A Tale of Two Hurricanes
By: Dana Houkal
Two major hurricanes, Ian in September 2022 and Milton in October 2024 directly affected the Lemon Creek Wildflower Preserve. These two hurricanes had very different characteristics that affected the Preserve in unique ways. Ian had very strong winds (wind gusts of 150 mph on Cayo Costa) and heavy rains at the Preserve (24.08 inches in September 2022). Milton had significantly weaker winds (wind gusts to 100 mph) and less rain at the Preserve (6.85 inches in October 2024), but brought a significant salt spray and storm surge. One thing both hurricanes had in common was that they caused a significant number of trees to become windthrown. Most of the windthrown trees were planted in 2020 as part of the restoration project.
A tree staking project was initiated shortly after each hurricane to try and save as many trees as possible. The staking process consisted of pounding a stake in the ground to which a rope was attached and used to pull up the tree to a vertical position. A total of 654 trees were staked following Ian, but only 89 trees were staked following Milton. Several reason account for this difference. First and foremost, fewer trees were windthrow by Milton due to its lower wind speeds. Second, the trees windthrown by Milton were significantly larger and more difficult to stake. One-foot-long wooden stakes and 3/8” rope was used to stake trees after Ian, but 6-foot-long steel posts and 1/2” rope was required to stake trees after Milton. The average height of staked pine trees in 2022 was 7.3 feet, but the average height increased to 11.6 feet by 2024.
Windthrow following Ian occurred in all upland habitats, while windthrow following Milton was concentrated in wetter habitats where the root systems were less able to withstand the winds. The survival of staked trees was virtually 100 percent following both hurricanes.
Volunteers have been planting some wind tolerant tree species all along and will continue to use this as a criterion for selecting species. The hope is that as the 2020 plantings mature, the trees will grow to become more wind tolerant and that wind susceptible to individual trees (e.g., those planted in low lying areas) will have already been windthrown such that future windthrow numbers decline.
One active measure that has been discussed is conducting a selective crown thinning to reduce wind resistance. This type of thinning would become more difficult as the trees become larger. Selective crown thinning of trees on the Preserve would be labor intensive and technically demanding. Also, the duration of any beneficial effect of crown thinning is unknown. For more details see: https://hos.ifas.ufl.edu/woody/wind-research.shtml and https://hos.ifas.ufl.edu/woody/documents/articles/EFG0702.pdf.
Hurricanes will occur in the future. Since the trees will have grown larger by then, if windthrown, they will be too large to stake.
Mother nature will find a way!