Forest Management in Central New England
By coupling the forest history of New England to an understanding of the ecology of the region, the biology of forest trees, and society's demands for natural resources, Richard Fisher developed a comprehensive approach to forest management that he and his students came to call "ecological forestry". Because this approach was based on the study of natural stands and native species and attempted to work with the basic biology of forests in their natural landscape setting, it provides a clear precursor to the "new forestry" and "ecosystem management" approaches that have emerged in the late 20th century.
- Early Treatment of a Hardwood Stand
- Improvement Cutting in A Hardwood Stand
- First Thinning in a Mixed White Pine - Hardwood Forest
- Third Thinning in a Mixed White Pine - Hardwood Forest
- Conversion of Cordwood to Future Sawtimber
- Increasing White Pine in Hardwood
- Release of Pine From Suppression by Gray Birch
- Pruning White Pine to Produce Better Logs
- Group Selection Method of Harvesting White Pine
- Shelterwood Method in White Pine (right) and Hardwoods (left)
Early Treatment of a Hardwood Stand
This diorama shows two early treatments to improve the quality of a hardwood stand following the cutting of an old-field pine forest.
On the far left is the edge of a 60-year-old white pine stand about to be clear-cut for lumber. Just prior to logging, seedlings and small saplings of hardwood species in the understory are being cut off close to the ground. After cutting, the very small stumps will send up well-formed sprouts that will grow rapidly and will be straight enough to form good timber. Therefore, this pre-cutting will actually ensure better young crop trees in the future.
In the center foreground is an area where the mature pines were logged six years earlier. Workers are cutting away the smaller stems among the multiple-stemmed hardwood sprouts and are removing the short-lived pioneer trees wherever they dominate and threaten to crowd out more desirable trees. This treatment, also known as weeding, selects the most desirable trees for the future stand at an early age. This treatment concentrates and speeds up wood production on a smaller number of the most desirable trees.
Improvement Cutting in A Hardwood Stand
Hardwood stands that have not been thinned or weeded in the first several decades of forest development contain trees of many species, conditions, and sizes. Improvement cutting generally removes inferior stems to favor the best-formed and healthiest trees of desirable species for the future.
In the lower center the improvement cutting is in progress, resulting in piles of fuelwood logs.
Foresters call a tree like the tall one in the center-left background a "wolf" tree: its size and wide-spreading branches indicate that it had grown under open conditions in the past. A remnant from an earlier stand, this tree was left standing because it was deemed unsound or of too little value to be worth harvesting. Now it is being killed in place, or "girdled," so that it will not compete with the younger, growing stand.
Local variations demand that all management activity be undertaken with careful attention to site and forest condition as well as history.
First Thinning in a Mixed White Pine - Hardwood Forest
The improvement-cutting stage is eventually followed by thinning, which continues the process of removing trees that compete with selected crop trees.
The thinning taking place in the hardwood stand to the right of the road is a "crown thinning" or "high thinning." Its purpose is to give the best oak, birch, and white ash plenty of crown space by cutting the poorest of the competing overstory trees. Great care is taken to save some overtopped smaller trees as trainers to shade the crop tree stems and help "prune off" their lower limbs.
At the left center, the thinning has been completed - the logs dressed and neatly stacked.
In the center, thinning is in progress.
On the right, a forester is marking the trees to be removed with spots of red paint.
Third Thinning in a Mixed White Pine - Hardwood Forest
This is the same stand as the one shown in the previous diorama, approximately 25 years later. Many of the largest trees are now 12 to 16 inches in diameter and of fine quality for timber. This excellence in growth and form for timber production is due to the weedings and thinnings applied periodically since the stand was quite young. Untreated stands do not yield timber of the same quality.
The third thinning reduces the number of timber trees in the hardwood portion of the stand to about 100 per acre, spaced about 20 feet apart. Only the best individuals of the most desirable species, such as red oak, white ash, paper birch, and sugar maple, are left to form the final stand.
Conversion of Cordwood to Future Sawtimber
On dry upland sites such as the one pictured, hardwoods often do not grow vigorously and are likely to develop crooked stems, like those in the stand on the far right. Pines, on the other hand, can grow quite well and produce high-quality timber on such sites, provided they are not crowded or overtopped by the hardwoods.
With some effort, a hardwood stand can be converted to pine or other conifer species. In the center, the hardwood forest has been cut for cordwood and the slash burned, and now two crews are at work planting conifers.
Today such labor-intensive tree planting is not cost-effective on most sites in central New England and, with the exception of Christmas tree farms, is seldom undertaken.
Increasing White Pine in Hardwood Stands
Pines are more competitive with hardwoods in areas of dry, sandy soil than on rich, moist sites. On these dry sites it may be advantageous to supplement the hardwood trees with groups of white pine. At the time the dioramas were developed there was a strong emphasis on managing forests for pine production because pines had the greatest value in the local market. Today hardwoods are more valuable and it is unlikely that efforts would be made to convert a hardwood stand to pine.
Approaches to conversion of a hardwood stand to pine:
On the left-hand side, a cluster of white pine seedlings is being planted on a small knoll.
In the center-right a young stand of white pine mixed with hardwoods is being "weeded." Poor quality hardwoods are cut to give the pines more room to grow
In each case forest management is seeking to establish a forest mosaic with groups of white pine and groups of hardwoods. These distinct groups create a diverse structural pattern in the landscape, which enables the pines to grow more effectively than they would if completely intermixed with the rapidly growing hardwoods.
Release of Pine From Suppression by Gray Birch
Some abandoned fields or other open sites seed in heavily with both gray birch and white pine. Although much shorter-lived than the pine, gray birch grows much more rapidly at first and soon completely overtops the pine. Although the gray birch doesn't cast dense shade, eventually, the white pines should be released from competition by cutting the birches when they start to whip against and damage the preferred pines.
Pruning White Pine to Produce Better Logs
One characteristic of white pine in pure stands is the persistence of dead branches that cause loose knots in the resulting lumber. If high-quality, knot-free lumber is desired, the lower branches must be sawed off close to the live stem when the trees are young. Such pruning also produces a more aesthetic appearance in a highly visible stand.
Naturally seeded dense stands on old fields are especially well adapted to pruning, because close spacing shades and kills the lower branches white the trees are small and forces them to grow straight. On the far left side of the model a young stand of such origin is now receiving its first pruning.
In the center a similar stand has reached the age (about 30 years) when the final pruning is in order. Crop trees with straight stems are typically pruned up 16 feet (a standard log length) from their bases.
Group Selection Method of Harvesting White Pine
In our local landscape, which typically contains different land uses and soils in close proximity, white pine frequently forms nearly pure stands on recently abandoned agricultural land and dry sites, whereas hardwoods dominate moister and more fertile soils.
If we wish to encourage white pine to persist, clear-cutting large areas of white pine is not only wasteful of the smaller trees, but undesirable from the standpoint of the next crop of trees. Where there are approximately even-aged small stands in proximity to other somewhat different-aged stands, a partial cutting system known as "group selection" is possible. This approach is based on the ability of a stand to naturally reseed a nearby area.
Barely visible on the left, a mature group of trees, about 60 years old, is being clear-cut. This small cleared area will be well seeded by the oldest neighboring group in the center background.
The still younger group on the right margin, about 30 years old, was also seeded by a nearby stand; it will not be ready to cut for several decades.
In the center foreground is the very youngest age class: seedlings that grew up after a group cutting about 10 years earlier.
Shelterwood Method in White Pine (right) and Hardwoods (left)
The shelterwood method is a silvicultural approach through which a new generation of trees is established naturally under the shelter of older trees by a series of partial cuttings intended to:
- stimulate seed production
- create favorable seedbed conditions on the forest floor
- supply the young seedlings with sufficient room and light for healthy growth.
This natural regeneration is less expensive than planting seedlings and more likely to succeed without continuing frequent treatments.