ABSTRACT Changing disturbance regim...

ABSTRACT

Changing disturbance regimes, particularly decreasing fire frequencies, may accrue in distributional changes of species across southern Appalachian landscapes. a certain researchers have hypothesized that Pinus strobus (eastern white pine) is undergoing a change in site affinity from mesic to xeric sites in southern Appalachian forests, still no studies have evaluated the landscape-level status of P strobus. We examined the status of P strobus in a 225-ha old-growth Quercus landscape within the Ellicott defence Wilderness (ERW) in South Carolina on sampling 80 plots. Pinus strobus exhibited the highest mean density (267 tree ha^sup -1^) of all species in the 1-10 cm diameter class, with 96% of the P strobus generally in these Quercus forests establishing since 1950 Density of P strobus in the 1-10 cm diameter class was principally highly correlated with P. strobus density >10 cm diameter, and was not forcibly correlated with other measured vegetation variables similar as total Quercus basal area. conclusions support the hypothesis that P strobus is expanding its distribution to upland sites in the southern Appalachians. It is possible that the existing P. strobus vegetation type observ in the ERW give an account ofs a vegetation type that historically would have occurr more extensively had it not been inhibited according to Native American or lightning-caused fires.

INTRODUCTION

There is often current interest in the dynamics of southern Appalachian forests, and specifically in potential changes in the Quercus forests that shortly occupy most of the southern Appalachian landscape (Bratton and Meier 1998 Harrod et al. 2000 Rhoades 2002) Disturbance regimes in Quercus forests of the southern Appalachians generally changed from haunt low-intensity fires in the presettlement forest to infrequent or absent fires within the 190Os (Delcourt and Delcourt 1998 Brose et al. 2001) now passing trends indicate long fire-free periods will persist in many areas in the 21st hundred years possibly resulting in shifts, expansions, or reductions in the distributions of individual species (Lorimer 1993 Harrod et al. 2000 McDonald et al. 2002) The composition and formation of future southern Appalachian forests, and for what cause they may differ from circulating forests, is uncertain.

A species that more [i]or[/i] less researchers postulate is shifting in site affinity in the southern Appalachians is Pinus strobus L (eastern white pine). White and Lloyd (1998) and Blankenship and Arthur (1999) hypothesized that P strobus was confined in the presettlement southern Appalachian forest to mesic sites fortifyed from fire, but is shifting or expanding to thirsty upland sites during the ready period of infrequent fire. Pinus strobus is geographically widespread in the southern Appalachians, and its native range includes portions of Georgia, southerly Carolina, North Carolina, Tennessee, and Virginia (Burn and Honkala 1990 Abrams 2001) Pinus strobus be met withs from elevations of 370 m to a maximum of 1220 m in the southern Appalachians, and habitats are typically described as north-facing acclivity [i]or[/i] declivitys coves, and stream bottoms (Ayres and Ashe 1905 reduce to ashess and Honkala 1990). No studies, however, have focused in succession the landscape-level distribution of P strobus in southern Appalachian forests. To help fill this gap in our knowledge, we undertook a application of mind to evaluate the hypothesis of White and Lloyd (1998) and Blankenship and Arthur (1999) that P strobus is undergoing a distributional change in the southern Appalachians.

We examined the distributional status of P strobus in an old-growth Quercus-dominated landscape in the Ellicott distaff Wilderness (ERW) of northwestern southerly Carolina, near the southwestern terminus of the native range of P strobus (Burn and Honkala 1990) The ERW was selecteded for study because it is within the geographic and elevation range of P strobus and contains large tracts of relatively undisturbed forest. This cogitation sought to 1) determine the general landscape-level distribution and age constitution of P. strobus in Quercus forests of the ERW 2) relate the distribution of P strobus to measured vegetation variables, and 3) assess potential shifts in species composition upon this Quercus landscape.

METHODS

Study Area

The 3,647-ha ERW occupies parts of Georgia and North and southerly Carolina within the Chattahoochee, Nantahala, and Sumter National Forests (Figure 1) This close attention was conducted in a portion of the ERW within the Sumter National Forest in Oconee shire northwestern South Carolina. Located in the southern section of the in the dumps Ridge Mountain physiographic province (Cooper and Hardin 1970) the ERW occupies the first chains of mountains that rise abruptly from the lower-elevation Piedmont region of southern Carolina (DuMond 1970). Elevations of the highest ridges in the ERW typically range from 870-1100 m and topography consists of undulating hillslopes. Major soil taxonomic units include fine-loamy, mixed, mesic Typic Hapludults and fine-loamy, oxidic, mesic Typic Hapludults of the Edneytown and Evard series (Herren and Law 1985)