Evaluating the Influence of Elevation and Impact of Hurricane Katrina on Radial Growth in Slash Pine (Pinus elliottii var. elliottii Engelm) on Cat Island, Mississippi, USA
Hurricane Katrina heavily affected the Mississippi barrier islands, in the northern Gulf of Mexico, on 29 August 2005. On Cat Island, Mississippi, field observations of geographic patterns in poststorm survival of slash pine (Pinus elliottii var. elliottii Engelm) suggested that its growth and resiliency to storm impact may depend substantially on ground elevation. This hypothesis was tested by evaluating the lifetime mean radial growth rate (in millimeters per year), stem (trunk) diameter (in centimeters), the percentage of change in the radial growth rate for the initial 5-y period after the storm (2006-10) vs. the 5-y period before the storm (2001-05), and the yearly percentage increase in stem radius and basal area for 2001-10 with respect to high-accuracy GPS measurements of growth-site elevation. Radial growth declined after the storm and remained suppressed in 2006-10. However, simple regressions indicated no relationship between growth and elevation, either over the lifetime of the trees or on a yearly basis in 2001-10. Instead, radial growth was related to tree age and, most strongly, to reciprocal age. Notably, the relationship with age diminished while growth was suppressed in 2005-10. Although tree growth was not related to elevation, a future study will explore the mechanisms underlying an observed 0.5-m elevation threshold for slash pine existence on Cat Island.