New experimental garden planted on Tall Timbers
In the Southeast, most objectives for prescribed fire seek to topkill shrubs or promote pine regeneration, but how species differ in tradeoffs between investment in evolutionary defenses that aid in survival versus rapid growth to escape fire remain poorly understood. For instance, are hardwoods that are repeatedly top killed capable of altering bark thickness? How does frequency of canopy loss alter photosynthetic rates and underground storage? How does the shape of individual shrubs alter fire’s heat transfer to vulnerable tissues such as cambium and buds? A new twelve-year experiment in joint collaboration of the USDA Forest Services Pacific Northwest Research Station and Tall Timbers Wildland Fire Program is investigating mechanisms of fire resistance in pyrophytic trees (trees that are resistant to fire) and hopes the work will connect mechanisms of plant response to observations of reprouting and survival noted in previous Tall Timbers research.
Seven species of hardwoods and three pine species were chosen to be planted in a two-acre area south of Tower Course under the shadow of the former television tower at Tall Timbers. These trees will be treated with fire and clipping at different intervals, with individuals of each species burned or clipped every two, four or six years. Novel observations of heat flux from fires on individuals will be compared to growth and patterns of tree damage. Other trees will be excavated to compare physical characteristics such as underground mass, bark thickness and texture, and branching. This experiment will allow us to see if increased rate of fire or clipping stimulates an increased investment in fire resistant strategies over controlled trees that were neither burned or clipped. We will also be able to compare these characteristics across species. The three pine species; longleaf (Pinus palustris), slash (P. elliottii), and loblolly (P. taeda) will be compared in one experiment and seven hardwoods; turkey oak (Quercus laevis), white oak (Q. alba), southern red oak (Q. falcata), sand live oak (Q. geminata), laurel oak (Q. hemisphaerica), red maple (Acer rubrum) and blackgum (Nyssa sylvatica) will be compared in the other.
In all, over 900 two-year-old trees were planted in two days by members of the Pacific Northwest Research lab and the Wildland Fire Program with the assistance of Tall Timbers land manager Eric Staller. With the substantial effort to get the trees in the ground over, trees will be given a few months of tender loving care before researchers begin to try to kill them with fire.
Ten species of trees are planted randomly in rows across the two-acre field. Over 900 individual trees were planted over two days.
A picture of a two-year-old turkey oak (Quercus laevis) showing bark texture at the time of initial establishment in the garden.
Wildland Fire Science technician Saunders Drukker mulching a laurel oak (Quercus hemisphaerica).