RESEARCH ARTICLE ABSTMCT: Previous qualitative surveys have suggestedthe Zoar Valley Canyon of western New York State contains a diverse tract of easternold-growth tbrest. In this first quantitative study of the site, we surveyed canopy trees >20 cm diameter at breast height (dbh) in twenty-three 30-m x 30-m quadrats on five prominent streamside terraces.We also catalogued understory trees 1-20 cm dbh in 10-m x 10-m quadratslocated within the 30-m x 30-m plots. Nineteen broadleafand two coniferous speciesexceeded 20 cm dbh and formed a multi-layered canopy. Four more broadleaf speciesoccuned only in the under- story. Thirteen species reached 80-126 cm dbh. Sugar maple (Acer saccharum Marsh.) accounted for 27.3Vcof canopy basal area and dominated the understory. Size distributions of all trees pooled and. of Canopyand shade-tolerantspecies individually, were uneven and negatively logarithmic. In contrast, shade-intoler- ant species occurred mostly in >40 cm dbh classes and were rare in the understory. Fourteen species reached 35.0-47.5 m in height in this tallest broadleaf forest yet described in the northeastern United Understory States. Increment cores from seven canopy species revealed ages of 170 to 305 years. The study area meets all objective criteria for easternold growth. Compositionof Old- Index terms: broadleaf forest, old growth, riparian forest, Zoar Valley CroMhRiparian
INTRODUCTION In this first quantitative study of Zoar Foresttn ZoarValley, Valley's woodlands,we describecanopy Since European settlementbegan, deci- and understorycomposition and structure NewYork,USA mation of the easternUnited States' on five prominentstreamside terraces, and original forest cover has been relentless. assessforest staturein terms of objective It is conservativelyestimated that >99.57o definitionsof easternold growth (e.g., Thomas P.Digginsl of pre-settlementtimber was cleared Martin 1992,Foster et al. 1996,FAO 2002, or heavily logged (Frelich 1995, Davis Frelichand Reich 2003).Subsequent stud- Departmentof Biology 1996, Kershner and Leverett 2003). As ies will quantify herbaceousflora, course YoungstownState University a result, there has emergeda popular as- woodydebris, seedling recruitment, and the One University Plaza sumptionthat easternold growth is gone, role of ripariandynamics in forestdevelop- Youngstown,OH 44555 exceptfor a few well-known "showcase" ment. Futureresearch will alsobe expanded sites.However, field surveysincreasingly to canyonslopes and ridge tops wheread- Bruce Kershner demonstratethat remnantsof old-growth ditional old growth hasbeen qualitatively State Universiw of New York at Buffalo forest, though often critically imperiled, identified (Hunt et al. 2002). York Old Growth ForestAssociation are more numerousand widespreadthan previouslyrecognized (Stahle and Chaney STUDY AREA 1994,Foster et al. 1996,Dunwiddie and Leverett1997, Davis 2003). The ZoarValleyCanyon (N 42'26', W 78' 52') is the seconddeepest vertical-walled A noteworthyrecent discovery is a diverse canyonsystem in NewYork State.encom- tract of broadleafwoodlands in New York passingthe Main and South Branchesof State'sZoar Yalley (Figure 1), a remote CattaraugusCreek (Figure lB), a tributary seriesof canyons60 km southof Buffalo to Lake Erie. The Main Branch Canyon (Kershner 1994,2000:,Hunt et al. 2002). extends I I km from its downstreamend surveyshave identified >300 ha Qualitative to where it abruptly widens into a broad of pre-settlementforest here,of which at agricultural valley upstream.The South least175 ha occurwithin the I I 82-haNew Branch Canyon is approximately 8 km York StateZoarYalley Multiple Use Area in length. The watershedof Cattaraugus (Hunt et al. 2002). Historical aerial pho- Creek totals 1430 km2, >807o of which tographsof this canyon (Fairchild Aerial lies upstreamof Zoar Valley.Typical low- Surveyslnc. 1929)reveal dense stands of flow dischargebelow the confluenceof largetrees blanketing streamside terraces, the two branchesof CattaraugusCreek is slopes(other than cliff faces),and some <5.0 m3/s.but floodscan exceed300 m3/s I Corresponding author: adjacentuplands, corresponding to today's (U.S. GeologicalSurvey 2004). Depth of tpdiggins @ysu.edu suspectedold growth. The conservation the Main Canyon rangesfrom 70 to 130 statusof thispublicly ownedsite has not yet m, while the South Canyon reaches100 been designated,and has beenthe source m. Canyon slopesvary from 60-90' bare Natural Areas Joumal 25:219 227 of debatebetween environmentalists and rock cliffs alone outside bendsto 30-60" stateofficials.
Volume25 (3),2005 NaturalAreas Journal 219 d^t vrrsru- ' New York Buffalo State
ZoarValley CattaraugusCreek,
500m Canyonrim I'. (335-408ma.s.1.)
/
lJ-!l{!rr1;;41\ Riverbed(262-274 m a.s.l.)
,,,,,,,,,'-y'
of B) Detail of cattaraugus creek in vicinity of Zoar valley canyon' c) Detail Figure l. Location and detail of zoarvalley study site. A) Regional location. boundaries of closed'canopy forest on the terraces' Numbers denote study area showing terraces, riverbed, and canyon rim. Solid dark lines are approximate locations of survey quadrats.
resentingportions of the study area, the forestedslopes on inside bends.Bedrock METHODS 30-m x 30-m quadrats(Figure lC) were is primarily late Devonian shalesof the of 2002, not locatedentirely randomly.Instead, each Canadawaygroup (Hunt et aI.2002). BetweenAugust and Novembet walking all canopytrees >20 cm diameterat breast quadrat was generally sited by identifiedto l0-50 m downstreamfrom the preceding Through much of the canYon system' height (dbh, ar 1.31 m) were twenty- quadrat. Starting point and orientation pronouncedmeanders have producedflat speciesand measuredfor dbh in tbr were then establishedby blindly tossinga terracesdownstream of each inside bend three30-m x 30-m quadratsaccounting -16%o markerflag. This procedureapproximated (FigurelC). This studycentered on thefirst of the total areaofthe five terraces. 2003' understory a stratifiedsampling design,with similar five terracesin the Main Canyonabove the DuringApril andMay of cataloguedin proportionsof each terracesurveyed. confluence(Figure 1C), totaling 12.7 ha. trees 1-20 cm dbh were quadrats,each Previousobservations had suggestedthat twenty-threel0-m x l0-m 30-m x 30-m Descriptivevariables quantifi ed included: here the broadleafforest (Figure 2) is the randomly located within a ( 1) densityof trees>20 cm dbh, (2) mean most diverseand the tallestin the canyon' canopy-treequadrat. dbh of trees >20 cm dbh, (3) total basal exceeding35 m in height(Eastern Native under-rep- area(including understory) at breastheight Tree Societv 2004). To avoid overlapping and/or
Volume25 (3),2005 22O NaturalAreas fournal ,ii i; ! .t'rj ,:$r
Figure 2. View of eastern edge of Skinny Dip Terrace where stream erosion has exposed canopy architecture. View extends -100 m from eastern tip of terrace to quadrat #2 (Figure 1). Note B. Kershner for scale, adjacent to 43-m tall Liriodendron tulipifura. for eachspecies and tbr the entirequadrat, representingseven canopy species (listed ing the study terraces.All other canopy (.1)species richness, (5) speciesdiversity in Results).Several T. canadensis<40 cm specieswere representedby multiple in- (Shannon-WeinerH') in termsof basalarea, dbh were cored,but all othertrees directly dividuals. and (6) percent shade-tolerantspecies in aged were >60 cm dbh. This preliminary terms of basal area. Shade-tolerantspe- samplingof canopytree ages was not in- Fifteen tree speciesoccurred in the un- cies (definedby Burns and Honkala 1990) tendedto generateage/size relationships. derstory(Table 2). Acer pensylvanicuntL. include Acer rubrum L., Acer saccharum (stripedmaple), Cornusflorida L. (flower- Marsh., Fagus grandifulia Ehrh., Tilia ing dogwood). Hamamelis virginiana L. RESULTS wnericano L., and Tsugacanadensis (L.) (witch hazel), and Carpinus caroliniana Carr. (red maple, sugar maple,American Walt. (American hornbeam)were found beech, American basswood,and eastern Speciesrichness and diversity only in the understoryduring the present hemlock, respectively). study. The woody shrub Lindera benzoin Twenty-onespecies exceeded 20 cm dbh (L.) Blume (spicebush)also occurred with- In addition to the quadrat surveys, we within the study area,and contributedto in the study area,but we did not include it identified all trees >80 cm dbh through- the mid- and overstories (Table l). Of in countsof understoryspecies more often out the five study terraces.Also, heights these,Magnolia acuminataL. (cucumber classifiedas trees. of notable trees were triangulated,with magnolia), Ostrya virginiana (Mill.) K. distanceto apex measuredusing either a Koch (eastern hop hornbeam), Robinia Speciesrichness in quadratsranged from BushnellYardage Pro 250 or a Nikon 400 pseudoacaciaL. (black locust), andPinus threeto 11 species.Richness pooled within laser range finder, and angle of elevation stobus L. (easternwhite pine) were rep- terraces,including speciesencountered measuredusing a Suunto inclinometer resentedby singlecanopy trees within the outsidequadrats. ranged from l6 species (EasternNative Tree Society 2004). area surveyed (Table 1;, although each on Knife Edge Terraceto 22 specieson was either more abundant elsewherein Elm Terrace (Table 3). Within-quadrat We useda 20-inchSuunto increment borer ZoarYalley or occurred in the understory. diversity ranged from 0.93 to 1.92, with to determineages of a non-systematicsam- Robiniapseudoacacia, which is expanding the highestterrace mean values on Hidden pling of 17 living and fallen trees,mostly from its naturalrange (Burns and Honkala and Skinny Dip Tenaces(Table 3). Across on the two terracesclosest to the iunction. 1990), has colonized floodplainsborder- the entirestudy area, species diversity was
Volume25 (3),2005 NaturalAreas Journal 221 Acer rubrum L. (red maple) l.l 36.3 88 Acer saccharum ldarsh. (sugarmaple) 21.3 38.9 100 Betula alleghaniensrsBritton (yellow birch) 1.7 30.8 69 Carya cordifurmis (Wangenh.) K. Koch (bittemut hickory) 4.1 41.5 62
Carya ovata (Mill.) K. Koch (shagbarkhickory) 0.1 29.g6 +l Fagus gandifolia Ehrh. (American beech) 13.6 35.4 t20 Fraxinus americana L. (white ash) 7.6 42.3 88 Juglans nigra L. (black walnut) 1.8 37.8 90 Liriodendron tulipifera L. (tulip tree) 16.5 47.5b 103" I u Magnolia acuminata L. (cucumbermagnolia) 18.5 26
Ostrya virginiana " (Mill.) K. Koch (hop hornbeam) z l.J 20 Pinus stobus "L. (white pine) 24.7 46 Platanus occidentalis L. (American sycamore) 5.3 46.6 lt'7 Populusdeltoides Bartr. Ex. Marsh. (eastemcottonwood) 1.7 39 126 Prunus serotina Ehrh. (black cherry) 0.9 36.4 76
Quercus ntbra L. (northem red oak) L.J 40 90
Robiniapseudoacacia " L. (flack locust) 27.7 JI Tilia americana L. (American basswood) 7.6 39.1 90 Tsugacanadersls (L.) Can. (easternhemlock) 5.8 3s 84 Ulmusamericana L. (American elm) 0.4 29.7" 82" Ulmus rubra Muhl. (slippery [red] elm) 2.1 36.7 81
u Only one canopyspecimen in study area- not in a quadrat. b Greatestheisht and dbh occur in sametree.
2.29.and evenness (i.e., observed diversity/ ash1,Liriodendron tulipiferu L. (tulip tree), but could be found alons edgesand in a maximum possiblediversity at observed and T. americana occurredin at least 15 few treefall gaps. speciesrichness) was 0.77. quadrats,and exceeded50/ha in at least one quadrat each.Tsuga canadensiswas DBH and basal area abundantprimarily on Knife EdgeTerrace, Tree density whereit exceeded50/ha in threequadrats. Within-quadratmean, dbh of canopytrees Thesesix speciescollectively accounted Within-quadratdensities of trees>20 cm >20 cm rangedfrom 3 | to 54 cm, with ter- for 85.47oof trees>20 cm dbh. dbh rangedfrom 100 to 31l/ha. Means racemeans fiom 38 cm on HiddenTerrace among quadratson each terrace ranged to 48 cm on Skinny Dip Terrace(Table 3). Understorytrees were dominatedin terms from l'72/haon BasswoodTerrace to 2781 Total basal area in quadratsranged from of abundanceby A. saccharum(51.87o) ha on HiddenTenace. Acer saccharumwas 24.80 to 55.03 m2ltra.and exceeded30 andF. grandfolia (29.77o).These species the most abundantcanopy specieswithin m2lha in all but three quadrats.Terrace were negativelycorrelated (R = -0.479,p the study area, accountingfor 38.07cof meansranged from .15.00m2/ha on Hidden < 0.05),and seldomcommon in the same all trees>20 cm dbh. It occurredin all 23 Terraceto 45.66m2lha on Skinny Dip Ter- 10-m x l0-m quadrat.Shade-intolerant quadrats,and at > lOOftrain sevenquadrats race (Table3). Acer saccharumexceeded species were rare in the closed-canopy distributedamong all five terraces.Fagus 10 m2lha basal area in nine quadrats, understory(- I 7oof treeswithin quadrats). grandifulia,Fraxinus americana L. (white distributed among all five terraces,and
222 NaturalAreas Journal Vofume25 (3),2OO5 the importantbiomass contribution of 40- Table 2, Species'percentcontribution to understory (stems1-20 cm diameter at breast height) in terms of stem abundance.A dash (-) indicates7o abundancecould not be calculatedfor speciesnot 80-cm dbh trees. occurringin surveyquadrats. Sizedistributions of shade-tolerantspecies generallyreflected that of all canopytrees. % Understory The distribution of A. saccharum across Species STEMS the entire study areawas also unevenand Acer pensylvanicum" L. (stripedmaple) negativelylogarithmic (Figure 4,\. R2 = 0.977), with trees <30 cm dbh abundant Acer nrbmm L. (redmaple) 0.4 on all terraces.Likewise, F. grandifolia Acer saccharum Marsh. (sugarmaple) 51.8 displayed a negative logarithmic size IA Betula allegheniensisBritton (yellow birch) l.a distribution(Figure 48. R2= 0.941).Size (Figure Carpinus caroliniana Walt. (American hombeam) 2.9 distributionsof T. canadensis 4C) andT.americana (Figure 4D) wereuneven Cornusflorida " L. (flowering dogwood) but not as distinctly logarithmic. Fagns grandifolia Ehrh. (American beech) 29.7 Frarinus americana L. (white ash) 0.1 Size distributionsof shade-intolerantspe- cies differed from thoseof shade-tolerant Hantamelisvirginiana L. (witch hazel) 0.7 trees, being generally shifted into larger Liriodendron tulipifera L. (fulip tree) 0.4 size classes.Distributions of L. tulipifura Magnolia acuminatau L. (cucumbermagnolia) and F. americrrnaacross the study area were uneven. but only modest numbers Ostn'a virginiana (Mill.) K. Koch (hop hornbeam) J.O were found in <40-cm dbh classes(Figure (American Tilia americana L. basswood) t.4 5,Aand B). Likewise, the pooled distribu- Tsugacanadensis L. (eastemhemlock) A1 tion of six lessabundant intolerant species (listedin Figure5 caption)was shifted into (Jlmusrubra Muhl. (slippery [red] elm) 0.7 >40-cmdbh sizes(Figure 5C). o Not found in quadrats. Large canopy trees
- accountedfor 27.37oof total basal area. Canopy tree size distribution Trees>75 cm dbh one suggestedeastern Fagus grandifulia, F. americttna, L. tulip- "large tree" standard(Martin 1992,Hardt - ifera, Platanusoccidentalis L. (American Size distributionof all trees>20 cm dbh. and Swank 1997,FAO 2002) occurred sycamore),T. americana, and UlmLts rubra acrossthe entire study area,was uneven at a densityof 11.1/haacross the study "giants" Muhl. tredelm,1 all exceededl0 m2Aain andnegatively logarithmic through 120 cm area.Our surveystor canopy >80 at least one ouadrat. dbh (Figure3,A, R2 = 0.970).Expressing cm dbh indicatedl3 speciesreached this size distribution in terms of basal area size (Table 1). The largestindividuals of insteadof abundance(Figure 38) reveals five species(Populus deltoides Bartr. Ex. Marsh. [easterncottonwood], F. grandfo-
Table 3. Mean values of canopy descriptor variables (t standard error) for each terrace. Tree density and mean dbh for trees >20 cm dbh, All other vari- ables include understory trees l-20 cm dbh. Shannon-Weiner diversity index (H') and percent shade-tolerant speciesgiven in terms of basal area. Shade tolerant species constitute Acer rubrum, Acer saccharum, Fagus grandfolia, Tilia americana, andTsuga canadensis.
Canopytrees >20 cm dbh All trees>l cm dbh (includesunderstory) Basalarea Species % Shade Terrace Densiry$er ha) Mean dbh (cm) (m2/ha) richness Diversity (H') tolerant Basswood 161+ 25 47+4 36.5+ 3.95 t7 1.37+ 0.09 67.6+ 8.8 Hidden 278+0 38+2 35 + 2.6 18 1.84+ 0.02 43.4+ 15.5 Elm 192+ 10 44+4 38.2+ 3.13 22 1.5+ 0.12 46.4t 6.8 Ikife Edge 229+ 24 42+7 42.4+ 4.63 16 1.34+ 0.ll 84.2+ 3.6 Skinny Dip ))'7 + )R 48+8 45.7t 3.1 17 1.7+ 0.13 38.6+ 5.4
Volume25 (3),2005 NaturalAreas Journal 223 severalmesic ecotypes - including beech- 70 maple,maple-basswood, hemlock-northern OU hardwood, rich-mesophytic,and eastern riverfront forest (Meadows and Nowacki Es0 1996, Edinger et al. 2002) - but they do b40 o- not fit neatly into any single ecotype. u, 30 o Zoar Valley's woodlandsmay representa E20 northern,glaciated variant of the diverse F mixed-mesophyticor "cove" forest(Braun 10 1938, Gordon 1 940, Greenberg et al. 1997). 0 TheAppalachian mixed-mesophytic forest '105 25 35 45 55 65 75 85 95 115 includes indicator speciesnot found in upstateNew York. and this ecotype is gen- 7 erally not recognizedas far north as Zoar A (6 Valley(Kuchler 1964, Muller 1982).How- ever, tree speciesrichness, diversity, and N-5 E evennessrevealed by the presentstudy are I in the rangeof thoseof mixed-mesophytic LJo (E andcentral hardwood forests (Martin 1992, Ez Hardt and Swank 1997, McCarthy et al. o G 2001, Zaczek et aI. 2002), and are notably 1 c0 higherthan expected in northernhardwood 0 ecotypes(Edinger et al.2002). 25 35 45 55 65 75 85 95 105 115 Giventhe undetermined conservation status Sizeclass (DBH in cm) of theZoar Valley State Multiple UseArea, critical evaluationof foreststature. includ- Figure 3' Size class distribution of all canopy trees >20 cm diameter at breast height (dbh), across the ing identificationof old growth,is essential. entire study area, in terms of abundance (A) and basal area (B). Ttee size (dbh) axis labels denote mid- FAO (2002) lists 105verbatim old growth points (p of size intervals. Significant R2 < 0.05) in panel A for negative logarithmic curve. definitions proposed by academic, gov- ernmental, environmentalist,and timber lia, P. occidentalis,L. tulipfera, A. saccha- legheniensis and T. canadensis,formed a managementparties. Eighty-six of these rum) exceeded1.00 m dbh (Table l). mid-story that does not generallyexceed are not obvious repetitions,and may be 30 m. Tsugacanadensis was a prominent broadlyapplicable to easternUnited States componentof the overstoryonly on Knife woodlandson favorablesites (i.e.. where Vertical development Edge Terrace. fire, weather,soil conditions,etc., do not constrain tree size and/or age). Among The tallest individuals of five species(P these,the mostfrequently cited old growth occidentalis, L. tulipfera, Can-a cordi- Canopy tree ages indicatorsare: formis (Wangenh.)K. Koch [bitternut 1) Presenceofold trees(31 hickory], F. americana,Quercus rubra L. Six T. canader?slscored ranged from 209 referencesin FAO [northern red oak]) exceeded40 m, and to 305 years of age. The oldest of these [2002]) 2) Minimal evidenceof human nine more specieshave been confirmed was only 35 cm in dbh. Three A. sac- disturbance(27) above35 m (Table 1).At the time of writ- charumranged from210-242 years.Two 3) Abundanceofsnags and coarse ing, individualtrees of 13 specieswere the L. tulipifera were 185 and 200 yearsold, woody debris(23) tallest ever measuredin New York State. and two Q. rubra were 180and 190years. 4) Late successional,or Canopy stratificationwas evident on the Single specimensof fi grandifolia and T. ecologicallymature stands (19) Zoar Yalley terraces,with major species americana were 220 and 170 years old, segregatinginto verticalzones. The largest respectively.A fallen P. occidentalis on 5) Unevencanopy tree sizeand/or L. tulipifera andP. occidenfa/iswere nearly Elm Terrace,80 cm dbh, exceeded190 agedistribution (16) always emergentsat >40 m, overtopping yearsof age. 6) High diversity of largecanopy (14) neighboring trees by 2-10 m. A variable trees assemblageof most other speciesformed 7) Canopystructured in multiple DISCUSSION a broadly defined overstoryof 30 to >40 layers(14) m. Slender individuals (<30 cm dbh) of 8) Presenceoftrees largefor The closed-canopyforests on ZoarValley's overstoryspecies, and most of the B. al- speciesand location(8) streamterraces display characteristicsof
224 NaturalAreas Journal Volume25 (3),2005 Any such criteria should be viewed not as rigid thresholdsthat might lead to summary rejection of a site, but as de- JC scriptive featuresexpected in many, but 30 not all, old-growth woodlands.We agree 25 with the contentionof Frelich and Reich (2003) 20 that field indicatorsof old growth are most valid when they are free from 15 arbitrary human size and time scales,but 10 insteadreflect natural ecological processes 5 and disturbanceregimes. Together with ecotype-specificdefinitions proposedby 0 the U.S. Forest Service'sNational Old Growth Task Group (e.g., Meadows and
8 Nowacki1996, Greenberg et al. 1997)and characteristicscited in peer-reviewedlitera- 7 ture (e.g.,Hough and Forbes1943, Martin 6 1992,Frelich 1995,Foster et al. 1996), 0 suchindicators provide one framework for 4 evaluatingthe Zoar Valley study area.
On the ZoarYalley terraces,old treeswere
G1 abundantin thecanopy. All treescored thus -c LU far,including both shade-tolerantand intol- o 65 75 85 95 105 115 erant species,exceeded 170 yearsof age. @ Also, trees>80 cm dbh almost uniformly o O1t L displayedqualitative old-growth features l- C. Isuga consistentwith agesof 150 yearsor older 10 ""r";:; (Kershnerand Leverett 2003). These in- clude species-specificdeeply furrowed and/orbalding bark, pronouncedroot but- 6 tresses,and swollen trunk bases,and, for broadleaf species,irregular crowns with stoutbranches that initiate aboveone-half 2 thetree's height. Some shade-tolerant trees 0 as modest as 40 cm dbh displayedthese 105 115 signs of advancedage.
7 Evidenceof intentionalhuman disturbance 6 on the surveyed terracessince first arrival of Europeansettlers in nearby Gowanda c. 1810 was absent.No remnantsof cut 4 stumpswere detectable,and no individu- 3 als of prolific stump-sprouters(Burns and Honkala 1990) such as Prunus serotina (black 1 Ehrh. cherry), A. rubra, F. ameri- cana,or Q. rubra possessedmultiple stems. 0 A numberof speciesshown to aggressively 45 55 65 75 85 95 105 115 recruit after logging (Hough and Forbes Sizeclass (DBH in cm) 1943, Orwig and Abrams 1999) were in the study area either absent(Betula lenta L. [black birch]) or constituted<27o of canopybasal area (A. rubrum, P. serotina, P. strobus, rubra). With 13 species Figure 4. Size class distribution of shade-tolerant canopy species >20 cm diameter at breast height (dbh), Q. across the entire study. Tiee size (dbh) axis labels denote midpoints of size intervals. R2 for negative exceeding80 cm dbh, it seemsunlikely logarithmic curve shown where significant (p < 0.05). that past harvesthas restrictedtheir size
Volume25 (3),2005 NaturalAreas Journal 225 Accumulation of deadwoodin Zoar Val- A. Liiodendron tulipifera ley has not yet been quantified,but large snagsand downed logs were conspicuous. 41 especially where >80-cm dbh canopy 31 trees are abundant.Coarse woody debris ^l may unfortunatelybe overabundantwhere beech-barkdi sease(Crr-ptococcus fagisuga 1 scalewith associatedNectia spp.fungus) 0 is evident.This infestationhas claimed a 95 105 115 numberof sizableF. grandfolia, including one that measured144 cm dbh.
Unevenand/or negatively logarithmic dbh o distributionsfor Zoar Valley canopytrees L q) altogether,and for major shade-tolerant a long-term that c) species,suggest recruitment o) L often typifies old growth (Lorimer 1980, F Martin i992, McCarthyand Bailey 1996). Shade-intolerantspecies were uncommon
95 105 115 <30-cm dbh. so recent systematicdistur- banceappears unlikely. An abundanceof shade-intoleranttrees 50-90 cm in dbh 7 (e.g.. t. tulipifera on Skinny Dip and b Elm Terraces)may suggestdisturbances 5 in the more distant past (Lorimer 1980, 4 Muller 1982,Busing 1995), but logging is
J not indicated,for reasonsoutlined above. 2 Alternatively,the presenceof largeintol- 1 erant treesmay reflectpatterns of erosion 0 and depositionof the Zoar Valley terraces 45 55 65 75 85 95 105 115 that could promote a mosaic of succes- sionalstages. An obvious.though not yet Sizeclass (DBH in cm) quantified.abundance of youngintolerant trees in Zoar Valley's nascentfloodplain
Figurc 5. Size class distribution of shade-intolerant canopy species >20 cm diameter at breast height, woodlands,including thosebordering the across the entire study area, "Other shade-intolerants" for which data are pooled in panel C constitute studyterraces, suggests the plausibility of Carya cordiformis, Juglans nigra, Platanus occidentalis, Populus deltoides, Prunus serotina, and,Quercus this hypothesis. rubra,Tree size (dbh) axis labels denote midpoints of size intervals, The woodlandsdescribed by the present distributions. Many large canopy trees biomass/diameterregression derived by study are highly varied and diverse,and possessstraight, branch-free trunks of high Brown et al. (1997),as much as 33% of collectively meet all objectivecriteria for commercial grade, and valuable Juglarts Zoar Valley's above-groundbiomass is in easternold growth forest.We agreewith the nigra L. andP. serotinnof exemplarysize >70-cnrdbh classes,which Brown et al. contentionof Hunt et al. (2002)that con- and form offer a compelling argument (1991)consider an indication ofun-logged servationo[ the intactriparian ecosystem against even selective timber extraction old growth. of Zoar Valley should receivethe highest (Braun 1938,Martin l992,McCarthy and priority. Zoar Yalley would then serve as Bailey 1996). Vertical development of the stratified a legacy for passiveenjoyment by future canopyinZoar Valleyis unrivaledamong generationsand as an invaluable living Zoar Valley's abundanceof trees>75 cm broadleaf woodlands in the Northeast laboratoryfor non-intrusivestudy ofnative dbh ( I l.l/ha) meetsold-growth standards (Eastern Native Tree Society 2004). ln woodlandsonce thought inexhaustible. suggestedby Martin (1992) and Green- defining easternmixed-mesophytic old ACKNOWTEDGMENTS berg et al. 1997) for mixed-mesophytic growth, FAO (2002) cite canopy heights woodlandsin southeasternKentucky and of 30-40 m and "complex vertical devel- Partial support for this project was pro- the SouthernAppalachians, respectively, opment" - both notable attributesof the vided by the University ResearchCouncil >4' latitude to the south.Accordine to a Zoar Yal\ey terraces.
226 NaturalAreas Journal Volume25 (3),2005 of YoungstownState University.Many Edinger.G.J., D.J. Evans, S. Gebauer, T.G. How- sis. New York Natural Heritage Program, peopleassisted in the collectionof data, ard, D.M. Hunt, and A.M. Olivero. 2002. Albany. includingR. Leverettof the EasternNative EcologicalCommunities of NewYork State. Kershner,B.1994. SecretPlaces - ScenicTrea- 2nded. (A revisedand Tree Society; J. Horowitz and F. Breglia expandededition of sures of WesternNew York and Southern CarolReschke's Ecological Communities of of the New York Old Growth ForestAs- Ontario. Kendall/Hunt Publishers,Dubuque, NewYork State).NewYork NaturalHeritage Iowa. sociation;C.Chuey, C. Willis, C. Johnston, Program, New York State Department of Kershner,B. 2000. Guide to the Ancient For- J. Isaac,B. Kale, J. Atwood, T. Delia, E. EnvironmentalConservation, Albany. estsof Zoar Valley Pfiel, A. Draa, K. Lupton, and G. Shook Canyon.New York Old EasternNative Tree Society. 2004. Tallest Trees Growth ForestAssociation. Buffalo. of Youngstown State University; and J. in the East. Available online
Volume25 (3),2005 NaturalAreas journal 227