Overview
Northeastern MN is comprised largely of a heterogeneous landscape of mesic mixed conifer/hardwood forests, woodlands and wetlands, with a broad band of northern hardwood forests along the North Shore. Management has the potential to sustain these natural forests as well as meet the varied objectives of different ownerships within the landscape. Natural disturbance processes important to the maintenance of these forest systems include fire and wind. The challenge is to define how best to manage these forests for sustained ecological and economic health, and develop a mutual understanding across ownerships for how best to retain natural processes or impose surrogate processes, and evaluate silvicultural options. For more on the project, visit https://sites.google.com/site/manitoucollab/home .
Silviculture Objective(s)
- Mimic a moderate natural disturbance event thru timber harvest and set >70% of a large patch of northern mesic mixed forest to a young growth stage, while retaining significant components of habitat for wildlife species of concern, sensitive NPCs, old-forest characteristics, and advanced regeneration of white cedar and white-spruce.
Figure 1: Goshawk stick nest reserve
- Protect/enhance forested cover along Manitou and Balsam Creek to maintain cold-water fishery.
- Transition the patch overstory vegetation from an even aged aspen/birch dominated cover type toward a multi-age mixed conifer-hardwood forest where natural regeneration of long lived conifer cohorts can self-replace after harvest or other management activities.
- Diversify wood product opportunities by supporting a wider range of tree species and age structures.
Pre-treatment stand description and condition
Stand establishment and management history:
The identified treatment areas within the patch have seen little active management in the past 70 years. Wind, pest outbreak, and ground fire disturbance have resulted in the development of mixtures of aspen, birch, spruce, and balsam fir and several intact legacy tree clumps of large diameter white cedar trees. Previous timber management access is limited by the presence of large trout streams and steep rock outcrop topography. Pine forests are not predominant with surprisingly little presence of old stumps. The patch lies within an MBS site of Moderate biodiversity ranking, where moderately disturbed native plant communities and landscapes have a strong potential for transitioning toward mature, mixed species composition including commercially important conifers like white spruce and white pine.
Pre-treatment species composition:
As of 2008: Stands are dominated by large diameter quaking aspen and paper birch (9-15”dbh). Additional species present include balsam fir, white spruce, black spruce, red maple, black ash, and white cedar. Basal area ranges from 40-130 sq. ft/acre. Birch is considered high-risk due to old age, top-dieback, and overall stand decline. Coarse woody debris (CWD) and snags are present in average numbers. The understory contains a moderate to heavy shrub understory along with abundant balsam fir seedlings. Few pine or spruce seedlings are present. Important natural heritage features include moose, white-tailed deer, northern goshawk, brook trout, and 38 other rare plant and animal species in the landscape.
Figure 2: Pre-harvest mature paper birch stand FDn43a NPC
Table 1: Overstory and understory species composition.
Overstory Species (>5”dbh) |
Volume/Acre |
Understory Species (<5”dbh) |
Trees/Acre |
Quaking Aspen |
16 cords |
Quaking Aspen |
50 |
Paper Birch |
10 cords |
Paper Birch |
200 |
White Spruce |
4 cords |
White Spruce |
30 |
Balsam Fir |
1.5 cords |
Balsam Fir |
1180 |
White Cedar |
1 cord |
White Cedar |
20 |
Red Maple |
0.2 cords |
Red Maple |
5 |
Black Spruce |
0.5 cords |
Black Spruce |
-- |
Black Ash |
0.1 cord |
Black Ash |
15 |
White Pine |
-- |
White Pine |
5 |
Figure 3: Pre-harvest mature aspen stand FDn43a NPC
Silviculture Prescription
In 2008, the DNR sold a four-block, 185-acre timber sale valued at over $54,000. In coordination with The Nature Conservancy and the USFS, an access bridge was installed over the Manitou river to facilitate efficient hauling of wood products during all phases of the operation.
- Blocks A and C are “shelterwood with reserves” treatments (moderate gap size from 80-200 ft). Harvest aspen and paper birch to a residual basal area of 40 sq. ft/acre. Selectively remove trees in a clumped and dispersed pattern to closely replicate conditions found after a moderate intensity natural disturbance. Block A is full tree skid during dry summer or fall conditions to reduce woody shrub component and to scarify and expose mineral soil. Maintain all non-hazardous snags. Reserve species include residual aspen, paper birch and all spruce, white cedar, red maple, and black ash.
- Blocks B and D are “seed tree with reserves” treatments (large gap >300ft). Block B is full tree skid during dry summer or fall conditions to reduce woody shrub component and to scarify and expose mineral soil. Block D is frozen ground harvest only. Reserve 6-12 (9-15”dbh) aspen /acre aggregated in clumps or as single, dispersed trees throughout the site. In addition, reserve all spruce, white cedar, red maple, and black ash.
Following harvest, portions of the block are planted to a mixture of white pine, white spruce, white cedar, and yellow birch. Although mechanical site prep was not employed for any of the blocks except block B, pre-commercial weeding and brush treatments have been conducted for much of the area.
Desired Future Condition:
Uneven aged mixed conifer-hardwood stand with a greater quantity of white spruce, white pine, and white cedar trees than currently present. A long-term white pine tree target would be 150 mature trees/acre by year 50. In addition, provide structural diversity by retaining and protecting:
- Fine and coarse woody debris, snags, and downed logs.
- Scattered and clump reserve areas outside and adjacent to harvest areas that function as legacy patches, and as sources of future seed trees.
- Scattered legacy of mature paper birch/quaking aspen, spruce, pine, cedar, black ash, and maple. Manage in variable density retention (VDR) pattern with marked reserve trees and as directed by the timber sale administrator.
What actually happened during the treatment
2009: Manitou collaborative finalizes bridge construction plan and TNC secures funding for installation.
2010: North Shore Forest Products contracts with Kuehl Logging of Ely, MN to start harvesting on USFS blocks and State blocks A & B. Conventional logging equipment is utilized in the operation.
2011: USFS stands, state cutting blocks A and a portion of cutting block B were planted with a mix of white pine, white cedar, white spruce, and yellow birch.
2011: DNR/TNC complete browse protection on white cedar and white pine planting.
2011-2012: TNC completes 1st year vegetation and invasive species monitoring.
2012-2013: Remaining blocks are harvested.
2013-2014: Remaining blocks B & C are planted to with a mix of white pine and white spruce.
Figure 4: Access bridge across Manitou River trout stream
Figure 5: Timber harvest large gap with coarse woody debris retention
Figure 6: Post-harvest Seed Tree with large gap regeneration of spruce, white pine, and cedar
Figure 7: White cedar legacy clump
Figure 8: Conifer planting
A post-harvest monitoring report was submitted in July 2011 by The Nature Conservancy. Permanent plots were also established as a baseline for future studies by The Nature Conservancy. Within these plots TNC staff will measure over time, regeneration success, residual structure, invasives, the forests response to climate change, and other metrics.
In 2014, 4500 red and 2000 bur oak seedlings were planted as part of a larger TNC climate adaptation project. Control areas with no treatments were established. Treatments were applied to DNR and USFS ownerships.
Post-treatment assessment
Figure 9: Post-harvest shelterwood with small gap regeneration of spruce, white pine, and cedar
Residual basal area and tree density objectives were generally met for the shelterwood (30-40 ft2/acre) and seed tree (20-30 ft2/acre) treatments.
Post-harvest shrub density was higher in the seed tree compared to the shelterwood treatment.
Within the shelterwood (moderate gap) treatment, overall dead wood volume showed little change. The 10-20 and 20-30 cm size classes increased, while snag volume decreased substantially from pre-harvest levels. The seed tree (large gap) treatment showed a significant increase in dead wood volume. All three downed wood size classes increased, while similar to the shelterwood (moderate gap) treatment, snag volume decreased significantly.
Invasive plant distribution and abundance prior to harvest and the first two years after treatment was examined. The highest establishment of invasive plants occurred on skid trails. Seed sources were generally less than 300 m. Survey and treatment prior to harvest could limit invasive plant establishment.
Nursery seedling stock and conditions of planting in 2013 resulted in poor survival. Vegetative competition resulted in high seedling mortality for some of the treatment blocks in the initial planting from 2011.
Plans for future treatments
1. Regeneration surveys and diversity planting for the next 8-10 years.
2. The Nature Conservancy supported treatments include:
a. Protection – Every year for 7-8 years or until above browse height.
b. Crop tree release – Every other year for 7-8 years or until crop trees can out-compete
aspen and shrub competition.
c. Terrestrial invasive control, as needed.
Additional monitoring and research projects being carried-out include:
- Climate Change Adaptation Project developed by The Nature Conservancy within the Northern Superior Uplands region;
- Analysis of remote sensing data (Residual BA, deadwood, crown bulk density).
- Master’s thesis work directed by Peter Walter of Iowa State University.
A second patch project monitoring report is scheduled in the next 7-10 years with the participation of both The Nature Conservancy and the MN DNR Division of Forestry.
Costs and economic considerations
Staff spent considerable time and planning effort in developing the patch plan and determining the overall management objectives. All season access and harvest units, logger-select cutting specifications, and the need for a temporary project access bridge were some operational aspects that were important in making the timber sale feasible. As a way to address economies of scale and make the timber sale more marketable, the planning team added additional unplanned stands to the project as well as reduced the stumpage value (-25%) on the timber appraisal.
Figure 10: Wood to market
Planting, seedling protection, and follow-up conifer release are expensive, but necessary investments in the Northeast landscape. Typical costs range from $500-800 /acre.
Other notes
What would you do differently if you could do over?
Most of the residual trees in the partial harvest areas will be 85-90 years old and in a condition that is unsuitable for overstory removal. Focusing on younger age-class birch-aspen stands (40-50 years) would improve the opportunity to manage and follow up with a final shelterwood removal and provide additional timber revenue to the agencies. Although residual overstory distribution helped reduce aspen suckering, establishing and maintaining conifers in aspen dominated stands is challenging. More emphasis on selecting birch-fir-spruce stands would be appropriate.
Active and retired Manitou Collaborative Partners [1] and MN DNR Staff [2]
Anna Heruth MN DNR Forestry [email protected] / 218-387-3037.
Paul Dubuque MN DNR Forestry [email protected] / 651-259-5294.
Jim Manolis The Nature Conservancy [email protected]
[1] Wes Habedank, Paul Moran (FOR); Bob Kirsch-retired, Al Anderson-retired (FAW); Lawson Gerdes (EWR); Wayne Russ-retired (USFS); Jim Manolis, Chris Dunham, Mark White (TNC);
[2] Emily Peters (EWR), Amber Ellering, Rick Klevorn, Jon Nelson (FOR); Keith Wendt-retired, and NE Region AFMP Team (Bill Schnell-retired, Mike Albers-retired, Dan Hanson (FOR); Dave Ingebrigsten(FAW).
Summary / lessons learned / additional thoughts
This project is a good example of how multiple divisions and partners can work together to create an economically feasible timber sale that crosses ownerships, contributes to larger patch management objectives, and increases species and structural diversity (similar to ecological forestry as defined in Franklin et al. 2007). Aspects of this project could easily apply to High Conservation Value Forests (HCVF), especially in a larger, mixed ownership landscape of high conservation value, and generally serve as an example of how to incorporate climate adaptation strategies into forest management. With a 15-year history, the Manitou Collaborative has been a leading example in the DNR for successful collaboration with multiple partners.
- Mapping of Native Plant Communities provided a common language and conceptual framework for communicating about ecological patterns and processes, and formulating compatible silvicultural prescriptions.
- Collaborating with TNC and the State Wildlife Action Planning program resulted in more robust monitoring and analysis capabilities. TNC contributed significant funding for installation and removal of the project access bridge, seedlings and planting crews, and monitoring support.
- The Manitou Patch Project serves as real world on the ground demonstration example for forest management in the Lakes States. Since 2010, the collaborative has hosted several field tours with various audiences including DNR, County, USFS natural resource professionals, University of MN Department of Forestry Master’s students, the Forest Guild members, and many more.
Some of the barriers to the project include:
- Acquiring long term funding for monitoring stand structural conditions, invasive species spread, and assessment of natural recruitment of long lived conifers after post-harvest treatments.
- Seedling condition and vegetative competition resulted in high seedling mortality for some of the treatment blocks in the initial planting. Because the Manitou Collaborative planning team agreed to less intensive mechanical site preparation and no application of herbicide to release conifers, seedling regeneration numbers vary considerably in the harvest units.
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