The strategy of selecting some red oak stands in the 80 to 100 year old age range for harvest and regeneration, with a prescription of clearcut with reserves harvest and post-sale killing of undesirable trees was very successful on this site.
The stand in 2019 is a healthy, diverse 30 year old central hardwood forest with a good component of red oak from stump sprout origin.
The timber sale reserves of scattered bur and red oak, an aspen clump and the sugar maple patch are still largely present and healthy.
Overstory
As shown in Table 2 below, the cohort of trees over 5" DBH resulting from the 1988 harvest is dominated by red oak, which has far greater basal area (28.3 ft2/ac) than other tree species. Also, red oak had the greatest frequency (83%) and was well scattered throughout the stand. The red oak is almost entirely from post-harvest sprout origin, and also some healthy residual stems. Virtually none of the red oak originating post-harvest is of seedling origin.
Table 2. Total and relative tree basal area of stems > 5” DBH (feet2), and frequency on 10 BAF plots (%) in 2019
Species
|
BA (ft2/ac)
|
Relative BA (%)
|
Freq (%)
|
Red oak
|
28.3
|
45%
|
83%
|
Bur oak
|
3.0
|
5%
|
26%
|
Sugar maple
|
6.5
|
10%
|
13%
|
Black cherry
|
2.6
|
4%
|
22%
|
White oak
|
2.2
|
3%
|
17%
|
Elm
|
5.7
|
9%
|
39%
|
Trembling Aspen
|
2.2
|
3%
|
9%
|
Red maple
|
0.9
|
1%
|
9%
|
Paper birch
|
1.7
|
3%
|
17%
|
Red pine
|
0.9
|
1%
|
4%
|
Boxelder
|
1.3
|
2%
|
9%
|
Basswood
|
0.4
|
1%
|
4%
|
Hackberry
|
6.1
|
10%
|
39%
|
Ash
|
0.9
|
1%
|
9%
|
Black walnut
|
0.9
|
1%
|
9%
|
Total BA
|
63.6
|
|
|
Understory
In addition to trees greater than 5" DBH shown above, there is a component of codominant and intermediate crown class oak trees in the 3 to 5" DBH range. This can be seen in table 3 below; These trees should largely survive and be part of the stand moving into the future, especially with the planned crop tree release work.
Table 3. Tree regeneration density in 2019 (ave stems/acre). Regenerants: trees less than 1’ tall; Seedlings: trees less than 1” DBH but taller than 1’; Saplings: trees 1-3” DBH and Small Trees” 3-5” DBH.
|
Regenerants
|
seedlings
|
saplings
|
small trees
|
Red oak
|
478
|
|
4
|
13
|
Bur oak
|
|
|
|
4
|
sugar maple
|
609
|
43
|
|
9
|
basswood
|
|
|
30
|
9
|
green ash
|
|
261
|
|
|
trembling aspen
|
|
|
|
4
|
hackberry
|
87
|
217
|
65
|
9
|
boxelder
|
|
239
|
70
|
22
|
Black cherry
|
|
261
|
4
|
13
|
paper birch
|
|
|
|
|
elm
|
1348
|
1565
|
100
|
39
|
red maple
|
43
|
43
|
|
|
black walnut
|
|
43
|
|
|
Totals (stems/ac)
|
2565
|
2672
|
273
|
122
|
Understory Plants
The understory plants are common plants that occur in MHs38 forests, a mesic hardwood native plant community class that supports a diversity of tree species, shrubs, and ground flora. (For more information on the MHs38 native plant community, refer to supplemental content.) Some of the mesic indicating plants that we found on site include blue cohosh (Caulophyllum thalictroides), large flowered bellwort (Uvularia grandiflora), zigzag goldenrod (Solidago flexicaulis), wild geranium (Geranium maculatum), maidenhair fern (Adiantum pedatum), bloodroot (Sanguinaria canadensis), interrupted fern (Osmunda claytoniana), red baneberry (Actaea rubra), wild ginger (Asarum canadense), spikenard (Aralia racemosa) and hairy solomon’s seal (Polygonatum pubescens). The shrub layer was very diverse and included round leaved dogwood (Corunus rugosa), pagoda dogwood (C. alternifolia), grey dogwood (C. racemosa), wild black currant (Ribes americanum), grape honeysuckle (Lonicera reticulata), wild honesuckle (L. dioica), winterberry (Ilex verticillata), downy arrowwood (Viburnum rafinesquianum), and juneberry (Amelanchier sp.). Other native weedy shrubs and vines like prickly-ash (Zanthoxylum americanum), wild grape (Vitis riparia), boxelder (Acer negundo), and raspberries (Rubus spp.) were common on site too.
Invasive Species
During our vegetation survey, we noted that buckthorn (Rhamnus cathartica) was common throughout the stand. It is common to find buckthorn at these levels in this part of Minnesota. Buckthorn was the only invasive plant we found on site.