RESTORATION OF VERNAL HERBACEOUS FLORAS TO
SECOND GROWTH APPALACHIAN MESOPHYTIC FORESTS
I.Project Rationale
Recently, public controversy has arisen concerning the impact of logging on the species-rich mixed mesophytic cove forests of the southern United States (described by Braun 1950). Duffy and Meier (1992) and Meier et al. (1995) found old growth forest stands in the southern Appalachian and the Cumberland Mountains had more species of vernal herbs in 1- m2 plots than did similar stands that had been logged. Meier et al. (1995) also reported a greater total number of species summed across all quadrats in a stand and a greater number of unique species occurring in the quadrats in an old growth stand. Perhaps herbaceous diversity in second growth cove forests is below an equilibrium or saturation level. Alternatively herbaceous diversity is at a new lower equilibrium resulting from different initial states, perhaps as a result of climate change or alteration in soil qualities.
Previous studies indicate that recovery of forest understories may require a century or more after major disturbance. Brewer (1980), working in old growth in Michigan, concluded that the herbaceous community was still recovering from a major disturbance event that occurred 150 years prior. Recovery of forest herbs after an area has been used for agriculture may take centuries (Peterken and Game 1984, Matlack 1994). Duffy and Meier (1992) and Meier et al. (1995) found no evidence of recovery of vernal herbs in second growth cove hardwood forests ranging from 5 to 87-years old.
Meier et al. (1995) proposed slow spread and dispersal of vernal herbs may retard recolonization of disturbed sites. Many vernal herbs are functionally clonal (Whitford 1949, Harper 1977). Meier et al. (1995) found that rates of clonal spread for vernal herbss are typically less than 10 cm per year. Many vernal herbs depend on gravity or ants for seed dispersal (Beattie and Culver 1981). Matlack (1994) and Meier et al. (1995) found that dispersal rates for spring wildflowers are often less than one meter per year. Blanton State Forest State Nature Preserve, Harlan County, Kentucky contains extensive old growth mixed-mesopohytic deciduous forest and some secondary forest stands. It provides an ideal location to test some of the hypotheses relating to restoration of vernal herbs.
II. Specific Aims.
A: Determine if differences exist between the vernal herbs of primary and secondary forests of Pine Mountain
B: Determine disturbance regimes in a limited set of habitats on pine mountain
C: Relate disturbance regimes to flora on Pine Mountain
III. Methods
Stands with similar topography on Pine Mountain will be selected using topographical maps. After initial selection criteria are met, I and a small team of students will quantify environmental characteristics including overstory composition, slope, aspect, elevation, and soil chemistry, for final site matching and selection. A Global Positioning System (GPS) receiver willl be used to georeference the location of the sites. Old growth sites will be located within Blanton Forest State Nature Preserve, Harlan County, Kentucky.
We will quantify disturbance histories using written records and interviews of local foresters following the methods of Harmon et al. (1983), and Bratton and Meier (in review). Dendrochronological techniques will also be used to detect growth releases after disturbances. At least 70 tree ring chronologies will be collected in Blanton Forest. At least 30 of these will be placed near the ridgeline where extremes of disturbance regimes are expected. Dendrochronological techniques will generally follow the methods of Lorimer (1976, 1985), and Veblen et al. (1991) and Bratton and Meier (in review). Along with increment cores, wedges will be examined from logs and stumps if permissible. These wedges will be particularly useful in attempts to quantify fire history.
Species composition of herbaceous understories will be compared using at least two scales of plots. Vernal species will be examined on 1-m2 plots. As many as 20 selected species will be examined on 100-m2 plots. For some relatively rare species, 400-m2 plots will be considered. Methods will generally follow those of Duffy and Meier (1992) and Meier et al. (1994).
IV. Project Schedule
Initial site selection will be completed by June 1998. Vegetation surveys and other environmental parameters will be measured and analyzed by October 1998. Disturbance hiastory will be quantified by December 1998.
V. Literature Cited
Beattie, A. J. and D. C. Culver. 1981. The guild of myrmecochores in the herbaceous flora of West Virginia forests. Ecology 62:107-115.
Bratton, S. P., J. R. Hapeman, and A. R. Mast. 1994. The lower Susquehanna River gorge and floodplain (U.S.A.) as a riparian refugium for vernal, forest floor herbs. Conservation Biology 8:1069-1077.
Braun, E. L. 1950. Deciduous forests of eastern North America. Hafner, New York.
Brewer, R. 1980. A half-century of changes in the herb layer of a climax deciduous forest in Michigan. Journal of Ecology 68:823-832.
Duffy, D. C., and A. J. Meier. 1992. Do Appalachian herbaceous understories ever recover from clearcutting? Conservation Biology 6:196-201.
Jackson, L. E. 1989. Mountain treasures at risk: the future of the southern Appalachian national forests. The Wilderness Society, Washington, D. C., and Global Printing Inc., Alexandria, Virginia.
Matlack, G. R. 1994. Plant species migration in a mixed-history forest landscape in eastern North America. Ecology 75:1491-1502.
Meier, A. J., S.P. Bratton, and D.C. Duffy. 1995. Possible ecological mechanisms for loss of vernal herb diversity in logged eastern deciduous forests. Ecological Applications 5:935-946.
Peterken, G. F., and M. Game. 1984. Historical factors affecting the number and distribution of vascular plant species in the woodlands of central Lincolnshire. Journal of Ecology 72:155-182.