Suffering the affects of of pine beetle infestation and lack of exposure to fire, many of the older slash pines at the Pine Island Flatwoods Preserve have succumbed to a great deal of stress. To address this, stewards of the preserve recently completed work on the property that lasted about two weeks to ensure a healthy future for younger pines.
“The stewardship strategy for the preserve is to improve the overall quality of the habitat for native plants and animals,” said Jeff Anderson, Conservation 20/20 land stewardship coordinator. “This is achieved through a number of methods, including exotic plant removal, fuel reduction, tree thinning and prescribed fire. The most important of these methods is prescribed fire.”
According to Anderson, healthy pine flatwoods depend on periodic fires to maintain plant diversity and the health of the trees. Typically, to maintain the health of pine flatwoods, the preserve should be exposed to a fire every two to four years.
“We have found that the pines on this site, having very little to no fire exposure in their lifetime, are very easily stressed to the point of mortality after fire exposure,” said Anderson. “By exposing the younger generation of pines to a natural fire regime, they will become fire tolerant throughout their lifetime.”
Anderson said that the management strategy was done in small sections called management units. The 20/20 staff had found that the preserve areas all contained a heavy fuel load on the floor and high overstory pine tree density which has seen little to no fire exposure.
In addition to the lack of fire exposure, many of the older trees have fallen victim to pine bark beetles. The pine bark beetles will oftentimes lay their eggs beneath the bark of a tree and will then attack and ultimately kill trees, specifically those that are already weakened by stress.
In the Pine Island Flatwoods Preserve, pine bark beetles have been the primary cause of the high mortality in the older, mature trees on the property.
According to Anderson, healthy pines will generally survive and tolerate beetles, but this has not been the case with the older pines primarily due to the lack of exposure to fire, which aids in the tree’s beetle tolerance.
“We believe that a reintroduction of the two to four-year fire regime will produce a fire tolerant pine overstory stand that will then also be more tolerant to pine bark beetle stress. In the meantime, our present strategy is to slow the spread of the pine bark beetle population into the unaffected areas,” said Anderson. “This is being done by selectively removing the infected trees from the site. The pine bark beetle mortality in the pines has so far been limited to the areas exposed to fire from controlled burning, however, with the recent wildfires this past May and June, there is a high potential for pine bark beetle mortality to spread into other currently unaffected areas.”
According to Anderson, there are several different species of beetle that affect the slash pine trees. The black turpentine beetle, which, as both adults and larval beetles, feeds on the tree which leads to girdling and ultimately, in some cases, will contribute to the death of the tree. Those trees that are not girdled may survive but are weakened, leaving them susceptible to attack by other species of bark beetles such as the Southern pine beetle. These beetles carry blue stain fungi on their bodies and introduce it into the tree. This fungus colonizes sapwood and disrupts water flow to the tree crown. When this happens, the tree cannot be saved. Another beetle, the Ips, feed on the pines as well and will construct egg galleries in the tree. They multiply rapidly and also carry the blue stain fungus.
Anderson said that to minimize the spread into these areas, his team has selectively removed pine trees with 100 percent crown scorch in an effort to slow the spread of beetles.
“The management strategy that is being followed on this site keeps our ultimate goal of improving the overall quality of the habitat for native plants and animals in sight,” said Anderson. “We will continue the introduction of fire through the use of prescribed burns to return the area to historic regimes which will prevent future wildfires that could possibly threaten the surrounding areas.”
The Pine Island Flatwoods Preserve is located at 6351 Stringfellow Road in St. James City. It is under the stewardship of the 20/20 Conservation staff and the Calusa Land Trust. The 729.4-acre preserve consists of nine native plant communities, including mesic pine flatwoods, freshwater marshes, tidal swamp, hydric hammock, coastal grassland, coastal berm, improved pastures, abandoned groves and unconsolidated