American Beech

American Beach (Fagus grandifolia)

American Beach (Fagus grandifolia)

It can be surprising  to see leaves clinging to deciduous trees in mid-winter.  In eastern North America, some oak species and American Hophornbeam (Ostrya virginiana) may retain their leaves but American Beech (Fagus grandifolia) trees are among the most conspicuous to do so.  By January its leaves are bleached to a papery pale tan, catching the bright winter light while fluttering in the winter wind.  The leaves look delicate, but give one a tug and you’ll see how tenaciously they adhere to their branches.  American Beech leaves typically stay on the trees until early spring, withstanding the effects of even ice and snow.

American Beach (Fagus grandifolia), in March

American Beach (Fagus grandifolia), in March

Why do American Beech and other trees keep some of their leaves in winter?  There are many theories:  the dry leaves may be a deterrent to winter browsing by deer, moose and other mammals;  holding some of the leaves until spring may be the trees’ way of time-releasing some nutrients for recycling into the soil;  the leaves may funnel more snow melt to the tree’s root system.  But no one knows for certain what caused this trait.

The smooth, pale gray bark is an unmistakable characteristic of American Beech, often tempting passers-by to carve their initials.  A more interesting possibility is a sighting of animal ‘tracks’ – claw marks from animals that may have climbed the tree at some point.

Animal 'tracks' on American Beach (Fagus grandifolia)

Animal ‘tracks’ on American Beach (Fagus grandifolia)

Trees are susceptible to frost cracks in winter, caused by warming from the low-angled rays of the winter sun, followed by rapid cooling when the sun sets or disappears behind a cloud.  Both the bark and the wood it encompasses expand in the warm sun, but the bark may cool more quickly than the wood when the sun disappears, causing lengthwise cracks to occur in the bark.  If temperatures are warm enough, portions of the inner bark may become active, only to be killed if a rapid refreeze occurs.  American Beech evolved to minimize the harsh effects of the sun by having light-colored bark that reflects the sun’s rays.  The winter leaves may provide an additional layer of protection from the warm sunlight.

American Beech’s long, sharply pointed copper-colored buds are another distinctive winter identification feature.

American Beach (Fagus grandifolia) buds

American Beach (Fagus grandifolia) buds

As spring approaches, American Beech buds grow longer and plump, eventually opening to reveal newly unfurling leaves, accordion pleated and hairy as they first emerge.  The long silky hairs are an adaptation to make the new leaves less appealing to the many species of hungry caterpillars and other insects that may eat the leaves later as the hairiness dissipates.

Newly unfurled leaves of American Beach (Fagus grandifolia)

Newly unfurled leaves of American Beach (Fagus grandifolia)

According to Bringing Nature Home by Douglas Tallamy, American Beech provides food for the caterpillars of over 100 species of butterflies and moths.  Among them is the Early Hairstreak butterfly, a rare species found in deciduous or mixed woodlands from the maritime provinces of Canada to northern Michigan and Wisconsin through the Appalachians to Tennessee and North Carolina.  Early Hairstreak caterpillars can only eat the leaves of American Beech and Beaked Hazelnut (Corylus cornuta).  The presence of caterpillars attracts predatory insects and arachnids to feed on them, including many species of spiders, wasps, ants and flies.  These insects are beneficial to the trees, because they help keep the caterpillar population in check.

In addition to butterfly and moth caterpillars, a few of the insects that use American Beech include Leaf-footed Bugs,

Leaf-footed Bug (Acanthocephala species) on American Beech (Fagus grandifolia)

Leaf-footed Bug (Acanthocephala species) on American Beech (Fagus grandifolia)

leaf-rollers,

Insect shelter, likely leaf-rolling weevil nest

Insect shelter, likely leaf-rolling weevil nest

and Woolly Beech Aphids.

Woolly Beech Aphids (Phyllaphis fagi)

Woolly Beech Aphids (Phyllaphis fagi)

The Woolly Beech Aphids’ honeydew in turn attracts other insects who eat it, including wasps and ants.

Ants harvesting Woolly Beech Aphid Honeydew

Ants harvesting Woolly Beech Aphid Honeydew

Ants help protect the tree from the insects that feed on its leaves, by aggressively attacking them.

The Harvester butterfly also feeds on the Woolly Beech Aphid’s honeydew, although its first choice is Wooly Alder aphids.  The Harvester’s caterpillars eat the aphids themselves.

Harvester Butterfly

Harvester Butterfly

A non-native scale insect (cryptococcus fagisuga) introduced through the nursery trade on European Beech threatens the health of American Beech by providing an opening in the bark that together with a fungus enables beech bark disease.  This is a good example of the importance of using native plants in your own garden, and the danger of using introduced exotic plants.

There is a fungus species that grows exclusively on the Woolly Beech Aphid’s honeydew, a sooty mold descriptively named Beech Aphid Poop-eater (Scorias spongiosa).  Some studies have shown that leaves covered in sooty molds are more effective at removing pollution from the air than other leaves are.

Beech Aphid Poop-eater (Scorias spongiosa)

Beech Aphid Poop-eater (Scorias spongiosa)

Oyster (Pleurotus ostreatus) and Burnt-Orange Bolete (Tylopilus ballouii) mushrooms, both edible, are among the other fungi that may be found on or near American Beech.

American Beech develops natural cavities that provide nesting sites for cavity nesting birds like Titmice, Chickadees, Woodpeckers and Nuthatches, all of whom rely on insects for a large part of their diet, and will help protect the tree from insect leaf-eaters.  Chipmunks, squirrels, porcupines and other mammals also take advantage of the natural shelter American Beech offers.

Gray Squirrel in cavity of American Beech

Gray Squirrel in cavity of American Beech

Other birds, like the Wood Thrush below, may nest on the limbs of American Beech, using some of the previous year’s fallen leaves as nesting material.

Wood Thrush on her nest in an American Beech.  Some old Beech leaves have been used as nest material.

Wood Thrush on her nest in an American Beech. Some old Beech leaves have been used as nest material.

American Beech’s fallen leaves may offer insect protein for ground-feeders like the Ovenbird.

Insect nest on fallen American Beech leaf

Insect nest on fallen American Beech leaf

Ovenbird in American Beech

Ovenbird in American Beech

Beechdrops (Epifagus virginiana) depends on American Beech for its survival, since it gets its food from the tree’s roots.  Look for the flowers in late summer or early fall, and the brown seed capsules throughout the winter.

Beechdrops (Epifagus virginiana) flowers

Beechdrops (Epifagus virginiana) flowers

Beechdrops (Epifagus virginiana) in winter

Beechdrops (Epifagus virginiana) in winter

American Beech flowers are wind pollinated, with separate male and female flowers both on the same plant.  They bloom as the leaves are opening.

Male flowers of American Beach (Fagus grandifolia)

Male flowers of American Beach (Fagus grandifolia)

Nuts are produced if the flowers are successfully pollinated, usually 2 or 3 three-sided nuts per husk.

American Beach (Fagus grandifolia) nuts

American Beach (Fagus grandifolia) nuts

The nuts are a source of high protein and fat for mammals and birds, including red, gray and flying squirrels, chipmunks, bears, Blue Jays, Tufted Titmice, Wild Turkey, and Ruffed and Spruce Grouse.

Tufted Titmouse eating American Beech nut

Tufted Titmouse eating American Beech nut

Nothing goes to waste in nature, so an empty beechnut husk may be reused as a shelter by an insect.

Insect nest in husk of American Beech

Insect nest in husk of American Beech

As the nights get longer and the temperatures drop in the fall, the American Beech begins to prepare for winter.  The leaves gradually stop producing chlorophyll, which reduces the green color visible in the leaves, revealing the yellows and oranges of carotenes, and the brown tannins, .

American Beach (Fagus grandifolia) leaf in fall

American Beach (Fagus grandifolia) leaf in fall

American Beech is native in moist woodlands in the eastern United States and Canada.  The bounty of insects supported along with its nutritious nuts makes it one of our most valuable tree species for wildlife.

Golden-crowned Kinglet in American Beech

Golden-crowned Kinglet in American Beech

 

Resources 

Cech, Rick; Tudor, Guy.  Butterflies of the East Coast.  2005.

Eastman, John.  The Book of Forest and Thicket.  1992.

Eaton, Eric R.; Kauffman, Ken.  Kaufman Field Guide to Insects of North America.  2007.

Lincoff, Gary H.  National Audubon Society Field Guide to North American Mushrooms. 1981

Rhoads, Ann Fowler; Block, Timothy A.  The Plants of Pennsylvania.  2007

Tallamy, Douglas W.  Bringing Nature Home, 2007,

Wojtech, Michael.  Bark A Field Guide to Trees of the Northeast.  2011.

USDA NRCS Plants Database

Tom Volk’s Fungi

iNaturalist.org
http://www.inaturalist.org/taxa/144013-Scorias-spongiosa

Butterflies and Moths of North America http://www.butterfliesandmoths.org/species/Erora-laeta

Illinois Wildflowers
http://www.illinoiswildflowers.info/trees/plants/am_beech.htm

Penn State Extension Natural Resources
http://extension.psu.edu/natural-resources/forests/news/2012/winter-leaves-that-hang-on

Northern Woodlands
http://northernwoodlands.org/articles/article/why-do-some-leaves-persist-on-beech-and-oak-trees-well-into-winter

Invasive.org
http://www.invasive.org/browse/subinfo.cfm?sub=300

 

An Orchid in Winter

On a walk in the woods the other day, I found what I was looking for: a leaf!   It may seem like it should be pretty easy to find a leaf on the forest floor, but I was looking for something very specific, not a fallen leaf, but the newly unfurled leaf of a native orchid called Puttyroot (Aplectrum hyemale).

Puttyroot (Aplectrum hyemale) leaf

Puttyroot (Aplectrum hyemale) leaf

Hyemalemeans winter, a reference to the fact that the leaves of this plant emerge in late November or December and are visible until spring.  Puttyroot is found in rich deciduous woodlands, often in the company of Sugar Maple (Acer saccharum) and American Beech (Fagus grandifolia).  It gathers its energy from the sun during the months when the forest canopy is open, while the leaves are off the trees.  Photosynthesis occurs in this plant at temperatures as low as 35ºF (2ºC).  During this time, Puttyroot also benefits from the nutrients released to the soil from the blanket of decomposing leaves from the neighboring trees.

In ideal conditions, Puttyroot sends up a single striped, accordion-pleated leaf in late fall, about 3-8 inches (.75 – 2 dm) long and 1-3 inches (.25 – .75 dm) wide. The leaf dies back by the time the single flower stalk blooms in May or early June.  The flower stalk height can vary from about 6 to 20 inches (1.5 – 5 dm).

Puttyroot (Aplectrum hyemale) flowers

Puttyroot (Aplectrum hyemale) flowers

Bees are likely the pollinators of Puttyroot, although the flowers can also self-fertilize if necessary.  Puttyroot’s many tiny seeds are dispersed by the wind.

Puttyroot (Aplectrum hyemale) flower

Puttyroot (Aplectrum hyemale) flower

There may be years when a Puttyroot plant doesn’t bloom, its presence only revealed by the winter leaf.  Some years the plant may be completely dormant, without even the leaf visible above ground.

This orchid species is native throughout the eastern half of the United States (except Florida) and in Quebec and Ontario provinces in Canada, but it is listed as rare, threatened or endangered throughout much of its range, including New York, New Jersey, Pennsylvania, Vermont and Massachusetts.

Non-native, invasive plants like Garlic Mustard (Alliaria petiolata) and Japanese Stiltgrass (Microstegium vimineum) are a serious threat to Puttyroot and its companion woodland plants. Not only do these invasive species compete for resources with native plants, they also alter the soil chemistry in a negative way, interfering with the mycorrhizal fungi that is present.  Most plants don’t get the nutrients they need directly from the soil, but rather through a partnership with mycorrhizal fungi.  Plants provide sugars to the fungi, and the fungi in turn make nutrients available to the plants. If the fungi aren’t present, the plants won’t get the nutrients necessary to continue to be viable.  The good news is that both Garlic Mustard and Japanese Stiltgrass are easy to remove by pulling.  Garlic Mustard is edible, so you can reward yourself for removing it by eating your ‘harvest’.  Garlic Mustard pesto, anyone?

Early settlers used a mucilaginous substance obtained from Puttyroot’s corms (part of the underground food storage system) to repair broken pottery, a practice that resulted in the plant’s common name.  Another common name, Adam and Eve, also refers to the plant’s corms, which are usually paired.

Puttyroot (Aplectrum hyemale) leaf

Puttyroot (Aplectrum hyemale) leaf

Go for a walk in the woods and see if you can find a Puttyroot leaf.  If you’re successful, make a mental note of its location.  Then visit the spot again in May or June, to see if you can find the flower stalk in bloom.  Repeat the process until you find this buried treasure!

Resources

Capon, Brian.  Botany for Gardeners.  2005

USDA Plants Database

Go Botany

New England Plant Conservation Program Aplectrum hyemale (Muhl. ex Willd.) Nutt. Puttyroot

Illinois Wildflowers

USDA National Invasive Species Information Center:
Garlic Mustard
Japanese Stiltgrass

 

 

 

 

 

Maple-leaf Viburnum

Maple-leaf (or Maple-leaved) Viburnum (Vibernum acerifolium) is spectacular this fall, with colors ranging from pale pink to deep magenta,

Maple-leaf Viburnum (Vibernum acerifolium)

Maple-leaf Viburnum (Vibernum acerifolium)

often with washes of blue and purple.

Maple-leaf Viburnum (Vibernum acerifolium)

Maple-leaf Viburnum (Vibernum acerifolium)

The combination of decreasing hours of daylight, the increasing length of darkness, and cool nighttime temperatures is nature’s signal that it’s time to prepare for winter. Plants gradually stop producing chlorophyll, which is responsible for the green color visible in the leaves during the growing season. The absence of chlorophyll reveals the colors of other chemical compounds present, like the yellows of xanthophylls, oranges of carotenes, and browns of tannins.

Many days this fall have been warm and sunny.  Nights have been cool with temperatures often in the low to mid 40s (4 – 8°C).  These conditions enable deciduous trees and shrubs to continue to produce sugars in their leaves during the day.  Some of the sugars combine with minerals obtained from the soil to manufacture anthocyanins, the chemicals that cause the red, blue and purple colors in the leaves.  The decreasing number of daylight hours combined with the cool temperatures signal the plant to stop nutrients from moving into the trees’ circulatory system as the leaves prepare to detach from the plant.  These chemical compounds are trapped in the leaves, resulting in the colorful fall display.

Maple-Leaved Viburnum (Viburnum acerifolium) with fruit

Maple-Leaved Viburnum (Viburnum acerifolium) with fruit

Fleshy, dark blue, berry-like fruits called drupes accompany the colorful leaves. Each drupe contains a single seed enclosed by a stony casing or pit, like a peach.  For many birds and other animals, the fleshy fruit is an enticement to dine in the coming weeks.   Maple-leaf Viburnum and many other plants have evolved to produce such fruits in order to enlist animals as partners in dispersing their seeds.  The animal consumes the fruit, passing the seed through its digestive system, and depositing the seed accompanied by other nutrients.  White-throated Sparrows,

White-throated Sparrow

White-throated Sparrow

Cardinals,

Northern Cardinal

Northern Cardinal

and Hermit Thrush, as well as chipmunks and squirrels are among those who consume the fruits and disperse the seeds.

In early summer, Spring or Summer Azure butterflies may lay eggs on the flower buds of this and many species of viburnums, dogwoods and other shrubs.

Summer Azure

Summer Azure

After hatching from the eggs, the butterfly’s caterpillars feed on the flower buds. That is, they do if they manage to avoid being eaten by a predator like a bird, a spider, an ant or other parasitic insect.

Maple-leaf Viburnum (Vibernum acerifolium) in bud.  Can you spot the two spiders waiting patiently for an unsuspecting caterpillar or other victim?

Maple-leaf Viburnum (Vibernum acerifolium) in bud. Can you spot the two spiders waiting patiently for an unsuspecting caterpillar or other victim?

Plenty of flowers survive the feeding frenzy to provide a beautiful summer display. Several species of native bees, flies and other insects visit the flowers for nectar, providing essential pollination services that result in the fall fruits.

Maple-leaf Viburnum (Vibernum acerifolium) in flower.  Look for the ants who are visiting the flowers for nectar.  They would also be happy to find a caterpillar.

Maple-leaf Viburnum (Vibernum acerifolium) in flower. Look for the ants who are visiting the flowers for nectar. They would also be happy to find a caterpillar.

Maple-leaf Viburnum is a great alternative to the non-native, invasive Burning Bush (Euonymus alatus), which is often planted in formal landscapes for its fall foliage.  Maple-leaf Viburnum offers an equally attractive, and more nuanced display.  More importantly, it provides food and shelter for the insects, birds and other animals that share its territory.

Maple-leaf Viburnum (Vibernum acerifolium)

Maple-leaf Viburnum (Vibernum acerifolium)

Maple-leaf Viburnum is a woodland understory shrub native to the eastern United States, and Quebec and Ontario provinces. If you live within it’s natural range, go for a walk in the woods near you to see if you can spot it.  Then think about adding it to your own landscape to guarantee a view of this gorgeous shrub.

Maple-leaf Viburnum (Vibernum acerifolium)

Maple-leaf Viburnum (Vibernum acerifolium)

For more information on fall foliage colors, see Nutritious Fall Foliage: What Makes Fall Leaves So Colorful?

Resources

Capon, Brian. Botany for Gardeners.  2005

Cech, Rick; Tudor, Guy. Butterflies of the East Coast.  2005.

Glassberg, Jeffrey. Butterflies through Binoculars A Field Guide to Butterflies in the Boston-New York-Washington Region.  1993.

Illinois Wildflowers

 

A Butterfly with Unusual Eating Habits: The Harvester

We often think of butterflies as relying on nectar from flowers as their primary source of food for adult butterflies, and many species do.

Clouded Sulphur and Honey Bee on Aster

Clouded Sulphur and Honey Bee on Aster

But there are others who feed mainly on minerals, often from mud or dung, or who consume both nectar and mineral sources.

Red-spotted Purple feeding on minerals in mud

Red-spotted Purple feeding on minerals in mud

One species that has more unusual eating habits is the Harvester (Feniseca tarquinius).

Harvester (Feniseca tarquinius)

Harvester (Feniseca tarquinius)

 

This butterfly rejects flower nectar in favor of honeydew, the sugary secretion produced by aphids. Harvesters also feed on mineral sources such as dung, sap and mud.  In the photo below, the butterfly is feeding on a mushroom.

Harvester (Feniseca tarquinius)

Harvester (Feniseca tarquinius)

The Harvester’s eating habits explain its habitat preference, wet woodlands or along streams, especially where alders are found.

Smooth Alder (Alnus serrulata)

Smooth Alder (Alnus serrulata)

Alders are hosts to the Woolly Alder Aphid (Prociphilus tessellatus), a favorite honeydew source for Harvesters.

Woolly Alder Aphids on Smooth Alder (Alnus serrulata)

Woolly Alder Aphids on Smooth Alder (Alnus serrulata)

Even more important for the Harvester, these aphids are a favorite diet source of its caterpillars. The Harvester is the only butterfly species in North America whose caterpillars are strictly carnivorous.   They feed primarily on several species of woolly aphids, often the Woolly Alder Aphid, but also the Woolly Beech Aphid, as well as others.  The caterpillars will sometimes disguise themselves from predators by using their silk to tie to their bodies the remains of the aphids they consume.  This is especially effective as protection from ants that may be tending the aphids for their honeydew.  The Harvester caterpillars share some of the chemical signature of their aphid diet, which also may give them protection from predatory ants.

So wooly aphids feed both the Harvester butterfly and its caterpillars.  Because of its habitat and food preferences, the Harvester is not commonly seen. So consider yourself lucky if you encounter one!

Harvester

Harvester

Resources

Brock, Jim P.; Kauffman, Ken. Kaufman Field Guide to Butterflies of North America.  2003.

Cech, Rick; Tudor, Guy. Butterflies of the East Coast.  2005.

Glassberg, Jeffrey. Butterflies through Binoculars A Field Guide to Butterflies in the Boston-New York-Washington Region.  1993.

Featured Creatures – University of Florida

Butterflies and Moths of North America