The Superior National Forest’s silviculture prescriptions are part of the National Environmental Policy Act (NEPA). The NEPA process includes proposal development, environmental analysis, and implementation of proposed activities. After the NEPA decision notice is finalized, the silviculture activities can begin in a given project area.
These NEPA prescriptions usually start with stands in mature forest condition. The regeneration harvest method is designated, followed by how the stand will be regenerated. Tending and intermediate treatments are completed based on need and whether funds are available to complete these types of activities. Five years after a timber harvest, stands are usually certified as reforested. Once stands have been certified, they may not be revisited for many years. However, the Superior National Forest would like to inventory reforested stands at 10-20 years after reforestation to determine if prescription objectives are being met.
There are several items that I would like to discuss. First, what was the desired future condition and the prescription for these stands? Management in the past was often more concerned with generating revenue from standing timber rather than desired future conditions. Consequently, the desired future condition and silviculture prescription can be hard to determine. For that reason, in this study I have recreated the desired future condition and silviculture prescription for the 3 study stands based on pretreatment stand conditions, management history, and current stand conditions. The second item is, does the prescription fit the site from an ecological stand point? Why or why not and how so? Third and finally, what would I do differently, and why?
• Even-aged white pine stand.
• White pine is the dominant conifer species present, accounting for at least 300 trees per acre and 50% of species composition.
• Paper birch, red pine, quaking aspen, balsam fir, white spruce, and tamarack are regenerating in the stand and contribute to tree species diversity.
• The trees in the stand are growing at an optimum rate and are resilient to insect and disease attacks.
Pre-treatment stand description and condition
Stand establishment and management history:
Harvest fir and blister rust White Pine. Underburn for site preparation. Seeding.
1998: PU 3 Rusty Geezer sale roller chop and some burn scarification before the blowdown
2003: Stand Clearcut, Corn Dog Two. Mechanical Site Prep for Planting
2004: Trees planted, white pine and red pine bare root at a density of 500 trees per acre (tpa)
2005: 1st year stocking survey 83% stocked, 100% survival
2006: tree release and weed
2007: 3rd year stocking survey 78% stocked, 100% survival; certified
Pre-treatment growth and stocking:
Mature white pine, fully stocked (> 70 ft2/acre BA), 12” dbh. Stand has been thinned in the past, but not currently regenerating. Mostly brush. Blowdown event prior to 1998. 2001: 50 ft2/acre BA, but 10-20 ft2/acre in another reference. Understory of merchantable fir, with scattered concentrated 6-10 ft. tall fir, with spruce budworm mortality. Stand is setting itself up for stand replacing fire.
Pre-treatment forest health issues:
Moose beds, scat, and browse abundant. White pine leaf adelgid present, and some white pine weevil damage, but minor damage observed. Moderate snow damage resulting in some deformed/leaning white pine.
Figure 5: Signs of White pine leaf adelgid on some shoots of a young white pine.
• Eliminate white pine blister rust and spruce budworm and reduce hazardous fuels.
• Establish a young white pine stand, but increase species diversity by allowing hardwood and other conifer species to regenerate in the stand.
• Maintain native vegetation communities in a forested condition.
• Maintain and improve wildlife habitat.
• Provide sustainable timber products to local operators.
• Fully stocked, mature, healthy white pine stand.
• Maintain or enhance species diversity.
• Maintain a strong conifer component in the stand. Recruit potential snags and downed wood into the stand.
Regeneration Harvest –
Clearcut with reserves. Reserve 5% of stand area as a legacy of clumps of trees. Reserve clumps shall, wherever possible, be at least 2 acres in size with a basal area of 80 ft2/acre or more and a dbh of 6” or more. Reserve single trees shall be scattered throughout the stand and retained at a density of approximately 6 to 12 trees per acre. Reserve trees shall be windfirm and selected in order of preference as: white pine, red pine, white spruce, quaking aspen, paper birch, and balsam fir.
Mechanically prepare the site for planting via tractor scarification. Scarify the ground to expose mineral soil and remove competing vegetation. Equipment shall work the soil to a depth of 3-4” on average.
Plant white pine at a density of 300 tpa. Plant red pine at a density of 200 tpa. Natural regeneration of white pine, paper birch, quaking aspen, balsam fir, white spruce, and tamarack.
Release red and white pine from deciduous competition so that conifers maintain a growth advantage over deciduous growth, especially brush. Release best formed red and white pine (those with no damage or disease, upright, straight, single stems) that are spaced approximately 8’ x 8’, but prioritize healthy trees over exact spacing. Use brush saws to clear all vegetation within a 2 foot radius of healthy red and white pine regeneration. Prune lower branches of white pine to help prevent white pine blister rust infection of regenerating trees.
Forest Type: White pine (with paper birch component). DBH: 2", Height: 15 feet; Density: 3,600 TPA
White pine: high density, even distribution, 3” dbh, 12 ft tall, 50% of composition
Paper Birch: high density, even distribution, 2” dbh, 20 ft tall, 30% of composition
Red Pine: moderate-low density, patchy distribution, 3” dbh, 15 ft tall, 10% of composition
Quaking aspen: low density, even distribution, 2” dbh, 20 ft tall, <10% of composition
Balsam Fir, White Spruce, Tamarack: very-low density, patchy distribution, 4” dbh, 15 ft tall, <10% of composition
Brush: high density (9,167 stems/acre), even distribution, but crop trees have grown above brush height
Residual Overstory: scattered white pine 10-24” dbh (average 14”), 75’ tall, 10 ft2/acre BA
Figure 1: Young aspen, paper birch, and balsam fir.
Figure 2: Surface boulder.
Figure 3: Brush in the foreground, with young and residual white pine in the background.
Figure 4: Brush in the foreground, with young white pine and paper birch and residual white pine in the background.
Ecologically, current conditions are similar to an FDn43 stand at age 35-55, even though the stand is only 14 years old. Under natural conditions, catastrophic fires would occur a regular intervals, where aspen and jack pine would have been the first cohort of trees to regenerate in this stand. The aspen and jack pine would eventually decline and be replaced by paper birch, white pine, red pine, and balsam fir. By planting red and white pine, management activities were able to eliminate the earliest ecological phase in this stand. The prescription for this stand fits the Native Plant Community type quite well. The regenerating trees are well-stocked, diverse, compositionally an excellent match for this NPC type and are relatively healthy.
Plans for future treatments
This stand looks excellent. Therefore, I have no recommendations for improving this prescription. Currently, the stand should be left to grow, but it should be monitored periodically (every 5 to 10 years) to ensure tree health is maintained. There is an outbreak of White pine leaf adelgid that has recently been identified on the Tofte Ranger District. The aphids were observed in the stand, but are not currently causing any mortality. When the paper birch have reached maturity (35 to 65 years from now) it will likely make economic sense to harvest the birch, but leave the white pine to continue to grow.
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.
Summary / lessons learned / additional thoughts
The purpose of the Sawbill Monitoring project was to review the previous prescription for a stand and answer three questions. The first question addressed the desired future condition and the prescription, following which I recreated the desired future condition and silviculture prescription based on pretreatment stand conditions, management history, and current stand conditions. The second question to answer was, does the prescription fit the site from an ecological stand point? Why or why not and how so? Third and finally, what would I do differently, and why? These three case studies also addressed a need to revisit stands at a more regular interval to determine if action needs to be taken. If a stand is certified regenerated and then not visited for decades the window for intermediate treatments may pass forest managers by and result in degraded quality when it comes time to harvest. Rather, revisiting a stand 10-20 years after its regeneration certification allows foresters to determine if prescription objectives are being met.
This original prescription for this stand was well suited to its NPC and the crop trees appear to be growing well and are relatively healthy.