Appendix C. Abundance of tree species in the macrofossil record and in vegetation surveys.
Plant macrofossils found in the organic soils are direct indicators of local vegetation cover. To verify how well the organic soils recorded the presence of tree species, we compared the relative basal area of each tree species in each stand to the relative percentage of tree macroremains found in the top 5 cm of soil monoliths (surface macrofossil record). They were highly related (adjusted R2 = 0.92; P < 0.0001), and only tamarack was consistently over-represented in the macrofossil record, probably because of the annual shedding of its needles. We then used the macroremains from the first 5 cm of organic matter overlying the uppermost charcoal layer (early macrofossil record) to assess postfire vegetation. Twenty of the 23 stands had an early macrofossil record dominated by black spruce, while three stands had a notable amount (20–40%) of other tree macroremains (Jack pine and tamarack). However the postfire cohort of these young (< 100 yr old) stands had only a minor component of these species (see Basal Area), meaning that Jack pine and tamarack macrofossils were overrepresented in the macrofossil record. ROM = Residual organic matter.