Restoration of Northwest Florida Sandhills Through Harvest of Invasive Pinus clausa

Abstract

Across much of the southeastern U.S.A., sandhills have become dominated by hardwoods or invasive pine species following logging of Pinus palustris (longleaf pine) and fire suppression. At Eglin Air Force Base where this study was conducted, Pinus clausa (sand pine) has densely colonized most southeastern sandhill sites, suppressing groundcover vegetation. The objectives of this study were: to determine if suppressed groundcover vegetation recovers following the removal of P. clausa; to compare species composition and abundance in removal plots with that in reference, high quality sandhills; to test the assumption that recolonization by P. clausa seedlings decreases with proximity to the centers of removal plots; and to measure the survival of containerized P. palustris seedlings that were planted on P. clausa removal plots. One year post‐removal (1995), the number of plant species decreased by 50%, but then increased by 100% from 1995 to 1997, followed by a small reduction in 1998. The number of plant species was greater in reference plots than in removal plots prior to 1997. Eighty‐five percent of the original species were recorded 4 years post‐harvest in removal plots. Shrubs and large trees remained at low density after harvest. Densities of graminoids, legumes, other forbs, woody vines, and small trees increased after harvest. Plant densities of all life forms, except woody vines, were greater in reference plots than in removal plots. The density of recolonizing P. clausa seedlings 2–4 years post‐harvest significantly decreased with increasing proximity to the centers of removal plots. On average, 80% of planted P. palustris seedlings survived their first 2 years. Harvest of P. clausa followed by fire and the planting of P. palustris is a reasonably effective restoration approach in invaded sandhills. However, supplementary plantings of some herbaceous species may be necessary for full restoration.

Stand structure, composition, and regeneration dynamics following removal of encroaching woody vegetation from Midwestern oak savannas

“…This approach might be successful in situations where encroachment has resulted in major structural alterations, such as canopy closure or development of midstory vegetation, which might inhibit the reestablishment of historic fire regimes (Sarr et al, 2004). Although active removal of encroaching woody vegetation has produced preliminary success in some conifer and aspen systems (Moore et al, 1999;Provencher et al, 2000;Jones et al, 2005), it is not known whether removing encroaching vegetation will restore historic regeneration dynamics (Allen et al, 2002). More research is needed, especially in understudied ecosystems such as oak savannas.…”

The Effects of Removal of Juniperus virginiana L. Trees and Litter from a Central Oklahoma Grassland

“…On the other hand, we believe that reductions in stems per quadrat in By comparison, the decreases in species richness over the course of this study suggest relatively little recruitment of new species occurred regardless of treatment. Provencher et al (2000) found that species richness also decreased after the application of felling and slash burning in Florida's sandhill vegetation. However, Provencher et al (2000) observed an increase in species richness two years after treatment application.…”

“…Provencher et al (2000) found that species richness also decreased after the application of felling and slash burning in Florida's sandhill vegetation. However, Provencher et al (2000) observed an increase in species richness two years after treatment application. Results from pRDA (see Figure 8) suggest a transition from pretreatment species composition dominated by mesic or forest species to post-treatment tallgrass prairie species.…”

“…Conversely, the positive response of disturbance favoring forb species like Amphiachyris dracunculoides, Ambrosia psilostachya and Croton monanthogynus may lead to further reductions in species richness if they become dominant. Several researchers, including Clary (1971), Clary and Jameson (1981), Brockway et al (1998), andProvencher (2000), have all observed increases in graminoid and forb cover following overstory tree removal. In this study, annual species increased in cut treatments; however, few annuals dominated cover in any treatment.…”

“…In the United States, two examples of fire adapted vegetation types that have received much attention regarding restoration are the longleaf pine sandhill vegetation of northwestern Florida (Kush et al 1999, Provencher et al 2000, Provencher et al 2001) and the tallgrass prairie of the eastern Great Plains (Axmann and Knapp 1993, Briggs et al 2002a, Briggs et al 2002b. In both instances the elimination of fire has caused a decrease in species richness and facilitated their conversion into forests.…”