Food for Wildlife

After three lean years, our oak trees finally produced a bumper crop of acorns last September. Forewarned by hordes of blue jays screaming from the treetops as they plucked ripe acorns from the oaks, I had to be careful on our steep trails not to slide on the fallen nuts that were more hazardous than marbles.

grey squirrel

Grey squirrel eating an acorn (Juraj Patekar image on Flickr, Creative Commons license)

Still, not every section of forested Pennsylvania had a good acorn crop, despite predictions from folks that should know better. Dr. Marc Abrams, a forestry professor at Penn State says there’s “no way to predict it,” calling a heavy mast year “one of the amazing mysteries in nature that we still do not have a handle on.”

Dr. Warren G. Abrahamson, a Bucknell University professor who conducted a long term study of acorn production from 1969 to 1996 with Jim Layne of the Archbald Biological Station in Florida, agrees, although he says that “the production of acorns definitely is not forecasting but hind casting the weather.” In their September 2003 report of their work they claimed that the size of the acorn crop each year is partly controlled by precipitation which affects acorns during different stages of development in prior years.

Other experts think that the group behavior of masting trees called synchrony most likely depends in part on the temperature during pollination in late April or May. Since oaks are wind-pollinated, meaning the wind must transfer pollen from staminate (male) to pistillate (female) flowers, a period of rain might disrupt the process.

For instance, a cold, wet spring in 2012 affected red oak production in 2013 because all the oaks in the black oak group (those with pointed lobes on their leaves) take two years to mature. Those in the white oak group (those with smooth lobes on their leaves) take only a year and would be affected by a late spring frost during pollination.

Still others believe that synchrony occurs as a way to outsmart nut predators by producing more nuts than the predators can eat, ensuring that at least some nuts will grow into trees. But whatever the causes, it is cyclic and occurs every three to five years.

On our dry mountaintop we have mostly chestnut oaks with an occasional white oak in the white oak group. Deer prefer these tastier acorns and squirrels eat them almost immediately because they spoil more quickly than those in the black oak group, which include scrub, black, northern red, and scarlet oaks here. Those acorns the squirrels store.

hickory nut

Hickory nuts form 10 to 25 percent of a squirrel’s diet in a good year (image by Peppysis on Flickr, Creative Commons license)

Acorns are not the only hard mast fruit. Others include the squirrels’ favorite—hickories, especially pignut, mockernut, and shagbark—which consists of 10 to 25 % of their diets in a good year and ripen before acorns. But like oaks, as well as the other hard mast producers—American beeches and black walnuts—they are also wind-pollinated.

Hard mast is high in fat, carbohydrates, and protein and is important to at least 180 species of birds and animals in fall and winter, but since it is highly variable in production from year to year, wildlife must depend also on a wide variety of soft mast throughout spring, summer, and fall. These fleshy, perishable fruits high in sugar, vitamins, and carbohydrates include a wide variety of native trees, shrubs, and woody vine species.

Foresters and wildlife biologists, in fact, consider mast to be the woody plant fruits and browse of native trees, shrubs and vines even though the word mast comes from the Old English “maest” which meant the forest tree nuts on the ground that fattened domestic pigs and other animals.

A wide variety of soft mast allows many mammals and birds to survive the lean years of hard mast. Of course, there are always some nuts every year, but ever since the extinction of American chestnut trees which, because they were insect-pollinated and didn’t bloom until summer, reliably produced an excellent crop of nuts, wildlife has had to adjust to a feast or near famine hard mast situation.

Consequently, encouraging biologically diverse meadows and forests, stocked with native trees, shrubs, and woody vine species produces food for wildlife throughout the year. And diverse food leads to diverse wildlife, as we’ve discovered on our property.

Other examples of trees that are insect-pollinated and produce a huge number of seeds every year as well as foliage, twigs and bark are red and striped maples. Striped maple, also called moosewood or goosefoot, has fruit that matures in early fall and is eaten by ruffed grouse, rodents, and songbirds. In addition, it produces browse for deer and bark for rabbits and beaver.

Elk eat the buds, foliate, twigs and bark of red maple, songbirds gorge on the seeds, and squirrels and mice store them for winter.

Basswood is another insect-pollinated tree, producing seeds squirrels and chipmunks consume while deer and rabbits browse its foliage.

The best of the soft mass fruit is that of wild black cherry trees. It fruits abundantly every third or fourth year in August and is pollinated by solitary bees. Seventy bird species feed on the fruit including grouse and wild turkeys. Black bears, raccoons, foxes, rabbits, squirrels, chipmunks and mice relish the dark cherries.

witch-hazel fruit and flowers

Witch-hazel fruit and flowers (Image by Rodger Evans on Flickr, Creative Commons license)

The fruit of sassafras trees, which is high in fat, is eaten by turkeys, bobwhite quail, black bears, pileated woodpeckers and gray catbirds. Rabbits and deer browse its twigs, black bears like its stems and deer its leaves. Despite its popularity, we have many sassafras trees in our forest.

Common witch-hazel, which flowers in late fall, develops woody capsules the following spring and summer. Those capsules contain a pair of shiny, black hard-coated seeds that shoot out in autumn before the next flowering. But squirrels, turkeys, quail, and grouse go after them, especially if the acorn crop fails. Deer browse heavily on witch-hazel, but it persists in growing above the deer line here.

Common spicebush (my personal favorite) produces brilliant spicy red fruits eaten by grouse, pheasants, and quail. It also provides shoots for rabbits and browse for deer, but it too survives and thrives, especially in wet areas along our stream. Our son Dave has planted it as an attractive shrub in our yard and his.

Both red-berried elder, which blooms the same time as the invasive barberry, has red berries available for birds in June or early July, although it only lives on steep slopes here because deer are fond of its browse. Deer also like common elderberry. It blooms in late June or early July and hangs heavy with clusters of dark purple berries favored by birds and humans in late August.

White-throated sparrow with staghorn sumac fruit

White-throated sparrow with staghorn sumac fruit (Kelly Colgan Azar photo on Flickr, Creative Commons license)

Staghorn sumac is making a recovery on our property, living on the sunny edges of meadows and forests. Blooming in late June and early July, its greenish-yellow, fragrant flowers morph into bright red, cone-shaped clusters of fruit that last through the winter, providing food for squirrels, songbirds, grouse, pheasants, turkeys and quail. Deer and rabbits browse on this shrub as well.

Wild berries are a popular summer food. First come the lowbush blueberries as early as mid-June on our powerline right-of-way, followed by the huckleberries. Black bears are particularly fond of them, but so are songbirds, grouse, chipmunks, pheasants, and mice.

Black raspberries ripen in early July and blackberries in early August. Both are incredibly important fruit for songbirds, skunks, opossums, foxes, squirrels, chipmunks, and black bears, while rabbits like their cover and rabbits and deer browse on their stems. Of course, the wildlife must also compete with me, especially in the blackberry patches.

Opossum eating wild grapes

Opossum eating wild grapes (photo by pverdonk on Flickr, Creative Commons license)

Greenbrier of several species has bluish-black berries eaten by songbirds and gamebirds and deer browse them. They browse wild grapevines too, but wild grapes are among the most important and valuable food for wildlife including songbirds, gamebirds, foxes, skunks, raccoons, opossums, squirrels and deer. The vines provide winter shelter for animals and birds too. I remember one winter when the hard mast failed and deer spent the season among the grapevines of the Far Field thicket, yarding up like they do in northern New England.

My list of native trees, shrubs and vines could be greatly expanded. In other parts of Pennsylvania, particularly south of us, still other wildlife food, such as common papaws, are important. But diversity remains the key to providing abundant wildlife food, even in years when hard mast is scarce.

The Beautiful Beech

beech leaves in snow

Beech leaves in snow

Ghostly leaves of American beech trees sway in February storms like tiny spirits alive in a frozen world.  But only small and medium-sized beech trees hold on to their leaves throughout the winter.

In the fall, I watch the toothed, leathery, single beech leaves turn from green to gold.  Then the gold leaks from them and they become the color of polished brass — a striking contrast to their silver bark.  Most of the leaves sift to the ground in the slightest breeze, but those on smaller beech trees curl up and cling tightly, even as the brass leaks from them, leaving them a brittle, beige-white that catches the weak winter light and sets them glowing like torches among the dark hemlocks.

American beech trees — Fagus grandifolia — gather in silvered clumps, especially in our north-facing hollow.  Over the largest beech trunks lie a patina of lichen green.  Only a couple large tree trunks , with smooth, elephantine-like bark, bear the marks of humans.  But each trunk is unique, displaying its history of lost branches on its skyward way.  Some patterns look like upside down wide smiles, others like triangles.  Large “eyes” keep watch on the world around them.  Still others bear mottled marks.

Most trunks are reasonably straight, but one beech is bent like a contortionist as it reaches for light under the hemlocks.  Another is wrapped from bottom to top by a thick grapevine.

beechdrops in September

Beechdrops in September

If I look closely on the ground beneath the smaller beech trees, I see what, to untutored eyes, looks like dried, branched stems but are, in reality, the remains of beechdrops (Epifagus virginiana).  These nonphotosynthetic, flowering parasites on beech roots produce small, tubular, dull magenta and pale brown, insect pollinated flowers near the ends of their branches that bloom in September and October.  But the flowers farther down the branches never open and are self-fertilized.  Looking even more closely at the plants, I sometimes see the yellowish, felt-like galls on their tiny leaves constructed by the eriophyid mite (Acalitus fagerinea).

Beech trees themselves are wind-pollinated. But those clumps of trees in our hollow are clones that are the result of root sprouts.  Even though beech trees thrive in the moist soils of valley bottoms and lower slopes, such as our hollow, a clone of small and medium-sized beeches also grows in our upland forest between the spruce grove and the Far Field Road. Because they can reproduce in dense shade, beeches live easily in mature hardwood forests.

From long, thin, “cigar-shaped” buds, as my botany professor described them, stiff, green leaves emerge along zig-zag twigs.  At almost the same time, in April and May, male and female flowers bloom.  The head-shaped clusters of beige male flowers dangle from long green stems while the paired female flowers have short stems and one- quarter-inch, urn-shaped flowers.

beech eyes

Beech eyes

If all goes well and we don’t have a late spring frost, I will find beechnuts on our driveway in October after the first autumnal frosts.  Beech trees must be at least 40 years old to bear a good crop of nuts and those 60 or more are the most prolific.  Back before the eastern forests had been logged, millions of passenger pigeons fed on nuts from old growth trees.

Native Americans also made use of them, extracting their oil for cooking and pioneers used the oil in their lamps.  Native Americans also chewed the nuts to expel worms, while pioneers dried them and roasted them as a coffee substitute.

Today, bears leave claw marks on beech bark as they climb them to feed on the nuts.  Squirrels, white-tailed deer, white-footed mice, raccoons, rabbits, chipmunks, red and gray foxes, opossums, ruffed grouse, wood ducks, wild turkeys, blue jays, rose-breasted grosbeaks, and red-bellied woodpeckers also feed on the sweet, small, triangular-shaped nuts, which are borne in pairs within the four-valved, prickled husks. The larvae of the early hairstreak butterfly also eat the nuts.

The leaves are tasty to a huge number of caterpillars with charming names such as the spun glass slug, elegant tailed slug, red-eyed button slug, purple-crested slug, the laugher, red-humped oakworm, wavy-lined heterocampa, blinded sphinx, saddled prominent, and the Bruce spanworm, to name a few. The larvae of the more familiar moths — Io, luna, and cecropia — and butterflies — the red-spotted purple (which we have by the dozen in the hollow) and the closely-related white admiral — also feed on the beech leaves.

beech leaves in May

Beech leaves in May

Leaves were valuable to the pioneers who dried them to stuff in their mattresses.  Native Americans boiled leaves and bark to treat frostbite and burns.  They also took an herbal decoction orally for bladder, kidney and liver problems.  Even the bark was valuable in making an ointment to treat sores and ulcers. Rappahannock Indians steeped the bark in saltwater to make a lotion to counteract poison ivy.  Folks in Kentucky were said to use beech sap to treat tuberculosis.  But, for those folks who might be wondering, Beechnut gum contains no beechnut product.

The light-colored, hard and strong beech wood today is used for firewood, furniture veneer, railroad ties, crates, boxes, and paper and early settlers prized it for making charcoal and water wheels. The leaves and bark are popular for fabric dyes now that natural dyes are all the fashion rage.

red-spotted purple

Red-spotted purple

Although mature beech trees reach a height of 60 to 75 feet and sometimes a trunk diameter of two to three feet, they cannot compare to those described by early North American travelers such as Prince Maximilian of Wied.  Writing from southern Indiana in June of 1833, he recounted that he “came to a tall, gloomy forest, consisting almost wholly of large Beech trees, which afforded a most refreshing shade.  The forest continued without intermission…The lofty crowns of the trees shut out the sky from our view.  They were the most splendid forests I had yet seen in America…”

We’ll never see forests such as those again and, if beech bark disease continues to spread, not even the large trees we see today.  Right now the current champion in Pennsylvania is in Montgomery County with a diameter of 6 feet 8 inches and a height of 87 feet.

So far beech bark disease has not reached our hollow, but it is probably only a matter of time.  Although the beech scale insect first came from Europe on nursery stock to Halifax, Nova Scotia before 1890, it was only after the Second World War that it began to move aggressively south, reaching Pennsylvania in 1958.

Dead beech in the Adirondacks

A victim of beech bark disease in the Adirondacks

The beech scale insect Crytococcus fagisuga causes the disease by inserting its needle-like mouthpart into the beech bark and tissues beneath and sucking out the nutrients. This opening allows a native fungal pathogen Nectria coccinea var. faginata to enter it via spores it produces that can be carried by the wind or insects.  The fruiting bodies of the fungus are red and show up easily on the silver beech bark.

If I see a waxy white crust on the trunk of a beech tree, I will know that beech scale insects have reached our hollow.  Under the waxy material produced by the beech scale are the pale yellow insects.  They lay their eggs there in the summer.  Those eggs hatch and the young crawl into bark fissures on their natal tree or move to other trees with the assistance of wind or wildlife.

It may take several years for the fungus to establish itself in scale-infested trees, but when it does, it forms cankers which kill patches of inner bark.  Sometimes cankers expand and join together to girdle and kill a tree by choking off water and nutrients.  Other times a tree will survive the onslaught.  Occasionally trees are resistant to the scale insect.  It is those trees that may provide hope for the future of this beautiful tree.

On the other hand, when beeches regenerate after a scale infection, they usually resprout from the roots of dead trees, instead of from the nuts of resistant trees, and form thickets of small, weak trees genetically the same as those killed by beech scale and liable to succumb again to the disease.

beech with a flying buttress

A beech with an unusual, cathedral-style flying buttress

In Pennsylvania the disease has killed many beeches in northern Pennsylvania and has moved as far south as the Philadelphia area.  But beech trees live from Nova Scotia to northern Florida and west to Wisconsin and Texas.  Since the beech scale insect has only gone as far south as southern West Virginia and west to Ohio, the beeches farther south and west are safe for now.

When artist/ornithologist John James Audubon painted a pair of passenger pigeons, he perched them on a beech bough somewhere in Kentucky where he was then living with his wife Lucy.  But he was amazed by the abundance and wholesale slaughter of the pigeons in the beech forests of Kentucky.

“The pigeons, arrived by thousands, alighted everywhere, one above another, until solid masses as large as hogs heads were formed on the branches all round.  Here and there perches gave way under the weight with a crash and, falling to the ground destroyed hundreds of the birds beneath,” Audubon writes. Farmers drove their hogs to feast on the pigeons and “a great number of persons, with horses and wagons, guns and ammunition, had already established encampments on the borders [of the beech forest].”

It’s difficult to imagine such abundance today in our depleted forests. For, as Donald Culross Peattie writes in his classic A Natural History of Trees of Eastern and Central North America, “…two withered beechen leaves [in Audubon’s painting] tell us that the season is autumn when the mast is ripe.  An autumn that will not come again but lingers, immortal, in those leaves that cannot fall.”

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All photos are by Dave Bonta, and all were taken in Plummer’s Hollow except the Adirondack beech. Click the photos to see larger versions.