Eleven Years of Old-growth Forest Dynamics Within. Wachusett Mountain State Reservation

Transcription

1 Eleven Years of Old-growth Forest Dynamics Within Wachusett Mountain State Reservation 1/15/09 David A. Orwig

2 Introduction The discovery of old-growth forest on Wachusett Mountain in 1995 and later confirmation of its structure, composition, and extent by a series of Harvard Forest studies (Foster et al. 1997; Orwig et al. 2001; Orwig 2004) has led to a growing awareness that this 80 ha of forest is truly unique and special (D Amato et al. 2006). One of the only old-growth forests east of the Connecticut River in central Massachusetts and dominated by both hemlock and hardwood species, this location is home to some of the oldest known yellow birch (Betula alleghaniensis) and black birch (Betula lenta) and harbors the oldest known northern red oak (Quercus rubra) trees in the world (Orwig et al. 2001). These findings originate from permanent plots that were established in four distinct old-growth forests on the upper slopes of Wachusett Mountain in It has been 11 years since the plots have been sampled, which is just beyond the original re-sampling interval recommended in the 1999 Wachusett Mountain State Reservation Resource Management and Protection Plan (Epsilon Associates 1999). To document changes in the structure and composition of these old-growth forests over the last 11 years, a follow-up study was conducted during summer and autumn 2008, focusing on resampling the original permanent plots. Objectives Specific objectives of this project include: re-sampling the permanent plots within the four old-growth areas originally sampled in (n = 20 plots); compiling a complete vegetative species list of each plot, estimating percent cover of all understory species, remeasuring all overstory tree diameters, calculating tree species overstory importance values for each plot, comparing data to original data to assess overall dynamics and health of old-growth forests and photo-recording all plots, plot corners, canopy nests and/or dens, and presence of disease or insect infestations. Study area Wachusett Mountain is located in the towns of Princeton and Westminster, Worcester County, in north central Massachusetts ( 'N, 'W) and lies within the Worcester/Monadnock Plateau subregion of the northeastern highlands of Massachusetts (Griffith et al. 1994). Extending from 320 to 611 m a.s.l., this monadnock is the highest peak in Massachusetts east of the Connecticut River and is formed from a sill of Wachusett granodiorite, an erosion-resistant rock that has steep talus (boulder field) slopes produced by post-glacial frost cracking (Robinson and Tucker 1992; Cogbill 1995). In 1899, Massachusetts bought the 560-ha area encompassing the summit and created the Wachusett Mountain State Reservation (WMSR; Massachusetts Department of Conservation and Recreation- DCR 1985). The mountain is one of the most visited state forests in Massachusetts and has received increasing use by hikers, skiers, and tourists travelling the many trails and summit roads. The summit is located in the center of the 817- ha Reservation which is managed by the Mass. DCR. A 182-ha area on the northern slope of the mountain that includes much of the old-growth forest is leased to Wachusett Mountain Associates. 2

3 Early reconnaissance of the mountain and subsequent intensive tree coring confirmed the existence of a large, nearly contiguous zone of old-growth forest with gnarled, tapering tree boles on the mid- to upper slopes of the mountain (Foster et al. 1997; Figure 1). Within this zone, which approximated the administrative boundary of old-growth forests on the mountain, we observed and intensively studied four separate stands during the summers of 1996 and 1997 (Orwig et al. 2001; Figure 1). Areas were selected based on preliminary ages obtained earlier and distinctive species composition that varied with topographic aspect, site and morphological characteristics. Figure 1. General location of the Old Indian (OI), Eastern Talus (ET), Southern Talus (ST), and Hemlock (H) Old-Growth Areas on Wachusett Mountain. Blue border is the original old-growth administrative boundary as determined by the Massachusetts Department of Conservation and Recreation. Methods In each area, I determined the structure and composition of the overstory vegetation and sampled the sapling-layer vegetation. During mid-summer and early autumn 2008, vegetation 3

4 was sampled in five, 20 x 20 m permanently marked plots established along transects oriented through the central portion of each area. Diameter at breast height (dbh) for every tree (stems 1.37 m tall and 8 cm dbh) was recorded in each plot. In each area, a relative importance value was calculated for each species by averaging relative density and relative basal area data from the five plots. All saplings (stems > 1.37 m tall and < 8 cm dbh) were counted by species within each plot. Percent cover of all understory species (tree seedling, herbaceous, fern, and shrub species) were estimated within each overstory plot using modified Braun-Blanquet cover classes (Mueller-Dombois and Ellenberg 1974). Nomenclature followed Gleason and Cronquist (1991). Photographs were taken of and from each plot corner to document stand condition and site characteristics (photographs are included in Appendix A. Copies of the Appendix were given to Wachusett Mountain Associates and DCR and are not included in this report). Results Since 1997, the four old-growth areas remained quite similar in overall overstory composition and structure (Table 1). Overstory importance values remained relatively stable as only two species across the 4 areas experienced more than a 5% change (i.e. red maple (Acer rubrum) importance decreased from 16.3 to 10.6 and yellow birch (Betula alleghaniensis) importance increased from 45.4 to 52.9 in 2008 within the Eastern Talus area). This is not to suggest that that the stands were not dynamic, as each experienced overstory mortality and several areas exhibited recruitment of new stems into the overstory size category. Changes in structure and composition will be presented for each old-growth area separately below, followed by a discussion of the major dynamics and overall stand health. Old Indian (OI) Area: Overstory composition remained dominated by beech (Fagus grandifolia), red oak (Quercus rubra), yellow birch, sugar maple (Acer saccharum), and red maple (Tables 1 & 2). Stand density changed from 470 ha -1 in 1997 to 380 ha -1 in 2008, although stand basal area remained almost identical at 34.0 m 2 ha -1 (Table 1). In the five plots, 28 stems died since 1997, comprised mostly of striped maple (Acer pennsylvanicum), red maple, and beech (Table 3). Recruitment of new stems consisted of striped maple, beech, and witch hazel (Hamamelis virginiana). Plots within the Old Indian area were characterized by a very dense sapling layer of striped maple, mountain maple (Acer spicatum), witch hazel, and yellow birch (Figure 2; Table 4). Total sapling density across the five plots was 5185 ha -1 (Table 4). The seedling layer was dominated by striped maple and mountain maple, with both species at least doubling since 1997, and witch hazel, which declined in abundance since 1997 (Table 5). Dominant overstory tree seedling abundance was quite low, with only yellow birch averaging greater than 4% cover. Herbaceous vegetation was rich (26 species), abundant, and dominated by Sarsaparilla (Aralia nudicaulus), spinulose wood fern (Dryopteris spinulosa), marginal wood fern (Dryopteris marginalis), and mountain aster (Aster divaricatus) (Table 5). Fringed bindweed (Polygonum cilinode- previously referred to as black bindweed cf. Foster et al. 1997) exhibited a sharp decrease in cover from ~ 21% in 1997 to only 1.7% in

5 Hobblebush (Viburnum alnifolium) and gooseberry (Ribes) species were the only commonly occurring shrub species in this forest. Overstory beech trees in this area were heavily infested with beech bark disease, caused by the combination of the scale insect (Cryptococcus fagisuga) and pathogenic fungi (Neonectria). While the disease has not yet resulted in widespread beech mortality, the extent of infestation, along with the poor bole conditions observed (Figure 3), suggest that higher beech mortality in the coming decade is very likely to increase. I did observe what appeared to be a large cavity near the top of a large red oak tree, which is likely a wildlife den (Figure 4). Table overstory species relative importance values* and general stand characteristics within the four sampled old-growth areas on Wachusett Mountain, Massachusetts. Species Old Eastern Southern Hemlock Indian Talus Talus American Beech Eastern hemlock Hophornbeam Red oak Red maple Striped maple Sugar maple Yellow birch Other species Total Density (ha -1 ) Basal area (m 2 /ha) Elevation (m a.s.l.) Aspect N - NW E SE - S W Slope (%) *Importance values were calculated by species as: (Relative density + Relative basal area)/2 5

6 Table tree diameters within the Old Indian old-growth area on Wachusett Mountain. Plot Species DBH (cm) Plot Species DBH (cm) 1 Striped maple Striped maple Striped maple Striped maple Red maple Red maple 28 1 Sugar maple Red maple Sugar maple Sugar maple Yellow birch Sugar maple Yellow birch Yellow birch Beech Red oak Beech Striped maple Beech Striped maple Beech Striped maple Beech Red maple Beech Sugar maple Beech Sugar maple Beech Sugar maple Hophornbeam 12 4 Sugar maple Red oak Sugar maple Red oak Sugar maple Red oak Yellow birch Striped maple Yellow birch Striped maple Beech 35 2 Red maple Beech 13 2 Red maple Beech Red maple Beech Red maple Striped maple Red maple 25 5 Striped maple Yellow birch 45 5 Red maple Beech 20 5 Sugar maple Beech Sugar maple Beech Yellow birch Beech Yellow birch Witch hazel Beech Witch hazel Beech Witch hazel Beech Witch hazel Beech Hophornbeam Beech 12 2 Red oak 77 5 Witch hazel Red oak Red oak

7 Table abundance of newly established stems ( 8 cm dbh) and dead stems by species since the 1997 sampling of four old-growth areas on Wachusett Mountain. Original stem density (total # of stems in all 5 plots) is listed in parentheses for each area. Old Indian (n = 76) Eastern Talus (n = 84) Southern Talus (n = 110) Hemlock ( n = 100) Species New Mortality New Mortality New Mortality New Mortality Striped maple Red maple Sugar maple Mountain maple Beech Witch hazel Black birch Yellow birch Hophornbeam Red oak Hemlock Mountain ash Chestnut Totals Figure 2. Dense sapling thicket within the Old-Indian old-growth area on Wachusett Mountain. 7

8 Table sapling (> 1.37 m tall and < 8 cm dbh) abundance (stems ha -1 ) within the four old-growth areas on Wachusett Mountain. Species Old Eastern Southern Hemlock Indian Talus Talus Striped maple Red maple Sugar maple Mountain maple Serviceberry Yellow birch Musclewood Shagbark hickory Alternate-leaved dogwood Beaked hazelnut Beech White ash Witch hazel Hophornbeam Chokecherry Red oak Mountain ash Hemlock Total

9 Table 5. Mean cover (% ± S.E.) of understory vegetation in 1997 and 2008 within 20 x 20 m plots in the Old Indian old-growth area on Wachusett Mountain. Species Common name Seedlings Acer pennsylvanicum Striped maple 12.6 ± ± 7.5 Acer rubrum Red maple 0.5 ± ± 0.4 Acer saccharum Sugar maple 1.5 ± ± 0.4 Acer spicatum Mountain maple 7.8 ± ± 6.4 Amelanchier arborea Shadbush ± 0.1 Betula alleghaniensis Yellow birch 1.0 ± ± 2.7 Fagus grandifolia American beech 4.9 ± ± 0.4 Hamamelis virginiana Witch hazel 10.2 ± ± 2.6 Ostrya virginiana Hophornbeam 0.1 ± ± 0.1 Prunus serotina Black cherry ± 0.1 Prunus virginiana Choke cherry 0.1 ± ± 0.1 Quercus rubra Red oak 0.9 ± ± 0 Sorbus americana Mountain ash 0.2 ± ± 0 Tsuga canadensis Eastern hemlock ± 0.02 Herb/Fern Aralia nudicaulus Sarsaparilla 2.0 ± ± 4.5 Arisaema triphyllum Jack-in-the pulpit 0.1 ± ± 0.1 Aster acuminatus Mountain aster 4.4 ± ± 3.2 Aster divaricatus White wood aster 0.2 ± ± 0.1 Carex spp. Sedge species ± 0.1 Clintonia borealis Blue-bead lily 1.0 ± ± 2.6 Dennstaedtia punctilobula Hay-scented fern ± 0.5 Dryopteris marginalis Marginal wood fern 3.4 ± ± 7.1 Dryopteris spinulosa Spinulosa wood fern 24.7 ± ± 12.5 Epifagus virginiana Beechdrops ± 3.0 Gymnocarpium dryopteris Oak fern ± 0.5 Lycopodium lucidulum Shining clubmoss 0.2 ± ± 0.5 Maianthemum canadense Canada mayflower 0.1 ± ± 0.1 Medeola virginiana Indian cucumber 0.1 ± ± 0.1 Monotropa uniflora Indian pipe ± 0.1 9

10 Table 5. (continued) Common name Herb/Fern Oxalis montana Wood sorrel 0.8 ± ± 0.6 Panicum spp. Panic grass 0.3 ± ± 0.1 Polygonatum biflorum Smooth Solomon s seal 0.2 ± ± 0.1 Polygonum cilinode Fringed bindweed 20.7 ± ± 0.5 Polypodium vulgare Common polypody ± 0.1 Prenanthus altissima Tall white lettuce ± 0.1 Streptopus amplexifolius Twisted stalk 0.4 ± ± 0 Trillium spp Trillium 0.2 ± ± 0.1 Trientalis borealis Starflower 0.4 ± ± 0.1 Uvularia sessilifolia Sessile-leaved bellwort 0.5 ± ± 0.1 Viola spp. Violet species 0.2 ± ± 0.6 Shrubs Cornus alternifolia Alternate leaf dogwood 0.1 ± ± 0.5 Corylus rostrata Beaked hazelnut ± 0.1 Lonicera canadensis American fly honeysuckle 0.1 ± ± 0.1 Ribes spp. Gooseberry 3.1 ± ± 8.7 Rubus allegheniensis Blackberry 0.2 ± ± 0.1 Rubus idaeus Red raspberry ± 0.1 Rubus pubescens Dwarf raspberry ± 0.5 Sambucus canadensis Common elder 1.0 ± ± 0.5 Viburnum alnifolium Hobblebush 3.0 ± 0 10 ±

11 Figure 3. Beech tree with symptoms of beech bark disease within the Old Indian oldgrowth area on Wachusett Mountain. Figure 4. Tree den in large red oak tree within the Old Indian old-growth area on Wachusett Mountain. 11

12 Eastern Talus (ET) Area: Overstory composition on this rocky, east-facing slope is dominated by yellow birch with an importance value of 52.9%, up from 45.4% in 1997 (Tables 1 & 6). Red oak (18.7%) and red maple (10.6%) are also common overstory inhabitants. Overall stand density is 420 stems ha -1, up from 355 ha -1 in 1997 and basal area is 19.8 m 2 ha -1, up slightly from 17.6 m 2 ha -1 in Across the five plots, 25 stems consisting of striped and red maple, yellow birch, and mountain ash (Sorbus americana) died since 1997 (Table 3). Twenty-five yellow birch stems recruited into the tree size category by Sapling density was high in this steep, open-canopied site, and was comprised of striped and mountain maple, yellow birch, witch hazel and chokecherry (Prunus virginiana) (Table 4). Total sapling density within the Eastern Talus was 3680 ha -1. Understory seedling cover was sparse overall, although mountain maple and striped maple increased in cover since 1997 and exceeded 4% (Table 7). Common polypody (Polypodium vulgare) carpeted many of the boulders on this talus slope and averaged 53% cover, up from 35% in 1997 (Figure 5). Large increases in cover were also observed in marginal wood fern, fringed bindweed, and sarsaparilla. Shrub species were also common in these plots, particularly red raspberry (Rubus ideaus), gooseberry (Ribes species), common elderberry (Sambucus canadensis), and Virginia creeper (Parthenocissus quinquefolia). While I did not directly observe any active den sites, porcupines were common in this area, frequently stripping bark on yellow birch stems (Figure 6). Figure 5. Abundant polypody fern on rock boulders within the Eastern Talus old-growth area on Wachusett Mountain. 12

13 Table tree diameters within the Eastern Talus Old-growth area on Wachusett Mountain. Plot Species DBH (cm) Plot Species DBH (cm) 1 Red maple Yellow birch Red maple Red maple 16 1 Yellow birch Red maple Yellow birch Red maple Yellow birch Red maple Yellow birch 49 3 Red oak Yellow birch Striped maple Yellow birch Striped maple Yellow birch Striped maple Red maple Yellow birch Red maple Yellow birch Red oak 92 3 Yellow birch Striped maple Yellow birch Yellow birch 13 3 Yellow birch Yellow birch Yellow birch Yellow birch Red maple Yellow birch Red maple Yellow birch Yellow birch Yellow birch Yellow birch Yellow birch Yellow birch Yellow birch Yellow birch Yellow birch 26 4 Yellow birch Yellow birch Yellow birch Yellow birch Yellow birch 9 2 Yellow birch Yellow birch Yellow birch Yellow birch Yellow birch Yellow birch Yellow birch Hophornbeam 14 2 Yellow birch 16 5 Hophornbeam Yellow birch Hophornbeam Yellow birch Pignut hickory Yellow birch Red maple Yellow birch Red oak Yellow birch Red oak Yellow birch 10 5 Striped maple Yellow birch Striped maple Yellow birch Striped maple Yellow birch Sugar maple Yellow birch Sugar maple

14 Table 6. (Continued) Plot Species DBH (cm) 5 Sugar maple White ash 37 5 White ash White ash Yellow birch Yellow birch 19.7 Figure 6. Evidence of bark chewing by porcupines on yellow birch branches within the Eastern Talus old-growth area on Wachusett Mountain. Past chewing scars are seen on branch in the right foreground. 14

15 Table 7. Mean cover (% ± S.E.) of understory vegetation in 1997 and 2008 within 20 x 20 m plots in the Eastern Talus old-growth area on Wachusett Mountain. Species Common name Seedlings Acer pennsylvanicum Striped maple 1.5 ± ± 2.6 Acer rubrum Red maple 0.3 ± ± 0.1 Acer saccharum Sugar maple 0.1 ± Acer spicatum Mountain maple 1.0 ± ± 2.5 Betula alleghaniensis Yellow birch 1.5 ± ± 0.6 Carya spp. Hickory species 0.1 ± Fraxinus americana White ash 0.3 ± Hamamelis virginiana Witch hazel 0.2 ± ± 0.5 Ostrya virginiana Hophornbeam 0.2 ± Prunus virginiana Choke cherry 0.2 ± ± 0.6 Quercus rubra Red oak 0.3 ± ± 0.5 Sorbus americana Mountain ash 0.3 ± ± 0.1 Herb/Fern Aralia nudicaulus Sarsaparilla 8.4 ± ± 6.4 Arisaema triphyllum Jack-in-the pulpit 0.3 ± Aster acuminatus Mountain aster 0.5 ± ± 2.8 Aster divaricatus White wood aster ± 0.5 Carex spp. Sedge species 0.3 ± ± 0.5 Clintonia borealis Blue-bead lily 0.1 ± Corydalis sempervirens Pale corydalis ± 0.1 Dryopteris marginalis Marginal wood fern 3.9 ± ± 0 Dryopteris spinulosa Spinulosa wood fern 3.9 ± ± 3.1 Erechtites hieracifolia Pilewort ± 0.1 Maianthemum canadense Canada mayflower 0.1 ± ± 0.1 Monotropa uniflora Indian pipe ± 0.1 Panicum spp. Panic grass ± 0.1 Polystichum acrostichoides Christmas fern 0.1 ± ± 0.5 Polygonatum biflorum Smooth Solomon s seal 0.1 ± ± 0.02 Polygonum cilinode Fringed bindweed 1.0 ± ± 7.2 Polypodium vulgare Common polypody 35.1 ± ± 12.4 Solidago spp. Goldenrod species ± 0.6 Streptopus amplexifolius Twisted stalk ±

16 Table 7. (Continued) Species Common name Celastris orbiculatus Asiatic bittersweet ± 0.1 Diervilla lonicera Bush honeysuckle ± 0.5 Parthenocissus quinquefolia Virginia creeper 0.3 ± ± 2.8 Ribes spp. Gooseberry 1.0 ± ± 3.1 Rubus idaeus Red raspberry 3.4 ± ± 7.7 Rubus occidentalis Black raspberry ± 3.0 Sambucus canadensis Common elder 0.3 ± ± 2.7 Toxicodendron radicans Poison ivy 0.1 ± ± 0.5 Southern Talus (ST) Area: Overstory composition on this south-facing rocky slope was dominated by red oak, yellow birch, and red maple (Tables 1 & 8). Since 1997, there has been only a slight decrease in stem density (590 to 550 stems ha -1 ) and a slight increase in stand basal area (27.3 to 29.1 m 2 ha -1 ). Within the Southern Talus area, 25 stems died over the last 11 years (Table 3). Most stems were in the lower size classes (i.e., < 20 cm dbh), with roughly half of the stems being red maple. Over this same time period, 17 stems recruited into the tree size category and consisted of 6 yellow birch and a few stems of several other hardwood species. Like the Eastern Talus, sapling densities of witch hazel, striped and mountain maple, and yellow birch were high throughout the Southern Talus area (Table 4; Figure 7). Seedling layer dominance mirrored the sapling layer, with maple species and yellow birch together averaging 35% cover in this forest (Table 9). The herb layer of this forest was very diverse, consisted of 26 species, and was dominated by sarsaparilla and mountain aster (Aster acuminatus). Additional common species included marginal wood fern, fringed bindweed, spinulose wood fern (Dryopteris spinulosa), and sedge (Carex) species. Total herbaceous cover was significantly higher in 2008 vs (Table 9). Shrub cover was low across the plots, as only gooseberry and common elder exceeded 1% cover. Beech bark disease was common throughout the Southern Talus area, although beech mortality was low over the last 11 years and tree condition was generally better than in the Old Indian area. 16

17 Figure 7. Dense sapling layer of striped and mountain maple within Southern Talus Area. Table tree diameters within the Southern Talus Old-growth area on Wachusett Mountain. Plot Species DBH (cm) Plot Species DBH (cm) 1 Beech Red oak Beech Sugar maple Hophornbeam Sugar maple 10 1 Hophornbeam Yellow birch Hophornbeam Yellow birch Red maple Yellow birch Red maple Yellow birch Red maple Yellow birch 18 1 Red maple Yellow birch Red maple Red maple 15 1 Red maple Red maple Red maple Red maple Red maple Red maple Red oak Red maple Red oak Red maple Red oak Red maple Red oak 32 3 Red maple Red oak Red oak Red oak Red oak Shagbark hickory Red oak Witch hazel 8 3 Red oak Yellow birch Red oak

18 Table 8. (continued) Plot Species DBH (cm) Plot Species DBH (cm) 1 Yellow birch Red oak Yellow birch 24 3 Yellow birch 14 1 Yellow birch Yellow birch Yellow birch Yellow birch Yellow birch Yellow birch Yellow birch Yellow birch Beech Yellow birch 20 2 Beech Yellow birch Beech 52 3 Yellow birch Beech Yellow birch Beech Yellow birch Hophornbeam Yellow birch Hophornbeam Beech 8 2 Red maple Hophornbeam Red maple Hophornbeam Red maple Hophornbeam Red oak 54 4 Hophornbeam Pignut hickory Sugar maple Pignut hickory Sugar maple Pignut hickory White ash Red maple Yellow birch Red maple 19 4 Yellow birch Red maple 29 4 Yellow birch 24 4 Red maple Red maple Red maple Striped maple Red oak Striped maple Red oak Striped maple Red oak Witch hazel 8 4 Red oak Yellow birch Red oak 19 5 Yellow birch Red oak Yellow birch Sugar maple Yellow birch Sugar maple Yellow birch

19 Table 9. Mean cover (% ± S.E.) of understory vegetation in 1997 and 2008 within 20 x 20 m plots in the Southern Talus old-growth area on Wachusett Mountain. Species Common name Seedlings Acer pennsylvanicum Striped maple 2.0 ± ± 6.4 Acer rubrum Red maple 1.0 ± ± 0.5 Acer saccharum Sugar maple 0.4 ± ± 0.4 Acer spicatum Mountain maple 0.4 ± ± 7.0 Betula alleghaniensis Yellow birch 3.9 ± ± 0.5 Carpinus caroliniana Musclewood ± 0.1 Carya ovata Shagbark hickory 0.2 ± ± 0.1 Fagus grandifolia American beech 0.8 ± ± 0.1 Hamamelis virginiana Witch hazel 5.4 ± ± 7.0 Ostrya virginiana Hophornbeam 0.3 ± ± 0.1 Prunus serotina Black cherry ± 0.1 Prunus virginiana Choke cherry ± 0.1 Quercus rubra Red oak 0.8 ± ± 0.4 Herb/Fern Aralia nudicaulus Sarsaparilla 3.8 ± ± 11.6 Arisaema triphyllum Jack-in-the pulpit 0.5 ± ± 0.02 Aster acuminatus Mountain aster 4.4 ± ± 8.8 Aster divaricatus White wood aster 0.3 ± ± 0.6 Athyrium filix-femina Lady fern ± 0.5 Carex spp. Sedge species 0.3 ± ± 2.8 Clintonia borealis Blue-bead lily 0.9 ± ± 0.5 Dennstaedtia punctilobula Hay-scented fern 0.3 ± ± 2.9 Dryopteris marginalis Marginal wood fern 0.5 ± ± 3.1 Dryopteris spinulosa Spinulosa wood fern 0.5 ± ± 2.5 Lycopodium lucidulum Shining clubmoss 0.1 ± ± 0.1 Maianthemum canadense Canada mayflower 0.8 ± ± 0.1 Medeola virginiana Indian cucumber 0.1 ± ± 0.1 Monotropa uniflora Indian pipe ± 0.1 Osmunda claytonia Interrupted fern 0.1 ± ± 0.04 Panicum spp. Panic grass 0.3 ± ±

20 Table 9. Continued Common name Herb/Fern Polystichum acrostichoides Christmas fern 0.2 ± ± 0.5 Polygonatum biflorum Smooth Solomon s seal 0.4 ± ± 0.02 Polygonum cilinode Fringed bindweed 3.3 ± ± 7.0 Polypodium vulgare Common polypody 0.2 ± ± 2.8 Smilacina racemosa False Solomon s seal 0.4 ± ± 0.5 Solidago spp. Goldenrod species 0.3 ± ± 2.8 Streptopus amplexifolius Twisted stalk 0.4 ± ± 0.1 Thelypteris noveboracensis New York fern 0.1 ± ± 0.5 Trientalis borealis Starflower 0.8 ± ± 0.1 Trillium spp. Trillium species 0.3 ± Viola spp. Violet species ± 0.1 Shrubs Corylus rostrata Beaked hazelnut ± 0.1 Diervilla lonicera Bush honeysuckle ± 0.02 Parthenocissus quinquefolia Virginia creeper 0.3 ± ± 0.1 Rhododendron spp. Azalea species 0.3 ± ± 0.5 Ribes spp. Currant 0.8 ± ± 3.0 Rubus allegheniensis Blackberry 0.3 ± ± 0.5 Rubus occidentalis Black raspberry ± 0.6 Rubus pubescens Dwarf raspberry ± 0.1 Sambucus canadensis Common elder 0.5 ± ± 0.5 Toxicodendron radicans Poison ivy 0.1 ± ± 0.5 Vaccinium angustifolium Low-bush blueberry 0.4 ± ± 0.5 Viburnum acerifolium Maple-leaf viburnum ±

21 Hemlock (H) old-growth area: The hemlock old-growth area, located on the southwestern flank of the mountain, exhibited the least amount of change over the last 11 years, with species importance values remaining essentially unchanged (Table 1). Stem density was slightly lower (560 stems ha -1 compared to 590 stems ha -1 in 1997) and basal area was higher (67 m 2 ha -1 compared to 61.2 m 2 ha -1 in 1997). Hemlock comprised roughly seventy percent of the total stand density and basal area in this forest (Tables 1 & 10). Since 1997, only 4 hemlock trees have died along with 1 red maple and 2 of the old black birch (Table 3; Figure 8). There was no new recruitment of overstory stems and only a few hemlock saplings in this dense stand (Tables 3 & 4; Figure 9). Figure 8. Dead black birch with presence of stem fungi in the Hemlock old-growth area on Wachusett Mountain. 21

22 Figure 9. View through the Hemlock old-growth area on Wachusett Mountain, with no visible sapling layer. Seedling layer vegetation abundance remained quite low overall, except for a marked increase (1.0 to 11.6%) in striped maple near canopy gaps since 1997 (Table 11). Mountain aster was very common in the understory, averaging 16% cover, while sarsaparilla, polypody fern, and blue-bead lily (Clintonia borealis) cover ranged from 4 to 5%. Hobblebush and fly honeysuckle (Lonicera canadensis) were the only shrub species to exceed 1% cover in this area. There was no sign of the invasive hemlock woolly adelgid (Adelges tsugae) or elongate hemlock scale (Fiorinia externa) which are attacking hemlocks in other surrounding towns. 22

23 Table tree diameters within the Hemlock Old-growth area on Wachusett Mountain. Plot Species DBH (cm) Plot Species DBH (cm) 1 Black birch Hemlock Black birch Hemlock Hemlock Hemlock Hemlock Hemlock Hemlock Hemlock Hemlock Red maple Hemlock Red oak Hemlock Black birch Hemlock Black birch Hemlock Black birch Hemlock Hemlock Hemlock Hemlock Hemlock Hemlock Hemlock Hemlock 30 1 Hemlock Hemlock Hemlock Hemlock Hemlock Hemlock Hemlock Hemlock Hemlock Hemlock Hemlock Hemlock Hemlock Hemlock Hemlock Hemlock Hemlock Red maple Hemlock Red maple 39 1 Hemlock Red oak Hemlock Yellow birch Hemlock Yellow birch Red oak Hemlock Red oak Hemlock Hemlock Hemlock Hemlock Hemlock 20 2 Hemlock Hemlock Hemlock Hemlock Hemlock Hemlock Hemlock Hemlock Hemlock 37 4 Hemlock Hemlock Hemlock Hemlock Hemlock Hemlock Hemlock

24 Table 10. (Continued) Plot Species DBH (cm) Plot Species DBH (cm) 4 Hemlock Hemlock Hemlock Hemlock Hemlock Hemlock 38 4 Hemlock 33 5 Hemlock Red maple Hemlock Red oak Hemlock Red oak 37 5 Hemlock 31 4 Red oak Hemlock Red oak Hemlock Red oak 44 5 Hemlock Red oak Hemlock Red oak Hemlock Red oak 47 5 Hemlock Yellow birch Hemlock Yellow birch Hemlock Black birch 44 5 Red maple Black birch Red maple Black birch Red oak Black birch Red oak Hemlock Red oak Hemlock

25 Table 11. Mean cover (% ± S.E.) of understory vegetation in 1997 and 2008 within 20 x 20 m plots in the Hemlock old-growth area on Wachusett Mountain Species Common name Seedlings Acer pennsylvanicum Striped maple 1.0 ± ± 7.0 Acer rubrum Red maple 0.4 ± ± 0.5 Acer spicatum Mountain maple 0.3 ± ± 0.1 Betula alleghaniensis Yellow birch 0.3 ± ± 0.5 Carya glabra Pignut hickory ± 0.1 Fagus grandifolia American beech 0.2 ± ± 0.1 Fraxinus americana White ash ± 0.1 Prunus serotina Black cherry ± 0.02 Quercus rubra Red oak 1.0 ± ± 0 Tsuga canadensis Eastern hemlock 1.0 ± ± 0.4 Herb/Fern Aralia nudicaulus Sarsaparilla 0.4 ± ± 2.8 Arisaema triphyllum Jack-in-the pulpit ± 0.02 Aster acuminatus Mountain aster 1.0 ± ± 8.7 Aster divaricatus White wood aster 0.2 ± ± 0.1 Athyrium filix-femina Lady fern ± 0.1 Carex spp. Sedge species ± 0.1 Clintonia borealis Blue-bead lily 0.5 ± ± 2.8 Dryopteris marginalis Marginal wood fern 0.5 ± ± 0.4 Dryopteris spinulosa Spinulosa wood fern 0.2 ± ± 0.1 Lycopodium lucidulum Shining club moss ± 0.1 Maianthemum canadense Canada mayflower 0.5 ± ± 0.5 Medeola virginiana Indian cucumber 0.1 ± ± 0.5 Monotropa uniflora Indian pipe ± 0.1 Panicum spp. Panic grass 0.1 ± ± 0.02 Polypodium vulgare Common polypody 0.4 ± ± 2.5 Streptopus amplexifolius Twisted stalk 0.4 ± ± 0.5 Trientalis borealis Starflower 0.4 ± ± 0.1 Uvularia sessilifolia Sessile-leaved bellwort 0.5 ± ± 0.1 Shrubs Cornus canadensis Bunchberry ± 0.5 Gaultheria procumbens Wintergreen ± 0.1 Lonicera canadensis American fly honeysuckle 0.5 ± ± 0.5 Mitchella repens Partridgeberry ±

26 Table 11. (Continued) Common name Shrubs Rubus allegheniensis Blackberry ± 0.02 Rubus pubescens Dwarf raspberry ± 0.02 Vaccinium angustifolium Low-bush blueberry 0.4 ± ± 0.5 Viburnum acerifolium Maple-leaved viburnum ± 7.5 Viburnum alnifolium Hobblebush 0.3 ± ± 0.5 Discussion Since plots were originally established and sampled in 1997, these old-growth areas have experienced low to modest levels of canopy disturbance, as determined by mortality levels. Each of the hardwood dominated old-growth areas lost from 23 to 36% of their stems over this time period, resulting in a large increase in understory striped maple, mountain maple, and witch hazel (Figure 10). This was particularly evident in the Old Indian area, where several large beech (25 40 cm dbh) opened the canopy for these opportunistic understory species (cf. Nyland et al. 2006), which were already established in Beech bark disease has and will continue to shape forest dynamics in both the Old Indian and Southern Talus areas, as trees will continue to deteriorate and create additional canopy gaps over time. Yellow birch continued to establish well in the two talus areas, due to their open, rocky conditions. The old red oak community appears to be doing fine, and there was no mortality in any of the old oak stems. Based on the sapling thickets that currently exist, oak regeneration and recruitment will likely be limited until larger gaps arise. Several of the old black birch died in the hemlock stand, but as they were near the known maximum longevity for the species, this is not unexpected. Short-lived mountain ash did not fare well on the talus slope as all stems previously sampled were dead by It did not appear that major wind or ice damage had occurred in any of the stands, but both disturbance agents contributed to the mortality that did occur throughout the study area. Understory vegetation appeared to be more abundant at all areas in 2008 compared to Aster, fern, and fringed bindweed cover exhibited large increases in 2008, likely due to continued canopy openings and several recent moist growing seasons. With the exception of beech, the old-growth areas appear to be in good forest health and continue to experience understory change associated with disturbance events and natural successional tendencies. With the exception of a small amount of bittersweet (Celastrus orbiculatus) on the eastern talus, invasive plant species were absent from all old-growth areas. 26

27 Figure 10. Sapling densities of striped maple, mountain maple, and witch hazel for 1997 and 2008 within the three hardwood old-growth areas on Wachusett Mountain. 27

28 Future Recommendations In terms of future work it is recommended that plots be re-sampled at least every 10 years to help elucidate the magnitude and agents of change that influence forest dynamics in these forests. More frequent visits are recommended to search for invasive pests and pathogens. It is uncertain how the December 2008 ice storm influenced these forests, but a spring 2009 visit to each site is desirable to examine the extent of damage that may have occurred. Late summer and early fall were not ideal times to examine bird activity or nests, and if this is a desired component, sampling during late spring and early summer should be undertaken. Acknowledgements This work was supported by Wachusett Mountain Associates. I would like to thank Jeff Crowley, Don Stoddard, Dwayne Ericson, and Chuck Pernaa for logistical support and technical assistance throughout this project. Literature cited Cogbill, C.V An assessment of the historical ecology of the forests on the northeast slope of Wachusett Mountain, Massachusetts. Report prepared by Vanasse Hangen Brustlin, Inc. D Amato, A.W., D.A. Orwig, and D.R. Foster New estimates of Massachusetts oldgrowth forests: useful data for regional conservation and forest reserve planning. Northeastern Naturalist 13: Epsilon Associates, Inc Resource Management and Protection Plan for Wachusett Mountain State Reservation. Boston, MA. Foster, D.R., D.A. Orwig, and J.F. O'Keefe Old-growth forest monitoring on Wachusett Mountain. Report to the Department of Environmental Management, Commonwealth of Massachusetts. Gleason, H.A., and A. Cronquist Manual of vascular plants of northeastern United States and adjacent Canada, 2nd ed. New York Botanical Garden, Bronx, NY. Griffith, G.E., J.M. Omernik, S.M. Pierson, and C.W. Kiilsgaard Massachusetts ecological regions project. Department of Environmental Protection, Commonwealth of Massachusetts, Publication

29 Massachusetts DCR Wachusett Mountain State Reservation guidelines for operations and land stewardship. Mueller-Dombois, D., and H. Ellenberg Aims and methods of vegetation ecology. New York, NY. Wiley. Nyland, R.D., A.L. Bashant, K.K. Bohn, and J.M. Verostek Interference to hardwood regeneration in northeastern North America: ecological characteristics of American beech, striped maple, and hobblebush. Northern Journal of Applied Forestry 23: Orwig, D.A., C.V. Cogbill, D.R. Foster, and J.F. O Keefe Variations in old-growth structure and definitions: forest dynamics on Wachusett Mountain, Massachusetts. Ecological Applications 11: Orwig, D.A An evaluation of the western slope forests of Wachusett Mountain. Report submitted to the Mass. DCR, Commonwealth of Massachusetts, Princeton, MA. 20pp. Robinson, P., and R.D. Tucker A traverse across the wild unknown of north-central Massachusetts from the Bronson Hill anticlinorum to the Fitchburg Pluton. Pages In Guide book for the field trip for the 84 th annual meeting of the New England Intercollegiate Geological Conference. 29

30 Appendix A. Permanent plot photographs (2008) of Old Indian (OI), Eastern Talus (ET), Southern Talus (ST), and Hemlock (H) Old-growth Areas Within Wachusett Mountain State Reservation All photographs taken by David Orwig (Stored at Wachusett Mountain State Reservation Headquarters and with Wachusett Mountain Associates) 30