The original 23 timber cruise GPS points were established as permanent plots for the case study. Comparing the 2017 pre-harvest data with the most recent regeneration survey confirms the stand is regenerating to a more diverse forest (Table 3). Prior to harvest only 8 non-ash species were found in relatively low numbers (326 non-ash regenerants and seedlings per acre surveyed). In June 2021, 4 years after harvest, 13 species were found with 2,278 regenerants and seedlings per acre surveyed. The regeneration success cannot all be attributed to the planting as 1,069 of the 2,278 regenerants and seedlings are quaking aspen that sprouted vegetatively.
It is hopeful to see the establishment of non-ash planted species off to a decent start. However, it is difficult to separate the amount of regeneration that came from natural seeding/sprouting origin and the planting except for the introduced species that were not present prior to timber harvest. Either way the regeneration established confirms the desired future condition for a more diverse non ash forest. At this time, it seems likely the 5-year standard check goal of 100-200 non-ash crop tpa with 75% of plots free to grow will be met.
Quaking aspen root sprouting is tremendous with over 1,000 stems per acre at the 3-year survey check. Regenerants and seedlings represent over 1/3 of the total regeneration and are present on 43% of the regeneration survey plots.
Of all the planted species silver maple seems to stand out as being the most successful on this site (Figure 3). Seedlings are larger stock compared to other planted species, have survived a fair amount of deer browsing and have outpaced grass competition. The 3-year survey results confirm 170 tpa and a 53% survival rate. Since it has survived these first 3 years it may continue to grow well and get above deer browse height.
The red maple are of smaller planting stock compared to the silver maple and many of them were leafing out when planted. The regeneration surveys indicate either the planted seedlings are starting to grow, or a fair amount of natural red maple regeneration is occurring. The 3-year survey check confirms red maple regenerants and seedlings at 300 tpa. The red maple also have deer browse but have managed to survive, grow, and struggle through the competition.
Paper birch is regenerating well and is most likely natural regeneration from seed. Most seedlings are found in mossy areas of the site where the seed germinated.
It is difficult to determine if cottonwood established. The regeneration surveys did not confirm any seedlings present. However, it is possible that cottonwood is very difficult to identify at this time and may have been recorded as quaking aspen. Our hope is we can find it in the future as the seedlings grow taller.
American elm seems to seed naturally in wet forest sites. The 3-year survey check confirms 30 tpa.
Bur oak and swamp white oak appeared to survive the initial planting but by the 3-year survey check have started to disappear. Deer browse is the likely culprit.
Hackberry is perhaps the biggest disappointment. After the initial planting it was difficult to find seedlings anywhere. There may have been an issue with the planting stock, it may be difficult to establish in wet forest conditions, or it may be hard to identify at this time. It also requires a process of “sweating the planting stock” to break dormancy. We suspect this was not done for the seedlings procured from the State Forest Nursery. We would be interested to learn results from others who have tried hackberry in their ash replacement plantings.
On this site black spruce is the conifer that appears to have the most promise. Seedlings are container plug stock which may be an unfair comparison with the other bare root stock. Most seedlings have survived despite the hare damage, have good growth, and look healthy.
White spruce initially survived after planting but by the 3-year survey check have nearly disappeared. Hare damage is not present on the existing seedlings, but it is possible that seasonal water table fluctuation is an issue. Black spruce may have some advantage over white spruce in this regard.
Tamarack is growing well. Only a small amount was planted in a wetter, sunny, and open location to provide the best chance at survival. The regeneration survey data are not very representative of this fact.
Balsam fir regeneration and survival seems to be steady and similar to the pre timber harvest counts. Planting balsam fir did not have a noticeable impact.
A small amount of white cedar regenerants are present which is promising for natural regeneration but given the deer browse pressure it is doubtful that few, if any, will be able to survive and grow to seedling size.
Recommendations to increase natural regeneration
If merchantable quaking aspen is present or adjacent to the stand, we recommend harvesting nearly all trees to establish a new cohort of root suckers to quickly occupy the growing space and maintain hydrological function. American elm, balsam fir, white cedar and red maple trees can be prescribed as retention species to increase natural seeding and regeneration opportunities. For balsam fir reserve clumps of small diameter trees (2 sticks and smaller). It seems the only way to maintain white cedar in wet forest sites is to reserve as much of the mature trees as possible and arrange for frequent timber sale supervision to limit bole and root damage during timber felling and skidding.