northern hardwood forest formation - vt fish & …...northern hardwood forest formation / 131...

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Northern Hardwood Forest Formation Forests of Widespread Distribution in Vermont’s Moderate Climate Areas he Northern Hardwood Forest Formation of Vermont is part of a broad forest region where sugar maple, American beech, yellow birch, and hemlock predominate. This region ranges from the upper-Midwest states of Wisconsin and Michigan east to Maine and southeastern Canada. The Northern Hardwood Forest Formation makes a transition to the Spruce-Fir-Northern Hardwood Forest Formation in colder areas, to the north and at higher elevations. It makes a transition to the Oak-Pine- Northern Hardwood Forest Formation where warmer and/or drier conditions prevail to the south and also locally on south-facing dry knobs or regionally, as in the Champlain Valley. The climate of the Northern Hardwood Forest Formation is cool-temperate and moist. Summers are warm and winters can be severely cold. Average annual tempera- tures range from 37º to 52ºF. Annual precipitation ranges from 35 to 50 inches in most areas and is distributed more or less evenly throughout the year. Average annual snowfall is about 100 inches. Growing season length averages 100 to 110 days. The Northern Hardwood Forest Formation is characterized by soils that are neither extremely dry nor extremely wet. Soil moisture varies with parent material, topography, and depth to a restricting layer. Soils are mostly developed from glacial till, and bedrock is close to the surface in some areas. Sandy or gravelly soils derived from glacial outwash are found only locally, as are soils formed in lake bed deposits. Bedrock varies from granite to schist or limestone. Broad-leaved deciduous trees are the dominant life form in this forest formation. These trees lose their leaves each fall and are almost completely dormant for the winter months, when cold temperatures and short days minimize the benefit a tree might gain from photosynthesis. This broad-leaved deciduous habit is in striking contrast to the needle-leaved evergreen life forms that prevail in Spruce-Fir Forests, where the growing season is so short that it is necessary to photosynthesize whenever there is a chance and the cost of producing an entirely new set of leaves each year is simply too great. It is also in striking contrast to the broad-leaved evergreen habit of the moist tropics, where there is no season of dormancy and therefore no need to shed all leaves for a number of months. Forests of the Northern Hardwood Forest Formation have several distinctive characteristics. Fall colors are one of the most remarkable. The northeastern United States has arguably the most striking display of fall foliage in the Americas, a display that attracts millions of tourists each autumn. The only other place in the world that features a comparable show is eastern Asia, where the climate is much like that of the northeastern United States. There are places in Japan that could easily be mistaken for New England, with closely related species, similar forest structure, and equally striking fall colors. T Northern Hardwood Forest Formation / 129

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Page 1: Northern Hardwood Forest Formation - VT Fish & …...Northern Hardwood Forest Formation / 131 Sugar maple, beech, yellow birch, and hemlock are the most abundant species in the Northern

Introduction / 129

Northern HardwoodForest FormationForests of Widespread Distribution inVermont’s Moderate Climate Areas

he Northern Hardwood Forest Formation of Vermont is part of a broad forestregion where sugar maple, American beech, yellow birch, and hemlockpredominate. This region ranges from the upper-Midwest states of Wisconsin

and Michigan east to Maine and southeastern Canada. The Northern Hardwood ForestFormation makes a transition to the Spruce-Fir-Northern Hardwood Forest Formation incolder areas, to the north and at higher elevations. It makes a transition to the Oak-Pine-Northern Hardwood Forest Formation where warmer and/or drier conditions prevail tothe south and also locally on south-facing dry knobs or regionally, as in the ChamplainValley. The climate of the Northern Hardwood Forest Formation is cool-temperate andmoist. Summers are warm and winters can be severely cold. Average annual tempera-tures range from 37º to 52ºF. Annual precipitation ranges from 35 to 50 inches in mostareas and is distributed more or less evenly throughout the year. Average annualsnowfall is about 100 inches. Growing season length averages 100 to 110 days.

The Northern Hardwood Forest Formation is characterized by soils that are neitherextremely dry nor extremely wet. Soil moisture varies with parent material, topography,and depth to a restricting layer. Soils are mostly developed from glacial till, and bedrockis close to the surface in some areas. Sandy or gravelly soils derived from glacialoutwash are found only locally, as are soils formed in lake bed deposits. Bedrock variesfrom granite to schist or limestone.

Broad-leaved deciduous trees are the dominant life form in this forest formation.These trees lose their leaves each fall and are almost completely dormant for the wintermonths, when cold temperatures and short days minimize the benefit a tree might gainfrom photosynthesis. This broad-leaved deciduous habit is in striking contrast to theneedle-leaved evergreen life forms that prevail in Spruce-Fir Forests, where the growingseason is so short that it is necessary to photosynthesize whenever there is a chanceand the cost of producing an entirely new set of leaves each year is simply too great.It is also in striking contrast to the broad-leaved evergreen habit of the moist tropics,where there is no season of dormancy and therefore no need to shed all leaves for anumber of months.

Forests of the Northern Hardwood Forest Formation have several distinctivecharacteristics. Fall colors are one of the most remarkable. The northeastern UnitedStates has arguably the most striking display of fall foliage in the Americas, a displaythat attracts millions of tourists each autumn. The only other place in the world thatfeatures a comparable show is eastern Asia, where the climate is much like that ofthe northeastern United States. There are places in Japan that could easily be mistakenfor New England, with closely related species, similar forest structure, and equallystriking fall colors.

T

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The fall colors result from the loss of greenpigment, chlorophyll, as the trees slow downtheir photosynthesis and prepare to enterdormancy. When the chlorophyll is gone,previously masked pigments such as xantho-phylls and carotenoids become visible. The treesof the Northern Hardwood Forest Formation,sugar maple and red maple in particular, are fullof colorful pigments. The weather here in thefall – cool nights with plenty of moisture –provide the perfect conditions for the gradualexposure and heightening of color.

Spring wildflowers are another strikingcharacteristic of the Northern Hardwood ForestFormation, as they are in the Central Hard-woods, the large forest region that dominatesthe Southern Appalachians. Most of the herba-ceous plants in these forests are long-livedperennials, a life form that is well suited tostable systems where catastrophic disturbanceis rare. Perennials store significant amounts offood in their roots, tubers, or bulbs. Most of thisfood is manufactured in the early spring, andsome in the fall, when leaves are off the trees

and sunlight reaches the forest floor. In fact, many of these perennials, like wild leeks,Dutchman’s breeches, and trout lily, photosyn-thesize only in early spring, going partially orcompletely dormant for the remainder of thesummer. This is a good strategy. When treesare fully leafed out, they intercept as much as99 percent of the light that strikes the canopy,leaving the forest floor in relative darkness.

Some forest communities in the NorthernHardwood Forest Formation are dominatedby evergreens, in particular eastern hemlock.Hemlock Forests have very sparse herb layersbecause there is essentially no good season forphotosynthesis on the forest floor. It is dark allthe time. The few herbs that can grow in thesedark forests, like partridgeberry and winter-green, are evergreens that photosynthesizeat a slower rate but for a longer period.Saprophytes such as Indian pipes are alsocommon in Hemlock Forests.

Patterns in the distribution of foresttypes in the Northern Hardwood ForestFormation can be seen in this springview of the Northern Green Mountains.

The Northern Hardwood Forest Formationis home to black bear. The nuts of Americanbeech, an abundant tree here, are afavorite fall food of black bear.

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Sugar maple, beech, yellow birch, and hemlock are the most abundant species in theNorthern Hardwood Forest Formation but other common species, roughly in order ofabundance, include white ash, basswood, red maple, white pine, red oak, red spruce,and balsam fir. White ash and basswood, both somewhat shade-intolerant, are mostcommon in areas of enrichment, or in moist areas created by shallow impermeablelayers in the soil, or in areas where mineral-rich bedrock or till influences soil chemistry.Red maple (most commonly a wetland species in Vermont) is also present in nutrient-poor upland areas, particularly if there has been some disturbance in the past. It isshade intolerant, and so does not generally persist in closed upland forests. White pineis most common where there has been some disturbance, but can persist naturallywhere soils are well drained. Red oak reaches its northern limit here. It is most commonon dry, warm sites but can also appear as a successional tree on moist sites.

Red spruce and balsam fir are most common in cooler, moister areas with shallowsoils.

Northern Hardwood Forest FormationNatural Communities

Read the short descriptions that follow and choose the community that fits best.Then go to the page indicated to confirm your decision.

Northern Hardwood Forest: A variable community, generally dominated bybeech, sugar maple, and yellow birch. Go to page 132.

Rich Northern Hardwood Forest : High diversity hardwood forests of sugarmaple, white ash, and basswood, with excellent productivity and high herb diversity.Maidenhair fern, blue cohosh and wood nettle are characteristic herbs. Go to page 138.

Mesic Red Oak-Northern Hardwood Forest: Northern hardwood species and redoak codominate. Mostly on south-facing slopes in the northern parts of Vermont.Go to page 142.

Hemlock Forest: Dominated by hemlock, often on shallow soils. Go to page 145.Hemlock-Northern Hardwood Forest: Mixed forest of hemlock and northern

hardwoods. Go to page 148.Northern Hardwood Talus Woodland: Characteristic species are mountain maple,

Appalachian polypody, red-berried elder, and Northern Hardwood species. Go topage 150.

HOW TO IDENTIFY�

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ECOLOGY AND PHYSICAL SETTINGThis is Vermont’s most abundant

forest, the forest that truly characterizesthe Northern Hardwood Forest Forma-tion. It blankets hills in every biophysicalregion of the state and creates a back-ground setting, a so-called matrix, for thesmaller communities – the swamps, fens,outcrops, and meadows. It is a broadlydefined community type, encompassinga great deal of variation. But there aresome things that all expressions of thiscommunity share in common. Beech andyellow birch are almost always present.Sugar maple is usually present, but insome cases red maple is more prominent.Most soils are formed in ablation or basaltill and are loamy, cool, and moist. Theseforests are found at elevations below2,700 feet on gentle to steep slopes.

Northern Hardwood Forests are onlyuncommon in the lower elevations of theChamplain Valley, where clay and sandprevail as parent materials, and in otherplaces where soils are specialized. Suchplaces include alluvial soils along streamsand rivers, glaciofluvial deposits of sandor gravel terraces, rocky or bedrock-controlled soils, and wet soils in depres-sions. Vermont’s warmest climate areasalso have other forest communities.

The variations within this communitytype stem from differences in climate,slope, landscape position, chemistry ofthe underlying bedrock and till, stoniness,depth to basal till or bedrock, and pastland use. Upper elevation NorthernHardwood Forests have lower overalldiversity, smaller trees, and sometimeslush fern populations. Forests on convexslopes tend to have more beech and redmaple, whereas concave slopes yieldmore sugar maple and white ash. Yellowbirch is dominant where stony soils andnatural disturbance provide the rightconditions for that species to germinateand grow. White pine occurs in areas ofshallow or sandy soils. These variationsare often small in scale: a beech-dominated knob may only be a fewhundred square feet within a forestotherwise dominated by sugar maple.

DISTRIBUTION/ABUNDANCE

NorthernHardwood Forestsare found through-out the state atelevations below2,700 feet, althoughthe upper elevationlimit is lower in thenorth.

NORTHERN HARDWOOD FOREST

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NORTHERN HARDWOOD FOREST

Therefore, we describe variants of this onecommunity rather than individual commu-nities. A large area, then, may be mappedas Northern Hardwood Forest, with therecognition that there is variability withinit. Foresters will find it useful to map thevariants as stands, so that each can bemanaged appropriately.

Natural disturbances in NorthernHardwood Forests include death ofindividual trees, which can create smallcanopy gaps; wind, whichcan cause small or largegaps depending on thenature and intensity of thestorm; ice loading, whichcan thin the canopyenough to significantlyincrease light to the forestfloor; snow loading, whichcan have the same effect,especially when snow fallswhile leaves are on thetrees; downslope move-ment of soil; and insectsand disease includingforest tent caterpillar,saddle prominent, andash yellows.

The variation invegetation and physicalfactors in NorthernHardwood Forests was studied by Marie-Louise Smith (1992) and James Fincherin two separate studies in the GreenMountains. William B. Leak et al. (1987) hasdescribed variation in this forest type basedon habitat types, mostly in New Hampshire.The references cited below will providemore insight into Northern HardwoodForests, their variations, and their ecology.

VEGETATIONVariations in vegetation are described

under “Variants.” The following generaliza-tions hold for most late-successionalNorthern Hardwood Forests. Beech, yellowbirch, and sugar maple are dominant in thecanopy. Sometimes red maple replacessugar maple. Hemlock, red spruce, whiteash, red oak, butternut, basswood,

hophornbeam, and other species can bepresent as well. The shrub layer is moder-ately well-developed, with striped maple,hobblebush, and shadbush among thecommon components. The herb layer isusually neither lush nor sparse, but thereare local variations. Herbs are long-livedperennials and many of them flower andfruit early in the year, before the forestcanopy leafs out. Many of the speciesfound in these forests are also found in

Montane Spruce-Fir Forests.

ANIMALSAs this is the dominant

matrix-forming communityin Vermont, large expansesof intact forest are criticalfor many animal speciesthat are sensitive to humandisturbance, including birdsthat nest in the forest interiorand some wide-rangingmammals. Some characteris-tic birds are hermit thrush,rose-breasted grosbeak,ovenbird, red-eyed vireo,eastern wood pewee, blackand white warbler, black-throated blue warbler, veery,and scarlet tanager. Charac-teristic mammals include

masked shrew, eastern cottontail, redsquirrel, southern flying squirrel, northernflying squirrel, white-footed mouse,woodland jumping mouse, deer mouse,chipmunk, porcupine, black bear, andwhite-tailed deer. Northern HardwoodForests also provide habitat for a number ofsalamanders, including redback salamander,spotted salamander, eastern newt, andalong brooks, northern two-lined sala-mander, dusky salamander, and springsalamander. Wood frogs and northernredbelly snakes are common here as well.

SUCCESSIONAL TRENDSSince this is such a variable community

type, its early-successional stages arevariable, too. Post-agricultural succession isoften to pure stands of white pine, whichare eventually replaced by hardwoods.Thus stands that are pine dominated today

Trout lily derives its name from itsbrown specked leaves.

Northern Hardwood Forest Formation / 133

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NORTHERN HARDWOOD FOREST

may actually be Northern HardwoodForests. It is necessary to look at soils topredict whether pine will persist or not.Coarse soils are more likely to support pineover long periods of time.

White pine is not the only post-agricul-tural successional species, however. Othercandidates are gray birch (on shallowersoils), bigtooth aspen, quaking aspen, blackcherry, pin cherry, and in the north, whitespruce, red spruce, balsam fir, and northernwhite cedar. The tree species that becomeestablished in an old field depend on thesoils, the nature of the agricultural distur-bance (pasturing vs. cropland), the durationand intensity of the disturbance, and thelocal seed sources.

Invasive non-native species can affectthe successional pathway, too. Althoughthere is no direct evidence, scientistssuspect that dense populations of invasiveshrubs such as Morrow’s honeysucklecan slow the return of native trees to anarea. Even when native trees becomere-established, honeysuckle can persist inthe understory for long periods of time,replacing native shrubs and herbs.

Where logging is the major disturbanceto a Northern Hardwood Forest, the mostcommon early-successional trees are yellowbirch, white ash, bigtooth aspen, quakingaspen, sugar maple, pin cherry, paper birch,and white pine. Pin cherry and paper birchare especially prevalent in large openingsleft by logging.

Large scale natural disturbances can havea similar effect on the canopy. For example,the species that come in after logging willalso come in after a large disturbance suchas a blowdown caused by a hurricane.In the case of the more common smallscale disturbances, such as the death orblowdown of individual trees, yellow birch,white ash, and sugar maple tend to comeinto openings.

Beech has its own story. In addition toproducing seeds, it reproduces vegetatively,sending up root suckers, or new sproutsfrom older trees. A beech that has been cutstill has the potential, for at least the firstyear, to produce a thicket of young new

sprouts. Where beech does well (on driermicrosites within Northern HardwoodForests), it can, following logging, remainthe dominant species or become moreabundant because of this strategy.

VARIANTSThe “core” community described above

is dominated by sugar maple, beech, andyellow birch. We recognize four variants:

Beech-Red Maple-Hemlock NorthernHardwood Forest: This variant differsfrom the core Northern Hardwood Forest inthat in mid-successional stands beech andred maple are the most common canopycomponents. Yellow birch and sweet birchcan be present, depending on climate(sweet birch is restricted to the warmerareas of the state). This variant occurs onconvex knobs, where soils are well drainedto somewhat excessively well drained. Soilsmay be coarser than in other NorthernHardwood Forests. These sites can beshallow to bedrock, or are moderately deepto basal till. They are on gentle to moderateslopes. Late-successional examples of thisvariant may be dominated by beech andhemlock, whereas red maple (a shade-intolerant tree) will decline as a standmatures. Common herbs in Beech-RedMaple-Hemlock Northern HardwoodForests are starflower, Canada mayflower,shining clubmoss, beech drops, and Indianpipes.

Sugar Maple-White Ash-Jack-in-the-pulpit Northern Hardwood Forest:This variant shows slight enrichment.Sometimes it is found in concavities in theslope, where nutrients accumulate. Or as iscommon in the Southern Vermont Piedmont,it occurs on ridgetops. Foresters andecologists believe that it occurs where thereis nutrient enrichment, either nutrientaccumulation or enriched bedrock or till.Mid-successional trees are white ash, sugarmaple, black cherry, and yellow birch withoccasional butternut, hophornbeam,basswood, and red oak. Minor componentsare red maple, hemlock, and red spruce.

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Late-successional trees are sugar maple andbeech. Characteristic herbs are Jack-in-the-pulpit, white baneberry, red trillium,Christmas fern, blue cohosh, early yellowviolet, lady fern, and wild oats. This variantdeserves more study to determine the varietyof factors that favor white ash over otherspecies and to learn more about thepotential longevity of white ash.

Yellow Birch Northern HardwoodForest: This variant occurs where yellowbirch is stable as acanopy dominant.In general, yellowbirch is consideredan early to mid-successional tree,capable of persist-ing long term onlywhen occasionallocal disturbancescreate the mineralsoil seedbed orsupply the nurselogs that thisspecies needs togerminate. Butwhere rocks and boulders are common atthe surface, there may be a perpetualsource of good sites for yellow birch seedsto germinate, and the species may thereforepersist here long term as a dominant in thecanopy. We have seen sites that appear tobe functioning in this way, but they needmore study.

White Pine-Northern HardwoodForest: This variant was recognized as adistinct community in our earlier classifica-tion (Vermont Nongame and NaturalHeritage Program (Thompson 1996)) butwas removed because white pine inNorthern Hardwood Forests is often a resultof past disturbance, at least in Vermont.White pine is a natural component ofNorthern Hardwood Forests, however,where soils are coarser and more welldrained. This variant describes those areaswhere white pine is a significant canopycomponent – but not because of pasthuman use. Wherever white pine is

common, it should be evaluated todetermine whether it is likely to persist overtime by looking at soils and the regenera-tion of pine in the understory.

RELATED COMMUNITIESRich Northern Hardwood Forest:

This community is most like Sugar Maple-White Ash Northern Hardwood Forest (see“Variants”), but it is more enriched, withgreater overall diversity, better productivity,

and more biomassin forest floor herbs.It is usually associ-ated with enrichedbedrock or till.

Hemlock-Northern Hard-wood Forest: Thiscommunity is mostlike the Beech-RedMaple-Hemlock-Northern HardwoodForest variant in thatsoils are shallowand well drained.In this case,

hemlock is co-dominant in the canopy.Mesic Red Oak-Hardwood Forest:

This community occurs in regions whereoak is common. Where there is a steadyseed supply for red oak, it may persist as acomponent of Northern Hardwood Forest,even though conditions are not necessarilythose we associate with red oak.

Northern Hardwood Talus Wood-land: Especially steep, rocky examples ofNorthern Hardwood Forests can be similarto this community.

Mesic Maple-Ash-Hickory Forest:This community occurs in warmer climateareas where hickories are common in theforest canopy. Its ground vegetation alsoshows its southern affinities, but in manyrespects it is similar to Northern HardwoodForest, with beech, sugar maple, and redmaple common in the canopy.

NORTHERN HARDWOOD FOREST

Spring beauty is typically found in NorthernHardwood Forests with greater mineral and nutrientenrichment.

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CONSERVATION STATUS AND

MANAGEMENT CONSIDERATIONSThere are very few Northern Hardwood

Forests that have not been logged orcleared at some time. Even those few areasthat were spared clearing or logging wereprobably used for maple sugar production.But the encouraging conservation story isthat Northern Hardwood Forests haverecovered amazingly well from the 19thcentury clearing of the land. Naturalecological processes are once againpredominant, and in most places nativespecies once again prevail. Today, thehuman disturbances in these forests includeforestry, sugaring, fragmentation fromroadbuilding and development of ruralresidential housing, and complete conver-sion to other uses. Human activities havebrought non-native pathogens such asbeech scale disease, gypsy moth, andhemlock woolly adelgid.

There are many human activities thatare compatible with conservation inNorthern Hardwood Forests. While it isimportant to have some areas that are freefrom human disturbance for long periodsof time, carefully managed NorthernHardwood Forests can also serve asconservation areas. Foresters managingNorthern Hardwood Forests should firstunderstand what they have by inventoryingand mapping natural communities andvariants. Management should encouragethe species that naturally occur in an area,in their natural proportions. For example,if white pine is present because of formeragricultural practice, it does not make senseto artificially maintain it. Red oak can alsobe present because of past disturbance. Itshould only be encouraged if the soils andseed sources suggest that it would persistover time naturally. On dry knobs, beech,red maple, and hemlock are the speciesthat should be favored, whereas it might beadvantageous to reduce beech in a moistcove where sugar maple will do well.

NORTHERN HARDWOOD FOREST

PLACES TO VISITCamels Hump State Forest, Huntington and

Duxbury, Vermont Department ofForests, Parks, and Recreation (VDFPR)

Mount Mansfield State Forest, Stowe andUnderhill, VDFPR

Coolidge State Forest, Plymouth, VDFPRLord’s Hill Natural Area, Groton State

Forest, Groton, VDFPRGifford Woods State Park, Sherburne,

VDFPRGreen Mountain National Forest, U.S.

Forest Service

SELECTED REFERENCES AND

FURTHER READINGFincher, James M. 1988. The relationship

of soil-site factors to forest plantcommunities in the Green Mountainand White Mountain National Forests.Master of Science Thesis, University ofNew Hampshire.

Leak, William B., Dale Solomon, and PaulDeBald. 1987. Silvicultural guide fornorthern hardwood types in theNortheast (revised). U.S.D.A. ForestService Northeastern Forest ExperimentStation, Research Paper NE-603.

Smith, Marie-Louise. 1992. Habitat typeclassification and analysis of uplandnorthern hardwood forest communitieson the Middlebury and Rochester RangerDistricts, Green Mountain NationalForest, Vermont. Master of ScienceThesis, University of Wisconsin.

Woods, Kerry D. 1987. Northern hardwoodforests in New England. Wild FlowerNotes 2:2-10.

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CHARACTERISTIC PLANTS

NORTHERN HARDWOOD FOREST

TREESAbundant SpeciesSugar maple – Acer saccharumYellow birch – Betula alleghaniensisAmerican beech – Fagus grandifoliaOccasional to Locally Abundant SpeciesEastern hemlock – Tsuga canadensisRed maple – Acer rubrumWhite ash – Fraxinus americanaWhite pine – Pinus strobusBlack cherry – Prunus serotinaSweet birch – Betula lentaBasswood – Tilia americanaRed spruce – Picea rubens

SHRUBSAbundant SpeciesHobblebush – Viburnum alnifoliumStriped maple – Acer pensylvanicumShadbush – Amelanchier spp.Occasional to Locally Abundant SpeciesCanada honeysuckle – Lonicera canadensisBeaked hazelnut – Corylus cornutaAlternate-leaved dogwood – Cornusalternifolia

HERBSAbundant SpeciesIntermediate wood fern – Dryopterisintermedia

Christmas fern – Polystichum acrostichoidesShining clubmoss – Lycopodium lucidulumSarsaparilla – Aralia nudicaulis

Occasional to Locally Abundant SpeciesPainted trillium – Trillium undulatumWhorled aster – Aster acuminatusWild oats – Uvularia sessilifoliaLady fern – Athyrium filix-feminaCanada mayflower – Maianthemum canadenseRed trillium – Trillium erectumSpring beauty – Claytonia carolinianaTrout lily – Erythronium americanumFalse solomon’s seal – Smilacina racemosaRose twisted stalk – Streptopus roseusStarflower – Trientalis borealisIndian cucumber root – Medeola virginianaIndian pipes – Monotropa unifloraBeech drops – Epifagus virginianaEarly yellow violet – Viola rotundifoliaJack-in-the-pulpit – Arisaema triphyllumLong beech fern – Thelypteris phegopterisZigzag goldenrod – Solidago flexicaulisCommon wood sorrel – Oxalis acetosellaHay-scented fern – Dennstaedtia punctilobula

INVASIVE NON-NATIVE PLANTSMorrow’s honeysuckle – Lonicera morrowiiTartarian honeysuckle – Lonicera tataricaJapanese barberry – Berberis thunbergiiCommon buckthorn – Rhamnus cathartica

RARE AND UNCOMMON PLANTSBroad beech fern – Thelypteris hexagonopteraMale fern – Dryopteris filix-masThree-birds orchid – Triphora trianthophora

Northern Hardwood Forest Formation / 137

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ECOLOGY AND PHYSICAL SETTINGRich Northern Hardwood Forests are quintessentially

Vermont. Sugar maple is abundant, making these forestsvital to three of Vermont’s economic staples: maple sugarproduction, forestry, and tourism. Rich Northern HardwoodForests are places where colluvial processes (downslopemovement) or mineral rich bedrock, or some combinationof the two, provide plants with a steady supply of nutrients.

Colluvial processes prevail on lower slopes and benchesand also in coves and gullies. Here organic matter and plantnutrients accumulate over time, forming a compost-like soil.If the bedrock or till on such a slope is enriched with calciumand other key plant nutrients, these nutrients will be washedfrom upper to lower slopes, giving the plants below thegreatest advantage. Productivity is high on the lower slopes,as is the overall diversity of plant species. The upper slopesor the convex knobs on such a hill, where nutrients areleached from the soils, will have communities such asNorthern Hardwood Forest, Hemlock Forest, Mesic RedOak-Hardwood Forest, or Dry Oak-Hickory-HophornbeamForest, with lower species diversity and lower productivity.

Rich Northern Hardwood Forests can also be found onrolling terrain where calcium-rich bedrock, such as lime-stone or dolomite, is found close to the surface. Althoughsoils on these sites can be shallow and droughty, thebedrock nevertheless provides ample plant nutrients.Pockets of rich soil are commonly mixed with the smalloutcrops of calcareous rock. These sites can be quiteproductive and diverse, with many plants that indicatemineral enrichment.

Overall, the soils in Rich Northern Hardwood Forestsrange from well drained to somewhat poorly drained.Sometimes there is dense basal till underlying the soil,generally about 18-24 inches from the surface. This

DISTRIBUTION/ABUNDANCERich Northern Hardwood

Forests occur throughoutVermont at low to moderateelevations, from approxi-mately 300 to 2,500 feet.They are most common wherethe bedrock is calcareousbut are also present in areasof nutrient-enriched till ortopographically inducedenrichment. This communityoccurs throughout the north-eastern United States andadjacent Canada but is lesscommon in neighboringstates. Vermont may havethe largest examples of thisnatural community type inthe northeast.

RICH NORTHERN HARDWOOD FOREST

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RICH NORTHERN HARDWOOD FOREST

restricting layer can be a factor in keepingmoisture and nutrients near the surface,where they are readily available to plants.Where soils are moist, productivity ishigher, trees produce higher quality wood,and herbaceous plants are more abundant.

VEGETATIONRich Northern Hardwood Forests are

high productivity forests: trees growquickly, and theygrow tall andstraight. Sugar mapleis dominant in thecanopy, but bass-wood and white ashare common as well,and butternuts arescattered to occa-sionally abundant.The shrub layervaries from beingalmost absent indense shade to well-developed in sunnyopenings. Herbs areoften abundant on the forest floor, forminga continuous carpet of lush vegetation inmid-summer. Where moisture is plentiful,ferns such as ostrich fern, glade fern, andsilvery glade fern grow together in fernglades. Most of the herbs are long-livedperennials. Many of them are springephemerals that flower and fruit early inspring before trees leaf out, when sunlightis plentiful. By mid-summer some of theseplants, like Dutchman’s breeches, have lostall their foliage and are completely invisibleabove ground. Other plants, like woodnettle and maidenhair fern, persist through-out the summer, displaying large canopiesof leaves to gather the filtered light on theforest floor.

The overall diversity of species is high inRich Northern Hardwood Forests, as is thesheer abundance of biomass on the forestfloor. A study of forests in Vermont andNew York showed that in plots of uniformsize (0.1 hectare, or about 1/4 acre), arepresentative Rich Northern HardwoodForest in the Green Mountains had anaverage of 48 herb species, while otherhardwood forest types in the Adirondacks

had an average of 27 species. Other studiesshow similar results.

ANIMALSMammals of Rich Northern Hardwood

Forests include black bear, masked shrew,deer mouse, white-footed mouse, wood-land jumping mouse, and chipmunk.Among the amphibians are redbacksalamander, spotted salamander, eastern

newt, wood frog,northern two-linedsalamander, duskysalamander, andspring salamander.Invertebrates are notwell studied in theseforests; the carefulstudy of snails andother invertebrategroups might yieldsome interestingresults. Birds aresimilar to thosefound in NorthernHardwood Forests.

SUCCESSIONAL TRENDSRich Northern Hardwood Forests that

have been undisturbed for long periodsof time will likely be dominated by sugarmaple, basswood, and beech, whereasforests where natural or human distur-bances have created openings may bedominated by a combination of sugarmaple, bigtooth aspen, white ash, stripedmaple, black cherry, white pine, yellowbirch, and pin cherry. Which of thesespecies dominate, and for how long, willdepend on climate, history, seed sources,and site conditions.

VARIANTSNorthern Hardwood Limestone

Forest: This is a Rich Northern HardwoodForest on shallow-to-bedrock soils, wherethe bedrock is limestone or other calcium-rich rock such as dolomite. Soils areshallow and well drained. Hophornbeamis typically common in the canopy. Thisvariant is very similar to Transition Hard-woods Limestone Forest, a variant of MesicMaple-Ash-Hickory-Oak Forest.

The early spring flowers of hepatica range frompurple to white.

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RELATED COMMUNITIESNorthern Hardwood Forest: This is

the community most closely related to RichNorthern Hardwood Forest; the two differin the availability of plant nutrients in thesoils and in species diversity. Often the twocommunities interfinger, with Rich NorthernHardwood Forest occurring in rich coves orbenches, surrounded by Northern Hard-wood Forest.

Mesic Red Oak-Northern HardwoodForest: These two communities canintergrade where oak is common. Apredominance of red oak and drier siteconditions distinguishes Mesic Red Oak-Northern Hardwood Forest.

Mesic Maple-Ash-Hickory-OakForest: This community can be very similarto Rich Northern Hardwood Forest, butdiffers in having southern species such ashickories and oaks.

Mesic Maple-Ash-Hickory-OakForest, Transition HardwoodsLimestone Forest variant: Found inareas of shallow soils over limestone in theChamplain Valley and other warm areas,this community has much in common withthe Northern Hardwood Limestone Forestvariant of Rich Northern Hardwood Forest,but species composition reflects a warmerclimate and southern affinities.

CONSERVATION STATUS AND

MANAGEMENT CONSIDERATIONSRich Northern Hardwood Forest is a

common community in Vermont, althoughmost examples are small. Exceptionallylarge examples occur in the eastern TaconicMountains and are protected there. Severalexamples elsewhere are protected asnatural areas, and a number of sites areunder timber management that considersthe long term ecological integrity of thenatural community. The observations offoresters and ecologists indicate that this

community type can recover well fromselective harvest, including long-term use assugarbush, if patch cuts are kept small andprecautions are taken against the encroach-ment of invasive non-native plants. On theother hand, clearing for agriculture prob-ably has a long-term impact on theseforests; the native flora may take a longtime to return when a Rich NorthernHardwood Forest site used for agricultureis allowed to return to forest. In general,activities that alter the downslope move-ment of soil and nutrients, such as thebuilding of roads across slopes, threatenthe integrity of this community.

PLACES TO VISITMount Equinox, Manchester, Equinox

Preservation Trust, The NatureConservancy and Vermont Land Trust

Gifford Woods, Sherburne, VermontDepartment of Forests, Parks, andRecreation (VDFPR)

Willoughby State Forest, Westmore andSutton, VDFPR

SELECTED REFERENCES AND

FURTHER READINGWoods, Kerry D. 1987. Northern

Hardwood forests in New England.Wild Flower Notes 2:2-10.

RICH NORTHERN HARDWOOD FOREST

Blue cohosh – Caulophyllum thalictroides

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CHARACTERISTIC PLANTS

RICH NORTHERN HARDWOOD FOREST

TREESAbundant SpeciesSugar maple – Acer saccharumWhite ash – Fraxinus americanaOccasional to Locally Abundant SpeciesBasswood – Tilia americanaSweet birch – Betula lentaBitternut hickory – Carya cordiformisYellow birch – Betula alleghaniensisAmerican beech – Fagus grandifoliaBlack cherry – Prunus serotinaButternut – Juglans cinereaHophornbeam – Ostrya virginiana

SHRUBSAbundant SpeciesStriped maple – Acer pensylvanicumAlternate-leaved dogwood – Cornusalternifolia

Occasional to Locally Abundant SpeciesMaple-leaf viburnum – Viburnum acerifoliumRed-berried elder – Sambucus racemosaRound-leaved dogwood – Cornus rugosaLeatherwood – Dirca palustris

HERBSAbundant SpeciesWood nettle – Laportea canadensisMaidenhair fern – Adiantum pedatumBlue cohosh – Caulophyllum thalictroidesWild leeks – Allium tricoccumDutchman’s breeches – Dicentra cucullariaHepatica – Hepatica spp.Canada violet – Viola canadensisPale touch-me-not – Impatiens pallidaWild ginger – Asarum canadense

Bulblet fern – Cystopteris bulbiferaChristmas fern – Polystichum acrostichoidesWhite snakeroot – Eupatorium rugosumOccasional to Locally Abundant SpeciesSquirrel corn – Dicentra canadensisEarly yellow violet – Viola rotundifoliaSilvery glade fern – Athyrium thelypteroidesWhite baneberry – Actaea pachypodaPlantain-leaved sedge – Carex plantagineaZigzag goldenrod – Solidago flexicaulisBlack snakeroot – Sanicula marilandicaRattlesnake fern – Botrychium virginianumWaterleaf – Hydrophyllum virginianumHerb Robert – Geranium robertianumCarex sprengellii – Sprengel’s sedge

INVASIVE NON-NATIVE PLANTSMorrow’s honeysuckle – Lonicera morrowiiTartarian honeysuckle – Lonicera tataricaJapanese barberry – Berberis thunbergiiCommon buckthorn – Rhamnus cathartica

RARE AND UNCOMMON PLANTSGinseng – Panax quinquefoliusGoldie’s wood fern – Dryopteris goldianaGlade fern – Athyrium pycnocarponWood millet – Milium effusumHitchcock’s sedge – Carex hitchcockianaSummer sedge – Carex aestivalisDavis’ sedge – Carex davisiiHooker’s orchis – Habenaria hookeriGoldenseal – Hydrastis canadensisBroad beech fern – Thelypteris hexagonopteraMale fern – Dryopteris filix-masPuttyroot – Aplectrum hyemale

Squirrel corn is a characteristic species of RichNorthern Hardwood Forests. It is named for thecorn-sized tubers growing on its undergroundshoots.

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ECOLOGY AND PHYSICAL SETTINGThese forests are similar to Northern

Hardwood Forests but differ in havingsignificant amounts of red oak in thecanopy. They are essentially northern incharacter, which is evidenced by the lackof white oak and hickories. In thenorthern part of the red oak range thiscommunity occurs mostly on warm, drymicrosites such as south-facing slopes.Soils are well drained to moderately welldrained and are derived from ablationtill or basal till. Mesic Red Oak-NorthernHardwood Forests are found on slopes,generally below 1,500 feet elevation inthe north and below 2,500 feet in thesouth. Ecological processes include singletree fall and downslope movement ofsoil, nutrients, and seeds. Ecologists andforesters theorize that red oak persists inthese sites because natural red oak standson drier ridgetop sites above themprovide a constant seed source. Fire mayplay a role, too, but this needs investiga-tion. Productivity can be high due to theconstant inflow of nutrients fromupslope.

This forest community needs morestudy. Questions about its ecology focuson soil-vegetation relationships, theorigin of red oak and its longevity,natural disturbance regimes, andsuccessional trends.

VEGETATIONMid-successional trees include red

oak, sugar maple, basswood, beech, andhemlock, with occasional butternut. Thecanopy is closed and trees are usually talland straight. The shrub layer is sparse,with maple-leaf viburnum, beaked hazelnut, witch hazel, and shadbush ascommon components. Herbs are sparse,too, and include Christmas fern, marginalwood fern, intermediate wood fern,Indian cucumber root, and blue-stemmedgoldenrod.

DISTRIBUTION/ABUNDANCE

This forest typeis occasional in allbiophysical regionsat low to moderateelevations (below1,500 feet in thenorth, below2,500 feet in thesouth). Similarcommunities arefound commonlyin neighboringstates to thesouth.

MESIC RED OAK-NORTHERN HARDWOOD FOREST

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MESIC RED OAK-NORTHERN HARDWOOD FOREST

ANIMALSAnimal populations in these forests

have not been studied, but they are likelyto be similar to those in Northern Hard-wood Forests and in Dry Oak-Hickory-Hophornbeam Forests.

SUCCESSIONAL TRENDSWe know little about successional trends

in these forests, but it may be that beech,hemlock, and sugarmaple woulddominate late-successional stands,with red oak presentin certain situationswhere a stable seedsource is provided.

VARIANTSNone recognized

at this time.

RELATED

COMMUNITIESNorthern

Hardwood Forest: This is a closelyrelated community, but has less red oakor none. The relationships between thesecommunities need further study.

Dry Oak-Hickory-HophornbeamForest: This is a somewhat similarcommunity, but has bedrock closer tothe surface, drier and shallower soils, andgenerally lower productivity.

Dry Oak Forest: This community isfound on ridgetops where soils are shallowand dry. Two or three species of oakdominate and other hardwoods are virtuallyabsent.

CONSERVATION STATUS AND

MANAGEMENT CONSIDERATIONSThere are no known examples of Mesic

Red Oak-Northern Hardwood Forest thatare free from human disturbance, though afew mature examples are known. With theirsometimes high productivity and presenceof high-quality red oak timber, these sitesare vulnerable to the selective removal ofhigh-quality timber, commonly referred to

as “highgrading.”Foresters

managing thesesites shouldevaluate them togain as muchinformation aspossible about thenatural successionaltrends and workwith these trendsin developingsilvicultural plans.For example, if itappears that redoak is regenerating

naturally, it makes sense to work towardmaintaining it. If, on the other hand, redoak appears not to be regenerating, otherspecies should be favored. Care should beused in steep sites to avoid soil erosion.

PLACES TO VISITLittle Ascutney Mountain Wildlife Manage-

ment Area, Weathersfield, VermontDepartment of Fish and Wildlife (VDFW)

Pine Mountain Wildlife Management Area,Topsham, VDFW

Large whorled pogonia is a rare orchid of acidicwoods. It can be found in Mesic Red Oak-NorthernHardwood Forests.

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CHARACTERISTIC PLANTS

TREESAbundant SpeciesRed oak – Quercus rubraSugar maple – Acer saccharumAmerican beech – Fagus grandifoliaOccasional to Locally Abundant SpeciesWhite ash – Fraxinus americanaBasswood – Tilia americanaButternut – Juglans cinereaEastern hemlock – Tsuga canadensisSweet birch – Betula lenta

SHRUBSOccasional to Locally Abundant SpeciesMaple-leaf viburnum – Viburnum acerifoliumWitch hazel – Hamamelis virginianaShadbush – Amelanchier spp.Striped maple – Acer pensylvanicumBeaked hazel nut – Corylus cornutaLow sweet blueberry – Vacciniumangustifolium

MESIC RED OAK-NORTHERN HARDWOOD FOREST

HERBSOccasional to Locally Abundant SpeciesIndian cucumber root – Medeola virginianaIntermediate wood fern – Dryopterisintermedia

Christmas fern – Polystichum acrostichoidesWhite wood aster – Aster divaricatusBlue-stemmed goldenrod – Solidago caesiaBlue cohosh – Caulophyllum thalictroidesStarflower – Trientalis borealisWild oats – Uvularia sessilifoliaCanada mayflower – Maianthemum canadenseSarsaparilla – Aralia nudicaulisBearded shorthusk – Brachyelytrum erectumPointed-leaved tick trefoil – Desmodiumglutinosum

Hay-scented fern – Dennstaedtia punctilobula

RARE AND UNCOMMON PLANTSSquawroot – Conopholis americanaMinnesota sedge – Carex albursinaGinseng – Panax quinquefoliusBroad beech fern – Thelypteris hexagonopteraSummer sedge – Carex aestivalisVirginia spring beauty – Claytonia virginicaFlowering dogwood – Cornus floridaLarge whorled pogonia – Isotria verticillata

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HEMLOCK FOREST

ECOLOGY AND PHYSICAL SETTINGThis is an important community in the

Northern Hardwood Forest Formation,although it occupies a small percentageof the landscape. Prior to Europeansettlement, hemlock comprised about tenpercent of the Vermont forest, but todayit probably covers less than five percentof Vermont’s land area. Hemlock wasused widely for tanning leather in the18th and 19th centuries, which is one ofthe factors leading to its decline in thestate. It is a shade tolerant, long-livedspecies, capable of living up to 1,000years. It is therefore a late-successionalspecies, persisting under the shade of ahardwood canopy for decades, eventu-ally becoming dominant.

Hemlock Forests are more or lesspure stands of hemlock, usually coveringsmall areas of locally favorable condi-tions. These include steep-sided ravines,summits, and bedrock-controlled areas.Soils are derived from a variety of parentmaterials, including basal till, ablation till,outwash, bedrock, and lake-depositedsediments. A shallow pan is present insome places. Some soils are seasonallywet. Others tend to be droughty. As istrue with other conifers, the needles ofhemlock can acidify the soils on whichthey grow, causing minerals to beleached from the upper soil layers. Astrong albic horizon, or ashy white layer,can result. Soil scientists in the northeastknow that often the best expression ofan albic horizon is under an old standof hemlock.

Hemlock Forests generally occurbelow 1,800 feet elevation, but theelevation varies from north to south.Hemlock is nearly absent from the colderareas of the state, including the North-eastern Highlands.

Natural ecological processes includefire, which is especially common onridgetops that attract lightning, andwindthrow, which affects these shallow-rooted trees.

DISTRIBUTION/ABUNDANCE

Hemlock Forestsare found in allbiophysical regionsexcept the North-eastern Highlands,at elevationsgenerally below1,800 feet. Theyare found throughoutthe northeasternUnited States andin the southernextremities ofQuébec andOntario.

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VEGETATIONHemlock occupies 75 percent to 100

percent of the canopy in Hemlock Forests,with beech, yellow birch, sugar maple, redspruce, and white pine mixed in. Typically,hemlock forests are very dark and henceare almost devoid of flowering plants in theunderstory.

ANIMALSNorthern saw-whet owl, red-breasted

nuthatch, hermit thrush, black-throatedgreen warbler, blackburnian warbler, andsolitary vireo nest in Hemlock Forests.Common mammals are red squirrel, deermouse, southern red-backed vole, porcu-pine, and white-tailed deer. Deer useHemlock Forests for winter cover. Northernredbelly snakes also breed here.

SUCCESSIONAL TRENDSEastern hemlock is a late-successional

species. Hemlock Forests are considered tobe stable over long periods of time, andmany forests that are dominated by otherspecies today will likely become hemlockdominated over time. Early-successionalspecies in hemlock forests include redmaple, paper birch, aspen, and white pine.Mid-successional species include hemlock,yellow birch, red spruce, and red maple.

VARIANTSHemlock-Red Spruce Forest:

Red spruce is common or co-dominantin the canopy. Balsam fir and beech maybe present as well.

RELATED COMMUNITIESHemlock-Northern Hardwood

Forest: This community is similar but witha canopy composition of less than 75percent hemlock.

Northern Hardwood Forest: Hem-lock is present in most Northern HardwoodForests but as a minor component of thecanopy. Forests that appear to match thedescription of Northern Hardwood Forestsshould, however, be evaluated to determinewhether they might succeed to HemlockForest over time. Soils and regeneration arethe main clues.

Lowland Spruce-Fir Forest: Lowelevation examples of Lowland Spruce-FirForest can have hemlock in significantquantities.

Limestone Bluff Cedar-Pine Forest:Hemlock is often common in thesecommunities, which differ in havingnorthern white cedar as a long-termcomponent and several herbaceous speciesthat characterize limestone in warm climateareas.

White Pine-Northern HardwoodForest: This community has hemlock also,sometimes in abundance. It may beadjacent to Hemlock Forest and intergradewith it.

Temperate Acidic Cliff Community:Hemlock Forests often occur on steep,rocky slopes which grade into cliffs.Temperate Acidic Cliffs often have abun-dant hemlock.

CONSERVATION STATUS AND

MANAGEMENT CONSIDERATIONSSeveral mature Hemlock Forests are

protected in conservation lands throughoutthe state. Most of these are small areas.Hemlock Forests should be managedkeeping long term successional trends inmind. Hemlock woolly adelgid, a non-native insect pest, threatens these forests.

PLACES TO VISITOld City Falls Ravine, Strafford, Strafford

Town ForestHelen W. Buckner Memorial Preserve at

Bald Mountain, West Haven, The NatureConservancy

Battell Biological Reserve, Middlebury, U.S.Forest Service

Pine Mountain Wildlife Management Area,Topsham, Vermont Department of Fishand Wildlife

HEMLOCK FOREST

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CHARACTERISTIC PLANTS

HEMLOCK FOREST

TREESAbundant SpeciesEastern hemlock – Tsuga canadensisOccasional to Locally Abundant SpeciesYellow birch – Betula alleghaniensisAmerican beech – Fagus grandifoliaRed maple – Acer rubrumWhite ash – Fraxinus americanaRed spruce – Picea rubensWhite pine – Pinus strobusSuccessional SpeciesPaper birch – Betula papyriferaQuaking aspen – Populus tremuloidesWhite pine – Pinus strobus

SHRUBSOccasional to Locally Abundant SpeciesStriped maple – Acer pensylvanicumHobblebush – Viburnum alnifolium

HERBSOccasional to Locally Abundant SpeciesMarginal wood fern – Dryopteris marginalisPainted trillium – Trillium undulatumCommon wood sorrel – Oxalis acetosellaPartridgeberry – Mitchella repensAppalachian polypody – Polypodiumappalachianum

Intermediate wood fern – Dryopteris intermediaIndian pipes – Monotropa unifloraCanada mayflower – Maianthemum canadenseGoldthread – Coptis trifoliaShining clubmoss – Lycopodium lucidulumGround cedar – Lycopodium digitatum

RARE AND UNCOMMON PLANTSPinedrops – Pterospora andromedea

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ECOLOGY AND PHYSICAL SETTINGHemlock-Northern Hardwood Forest are mixed forests

of hemlock, pines, and hardwoods that are not nutrient-demanding. They are found in areas of shallow bedrock orsandy to gravelly outwash, where soils are well drained toexcessively drained. In many respects, they are similar toHemlock Forests, but hardwoods comprise 25 to 75 percentof the canopy. Because of its shade tolerance, hemlock cansurvive under the hardwood canopy for long periods.

VEGETATIONEastern hemlock shares the canopy with one or more

of the following species: red maple, beech, red pine, whitepine, paper birch, and red spruce. The canopy componentsvary with climate and soils. Red oak, for example, can bea common associate in warmer regions. The herb composi-tion has some similarities with that of acidic NorthernHardwood Forests.

ANIMALSAnimal populations are similar to those found in

Hemlock Forests and in Northern Hardwood Forests.

SUCCESSIONAL TRENDSEarly-successional species include aspen and paper

birch. These forests need more study to help us understandlong term successional trends.

VARIANTSHemlock-White Pine-Northern Hardwood Forest:

White pine is an important component of the canopy and isbelieved to be persistent over time. These forests occur oncoarse outwash soils.

DISTRIBUTION/ABUNDANCEThis is a common

community at elevationsbelow 1,800 feet in Vermontin all biophysical regionsexcept the NortheasternHighlands. It is commonthroughout the northeast.

HEMLOCK-NORTHERN HARDWOOD FOREST

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CHARACTERISTIC PLANTS

HEMLOCK-NORTHERN HARDWOOD FOREST

Yellow Birch-Hemlock Forest: Foundon rocky sites where there are suitable sitesfor yellow birch to germinate. Yellow birchmay therefore be a major component of thecanopy and be stable over time.

RELATED COMMUNITIESNorthern Hardwood Forest: The more

nutrient-poor variants of this community areperhaps the most similar to Hemlock-Northern Hardwood Forest, but they aremore likely to be found on till-derived soilsthan on shallow-to-bedrock soils, and if theyhave hemlock, it is a minor component.

Hemlock Forest: Hemlock is dominant,comprising over 75 percent of the canopy.

White Pine-Red Oak-Black OakForest: Hemlock may be important locallyin these forests, but they differ fromHemlock-Northern Hardwood Forests inhaving significant amounts of red oak andblack oak. They are most likely to occur insandy or gravelly outwash.

CONSERVATION STATUS AND

MANAGEMENT CONSIDERATIONSThere are no known old growth

examples of this community in Vermont,though there may be a few in Massachu-setts. Silvicultural practices should considerthe long term ecological trends of the siteas well as the limitations due to steepnessand thin soils.

PLACES TO VISITMount Mansfield State Forest, Stowe and

Underhill, Vermont Department ofForests, Parks, and Recreation

Roaring Brook Wildlife Management Area,Vernon, Vermont Department of Fishand Wildlife

TREESAbundant SpeciesEastern hemlock – Tsuga canadensisAmerican beech – Fagus grandifoliaYellow birch – Betula alleghaniensisOccasional to Locally Abundant SpeciesSugar maple – Acer saccharumRed maple – Acer rubrumPaper birch – Betula papyriferaWhite pine – Pinus strobusRed oak – Quercus rubra

SHRUBSOccasional to Locally Abundant SpeciesStriped maple – Acer pensylvanicumHobblebush – Viburnum alnifolium

HERBSOccasional to Locally Abundant SpeciesPainted trillium – Trillium undulatumPartridgeberry – Mitchella repensAppalachian polypody – Polypodiumappalachianum

Intermediate wood fern – Dryopteris intermediaIndian pipes – Monotropa unifloraCanada mayflower – Maianthemum canadenseGround cedar – Lycopodium digitatumWintergreen – Gaultheria procumbensPink lady’s slipper – Cypripedium acauleSarsaparilla – Aralia nudicaulisStaghorn clubmoss – Lycopodium clavatum

RARE AND UNCOMMON PLANTSPinedrops – Pterospora andromedea

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ECOLOGY AND PHYSICAL SETTINGNorthern Hardwood Talus Woodlands

are found in areas where large bouldershave accumulated below cliffs or steepslopes. They occur as small, isolatedfeatures in the landscape and are oftenassociated with Open Talus, whichusually occurs higher on the slope. At thebase of such slopes, soil accumulates inthe spaces between the rocks or in smallconcavities on large boulders. Trees thatdo well in rocky soils, such as yellowbirch and hemlock, are common.

VEGETATIONTrees are scattered and most do not

attain great size. Shrubs are mostlyscattered, though mountain maple canform dense thickets locally. Vines arewell adapted to talus and are thereforecommon. They root in shaded crevicesbut send their foliage out into open sunof the bare rocks. Very few herbs dowell in these woodlands; Appalachianpolypody is perhaps the most successful.Mosses and lichens are frequent, andthey deserve more study.

The species composition of taluswoodlands is especially interesting whencompared with that of floodplain forests.A few species that seem very characteris-tic of floodplain forests, including ostrichfern and wood nettle, are also commonlyfound in Northern Hardwood TalusWoodlands. Both communities receiveregular inputs of nutrients and soil, onefrom above and the other from upstream.

ANIMALSLittle is known about animals

inhabiting Northern Hardwood TalusWoodlands.

VARIANTSNone recognized at this time.

DISTRIBUTION/ABUNDANCE

NorthernHardwood TalusWoodlands arefound throughoutVermont, atelevations to2,500 feet.They are foundthroughout thenortheast aswell.

NORTHERN HARDWOOD TALUS WOODLAND

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CHARACTERISTIC PLANTS

NORTHERN HARDWOOD TALUS WOODLAND

RELATED COMMUNITIESBoreal Talus Woodland: This commu-

nity is similar in structure to NorthernHardwood Talus Woodland but is found athigher elevations or more northernlatitudes. Red spruce and heart-leavedpaper birch are present. Basswood, whiteash, and sugar maple are absent, andoverall diversity is lower.

Transition Hardwood TalusWoodland: This community is found inareas of highly calcareous bedrock. It isricher in species than Northern HardwoodTalus Woodland and has several calciphilicspecies, including northern white cedarand climbing fumitory.

Northern Hardwood Forest: Thiscommunity is usually adjacent to NorthernHardwood Talus Woodland and shares anumber of species in common. It has aclosed canopy and well-developed soils.

Rich Northern Hardwood Forest:This community is often associated withNorthern Hardwood Talus Woodland thatis found on calcareous bedrock, and thedistinction between the two communitiesis not always clear. They share manyspecies, including white snakeroot, woodnettle, and Goldie’s fern.

CONSERVATION STATUS AND

MANAGEMENT CONSIDERATIONSIn general, talus woodlands are not

threatened communities because they areunsuitable for forestry, agriculture, ordevelopment. But because they areuncommon, representative examplesshould be protected. When trees areharvested, logging should be done withcare to minimize soil erosion.

PLACES TO VISITMarshfield Cliffs, Marshfield,

Groton State Forest, VermontDepartment of Forests,Parks, and Recreation

Mount Moosalamoo, Salisbury,Green Mountain NationalForest

TREESAbundant SpeciesYellow Birch – Betula alleghaniensisWhite Ash – Fraxinus americanaPaper birch – Betula papyriferaOccasional to Locally Abundant SpeciesSugar maple – Acer saccharumBasswood – Tilia americanaEastern hemlock – Tsuga canadensisRed Oak – Quercus rubraButternut – Juglans cinerea

SHRUBSAbundant SpeciesMountain Maple – Acer spicatumRed-berried elder – Sambucus racemosaOccasional to Locally Abundant SpeciesCanada yew – Taxus canadensisBristly black currant – Ribes lacustrePurple-flowering raspberry – Rubus odoratusRed raspberry – Rubus idaeus

HERBS AND VINESAbundant SpeciesVirginia Creeper – Parthenocissus quinquefoliaAppalachian polypody – Polypodiumappalachianum

Occasional to Locally Abundant SpeciesMarginal wood fern – Dryopteris marginalisRusty woodsia – Woodsia ilvensisFringed bindweed – Polygonum cilinodePoison ivy – Toxicodendron radicansWood nettle – Laportea canadensisWhite snakeroot – Eupatorium rugosumClearweed – Pilea pumilaPale touch-me-not – Impatiens pallidaOstrich fern – Matteucia struthiopteris

RARE AND UNCOMMON PLANTSNorthern stickseed – Hackelia deflexa var.americana

Goldie’s wood fern – Dryopteris goldiana

Appalachian polypody typicallycovers boulders and rocky outcropson talus woodlands where sufficientsoil has developed in cracks.

Northern Hardwood Forest Formation / 151