Mersey Tobeatic Research Institute (MTRI)

The logic of survival of the Black Ash in Nova Scotia

MacGregor, P., Garbary, D.J., Collet, E., Stewart, P. , Phillips, B., Keys, K., Bockstette, J., Neily, P., Jermey, S., Nickerson, S. and Hill, N.M.

Wisqoq, Fraxinus nigra, or black ash, is a cultural keystone species to indigenous people in eastern North America. The tree is Threatened because of a loss of habitat (e.g. river floodplain), development and disease. We have been studying black ash in two disparate habitats: treed swamp and floodplains. We have documented the population age structure, regeneration, water table fluctuation and soil nutrient concentrations at five sites and at each site, made comparisons between the black ash and its most common associate to understand how the niche of black ash differs from its competitors.  To date, we can say that over Nova Scotia, black ash is more commonly associated with soils of higher calcium content, yet does occur in swamps in Meguma terrane (e.g. greywacke). In northern Nova Scotia, black ash occurs both in peat swamp and in stream and river floodplain (upland and wetland portions) but in poorer soils, it appears restricted to peat swamps. At mixed upland/wetland floodplain sites, black ash distinguishes itself from white ash through greater survival in anaerobic soils. At upland river floodplain sites, black ash was better able to survive and trunk sprout after spring 2022 high water ice damage than sugar maple or choke cherry. In this peat swamp arena, black ash most commonly co-occurs with red maple; black ash can occupy swamp hollows whereas the red maple is restricted to hummocks (trunk base = 22cm higher than black ash).  Hurricane Fiona showed how the ability to root lower down in the swamp hollows might account for the fact that while uprooting of red maple hummocks was common, no black ash were undermined.

Presentation type: Oral presentation