Frost damage in northern
Second flush leaves produced two different morphological responses depending on frost damage severity. Severe frost damage was characterized by patchy canopy leaf flushing with leaves that were on average four times larger than first flush leaves. Less severe frost damage produced full canopy flushes with second flush leaves that were 50% smaller than first flush leaves. Second flush leaves tended to be thicker, and had significantly lower nutrient (~30%) and carbohydrates concentrations. In contrast, phenolic glycoside content was significantly higher (2-3 fold) in second flush leaves. We hypothesize that defense chemistry induction following abiotic defoliation serves as insurance against a second defoliation event by herbivores that may further deplete nutrient and carbohydrate leaf resources below critical thresholds. Resource dilution and allocation to secondary defense may however, place constraints on growth capacity.