| This study focuses on the fire response of four herbaceous species suspected of being "fire sensitive." Micro-scale experimental burns were used to reassess the results of two previous fire studies in the Upper Peninsula. Thirty-six plots (4-25 m2), nine for each species, were established in sugar maple stands near Big Bay, MI. For each target species, three separate populations were chosen and assigned the following treatments: spring burn, fall burn, and unburned control. Several non-target species that occurred in plots were also monitored. Three of the four target species had significant (ANOVA, P ≤ 0.05) mortality from spring and fall burns. The highest mortality (90-100%) was for two clubmosses, Lycopodium clavatum and Huperzia lucidula, which both lack rhizomes. Coptis trifolia had 40% fewer leaves post-fire, but ramet mortality and the addition of new ramets did not differ significantly among burn treatments and control. In contrast to the above species, Trientalis borealis, Gymnocarpium dryopteris, Dryopteris carthusiana, and Streptopus roseus ramets all increased following burns. The results for T. borealis were unexpected given that its stolons are in the leaf litter, but the others have deep rhizomes. The positive response to fire probably resulted from the removal of leaf litter that otherwise smothers emerging ramets. No significant differences in plant mortality were detected for spring vs. fall fires in this study, but seasonal responses to fire may be species specific and highly variable depending on the exact timing of fires.;Key words: clonal plants, disturbance, ramets, rhizome, seasons of burn, mortality. |
