Groundcover Restoration in Forests of the Southeastern United States

More documents

Recommendations

Info

Chapter 3: Tailoring Restoration Strategies to Initial Site Conditionsand duration of smoldering duff fires have been implicatedin increased native pine mortality (Varner et al. 2005). Iffuel ladders exist, they can be thinned mechanically (e.g.,brush hog or gyro-trac) or herbicides can be applied totop kill shrubs and cause leaf drop. If there is a concernthat deep litter and duff layers could cause unnecessarytree or rare species mortality during normal prescribedburning, two activities can be employed. First, the thick duffaround individual plants can be raked away from the roots.Second, the first few prescribed burns can be implementedduring environmental conditions that will ensure a “cool”fire (dormant season or when duff is wet) to remove theduff layer incrementally. These fires may not be usefulin top-killing encroaching shrub species or promotingreproduction in most herbaceous species, but once the dufflayer is reduced, hotter prescribed fires with more completecoverage can be introduced to achieve this objective (Outcalt2006). Finally, recent research has shown that prescribedfire is both an effective and inexpensive tool for restorationbut that it can take a minimum of three prescribed firesbefore groundcover responses reach restoration goals in firesuppressedlongleaf sites (K. Outcalt, USFS, pers. comm.).Answer (YES to question 1, NO to question 2):If the community to be restored is fire dependentbut adequate fine fuels are not present at the site, therestorationist must use mechanical or chemical treatments(especially cut-and-treat or basal spray) to remove woodyvegetation in the midstory and canopy to increase light atthe forest floor. Some restorationists are able to introducefire once this treated vegetation has aged (dried) but for thecontinued application of prescribed fire, it is essential thatpopulations of native groundcover species that can carry fire(e.g., wiregrass) increase in cover on the site. If the coverageof these species does not increase following the initialthinning and/or burning treatments, it will be necessary toseed or plant these species on the site.Answer (NO to questions 1 and 2):If fire is not a driver (or is extremely infrequent) in thereference community for your site, the second most likelycause for degradation is human interference in an ecologicalprocess such as hydrology, regeneration (forest productremoval impacts), or dispersal through the separation of thesite from intact communities by barriers, roads, or trails.The first two impacts can be addressed immediately. Ifthe site is to be restored, any impediments to the naturalhydrology must be removed first. In addition, forest productharvesting (plant or seed removal) must be prevented untildata indicate that harvest levels will not affect the long-termviability of populations on that site.If the restoration site is an island of remnant vegetation ina sea of highly degraded habitats, the restorationist mustconsider that the degradation of that habitat may be dueto the loss of specialized pollinators or seed dispersers oran imbalance in herbivores and/or predator populations.Extremely small or isolated restoration sites may not havethe resources necessary to maintain populations of essentialfauna or maintain balance in their populations. One of theunforeseen results of habitat fragmentation and urbanizationhas been the loss of specialized pollinators. When studyingseed set and predation in urban environments, it has beenfound that seed predation is higher and seed set is lowerin fragmented habitats (Aizen and Feinsinger 2003). Inaddition, in remnant patches in an urban matrix, pesticidedrift may be responsible for the loss of pollinators andreduction of insect diversity (Buchmann and Nabhan1996; Heuberger and Putz 2003). Conducting an inventoryof organisms responsible for pollination, seed dispersal,herbivory, and predation at a restoration site may be a usefulmeans of identifying necessary modifications of fauna.Once the role of fire has been assessed at the restoration site,the next major question is:Question 3. Are non-native invasive species present?Answer (YES):If invasive species are present on the restoration site and youplan to restore fire to the site, it is very important that youdetermine the response of the invasive species to fire prior toignition. Many invasive species can be reduced or eliminatedmechanically or with the application of selective herbicidesprior to burning. However, some invasive species respondto fire with copious regeneration, increasing in cover afterprescribed burning (e.g., Zedler and Scheid 1988).Cogongrass is an invasive species that is particularly difficultto control. The species is highly flammable and can changethe intensity and pattern of fire, leading to the reductionof native species that normally respond favorably to fire(Lippencott 2000). Treating cogongrass with herbicidesprior to fire is not recommended, as this can lead to evenmore intense fires. Implementing a cool fire or mowing thecogongrass stand before herbicide treatment during thefall is likely to reduce the amount of herbicide needed andimprove control of the species (G. Tanner, University ofFlorida, pers. comm.).| 28 |
Chapter 3: Tailoring Restoration Strategies to Initial Site ConditionsWhether or not prescribed burning is a part of yourrestoration activities, you should investigate availablerecommendations regarding the control methodologiesknown to be most effective for the invasive species presenton the site (Murphy et al. 2007). It is important to keep inmind that many control efforts must be repeated multipletimes before control is gained over invasive populations.Answer (NO):If your site is fortunate enough not to have invasive speciespresent, you are ready to monitor how the vegetationresponds to the restoration activities you have completed toaddress the source(s) of degradation at the site.EXAMPLE 1: Fire-suppressed longleaf pine standson Eglin Air Force Base (native overstory, nativeunderstory).Goal: Restore longleaf pine sandhill communitiesthat have been encroached by hardwoods (oaks) inthe midstory.Fuels Present: YesInvasives Present: NoRestoration Activities: Eglin has employedmechanical, chemical, and prescribed burningtreatments to reduce the midstory oak coverage intheir sandhill sites. All methods were effective butonly prescribed fire increased groundcover speciesdiversity and density through the removal of heavyoak litter that had accumulated. Since fire was themost cost effective of the treatments, prescribedburning is the management action of choice on Eglin.Prescribed fires are ignited every 3-6 years to meetrestoration needs. Finally, when immediate hardwoodreduction is needed near red-cockaded woodpecker(RCW) nesting trees, large hardwoods are removedby felling or girdling.Monitoring: Eglin has installed 200 permanent 1ha monitoring plots to track vegetation responsesin different habitats that are measured on a rotatingbasis (4-5 years).Scenario B: Areas with Off-Site OverstorySpecies Lacking Native GroundcoverMany groundcover restoration sites in the SoutheasternUnited States are pine plantation sites that have an intactcanopy but lack native groundcover. Many of these siteshave heavy canopy coverage of off-site pine species with avariable groundcover component that depends on the sitepreparation methods used in establishing the plantation,the occurrence of prescribed fire, and the degree of canopyclosure. When planning the restoration of a pine plantationsite, just as in a site with intact groundcover, the first twoquestions are whether fire should and can be re-introducedto the site and whether invasive species are present (seeprevious section for details). In addition, two moreconsiderations must be taken into account: When and howshould native on-site tree species be introduced? and, Whatactivities need to be performed to introduce or promote theestablishment of native groundcover species?Question 4. When and how should native on-site treespecies be introduced?On-site tree species are typically introduced to plantationsites comprised of off-site species via one of two methods:planting after clearcutting the off-site tree species or plantingin “gaps” created by selective harvest. Clearcutting is usedwhen:• plantation trees are young and do not provide neededshade or fuel source.• the off-site tree species is sand pine in a fire-dependentecosystem.• proceeds from the sale of merchantable timber arerequired to fund other restoration activities.When off-site trees are young or when sand pine isdominant at the site, the re-introduction of prescribedfire becomes problematic. In a young plantation, theundergrowth is composed of weedy species such asdogfennel (Eupatorium capillacifolium), winged sumac(Rhus copellina), blackberry species (Rubus spp.) andwoody shrubs (oak (Quercus spp.) species and gallberry(Ilex glabra)) that are native but do not carry fire well. Inaddition, without their removal, the young off-site treeswould compete for resources with any native tree plantings.In contrast, sand pine (Pinus clausa) is an aberrantspecies with a very different fire pattern than other nativeSoutheastern pine species. When burned, fire is carried intothe canopy of sand pines by their dense lateral branches and| 29 |
Page 5: Table of ContentsIntroduction .....
Page 9: Part IDesigning and Executing aGrou
Page 12 and 13: Chapter 1: Planning a Restoration P
Page 15 and 16: Chapter 2Implementing a Restoration
Page 18 and 19: Chapter 2: Implementing a Restorati
Page 27: Chapter 3Tailoring Restoration Stra
Page 31 and 32: Chapter 3: Tailoring Restoration St
Page 33 and 34: Chapter 3: Tailoring Restoration St
Page 35 and 36: Chapter 4Important Considerations f
Page 37 and 38: Chapter 5Costs Associated with Grou
Page 39 and 40: Chapter 5: Costs Associated with Gr
Page 41 and 42: Literature CitedAbrahamson, W. G. a
Page 43 and 44: Literature CitedEgan, D. and E. A.
Page 45 and 46: Literature CitedLeopold, A. 1949. A
Page 48 and 49: Literature CitedTrusty, J. L., and
Page 51 and 52: Chapter 6Location of Groundcover Re
Page 53 and 54: Chapter 6: Location of Groundcover
Page 59: Chapter 6: Location of Groundcover
Page 62 and 63: Chapter 7: Forested Communities of
Page 64 and 65: Chapter 7: Forested Communities of
Page 66 and 67: Chapter 8 : Plant Species of the Fo
Page 76: Chapter 8 : Plant Species of the Fo
Page 79 and 80:
Chapter 8 : Plant Species of the Fo
Page 81:
Page 84 and 85:
Page 86 and 87:
Page 88 and 89:
Page 90 and 91:
Page 92 and 93:
Page 94 and 95:
Page 96 and 97:
Page 98 and 99:
Page 100 and 101:
Page 103 and 104:
Chapter 9Online Resources for Resto
Page 105 and 106:
Chapter 10Comprehensive Bibliograph
Page 107 and 108:
Chapter 10: Comprehensive Bibliogra
Page 109 and 110:
Page 111 and 112:
Page 113 and 114:
Page 115:
show all

Groundcover Restoration in Forests of the Southeastern United States

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?