Very little is known about American chestnut’s (Castanea dentata) relationship with fire because the species became functionally extinct prior to modern fire science. However, because of its proven success in high light environments and its ability to resprout from root collar buds, chestnut may be functionally similar to oak (Quercus spp.), which has a proven positive relationship with fire. However, no one has considered that chestnut burs, the spiny husks or cupules that surround the nut prior to release, are no longer present in Eastern deciduous forest litter and fine fuels segment. Our question asks: Do these annually contributed structural additions change the flammability of the forest litter? Nine forest floor samples (30 × 50 cm) were taken in autumn of 2016 after leaf fall, keeping the organic layers intact. All samples were dried then split to create a paired comparison. Experimental fuel beds were prepared, then moisture contents typical of regional forests were added to mimic forest conditions. Chestnut burs were then randomly added to half of the samples. Typical measures of fire intensity and character were observed and measured.
Results/Conclusions
The samples that contained bur additions remained flaming for significantly greater duration (P = 0.007). The mean difference was an increase in 40 seconds for samples with bur additions. The mean duration of smoldering time was also greater duration (P = 0.81) in the samples containing burs, increasing the mean smoldering by 66 seconds. However, bur presence did not change the mean maximum flame height, with a difference < 1.0 cm. This experiment examines one of the key aspects of fire resilient species that has not been considered in the context of American chestnut because of its functional disappearance from the landscape since the introduction of chestnut blight. The structural addition of chestnut burs to leaf litter may have, historically, created a smoldering fire that consumed burs and leaf litter, even in conditions that would normally be beyond the moisture of extinction. Moreover, these conditions may have promoted an environment differentially conducive to chestnut regeneration. The fire behavior changes caused by unique fuels can be used by forest managers to build understanding of fire as a management technique in eastern forests, while facilitating the successful restoration of American chestnut.