A unit of Lasting Forests Sustained forests; sustained profits evolving since March 30, 1999

In every forest there is usually "dead and down" wood. Such wood is primarily (1) standing dead logs or snags and dead trees on the ground. By making a count or estimate of the numbers, it is possible to draw many conclusions about a forest stand. The following is our analyses of each stand. After it, we present things that we know or that can be deduced from our present knowledge of wildland and their management needs.

1. In your area there are ____ species of large animals that use dead trees, trees with significant decay, trees with "witches brooms", hollow logs, snags, and fallen trees.
2. Animals use these for foraging, gaining shelter, nesting, denning, drumming (grouse and woodpeckers), roosting, resting, and above-ground run-ways. Snags and down logs have ecological value, enhance soil health, ensure seedling regeneration, retain moisture, recycle nutrients, and provide many needs of wild animals.
3. Some animals, like the woodpeckers, create cavities for winter roosts and for nesting.
4. About ____percent of the bird species nesting in Virginia and nearby areas are cavity nesters.
5. These same birds often play an important role (provide a "service"), reducing insect pest populations.
6. Absence of down wood in a forest signifies great disturbance (e.g., fire, fire-wood harvests, grazing, etc.).
7. How many dead logs should there be in a well-managed forest? It depends on the rotation. It should be 15% of the number of stems in the previous 5-year age class. Where q = 1.2, and there are 200 stems per acre, then the down logs and snags should number ____. You have an average of ____ stems, plus or minus about _____. A resilient, healthy forest with opportunities for the many, yet unknown processes and functions of the forests are likely to be achieved if the dead wood is over ______ stems.
8. The estimated volume of dead wood (class 1 and 2) to commercial wood is ____. Our first approximation is that this ratio should be about 10%. (The number is under study.) Too small amounts of dead wood suggest nutrients are not being made available for the future forest. Excessive removals may similarly be involved as well as past fires. Only when levels are high will there be a rich, diverse fauna.
9. Decay rates differ by sites. Rates are now under study. Class 3 down wood rapidly disappears on low, moist, northerly aspects.
10. Management is needed for woody components of wildlands. Each alpha-unit has a different rate of production and decay or loss (called respiration, R). Ecologists often look for P/R = 1.0 in wilderness, ancient forest, or undisturbed sites. Your ratio in each stand is approximately as follows:
    • A
    • B
    • C
    • Overall, your P/R ratio is 0.XX.
11. There are many areas where trees are not harvested (for many reasons, including slopes are too steep for equipment to operate, erosion potential is too high, color and visual quality will be impaired, etc.). These stands, adjacent or not, are important contributors to the dead and down wood resource of an ownership.
12. The estimated down and dead wood volume is ______, ______times the total faunal volume. In general, the greater the volume and the percentage, the more rich will be the animal life over time.
13. The only way to obtain a hollow dead tree is to have one started as a large living tree hollowed out by decay.
14. Heart rot fungi do not typically kill trees; hollow trees many provide habitat for years before they eventually die and become hollow snags or fall as hollow logs.
15. Only certain trees form high quality cavities. "Large" is not the only criterion for selecting trees to retain. Large ones of select species need to be retained such as oaks, sycamore, hemlocks.
16. About 1.5 large (greater than 24 inches in diameter) hollow trees per acre are needed. Your average is ____.
17. Retaining all large hollow trees in managed landscapes can be justified because so little of the landscape has them.
18. Clear-cut silviculture, on typical rotation ages of 50, cannot "produce" large trees. Short rotations cannot produce the number of large hollow trees, well distributed, that are needed for abundant, rich animal and plant populations. We have developed a preliminary list of tree species ranked in order of their probable decay rates and thus tendency to rot in a manner that will produce suitable cavities for the most years.
19. Snags should be retained but, in addition, all these structural classes should be represented across the landscape. A distribution score is: (*mean 30-inch snags per acre - 2* mean condition class) + 1(number of 10-inch or greater / 4 snags) / x 100. Both of the first two measures should be about 1.5 but are usually less; the density is viewed as important as the condition class. Your score is______.
20. Snags should be left in clusters in each stand (at least for safety of workers and area users) . . . but greater abundance will result if they are evenly, systematically spread.

OSHA rules say that no work shall be conducted within 2 tree lengths (L) of a dead tree or snag. The area (A) influenced by a snag is A = (2L)2TT. A snag is a pre-existing type of tree, not one in the process of being felled. It may be "any dead standing tree" but probably is "any standing, dead, partially dead, or defective (well) tree at least 10 inches in diameter at breast height and at least 6 feet tall." Logging rules say "leave 2-4 snags 15-20" dbh per acre, creating conflicts with OSHA rules, feasible logging, and the role of dead trees in watershed management, the life of wild animals and plants and in ecosystems.

Danger Tree Rule

OSHA 29 CFR 1910 (1995, Final Standard)

A danger tree is a standing tree that presents a hazard to employees due to conditions such as, but not limited to, deterioration or physical damage to the root system, trunk, stem, or limbs, and the direction and lean of the tree. (h.1.vi) Each danger tree shall be felled, removed or avoided. Each danger tree, including lodged trees and snags, shall be felled or removed using mechanical or other techniques that minimize employee exposure before work is commended in the area of the danger tree. If the danger tree is not felled or removed, it shall be marked and no work shall be conducted within two tree lengths of the danger tree unless the employer demonstrates that a shorter distance will not create a hazard for an employee.

This Web site is maintained by R. H. Giles, Jr.
Last revision January 17, 2000.