Single tree selection is a valuable tool that may be thought to be used often, but is commonly not performed correctly. This prescription provides a thorough example of a single tree selection prescription, and a demonstration of how it can be implemented.
The current stand is even-aged northern hardwood. Through single tree selection and uneven-aged management, the goal of the prescription is to increase the structure, function, and composition quality of the stand.
Objectives include moving the stand towards a balanced, uneven-aged stand with 3 or more age classes significantly represented and more snags and coarse woody debris in the next 2 – 3 entries. This will be done with single tree selection and group selection to recruit the new age classes and promote diversity. This method will also improve the vigor of the residual mature trees and help establish a balanced stand. The improved structure will benefit wildlife and the stand entries will provide timber to local operators.
Pre-treatment stand description and condition
Pre-treatment species composition:
The stand is comprised of 76% sugar maple by basal area, 15% red maple, and 3% black ash and yellow birch. The remaining trees are white ash, American basswood, balsam fir, quaking aspen, eastern cottonwood, black cherry, American elm, white spruce, and paper birch. Sugar maple has a mean dbh of 11.4 inches. Red maple has a mean dbh of 12.0 inches.
Pre-treatment growth and stocking:
Figure 1: Pre-treatment Growth and Stocking: Diameter Distribution by Species.
Figure 2: Stand quality is important to single-tree selection. Acceptable growing stock (AGS) are trees that meet the objective. Unacceptable growing stock are trees that do not meet the objective.
The current stand is dominated by sugar maple sawtimber and poletimber, with 76% of the stocking in sugar maple. As the stands grades to wetter soil, red maple (15%), yellow birch (3%), and black ash (3%) increase. The stand is even-aged, of fair to good quality. Average diameter is 10“ DBH with a stocking of 135 ft2 / acre. The stands holds an average of 246 trees per acre. While size classes above are all represented, age class diversity is absent. The understory is open, with small maple seedlings low to the forest floor, less than 1 foot in height. Where a few small gaps occurred in the stand, sugar maple saplings 6 feet tall are present.
The pre-treatment growth and stocking can be seen in Figure 1 and 2 above. The diameter distribution by species can be seen in Figure 1. The diameter distribution for acceptable and unacceptable growing stock can be seen in Figure 2.
Pre-treatment forest health issues:
Protecting ephemeral ponds from damage by harvesting equipment.
The stand is bordered extensively by swamp conifer and swamp hardwood.
No invasive species were identified within the timber sale boundary during establishment. Logging equipment will be pressure washed prior to accessing the sale area in order to minimize introduction.
Ash (white and black) are scattered throughout the sale area and were considered a high risk tree.
The goal is to manage the property for its optimum forest wildlife habitat and to provide public hunting, trapping, and compatible outdoor recreation. This stand is not suitable for biomass harvesting because this conflicts with the wildlife management objectives for the property.
Restricting harvesting to winter months to provide top browse for deer. Adjusting crown closure to allow sunlight penetration to stimulate recovery of shrub understory deer browse species.
Stand topography is level to gently rolling. The soils are mostly Shanagolden & Peeksville fine sandy loams. This moderately well-drained, moderately steep soil is found on crests and sides of drumlins and on knolls and ridges. The major concerns are equipment limitation in wet periods and windthrow hazard. Given the distribution of diameters and the density of shade tolerant species, this stand is a good candidate for continued single tree selection harvesting. The prescription calls for a reduction in BA/ac to 90% crown closure. For this stand, that will bring the BA/ac down to about 84 square feet. Thinning through the matrix and the establishment and future expansion of canopy gaps will increase age class diversity. Favoring mid-tolerant species for retention and creating larger (60-75’) gaps will maintain and increase species diversity in the stand.
Several ephemeral ponds are scattered throughout the stand and will be protected with appropriate mitigation measures by following WI BMPs for Water Quality. Access to the stand from Hoffman Lake Road is poor. The extreme northwest part of the timber sale borders private property and is painted blue.
Use group selection and single tree selection to release existing regeneration, and establish more regeneration. Basal area will be reduced to approximately 84 sqft/ac in trees greater than 5” DBH.
<5 ft2 of basal area in large sawtimber 16+” DBH (High risk only)
10 ft2 of basal area in the small sawtimber class (approximately 1 of every 3 trees)
30 ft2 of basal area in the pole class (approximately 1 of every 2 trees)
Prioritize harvest of sugar maple over yellow birch and black cherry, retaining the latter two species when possible. Reserve all conifers except balsam fir. Reserve snags and live den trees, up to 10/ac, unless they are a safety hazard. While marking for these guidelines, create 2 to 4 25’ - 40’ and 1 or 2 60’ - 75’ canopy gaps per acre, especially where regeneration is abundant and/or stem quality is poor, near mid-tolerant seed trees (yellow birch, black cherry, white pine). This northern hardwood stand should continue to regenerate naturally with periodic harvests using mechanized equipment into the future. Many of the gaps are established adjacent to large yellow birch; and by removing groups of poor quality and high risk maple. Five patches of aspen within the sale area are designated for coppice with standards. In these gaps, cut all stems greater than 1” DBH. Locate these gaps southeast of seed trees. All merchantable ironwood, balsam fir, and aspen with at least 2 sticks shall be harvested. With the exception of balsam fir, all other conifers (white pine, hemlock, white cedar, white spruce) will be retained. Large den and snag trees, especially yellow birch, remain for wildlife purposes.
There should be at least 3 to 6 live cavity or den trees and 3 trees per acre greater than 15” DBH left in the stand.
What actually happened during the treatment
Treatment has not happened yet.
Treatment has not happened yet.
Plans for future treatments
This northern hardwood stand should continue to regenerate naturally with periodic single tree selection harvests using mechanized equipment into the future.
Costs and economic considerations
The costs thus far to the Wisconsin DNR have incurred through the marking contract bid awarded to Sound Forest Management, LLC at $12,893.00 and broken down into three parts:
- Marking of trees to be removed during harvest, which includes costs of paint, and hours spent marking ($10,068.00).
- Establishing (marking gap center with ribbon, GPS boundary, plotting gaps on timber sale map) and identifying canopy gaps ($1,575.00).
Cruising of the marked timber sale for harvest cut volumes ($1,250.00).
Summary / lessons learned / additional thoughts
Will consider lessons learned and additional thoughts post-treatment.
This case study was developed with support from the United States Department of Agriculture's National Institute for Food and Agriculture (USDA-NIFA), Renewable Resources Extension Act (RREA). Project #MIN-44-E02, principal investigator Eli Sagor, University of Minnesota.