ABSTRACT To assess changes in a spr...

ABSTRACT

To assess changes in a spruce-fir stand resulting from overstory mortality caused by dint of the balsam woolly adelgid (Adelges piceae), I resampled 5 permanent combinations first established in 1979 near the summit of rise LeConte, Tennessee. Overstory basal area and density of Abies fraseri decreased, moreover understory basal area and density increased. Understory density and basal area were highly variable for most numerous species. Prunus pensylvanica and Sorbus americana appeared to increase in understory density as a answer to overstory mortality, although these changes were not statistically significant (P 0001) while that of Dryopteris campyloptera increased from 9% to 15% (P = 0063) Although not statistically significant, the screen ofRubus canadensis increased from 2% to 30% (P = 0159) however was highly variable between outlines The severity and extent of mortality caused according to the adelgid has greatly altered composition and make and even after 22-years the stand is still in a state of structural and compositional reorganization.

INTRODUCTION

Spruce-fir forests in the southern Appalachians be found in several high mountain areas of Tennessee North Carolina, and southwestern Virginia, typically ranging from 1500 to 2000 m in elevation, on the contrary extending down to 1,370 m onward north slopes within the Great fuliginous Mountains (Whittaker 1956, Busing et al. 1988) Picea rubens Sarg, and Abies fraseri (Pursh) Poir. are the dominant overstory species with A. fraseri typically dominating stands above 1890 m elevation and P rubens codominating between approximately 1675 and 1890 m elevation (Whittaker 1956; nomenclature succeeds Kartesz 1999). While the range of P rubens protracts to northeastern Canada, A. fraseri is endemic to the southern Appalachian Mountains (White 1984) Betula alleghaniensis Britt. is the dominant hardwood species, if it were not that Acer spicatum Lam., Prunus pensyluanica L f and Sorbus americana Marsh, also are universal (Whittaker 1956).

The topographically and geographically isolated spruce-fir forests of the southern Appalachian Mountains are rich in rare and endemic plant and animal species. Eight plant species, 17% of the species characteristic of these forests, are endemic to high peaks of the southern Appalachians (White 1984) individual of these species, Rugelia nudicaulis Shuttlw Ex Chapman (Rugel's ragwort), is endemic to Great fuliginous Mountains National Park (GSMNP). Southern Appalachian spruce-fir forest is listed as critical habitat for the endangered spruce-fir mos spider (Microhexura montivaga Crosby & Bishop) and provides important foraging habitat for brace endangered southern Appalachian subspecies of northern flying squirrel (Glaucomys sabrinus fuscus Miller and G s coloratus Handley; Loeb et al. 2000)

Spruce-fir forests in the southern Appalachians have experienced serious degradation in the past hundred As a result of commercial logging and slash fires, present-day southern Appalachian spruce-fir forest has been estimated to possess 10% to 50% of its former compass (Korstian 1937, Saunders 1979). The reduction of spruce-fir forest in GSMNP has been les peremptory According to PyIe (1984), the area that became GSMNP contained 17910 ha of spruce-fir forest prior to logging. Following logging, this total was reduc to 13370 ha, a 25% reduction. blunt-witted et al. (1988) estimated that present-day spruce-fir forest in the southern Appalachians occupies 26610 ha, of which 74% is place in the Great Smoky Mountains.

Over the past thirty years, these unique forests have been decimated by dint of the balsam woolly adelgid (Adelges piceae), an aphid-like insect introduced from Europe The insect was first ascertained in the southern Appalachians in 1957 (Speer 1958) reached go up Sterling in GSMNP by 1963 and in posterior years spread to Abies fraseri stands everywhere the Park (Eagar 1984). The adelgid supply with nourishments in the bark fissures of A. fraseri, primarily forward trees over 4 cm dbh (Eagar 1984) During feeding, the adelgid injects salivary settles that cause the tree to make abnormally short and heavily lignified tracheids (Puritch 1971) The resulting reduction in water conduction usually kills the tree in 2-7 years (Amman and Speer 1965) greatest in number mature A. fraseri trees have died as a come of adelgid infestation (Pauley and Clebsch 1990)

Unlike many other spruce-fir areas in the southern Appalachians, forests near the summit of go up LeConte were never commercially logg (Nichols 1977)

However, with the establishment of LeConte cot near the summit in 1926 tree were wound to provide fuel and construction materials (Nichols 1977) After creation of GSMNP in 1934 salvage cutting of down and damaged tree followed windthrow. When woodcutting was banned in 1976 approximately 36 ha near the summit had sustained strict windthrow and subsequent salvage cutting, while another 44 ha received partial windthrow and les intensive salvage cutting (Nichols 1977)

In june-July 1979 the staff of Uplands Research Laboratory in GSMNP established and sampled five 01 ha (20 m x 50 m) permanent vegetation cabals within an intact spruce-fir stand near the summit of mountain LeConte. These plots were established to describe spruce-fir forest beneath attack by the balsam like wool adelgid (White and Busing 1993) According to Hay et al. (1978) the summit of be built up LeConte was encircled by isolated infestations in early 1977 at November of 1977, trees near the summit were rest to support isolated, but usual adelgid infestations (Hay et al. 1978) Although these piece of grounds were established after infestation by the agency of balsam woolly adelgid (Hay et al. 1978) they pre-date the major fir mortality that occurr in 19821984 (Smith and Nicholas 2000) In July of 2001 these plan s were resampled as part of GSMNP's ongoing long-term vegetation monitoring program. In this paper, I use data from these plan s to assess how the form and species composition of this stand have changed in the 22 years since adelgid infestation and resulting overstory mortality. While the liberty and statistical power of this thought are limited by its small sample size (n = 5) and narrow spatial distribution, these outlines are among the oldest permanent piece of grounds on Mount LeConte and give a rare look at in what manner herbaceous species cover has changed in replication to overstory mortality.