Another regeneration survey was conducted October, 2020 to evaluate the effectiveness of the treatment.
Table 2: Regeneration stocking in 2020, one year after anchor chain treatment
||Plantskydd portion (Red)
||Non-Plantskydd portion (Green)
||Unseeded portion (Blue)
|Northern red oak
|Total Trees per acre
Overall, there was great recruitment across the board. It was difficult to initially discern, by just looking at this table, whether the anchor chain treatment was effective or even necessary. The conditions in each of the 3 portions, post harvest but prior to anchor chaining greatly influenced how I interpreted the data. I concluded that the anchor chain was effective at soil scarification conducive to acorn establishment. The anchor chain will set back competition temporarily but followup release treatments should be expected.
The Blue area (NE), not scarified and not seeded, portion has excellent stocking of northern red oak, moderate stocking of aspen, ash, and maple and we did nothing besides the first cut of the shelterwood harvest. The residual 60% canopy closure prescription seems effective at producing conditions conducive to regenerating northern red oak, while somewhat shading out the aspen and is exactly what we were hoping for in the initial harvest prescription. However, this area was already decently stocked in the 2018 regeneration survey and its success was expected.
The Red area (S), scarified and Plantskydd acorn seeded, portion now has the highest stocking of northern red oak between all 3 areas despite having absolutely no regeneration in this portion in 2018. The residual overstory is similar to the Blue portion, so the massive increase in northern red oak regeneration is likely a direct result of the bumper acorn crop from residual canopy trees in conjunction with the anchor chain treatment/scarification. There was no aspen here in the 2018 regeneration survey, the spike in aspen regeneration noted in the table is largely limited to the large pocket where the landing was - clearly seen in the aerial photo. This area had a "slash mat" of biomass chips that did not get removed during harvest operations, and the anchor chain broke up that mat, stimulating new growth in that area. Regardless, the entire Red portion will need release in order to maintain the oak that have established.
The Green area (W), scarified and "plain" acorn seeded, portion also has excellent stocking of northern red oak. This portion was initially where all the aspen regeneration was in the 2018 survey, and very few oak seedlings. This portion had very few residual canopy trees, which is why there are not as many oak trees per acre as there were not many overstory trees contributing to the acorn crop. The anchor chain did set back the aspen in this area temporarily, acorns would not have been able to establish in this area prior to the anchor chain treatment due to the density of aspen, but a full return of the aspen is expected and this portion will need release in order to maintain the oak that have established.
Contributing factors: 1. The Northern Red oak acorn bumper crop
- The bumper crop was great for contributing to oak regeneration, but made the conclusions harder to determine.
- We were unable to evaluate the effectiveness between Plantskydd acorns vs "plain" acorns that we seeded, due to the extreme numbers of naturally seeded northern red oak acorns.
2. Residual tree retention
- Red area is similar to the Blue as far as species and residual density, pre and post harvest and make a good comparison to each other.
- Green area was mostly basswood, aspen and maple and had low residual density of oak pre and post harvest. It cannot not be compared to Red or Blue area. However, conclusions can be drawn from the lack of residual oak canopy presence and the previous prevalence of aspen regeneration in this area.
- The best results were in the untreated/unseeded (Blue), but oak regeneration was already good in this area. The 60% canopy closure prescription was effective at regenerating this portion of the stand naturally. Why it did not regenerate oak in the other 1/2 is up for debate. This area is 5-10' higher in elevation than the rest of the stand, there was also no woolgrass noted in competition in the 2018 survey so perhaps the soils were slightly different also.
- The anchor chain created soil scarification conducive to acorn establishment.
- In the treatment (Red & Green) area there were very few oak seedlings or stump sprouts in 2018 (before treatment).
- 2020: there now are almost twice as many oak in the Red area vs Blue area, that was already successfully regenerating oak in 2018.
- Oak recruitment was 10% higher in the Red vs already successfully regenerating (Blue) area.
- The Green treatment area is a poor comparison to Red or Blue area due to the low residual trees/lack of oak crop trees. However:
- In 2020 there were 931 seedlings per acre of oak in what was an aspen sea at the 2018 regen survey. The 931 oak seedlings per acre would not have established without the treatment.
3. Hand seeding was not necessary.
- If we had known it was going to be a bumper acorn crop, we would not have seeded.
4. Plantskydd effectiveness was inconclusive
- Only a couple bur oak were found on site and none fell in the plots in the 2020 regen survey.
- Eaten? Or didn’t germinate? I would suspect some natural regeneration, or at least seedlings in the Blue, even if the acorns we seeded did not germinate, but bur oak was absent from all 3 areas/entire acreage.
- Possibly they are there but bur oak germinates are too similar in appearance to northern red oak to tell the difference in our survey. But we're pros so this is not possible (j/k)