A species/area plot was installed on 7/3/2010, prior to treatment, and remeasured on 9/11/2013, after harvest. Its purpose was to measure species richness, responding to the secondary goal of maintaining elements of the native plant community. We tallied 77 species in the pre-treatment measurement and 96 species in the post-treatment measurement.
Twenty-five species identified in the pre-treatment visit were not found on the plot afterward. However, some were present in other locations within the project area. One of those (Kentucky bluegrass /Poa pratensis), is non-native and, although it wasn’t found on the plot after harvest, it has since run rampant throughout the project area. Four species were native grasses. Six were native shrubs. One (balsam fir /Abies balsamea) was a native tree species that invades Fire Dependent Native Plant Communities that are deprived of their natural disturbances for extended periods.
Forty-five new species were found in the post-treatment visit. Ten were non-native species. Five were native grasses. Two were native shrubs. The others were native forbs and ferns.
A species turnover of 57% is extraordinary. Could no tree cover, and the agricultural mechanical and chemical treatments that took place over a span of 19 years prior to establishment of jack pine in the 1960s show such profound effects, 45 years later? Certainly, the presence of non-native species in the access road prior to harvest also affected the post-treatment species composition.
Jack pine stocking in the reserve strips may have been adequate for seed production and dispersal, except that a high percentage of the cones were likely serotinous, something we didn’t realize until late in the project.
An east-west orientation of strips may be a better plan if we had indeed been dealing with semi-serotinous cones. Prevailing winds are more likely to be southerly during the warm seed dispersal days. Jack pine seedlings seem to survive more readily with a little shade which would have been more available along the south edge of strips running east/west.
Kentucky bluegrass (Poa pratensis) was abundant in the access road and nominally present within the stands prior to harvest. After harvest, it quickly colonized and proliferated throughout the stands. It is a formidable competitor for soil moisture. Its rooting zone is within 5” of the surface, competing directly with tree seedlings. Its primary growth period is spring, the same as for jack pine. Jack pine easily invades native deep-rooted grasses like big bluestem (Andropogon gerardii), but cannot compete with Kentucky bluegrass on droughty sites.
The adaptive management project team dropped the ball on coordinating follow-up treatments. Trying to convene five busy people to make assessments and prescriptions was challenging. We should have anticipated needs and scheduled them early in the project with the idea that they could be cancelled if they were determined to be unnecessary.
Herbivory by white-tailed deer could have been a factor. It is common in the area, but we saw no evidence of it.
A wind storm during the summer of 2016 laid down 40-60% of the reserved seed trees and exposed the remaining trees to increased risk.