The Central Coast of California is an understudied, fire-prone system dominated by redwoods (Sequoia sempervirens), tanoaks (Notholithocarpus densiflorus), and oaks (Q. agrifolia, Q. parvula, Q. chrysolepis). These species are able to regenerate post-disturbance sexually via seed and, more commonly, asexually via resprouting from an underground lignotuber that stores carbohydrates and terminal buds. Although advantages and physiology of resprouting have been thoroughly studied in California shrub species, they are poorly understood in the trees of Big Sur. We investigated the competitive advantages of resprouting over seeding and examined whether the advantage of faster growth, sooner establishment post-fire, and taller heights is driven by larger lignotubers. During the summer of 2015, we visited 22 500-m2plots in the redwood-tanoak forest in Big Sur, Monterey County, CA, 13 that burned in the 2008 Basin Complex Fire and nine plots that did not burn. We collected 128 tanoak, 119 oak, and 102 redwood seedlings from the perimeter of these plots. We determined above and belowground ages by counting annual rings directly above and below the lignotuber.
Results/Conclusions
In post-disturbance landscapes, we found that resprouts were significantly taller and faster growing than recruits from seed. Resprouts were significantly older underground and had significantly larger lignotubers. Growth rate and height were correlated to lignotuber size, but not related to whether the individual generated from seed or resprouted. The advantage that resprouters had over seeders was attributed to their larger lignotubers. Larger lignotubers were more resilient to fire, and could persist through disturbance better than trees with smaller lignotubers. Trees with larger lignotubers may be more capable of post-fire persistence. In addition, resprouts that survived top-killing during fire likely are older underground compared to seedlings that colonize immediately post-fire, so, these individuals have larger lignotubers and are more competitive in disturbed environments.