Canopy disturbance patterns in a bottomland hardwood forest in northeast Arkansas, USA

We characterized canopy disturbance patterns in a bottomland hardwood forest and identified linkages to tree species characteristics and interannual flooding patterns. We located 116 newly formed canopy gaps created by 136 gapmakers of 13 species. Over 83% of the gapmakers were snapped or uprooted (i.e., windthrow). The probability of any given gapmaker snapping or uprooting differed among years, species, and elevations. Neither wood properties nor diameter were major factors in determining the probability of snapping versus windthrow. Quercus texana, which had individuals with larger diameters-at-breast height than trees of other dominant species, was the most frequent gapmaker. The effects of elevation and flooding on the probability of snap versus windthrow seem to be tempered or amplified by interspecific rooting habits and tree morphology. Across species, windthrow occurred at lower elevations than snaps, and Q. texana and Q. lyrata showed differences in elevation between the two disturbance types. The total amount of area in newly-formed canopy gaps, as well as gap size, was relatively low compared to estimates for other forests. Our results suggest that natural disturbance patterns in bottomland hardwood forests are complex and are affected by the interactions among forest structure and composition and flooding patterns.