Southeastern Naturalist C. Cherefko, C. Fridley, J. Medsger, M. Woody, and J.T. Anderson 2015 Vol. 14, Special Issue 7 218 Canaan Valley & Environs 2015 Southeastern Naturalist 14(Special Issue 7):218–231 White-tailed Deer and Balsam Woolly Adelgid Effects on Balsam Fir in Canaan Valley Chad Cherefko1,2, Collin Fridley1, Jason Medsger1, Melvin Woody1, and James T. Anderson1,* Abstract - Abies balsamea (Balsam Fir) was historically abundant in parts of West Virginia, but it was drastically reduced by extensive logging around the turn of the 19th–20th centuries. More recently, intense herbivory by Odocoileus virginianus (White-tailed Deer) and an infestation of Adelges piceae (Balsam Woolly Adelgid), among other possible factors, have caused Balsam Fir to decline in the region. Understanding the impacts of White-tailed Deer and Balsam Woolly Adelgid is important for restoring Balsam Fir in Canaan Valley. On the Freeland Tract of the Canaan Valley National Wildlife Refuge, we surveyed the intensity of browsing on Balsam Fir and estimated deer population levels, while Refuge personnel assessed the intensity of the adelgid infestation. Even though estimates of deer density were significantly greater during 1999–2000 than in 2001–2002, the percent of buds browsed was similar during the two periods. During 2001–2002, browsing was more intense on Balsam Fir trees that were outside than on trees inside an exclosure. Deer had minimal to moderate impact on mature trees, but in many cases, they completely browsed all of the buds on trees <3.3 ft (1 m) tall. The proportion of trees infested by Balsam Woolly Adelgid rose by 17.4%—from 51.3% in 2000 to 68.7% in 2002. The average diameter at breast height of Balsam Firs heavily infested by adelgids was significantly larger than of those trees classified as moderate, light, or not infested. The Balsam Woolly Adelgid is of greater conservation concern than White-tailed Deer because some of the trees tallied in the first phase of our survey were already dead. Restoration efforts that involve the planting of seedlings should consider the impacts of deer on seedlings and the impacts of adelgids on mature trees. Introduction Located in northeastern West Virginia, Canaan Valley (hereafter, the Valley) harbors diverse floral and faunal communities in large wetlands that are otherwise uncommon throughout the Appalachian region. The Valley’s climate is typical of higher latitudes, which in part has allowed the persistence of northern species (Fortney 1975). One such plant is Abies balsamea (L.) Mill. (Balsam Fir, hereafter “Fir”), which in West Virginia is commonly found in damp woods and wetlands >3218 ft (975 m) above sea level (Michael 1992). Its local presence is interpreted as a relic of southward dispersal during the Pleistocene glaciations (Core 1966). 1Division of Forestry and Natural Resources, West Virginia University, PO Box 6125, Morgantown, WV 26506. 2Current address - USDA Natural Resources Conservation Service, 687 Pittstown Road, Frenchtown, NJ 08825. *Corresponding author - jim.anderson@ mail.wvu.edu. Southeastern Naturalist C. Cherefko, C. Fridley, J. Medsger, M. Woody, and J.T. Anderson 2015 Vol. 14, Special Issue 7 219 Fir was once locally abundant in parts of West Virginia, but extensive logging during 1885–1924 and subsequent fires devastated many stands (Cl arkson 1964, Fansler 1962). After logging ended, intense fires burned the remaining trees and the organic soils, leaving scattered stumps and rotting logs perched on exposed rocks (Clarkson 1964, Fortney 1975). Fir is valued as a timber species in northern latitudes, where it is cut for pulpwood and Christmas trees (Bakuzis and Hansen 1965). In the Valley, however, natural stands of Fir have intrinsic and scientific values (Michael 1992), due in part to its membership in a relict ecosystem. Fir is rare this far south; in West Virginia it occurs only in Grant, Tucker, Randolph, and Pocahontas counties (B.R. McDonald, Natural Heritage Program, Elkins, WV, pers. comm.; Stephenson and Adams 1986). Unfortunately, Fir is threatened by several stressors. Although potential threats include Castor canadensis (Kuhl) (North American Beaver) and the atmospheric deposition of pollutants, two issues of greater significance are intense browsing by Odocoileus virginianus Zimmerman (White-tailed Deer, hereafter “Deer”) and infestation by the Adelges piceae (Ratzeburg) (Balsam Woolly Adelgid, hereafter “Adelgid”). Fir is a preferred winter browse species of Deer (Chouinard and Filion 2001, Leopold et al. 1998, Stephenson 1993). The negative effects of browsing by Deer on tree regeneration are well known (Jones 1984, Michael 1992). In much of Central Appalachians, one of the most notable concerns about wildlife has been the overabundance of Deer and its effects on native plant communities (Stromayer and Warren 1997), but little is known about the specific impacts of Deer on Fir in West Virginia. The Adelgid, an exotic pest first recorded in North America in 1908, can be identified by the white wool-like balls of hair that are apparent on the bark of infested trees (Bakuzis and Hansen 1965). This sap-sucking insect has been reported to disperse from poorly drained sites, which are characteristic Fir habitat, and the Adelgid can kill its host within 2–3 y after the initial infestation (Bakuzis and Hansen 1965). The 3 objectives of this study were to determine the number of Deer using Fir stands, quantify the browse intensity of Deer on Fir, and evaluate the impacts of Adelgids on Fir. Study Area We conducted this study in the Valley, a highland basin at an elevation of 3218 feet (975 m). The Valley hosts one of the East’s largest shrub-swamp forests (10325 ac [4130 ha]; Fortney 1975). Weedfall and Dickerson (1965) classified the Valley’s climate as cold humid, featuring cool summers, moderate to severe winters, and relatively high precipitation. The Valley’s mean annual precipitation of 54 in (137 cm) and mean annual snowfall of 120 in (305 cm) are higher than in surrounding areas. Its average temperature is 46 °F (7.5 °C), with a 92-day frost-free growing season (Weedfall and Dickerson 1965). Our study area was located on the Freeland Tract of the Canaan Valley National Wildlife Refuge (CVNWR; Fig. 1) in the southeastern end of the Valley. In Southeastern Naturalist C. Cherefko, C. Fridley, J. Medsger, M. Woody, and J.T. Anderson 2015 Vol. 14, Special Issue 7 220 1994, the Freeland Tract, which includes 87 ac (34.8 ha) of shrub-swamp forest and meadows, was the first piece of land purchased for the CVNWR. Most of the tract (70 ac [28 ha]) was formerly used for hay production (Warren 2001). The Freeland Tract’s floor is mainly Atkins silt loam, which is a poorly drained soil of bottomlands (USDA 1967). We sampled two areas within the Freeland Tract: (1) beaver stand—a small, isolated, and moderately dense 0.35-ac (0.14-ha) Fir stand with a small stream running through its eastern edge; and (2) main stand—a dense 5.9-ac (2.35-ha) Fir stand near the Freeland Tract’s north-central border. We divided main stand into two sampling areas separated by a small stream. Both study stands included minor components of Tsuga canadensis (L.) Carriere (Eastern Hemlock), Picea rubens Sarg. (Red Spruce), and Betula alleghaniensis Britt. (Yellow Birch). Figure 1. The Freeland Tract study site located in Canaan Valley National Wildlife Refuge in the southeastern end of the Valley, Tucker County, WV, 1999–2002. Southeastern Naturalist C. Cherefko, C. Fridley, J. Medsger, M. Woody, and J.T. Anderson 2015 Vol. 14, Special Issue 7 221 Methods Field techniques We conducted pellet-group or fecal-group counts to estimate relative Deer abundance (Neff 1968) during November 1999–April 2000 and October 2001– March 2002. We delineated 15 randomly sited (Ratti and Garton 1996) 16.5 x 16.5 ft (5 x 5 m) plots in 1999–2000 and 20 plots in 2001–2002. Prior to the first search, we cleared all plots of pellet groups by crushing them with our boots or removing them from the plot (Neff 1968). We made a total of 5 systematic searches during the 1999–2000 season and 8 searches in 2001–2002. To prevent pellet groups from being counted in future visits, we tallied and then removed all pellet groups from the plots following each search (Neff 1968, Ratti and Garton 1996). During the 2001–2002 season, we conducted 8 searches during 11 visits because complete or partial snow cover prevented accurate counts. To improve the accuracy of the 2001–2002 Deer-use data, we surveyed at two-week intervals during the season. To estimate relative Deer abundance, we used the equation, t = 1 / na’* y (Neff 1968), in which t is the number of pellet groups per unit area, n is the number of plots, a is the area of 1 plot, and y is the sum of the pellet groups in all plots. We assumed a defecation rate for a winter herd on good range to be 15 pellet groups per day (Neff 1968). To measure browse intensity, we randomly selected 15 Fir trees for the browse survey during both sampling periods—1999–2000 and 2001–2002. During the first time block, 4 of the selected trees were growing in the beaver stand, 3 of which remained in the latter period. All other trees sampled were in the main stand. During the 1999–2000 period, we also sampled 2 trees within a fenced Deer exclosure in the main stand. During the 1999–2000 sampling period, we divided each tree into four quadrants (Aldous 1944). For one randomly selected quadrant of each tree, unless a whole-tree count was needed due to small tree size (less than 30 buds), we recorded the number of buds present for that quadrant up to the 6-ft (1.83-m) browse line (Doenier et al. 1997). The decrease in bud number through the browse season represented the number of buds browsed (Aldous 1944, Doenier et al. 1997). While using the method described above, we sometimes questioned whether part of a tree branch was in or out of the quadrant or was above or below the browse line, so we changed the procedure for 2001–2002. To reduce error, we marked and counted buds on two branches within the browse line on each sample tree, except when whole-tree counts were needed due to tree size. In this way, we avoided debates about whether part of a tree branch was in vs. out of the quadrant or above vs. below the browse line. We completed 3 browse tallies during 1999–2000 and 9 tallies during 2001– 2002. Lateral buds expanded throughout the winter, so we had difficulty determining the actual percent of buds that had been browsed between survey periods. Therefore, we took the difference in the number of buds between the previous and latter survey dates. If the number of buds increased due to bud re-growth or stayed the same, zero percent of the buds were recorded as having been browsed. Southeastern Naturalist C. Cherefko, C. Fridley, J. Medsger, M. Woody, and J.T. Anderson 2015 Vol. 14, Special Issue 7 222 If the number declined, it was recorded as a percentage of the total buds counted for that tree. This difference provided a conservative estimate of the percentage of buds browsed. To assess Adelgid infestation levels on Fir, CVNWR staff studied 100 Firs in the main stand and 50 in the beaver stand in September 2000 and August 2002. To find the woolly clusters indicative of Adelgids, they used a hand lens to carefully inspect the bark, twigs, and branches of each tree. Infestation level was reported as none (zero clusters), light (1–5 clusters per tree), moderate (6–49 clusters per tree), or heavy (50 or more clusters per tree) (K.K. Sturm, US Fish and Wildlife Service, CVNWR, Davis, WV, unpubl. data). They also recorded the diameter at breast height (DBH) for each tree surveyed. In 2002, samplers also measured the DBH of dead Fir trees. To determine species, trees per acre, total height, and basal area, we completed a point-sampling cruise (Smith et al. 1997) on the main stand and a 100% tally of the smaller beaver stand. On the main stand, we plotted 634-ft (192.2-m)-long transects every 51.5 ft (15.6 m) along the tract’s western boundary for the length of the stand (Smith et al. 1997). We laid out 0.01-acre (0.04-ha) plots every 206 ft (62.5 m) in beaver stand and 310 ft (93.8 m) in main stand (Avery and Burkhart 2002). To determine tree density, we tallied the number of trees per plot and extrapolated that number into number/ac (ha). We calculated basal area from DBH. Statistical analyses For sets of continuous data, we evaluated normality using the Shapiro-Wilk statistic and homogeneity of variances by plotting residuals (Cody and Smith 1991). Our data violated the assumptions of normality, so for 2001–2002, we used the Kruskal-Wallis test (Sokal and Rohlf 1995) to compare average DBH between dead trees and trees within each infestation category, Deer densities between years, browse intensity between years, and browse intensity of Firs in and out of the exclosure. We analyzed infestation rates of Firs by Adelgids between years and among infestation categories using G-tests (Sokal and Rohlf 1995). We set statistical significance at P < 0.05. Results Deer density estimates were greater for 1999–2000 (mean = 1.55 per ac [3.84/ ha], SE = 0.18 [0.44]) than during 2001–2002 (mean = 1.16 per ac [2.87/ha], SE = 0.11 [0.27]; χ2 1 = 7.15, P = 0.008). However, the percent of buds browsed was similar (χ2 1 = 1.33, P = 0.249) between the former (mean = 20.06%, SE = 6.01) and latter (mean = 26.09%, SE = 7.22) periods. During 2001–2002, the browsing intensity on Fir was substantial outside the exclosure (mean = 26.09 buds per quadrant, SE = 7.22) but completely absent inside the exclosure (mean = 0; χ2 1 = 4.88, P = 0.027). The number of Fir trees infested by Adelgids increased by 17.4% from 2000 (51.3%) to 2002 (68.7%) (G1 = 9.44, P = 0.002). However, of the trees infested, overall infestation levels were similar between years (G2 = 2.60, P = 0.2725; Southeastern Naturalist C. Cherefko, C. Fridley, J. Medsger, M. Woody, and J.T. Anderson 2015 Vol. 14, Special Issue 7 223 Fig. 2). Infestation levels differed between the main and beaver stands during both 2000 (G2 = 12.30, P = 0.002) and 2002 (G2 = 7.26, P = 0.027) (Fig. 3). During both years, the main stand included a higher proportion of heavily infested trees compared to the beaver stand. In 2000, the beaver stand also had a greater proportion of trees classified with a light infestation level when compared to the main stand. The average DBH of heavily infested Firs was greater than the DBH of moderate, light, or non-infested trees (χ2 4 = 102.15, P < 0.001; Fig. 4). However, the DBH of Firs that had likely been killed by Adelgids was similar to the DBH of Firs classified with heavy or moderate infestation (Fig. 3). In addition to Fir, the following 6 tree species grew in the survey plots: Eastern Hemlock, Yellow Birch, Ulmus americana L. (American Elm), Acer rubrum L. (Red Maple), Fagus grandifolia Ehrh. (American Beech), and Red Spruce. In the main stand, Fir had the highest density (102 trees per ac [253/ha]). Eastern Hemlock was second-most dense with 83 trees per ac (206/ha) (Table 1). In the main stand, the density of all trees was 239 per ac (590/ha) and their basal area was 51.4 ft2 per ac (11.8 m2/ha). In the main stand, Fir had the greatest basal area (23.1 ft2 per acre [5.3 m2/ha]), and Eastern Hemlock was second with 17.6 ft2 per acre (4.05 m2/ha) (Table 1). The beaver stand had a Fir density of 846 trees per ac (2090/ha) and a Red Spruce density of 140 trees per ac (347/ha) (Table 2). Figure 2. Balsam Woolly Adelgid infestation rates on Balsam Fir, by category (light = 1–5 Adelgid masses observed, moderate = 6–49, heavy = 50 or more), for Freeland Tract, Canaan Valley National Wildlife Refuge, 2000 and 2002. Southeastern Naturalist C. Cherefko, C. Fridley, J. Medsger, M. Woody, and J.T. Anderson 2015 Vol. 14, Special Issue 7 224 Fir and Spruce had the greatest basal areas, with values of 26.6 ft2 per ac (6.1 m2/ ha) and 6.1 ft2 per ac (1.4 m2/ha), respectively (Table 2). In the beaver stand, the total tree density was 1081 trees per acre (2670/ha), and total basal area was 38.8 ft2 per ac (8.9 m2/ha). Discussion Browsing by Deer and infestation by Adelgids negatively impacted Fir in the Valley. From our data, we estimated Deer density to be 995 individuals per mi2 (384/km2) in 1999–2000 and 743 Deer per mi2 (287/km2) in 2001–2002. These values clearly indicate that the Fir stand in the Freeland Tract was a high-use area for Deer. We do not believe that our estimates of Deer abundance were true representations of the actual population present on the CVNWR. Pellet surveys have several inherent biases, including defecation rate, pellet loss, quadrat placement, and observer bias (Langdon 2001). However, we believe our estimates indicate that Fir stands were heavily used and that the use of the Freeland Tract declined between the two survey periods. Between 1979 and 1991, Michael (1992) estimated the Deer density was 243 Deer per mi2 (94/km2) on the Freeland Tract and 518 Deer per mi2 (200/km2) in the Fir stand. However, Michael (1992) used 25 Figure 3. Balsam Woolly Adelgid infestation rates on Balsam Fir between stands, by category (light = 1–5 Adelgid masses observed, moderate = 6–49, heavy = 50 or more), for Freeland Tract, Canaan Valley National Wildlife Refuge, 2000 and 2002. Southeastern Naturalist C. Cherefko, C. Fridley, J. Medsger, M. Woody, and J.T. Anderson 2015 Vol. 14, Special Issue 7 225 pellet groups per day whereas we used only 15, indicating that population densities were similar between his study and ours. The browsing intensity by Deer on all Fir ranged from 20% to 26%, but browse on individual trees outside of the exclosure ranged from 0.3% to 100%. Although we did not include trees shorter than 6.6 ft (2 m) tall in our analyses, we observed that trees shorter than 3.3 ft (1 m) always had 100% browsed branches. In contrast, 2 trees protected by an exclosure were completely unbrowsed. Therefore, Deer were impacting the growth of Fir in the Valley. Fir-stem density was lower in areas with the highest Deer density (Michael 1992). Christmas-tree growers believed that tree growth was being severely reduced by Deer browsing and rubbing (Atkins 1994). Chouinard and Filion (2001) have also documented that high browse-intensity reduces vertical and radial growth of conifers. In addition, browsing by Deer seems to alter stand structure in favor of Red Spruce. In support of this hypothesis, Stromayer and Warren (1997) suggested that Deer create alternate stable states of plant communities in northern temperate forests by browsing on woody vegetation. They stated that sustained, long-term suppression of regeneration contributes to local extirpation of some tree species. This effect could prevent regeneration in sites Figure 4. Average diameter (+ SE) at breast height (DBH) of Balsam Fir trees infested with Balsam Woolly Adelgid on the Freeland Tract, Canaan Valley National Wildlife Refuge, 2000 and 2002. Dead (presumably due to Balsam Woolly Adelgids), none = 0 Adelgid masses observed, light =1–5, moderate = 6–49, or heavy = 50 or more). Southeastern Naturalist C. Cherefko, C. Fridley, J. Medsger, M. Woody, and J.T. Anderson 2015 Vol. 14, Special Issue 7 226 Table 1. Trees/ha and basal area (m2/ha) for 5 species of trees measured on the Main Stand (Freeland Tract) of Balsam Fir in the Valley, March 2002. Diameter at breast height (DBH) classes are presented in cm with inches in parentheses. HEM = Eastern Hemlock, YB = Yellow Birch, BF = Balsam Fir, AE = American Elm, and RM = Red Maple. Multiply by 0.41 to convert # trees/ha to # trees/ac, and by 0.23 to convert m2/ha to ft2/ac. # trees/ha Basal area (m2/ha) DBH Class HEM YB BF AE RM Total HEM YB BF AE RM Total 2.54 (1) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5.08 (2) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 7.62 (3) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 10.16 (4) 50.39 28.41 24.45 0.00 0.00 103.25 0.44 0.22 0.22 0.00 0.00 0.89 12.70 (5) 37.54 40.26 67.43 18.03 0.00 163.27 0.44 0.44 0.89 0.22 0.00 2.00 15.24 (6) 39.52 0.00 81.76 0.00 0.00 121.28 0.67 0.00 1.56 0.00 0.00 2.22 17.78 (7) 33.10 18.28 42.48 0.00 0.00 93.86 0.89 0.44 1.11 0.00 0.00 2.45 20.32 (8) 36.31 6.67 14.82 0.00 0.00 57.55 1.11 0.22 0.44 0.00 0.00 1.78 22.86 (9) 6.18 9.88 6.18 0.00 0.00 23.96 0.22 0.44 0.22 0.00 0.00 0.89 25.40 (10) 0.00 4.69 9.14 0.00 0.00 13.83 0.00 0.22 0.44 0.00 0.00 0.67 27.94 (11) 0.00 0.00 3.95 0.00 0.00 3.95 0.00 0.00 0.22 0.00 0.00 0.22 30.48 (12) 3.21 0.00 2.96 0.00 0.00 6.18 0.22 0.00 0.22 0.00 0.00 0.44 33.02 (13) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 35.56 (14) 0.00 0.00 0.00 0.00 2.47 2.47 0.00 0.00 0.00 0.00 0.22 0.22 Total 206.25 108.19 253.18 18.03 2.47 589.59 4.00 2.00 5.34 0.22 0.22 11.78 Southeastern Naturalist C. Cherefko, C. Fridley, J. Medsger, M. Woody, and J.T. Anderson 2015 Vol. 14, Special Issue 7 227 Table 2. Trees/ha and basal area (m2/ha) for 5 species of trees measured on the Beaver Stand (Freeland Tract) of Balsam Fir in the Valley, March 2002. Diameter at breast height (DBH) classes are presented in cm with inches in parentheses. HEM = Eastern Hemlock, YB = Yellow Birch, BF = Balsam Fir, RS = Red Spruce, and AB = American Beech. Multiply by 0.41 to convert # trees/ha to # trees/ac, and by 0.23 to convert m2/ha to ft2/ac. # trees/ha Basal area (m2/ha) DBH Class HEM YB BF RS AB Total HEM YB BF RS AB Total 2.54 (1) 0.00 0.00 118.44 70.27 0.00 188.71 0.00 0.00 0.01 0.04 0.00 0.05 5.08 (2) 0.00 15.44 130.17 69.78 0.00 215.38 0.00 0.01 0.05 0.10 0.00 0.15 7.62 (3) 0.00 0.00 279.48 68.42 0.00 347.90 0.00 0.00 0.22 0.05 0.00 0.28 10.16 (4) 0.00 0.00 361.73 42.85 0.00 404.59 0.00 0.00 0.49 0.22 0.00 0.71 12.70 (5) 0.00 0.00 303.44 13.71 0.00 317.15 0.00 0.00 0.65 0.03 0.00 0.68 15.24 (6) 0.00 0.00 235.02 27.42 0.00 262.44 0.00 0.00 0.72 0.09 0.00 0.81 17.78 (7) 0.00 0.00 217.73 13.71 33.86 265.30 0.00 0.00 0.88 0.06 0.06 1.01 20.32 (8) 0.00 0.00 188.71 13.71 67.72 270.14 0.00 0.00 1.02 0.08 0.15 1.25 22.86 (9) 0.00 0.00 118.34 0.00 33.86 152.20 0.00 0.00 0.78 0.00 0.10 0.88 25.40 (10) 0.00 0.00 41.15 0.00 33.86 75.01 0.00 0.00 0.19 0.00 0.12 0.31 27.94 (11) 0.00 0.00 82.33 0.00 0.00 82.33 0.00 0.00 0.87 0.00 0.00 0.87 30.48 (12) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 33.02 (13) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 35.56 (14) 0.00 0.00 13.71 0.00 0.00 13.71 0.00 0.00 0.24 0.00 0.00 0.24 38.10 (15) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 40.64 (16) 0.00 0.00 0.00 0.00 33.86 33.86 0.00 0.00 0.00 0.00 0.33 0.33 43.18 (17) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 45.72 (18) 0.00 0.00 0.00 27.44 0.00 27.44 0.00 0.00 0.00 0.77 0.00 0.77 48.26 (19) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 50.80 (20) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 53.34 (21) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 55.88 (22) 13.58 0.00 0.00 0.00 0.00 13.58 0.58 0.00 0.00 0.00 0.00 0.58 58.42 (23) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 60.96 (24) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Total 13.58 15.44 2090.24 347.31 203.16 2669.73 0.58 0.01 6.12 1.45 0.76 8.91 Southeastern Naturalist C. Cherefko, C. Fridley, J. Medsger, M. Woody, and J.T. Anderson 2015 Vol. 14, Special Issue 7 228 after overstory release (Stromayer and Warren 1997). These factors could be deleterious to stands of Fir in the Valley. Indeed, Michael (1992) predicted that Red Spruce would replace Fir in the Valley because Deer seldom browse Spruce. Adelgids also impacted Fir. Between 2000 and 2002, the Adelgid infestation rate increased by 17.4%. By 2002, about 69% of the trees were infested. There was evidence of heavier infestation levels in 2002 than in 2000. From 2000 to 2002, Fir classified as lightly or moderately infested declined, while the proportion of heavily infested trees rose by 10%. Further, 43% (n = 64) of all trees measured in 2002 were dead. Therefore, more trees were both heavily infested and dead in 2002 than in 2000, indicating that a growing proportion of trees were being impacted by Adelgids. Heavy Adelgid infestation can kill Fir trees within 2–3 years (Hagle et al. 1987, Johnson and Lyon 1988), thus, it is likely that the mortality we observed was caused by the Adelgids. The Fir trees that were heavily infested by Adelgids were larger than the trees with light, moderate, or no infestation. Additionally, dead Firs were larger than those lightly or not infested. In general, old, large Firs are more susceptible to Adelgids (Johnson and Lyon 1988). Because larger trees typically produce the most seeds (Hardin et al. 2001), we conclude that Adelgids are likely reducing the survival and recruitment of Fir on the Freeland Tract. Deer and Adelgids are not the only threats to Balsam Fir. Castor canadensis Kuhl.(North American Beaver, hereafter referred to as “Beaver”) and atmospheric deposition are also potential threats. Beaver are common throughout the East and have re-established themselves as pests in some areas by flooding roadways and timber stands (Muller-Shwarze 1992). Because of their direct and often significant impact on ecosystem structure and function, Beaver are considered a keystone species (Gurnell 1998). By building dams and inundating areas, Beaver kill trees; flooding is a greater threat to Fir than their actual consumption of trees because Fir and other evergreens are not a desirable food of Beaver (Gurnell 1998, Muller-Shwarze 1992). It has been suggested that atmospheric deposition causes declines in subalpine coniferous forests, where the strong acids added to the system can leach soils of nutrients including calcium (McLaughlin et al. 1990). The atmospheric input of acid can increase the solubility of aluminum and other toxins, which plants then take up in excess, compounding the effects of deposition (McLaughlin et al. 1990). The additional stressors of Beaver and pollutant deposition may further complicate Fir restoration. Management Implications The effects of White-tailed Deer and Balsam Woolly Adelgid need to be considered in crafting Balsam Fir restoration plans. Of the two, the Adelgid is the more pressing stressor in the Fir stands on the Freeland tract because trees there are heavily infested. The Adelgid has some natural insect predators, but most are not effective in limiting populations (Martineau 1984). Martineau (1984) indicated that artificial control is difficult because the Adelgid lives under the Southeastern Naturalist C. Cherefko, C. Fridley, J. Medsger, M. Woody, and J.T. Anderson 2015 Vol. 14, Special Issue 7 229 swellings on twigs, where the insect cannot be reached by chemical insecticides. Although it has been attempted, biological control remains mostly unsuccessful in stopping the spread of Adelgids (Fowler 1999). Even if the Adelgid could be controlled, natural regeneration of this stand will be difficult because of the browsing pressure from Deer. Our exclosure prevented browsing on trees within it, but the option of fencing the entire stand, or even just the seedlings until they reach heights above the browse line, may be too costly and labor-intensive to implement at an ecologically meaningful scale. Fencing would also exclude Deer from an area they have been using extensively. Reducing Deer numbers by increasing their harvest may be a more practical solution. So what does all this mean for Balsam Fir? If managers do nothing to intervene, these stands will likely be extirpated from the area, and other tree species, such as Red Spruce, will replace it. Immediate and forceful action is necessary to conserve Balsam Fir as a viable part of the Valley’s flora. Without intervention, Balsam Fir may suffer the same fate as Castanea dentata (Marsh.) Borkh. (American Chestnut) and become extirpated, thereby lowering the overall biodiversity of the Appalachian landscape. 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