Stand condition in 2019 for the entire nine acres is a 30 year old, high quality central hardwood stand with a significant red oak component. Therefore all silvicultural objectives were achieved for all nine acres of the stand.
Table 2. Basal area (ft2), relative basal area (RBA, %), and frequency (% of plots) of stems greater than 5” DBH in 2019
Species BA (ft2/ac) RBA (%) Frequency (%)
Red oak 26.7 49% 93%
Basswood 8.5 16% 52%
Aspen 4.8 9% 19%
Black cherry 3.3 6% 22%
Bur oak 2.6 5% 19%
American elm 2.2 4% 22%
Hackberry 1.1 2% 7%
Paper birch 1.1 2% 11%
Butternut 0.4 1% 4%
White oak 0.4 1% 4%
Black walnut 2.6 5% 7%
Total BA 54.1
Mechanical Site Preparation Results
First, a note of caution about assessing the mechanical site preparation results: Unfortunately, GPS technology was not available for our use at the time of project initiation, and none of the location markers that were established appears to have survived the 28 years since the last regeneration plots for the project were taken. This means that it is not possible to now definitively re-locate exact boundaries of the treatment areas. However, use of maps produced during the project, and also knowledge that the bulldozer only operated on the flattest 4 acres of the site, enabled us to delineate treated vs. untreated area with what we think was reasonable, if imperfect, accuracy. It is important to be mindful of this as results are examined.
While the four acres of mechanical site preparation treatment appears to have had several effects, none of them seems to have significantly impacted red oak regeneration success on this site after 29 years, compared to untreated portions of the stand.
Bottom line is that we found no major differences between bolddozed and non-bulldozed areas in establishment success for red oak twenty nine years after treatment.
Most of the nine acre stand now contains a good component of red oak greater than 5 inches DBH. There is little difference in 5“-plus DBH red oak basal area between treated and untreated areas. Also, frequency with which we found red oak in plot samples was similar, thus red oak was well distributed through the site in both bulldozed and non-bulldozed areas. The bulldozed areas did have greater aspen basal area and frequency than the non-treated areas, but this could be a function of landscape position and location of aspen before harvest rather than treatment differences, as aspen tends to occur near the tops of the hills rather than at the bottom. Overall, there was similar tree species composition and basal area between treated and untreated sites; there were some minor differences, which we can’t say are significant or not. Cherry may have done slightly better in the non-bulldozed area but that could be related to sampling effort (8 plots in the bulldozed area vs. 19 plots in the non-bulldozed area).
Table 3. Basal area (ft.2/ac), relative basal area (RBA, %) and frequency (% of plots) of overstory trees (DBH > 5 in) by DBH class in 2019
Bulldozed (8 plots) Non Bulldozed (19 plots)
Spp by DBH class (in) BA (ft2/ac) RBA (%) Freq (%) BA (ft2/ac) RBA (%) Freq (%)
Red Oak (5-10) 15.0 29 75 15.8 29 74
Red Oak (10-15) 2.5 5 25 8.4 15 53
Red Oak (15-20) 2.5 5 25 2.6 5 26
Red Oak (20+) 1.3 2 13 2.1 4 16
Black cherry (5-10) 1.3 2 13 4.2 8 26
Hackberry (5-10) 0.0 0 0 1.6 3 11
American elm (5-10) 2.5 5 25 2.1 4 21
Butternut (5-10) 1.3 2 13 0.0 0 0
Basswood (5-10) 6.3 12 38 7.9 14 53
Basswood (10-15) 0.0 0 0 1.6 3 11
T. Aspen (5-10) 11.3 22 25 1.6 3 11
T. Aspen (10-15) 1.3 2 13 0.0 0 0
Paper birch (5-10) 1.3 2 13 0.5 1 5
Paper birch (10-15) 1.3 2 13 0.0 0 0
Bur oak (10-15) 0.0 0 0 1.1 2 5
Bur oak (15-20) 0.0 0 0 0.5 1 5
Bur Oak (20+) 3.8 7 25 0.5 1 5
White oak (5-10) 0.0 0 0 0.5 1 5
Apple (5-10) 0.0 0 0 0.5 1 5
Black walnut 0.0 0 0 3.7 7 11
Total BA 51.3 55.3
The main story of this case study is in trees that are over 5” DBH shown in table 3 above. However, the cohort of three to 5 inch DBH trees is also important, since some of them are codominant. A summary table of average stem density and frequency of these trees are below (Table 4).
The non-bulldozed area has slightly greater red oak density and frequency than the bulldozed area in the 3-5 inch DBH class. However, basswood, black cherry, paper birch, and aspen have greater density and frequency in the bulldozed area. One difference to note is that 3-5 inch buckthorn did better in the bulldozed area than in the non-bulldozed area. However there is slightly more smaller diameter buckthorn (1-3 inch DBH), in the bulldozed area compared to non-bulldozed (241 stems/ac vs 395 stems/ac, respectively). It is not possible at this point to say with certainty if differences are due more to the bulldozing treatment, or to other factors such as topography or pre-existing vegetation differences prior to treatment, or to a combination of all of those factors. Regardless of which treatment had more buckthorn and at what size class, there was still a high density of buckthorn throughout the site (data not shown). It should also be noted that high buckthorn densities are common in the Hay Creek area
Table 4. Sapling and small tree regeneration density (ave stems/acre) and frequency (% plots present) in 2019
Small trees (3-5 in DBH)
bulldozed non bulldozed
Species density frequency density frequency
Red Oak 25 25% 63 42%
American elm 25 25% 26 26%
Basswood 100 63% 47 37%
Black cherry 63 38% 26 26%
Paper birch 38 13% 5 5%
T. aspen 25 25% 5 5%
White oak 0 0% 5 5%
Green ash 0 0% 11 5%
Red maple 0 0% 5 5%
Buckthorn 63 25% 11 11%
Plant Diversity and Invasive Species Observations
In terms of plant diversity, we found 69 plant species in 1024 m2 (~0.25 acre) plot. Six of these were introduced species and included buckthorn (Rhamnus cathartica), oriental bittersweet (Celastris orbiculatus), European high-bush cranberry (Viburnum opulus), Tatarian honeysuckle (Lonicera tatarica), common dandelion (Taraxacum officinale), and heal-all (Prunella vulgaris). Many of the plants we found at our site are commonly found in MHs37 and other Mesic Hardwood sites in the Blufflands subsection and included plants like Two-leaved miterwort (Mitella diphylla), maidenhair fern (Adiantum pedatum), and red baneberry (Actaea rubra) that indicate shady, rich sites.
The buckthorn density was very high at this site (especially in sizes below 3 inches DBH) but we should note that high buckthorn densities are common in the Hay Creek area. We found oriental bittersweet on this site. It’s incredibly difficult to identify oriental bittersweet from the native bittersweet and we were not sure if we had the native, the exotic, or both. We do know that there are a few infestations of oriental bittersweet in the Hay Creek Unit. The oriental bittersweet, if present, could harm both the young crop trees and the integrity of the forest. So, determining which species we have is something we plan to do in the near future. Lastly, while not captured in our species area plot, we did find a small amount of garlic mustard (Alliaria petiolata). Invasive species will all be monitored, with control actions taken as needed.