Contrasting sapling bark allocation of five southeastern USA hardwood tree species in a fire prone ecosystem

Abstract

Abstract. Fire affects numerous aspects of plant growth and anatomy, particularly in those species adapted to persist in fire-prone environments. A key aspect of tree survival is rapid accumulation of protective bark within fire return intervals. We compared bark accumulation in five co-occurring hardwood species within a longleaf pine (Pinus palustris) ecosystem in the mountains of northeastern Alabama, USA. Sampled species included blackjack oak (Quercus marilandica), sand hickory (Carya pallida), common persimmon (Diospyros virginiana), rock chestnut oak (Quercus montana), and red maple (Acer rubrum). Using bark thickness and inside bark diameter measurements taken at 20-cm intervals along the main stem of saplings (average age 4-5 years) we found that, while average wood diameter did not differ across species, significant differences occurred in the ratio of bark to wood. Bark comprised over half (bark:wood ¼ 0.55) of the basal diameter of blackjack oak, which was 33, 43, and 63 greater than the bark:wood ratio of sand hickory and rock chestnut oak, common persimmon, and red maple, respectively. Bark taper revealed that while other species allocated similarly to bark along the length of their stem, blackjack oak allocated much more at its base (in the flaming zone) and relatively less as height increased. Red maple, a commonly cited invader during fire-free intervals, invested the least in bark thickness and, with rock chestnut oak, had an average height and height:diameter ratio significantly greater than blackjack oak and all other species, respectively. These results confirm the adaptive importance of bark thickness to enhancing species survival in frequent fire regimes.

Long‐term response of oak‐hickory regeneration to partial harvest and repeated fires: influence of light and moisture

“…The "super-generalist" red maple (Abrams 1998) is often the most intense competitor to oakhickory regeneration in many areas of the Central Hardwoods, and sprouts vigorously following a harvest or a single fire (Albrecht and McCarthy 2006, Iverson et al 2008, Schuler et al 2013, Thomas-Van Gundy et al 2015. However, we found that subsequent fires continually reduced abundance of red maple in the large seedling and sapling layers, and by Y13, most of the larger red maple stems had been eliminated; the thin bark of red maple makes it especially sensitive to heat damage and its sprouting capacity was reduced with multiple fires (Hare 1965, Harmon 1984, Hammond et al 2015. Similar results on fire impacts on red maple were reported by Arthur et al (2015) in Kentucky.…”

“…However, we found that subsequent fires continually reduced abundance of red maple in the large seedling and sapling layers, and by Y13, most of the larger red maple stems had been eliminated; the thin bark of red maple makes it especially sensitive to heat damage and its sprouting capacity was reduced with multiple fires (Hare , Harmon , Hammond et al. ). Similar results on fire impacts on red maple were reported by Arthur et al.…”

Short-term stem mortality of 10 deciduous broadleaved species following prescribed burning in upland forests of the Southern US

“…Although allometric equations that predict bark thickness from DBH exist for a portion of the upland forest tree species examined (e.g. Harmon 1984;Hengst and Dawson 1994), in eastern forests, where the historic fire regime was dominated by frequent low severity fire (Lafon et al 2017), it is possible that bark thickness at the base of the bole rather than at breast height is more of a factor influencing fire-related mortality for the species examined (Graves et al 2014;Hammond et al 2015). In regard to the limitations of the data, for Acer rubrum, Cornus florida, Oxydendrum arboreum, Nyssa sylvatica and Sassafras albidum, there is a limited number of trees in the larger size classes (e.g.…”

Short‐ and long‐term effects of fire in subtropical cloud forests on an oceanic island

“…Fires impact forests at different scales, depending upon their intensity, duration, return interval (Brooks, Richardson, & Grace, ; Certini, ), and on the resilience of the affected ecosystem (Díaz‐Delgado, Lloret, Pons, & Terradas, ; Larson, Belote, Cansler, Parks, & Dietz, ). Although there are forests in which fire is part of their natural dynamic (Appiah, ; Larson et al, ), in forests that are adapted to a low frequency of fires, these events can cause variable mortality among species that are lacking the usual adaptive traits to fire (Hammond, Varner, Kush, & Fan, ; Nasi et al, ) and may irreversibly change floristic composition (Cochrane & Schulze, ; Woods, ). These effects are exacerbated due to the clear increase in human‐caused fires (Syphard, Radeloff, Hawbaker, & Stewart, ; Wittenberg & Malkinson, ).…”