Regenerating Northern Red Oak After Salvage Using Bud Caps, Cages, and Brushsaw Treatment (MN DNR)

State or Province
Nearest city or town
Hill City
Describe the location
36-052-27W. Location of site is adjacent to CR #67 on the South side of the road about 2.5 miles east of Shovel Lake
School Trust Fund- MN State; Managed by MN DNR- Aitkin Area Forestry
Cover type
Plant community detail and growth stage
MHn35 – Northern Mesic Hardwood Forest; stand age- 7 years old
Forest health threats
Adaptive silviculture options
Silviculture system
Estimated year of stand origin
Additional information about stand origin
Timber Permit 2009-2012, Timber Stand Improvement Proposal 2012-2013, Regeneration Survey 2015, Site History 2004-2015
Site index
80 feet
for species
northern red oak
Brief silvicultural objective
To increase the quality and stocking of northern red oak and saplings at the site through the protection of bud caps to reduce browsing, and limit competitor species such as, aspen, ironwood and beaked hazelnut.
Site preparation method
Soil texture
Soil details
Majority of the stand soil composition is: 928C – Cushing 2 – 10 percent slopes
Stand area
22 acres
Treatment area
22 acres

46.956389, -93.715833


In 2009, the west side of the 22.5 acres were harvested and the later the south side was salvaged cut, to eliminate two-lined chestnut borer in the stand. The objective after cutting was to create an even-aged stand that increased the stocking of northern red oak and maple, essentially making it a northern red oak stand through natural regeneration. The reduction of competitor species such as quaking aspen, ironwood and beaked hazel was meant to maintain the oak, paper birch and basswood components of the stand oak stocking. The placement of bud caps was a prescribed treatment, as well as using a brush saw to accomplish these tasks. 

Silviculture Objective(s)

Figure 1: Oak overstory

This site has a suitable soil composition to support northern hardwoods, sugar maple, northern red oak, and other species as well, paper birch, red maple and basswood. The main objective is to regenerate northern red oak to 700 trees/acre and maple to 200 trees/acre in the stand. In order to increase the stocking of northern red oak, competitor species would be reduced through various actions. The damage to northern red oak seedlings and saplings from animals would be reduced with the protection of bud caps, as well as reducing disturbances to prevent susceptibility to diseases and infestation of insects that can occur when tree species are in a weakened state. 

Pre-treatment stand description and condition

Stand establishment and management history: 

Figure 2: Snag

Pre-treatment stand establishment was in 2003. Over 70% of northern red oak became infested with the two-lined chestnut borer (TLCB). Stress conditions such as drought, construction and/ or defoliation made trees susceptible and allowed the native beetle to attack weakened oak trees. In 2000, there was an outbreak of Forest Tent Caterpillars (FTC) in the Hill City region. FTC defoliated the northern red oak species in the stand and made them susceptible to the two-lined chestnut borer.  TLCB can infest all oak trees in MN, but prefer northern red oaks (MN DNR). To manage TLCB, a salvage cut was prescribed at the stand age of 65 years old, and later with treatments to promote northern red oak regeneration and limit competitor species.

Plant Community (NPC) and Growth Stage:

  • MHn35
    • Northern Mesic hardwood Forest
      • Shrub layer- sugar maple, beaked hazelnut, balsam fir, chokecherry, pagoda dogwood, fly honeysuckle
      • Sub canopy- sugar maple, ironwood
      • Canopy- sugar maple, basswood, northern red oak, paper birch, quaking aspen
      • Stagnation moraines-
        • Parent material is fine textured till with loamy or sandy loamy layers
        • Till is non-calcarcous
        • Soil well-drained
    • 0-55 Years Old
      • Recovering forest dominated by paper birch and quaking aspen; less sugar maple, northern red oak, basswood
      • Growth Stage
        • 7 years old
  • Overall well-drained soil
    • 928C- Cushing soil
    • 870C- Itasca soil
    • 292- Alstad soil

Pre-treatment species composition: 

Northern red oak, quaking aspen, paper birch, red maple, ironwood, balsam fir, basswood, beaked hazelnut, sugar maple

Pre-treatment growth and stocking: 

Table 1. Crop Tree Species Summary from Regeneration Survey 2015

Crop species Stock (%) Trees/acre Average height (ft) Height range (min) Height range (max) Damage type
Northern red oak 40 375 7 1 14 Deer browsing
Basswood 30 250 5 3 10 Deer browsing
Red maple 50 300 5 2 9 Deer browsing
Paper birch 5 55 2 2 2 Deer browsing


Table 2. Competitor Tree Species Summary from Regeneration Survey 2015

Competitor species Stock (%) Trees/acre Average height (ft) Height range (min) Height range (max)
Ash 5 175 1 1 1
Aspen/Balsam Fir 35 350 5 2 9
Ironwood 10 175 2 2 2

Pre-treatment forest health issues: 

  • 2000- Forest Tent Caterpillar (FTC) defoliated oak trees
  • 2003- Active infestation of two-lined chestnut borer (TLCB); 70% of oak dead
  • Presently- Heavy deer browsing on saplings and frost damage (deer population was low in 2010)

Silviculture Prescription

 Silviculture Prescription – 2009-2015
  • The prescription for the stand was a combination of a harvest/salvage cut, brush sawing and the placement of bud caps on northern red oak regenerants. The harvest was prescribed in the fall of 2009, to cut hardwoods and aspen, then in 2010, northern red oaks became infested with TLCB, and a salvage cut was prescribed to eliminate the disease. The entire stand was harvested for these specific species. The stand was 60 years old when harvested. Brushing sawing competitor species, such as aspen, ironwood and beaked hazel would allow favorable species, like northern red oak and maple to become established as the dominant species in the stand. This treatment was conducted July 2014 to October 2014 and prescribed for the 22.5 acres. After natural regeneration, oak seedlings were capped two different times, once in September 2014 and in October 2015, to reduce the damage done by deer browsing and extended throughout the entire stand.
  • The harvest/ salvage cut was in hope to remove the TLCB and infected trees, as well as harvesting merchantable tree species, including northern hardwoods and trembling aspen. Species that were reserved during the cutting was balsam fir, ash and trees marked with orange paint. The appraisal was for 120 cords of trembling aspen, 180 cords of northern hardwoods, and 75 cords of red oak. Refer to Table 3. below for specifics and for harvest specifications refer to PDF “Harvest Specifications” in Supplemental Content.  
  • A regeneration survey was conducted in late spring of 2015. A species summary was collected for both crop species and competitor species. The stocking for northern red oak species and red maple was at 40% and 50% and aspen/ balsam fir was 35%. Based off the regeneration survey of 2015 for this stand, a second application of bud caps were prescribed as treatment in the fall of 2015. Refer to Table 4. below for specifics.

Table 3. Amount of Cords Harvested in Salvage Cut 2009

Type of Cordwood

Amount of Cords (cd)

Value per Cord ($)

Northern Hardwoods



Quaking Aspen





0.40 per thousand pounds

Northern Red Oak




Table 4. Crop and Competitor Species Summary from Regeneration Survey 2015

Crop Species

Stock %


Competitor Species

Stock %


Northern Red Oak



Aspen/ Balsam Fir



Paper Birch



Green Ash



Red Maple












What actually happened during the treatment

Treatment 1: Salvage Cutting 2009- 22.5 acres
  • The sale was cut in October 2009 by the Guertin Inc. Logging was held off for a week or two due to precipitation and started back up in December 2009 when the ground was frozen. Conditions in September 2010 allowed logging to proceed and noticed TLCB in oak trees, only healthy oak trees were left, and then a large amount of precipitation in October 2010 slowed down progress. By September 2011, all trees were felled and removed from the landing. Random skidding was done to create extensive soil scarification. Once logging started they discovered that 70% of northern red oaks were infested with TLCB, an “Added Timber” sale was conducted and the harvest of northern red oak was added to sale for harvesting during the second cutting.
    • Equipment used:
      • Conventional skidder
      • John Deer wheeled harvester
      • Limber
      • Slasher
Treatment 2: Brush Sawing to Release Species 2014- 22.5 acres
  • In July 2014, a majority of aspen stems were brush sawed to release other species, mainly northern red oak and maple in the stand. The brush sawing of the stand was completed in October 2014. A free to grow tree was left every 15 feet, a 45% stocking of northern red oak and a 50% stocking of maple. When neither free to grow tree was present, aspen was left every 15 feet in the understory.
    • Equipment used:
      • Brush saw

Figure 3: Brush sawed stem

Treatment 3: Bud Capping 2014 & 2015- 22.5 acres
  • In September 2014 and in October 2015, bud caps were placed on northern red oak species to help regenerates reach above five feet. Buds caps are pieces of paper folded over the tip, held together by staples. Many regenerates below five feet with bud caps present in the northern half of the stand, were heavily damaged by deer browsing, and frost damage. Deer browsing damaged continued throughout the entire stand. Also, many bud caps slid off due weather conditions and improper assemblage.
    • Equipment used:
      • Paper
      • Staples

Figure 4: Red oak bud cap success

Figure 5: Bud cap and deer browse

Treatment 4: Oak Cages 2014 & 2015- 22.5 acres
  • In September 2014 and in October 2015, metal cages were placed over northern red oak regenerates as well. This treatment was also used to reduce damage done from deer browsing.
    • Equipment used:
      • Metal cages

Figure 6: Caged oak

Post-treatment assessment

Figure 7: Red oak regeneration stand map

Figure 8: Red oak regeneration soils map

A 2016 regeneration survey showed the following figures are per acre. Based off these results below and the Regeneration Summary, TSI and a more intense brush sawing of quaking aspen would occur to  allow northern red oak to become better established and thrive within in the stand against competitor species. As well as a larger distance to leave free to grow trees, and reduce the completion among species. Refer to PDF “Regeneration Summary” in Supplemental Content.

Table 5. Survey of Northern red oak stems per acre.

Northern red oak

Regenerates (<1”dbh, <1’tall)

275 stems per acre

Seedlings (1”dbh, >1’tall)

675 stems per acre

Saplings (1-3”dbh)

10 stems per acre

Small trees (3-5”dbh)

5 stems per acre

Basal area

13.5 square feet

Table 6. Survey of all seedling species stems per acre.

Seedlings (<1’dbh, >1’tall)

Quaking aspen

2,475 stems per acre


825 stems per acre

Red maple

775 stems per acre

Northern red oak

675 stems per acre

Big-toothed aspen

500 stems per acre

Black ash

350 stems per acre

Sugar maple

200 stems per acre


25 stems per acre

Plans for future treatments

  • TSI
  • Protection - Mechanical - Bud Caps
  • Planned Onsite Visit - Regen - Regen Survey
  • Planned Onsite Visit - Regen - Standards Check

Costs and economic considerations

Actual Action Cost Subtotal: $5,127.50

  • Onsite Visit-Inventory-Re-Inventory, 22.5 acres
    • Start Date: 4/13/2008
    • End Date: 4/13/2008
    • Costs: $87.50
    • TSI Mechanical- Brush Saw, 22.5 acres
      • Start Date: 7/01/2014
      • End Date: 10/07/2014
      • Costs: $2,025.00
      • Protection Mechanical- Bud Caps and Metal Cages, 22.5 acres
        • Start Date: 9/22/2014
        • End Date: 9/22/2014
        • Costs: $1,260.00
        • Protection Mechanical- Bud Caps and Metal Cages, 22.5 acres
          • Start Date: 10/19/2015
          • End Date: 10/19/2015
          • Costs: $1,755.00

Other notes

The site was first typed as a MHc26 forest; an error made by myself, but was later corrected to a MHn35 forest. 

Summary / lessons learned / additional thoughts

The salvage cut created scarification in the soil, making it suitable for northern red oak natural regeneration. Also, from treatments described above, this resulted in an ample amount of regeneration of northern red oak than years in the past and other sites that were heavily browsed by deer. The bud caps and bud cages were not a success in every case but overall allowed northern red oak to become established as one of the predominant species in the understory. With a larger range of 14 feet for free to grow trees, would reduce the thick understory layer of competitor species allowing northern red oak to thrive and have more success. 

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.

Supplemental content