then learn what tree species, size, and wood quality are required for those products. During TSI (Figure 5-1), encourage the growth of potential crop trees that:
- Are desirable species in the marketplace.
- Have tall, straight stems.
- Have few branches on the main stem.
- Have healthy crowns in dominant or codominant positions in the canopy.
- Are relatively free of insect and disease problems.
- Show no signs of bark damage or wood decay.
If your goal is to improve wildlife habitat, decide which wildlife species or groups of species you want to encourage and learn about their habitat needs. Use TSI to create appropriate habitat, such as:
- Food (fruit, nuts, seeds, buds)
- Shelter (hollow trees, thickets, brush piles, dead standing trees, downed logs, large woody debris in streams)
- Escape cover (dense thickets, hollow trees, large trees)
- Breeding sites (permanent openings, dense thickets, mixed hardwood and conifer stands)
- Nesting sites (Several horizontal layers of vegetation?\ground cover, understory, mid-story)
If visual quality is a concern during TSI:
- Remove trees or prune off lower branches to provide a pleasing vista.
- Save trees with beautiful flowers, fall leaf color, or interesting bark.
- Protect trees with interesting shapes.
- Save large trees.
- Encourage species diversity, especially a mix of hardwoods and conifers.
TSI may be commercial or pre-commercial, depending on whether cut trees can be sold for a profit. Pre-commercial TSI, however, is often economical in the long run because it sustains tree growth, shortens the time to harvest, and improves tree quality.
The following TSI recommendations are aimed at sustaining a healthy forest primarily for timber:
- Where stump sprouts occur on desirable species, wait until they are 3 to 5 years old, then thin them with loppers or a handheld, motorized brush saw to one or two vigorous, straight stems that are more than 10 inches apart.
- Thin sapling stands with a motorized brush saw, leaving 1-inch diameter stems 3 feet apart.
- When thinning dense sapling and small pole-sized stands, it may be more practical and economical to remove whole rows or swaths of trees than to selectively remove scattered trees. Follow a stocking guide (pg. 207) for the main crop species to determine how many trees to leave. In stands with large pole-sized trees and enough space between trees to maneuver logging equipment, selectively harvest trees, leaving the best and largest trees. Leave potential crop trees with dominant or codominant stems. Intermediate and suppressed trees have fallen behind in the competition for growing space and are unlikely to ever become quality dominant trees, even after release.