Native trees and shrubs for wildlife: what deer, squirrels, bears, bats, turtles and salamanders actually get from a planting

For the animals with fur, scales and moist skin, a native tree is food, shelter and a nursery at once, and almost none of that comes from ornamentals. Acorns alone are eaten by more than 150 species of wildlife. In a six-year study in western Massachusetts, 26 of 28 female black bears produced cubs after autumns with a heavy nut and berry crop, and in the poor years 10 of 10 produced none. The litter under a Missouri oak forest holds roughly 3,000 to 5,000 salamanders per acre. This article covers mammals, reptiles and amphibians; birds and insects have their own.

Hard mast is the main event

Hard mast is the fat-rich seed that keeps: acorns, hickory nuts, walnuts, beechnuts, hazelnuts and chestnuts. It drops in September and October, and through fall and winter it is the main thing a deer, squirrel, chipmunk or mouse lives on, and what a bear fattens on before denning. In an oak woodland in fall, acorns can be more than 70 percent of what a deer eats, and raccoons make them their most important winter food. White oak (Quercus alba) acorns are a choice food for white-footed mice, fox squirrels, black bears, red squirrels and cottontails, and in one set of studies animals took 72 to 83 percent of the entire crop.

Hickory nuts are the richer prize. Black bears, red and gray foxes, white-footed mice, chipmunks and rabbits all feed on shagbark hickory (Carya ovata) nuts, fox squirrels prefer them from August through October and again in February and March, and in some regions hickory nuts are 5 to 10 percent of an eastern chipmunk’s diet. Black walnut (Juglans nigra) is about a tenth of the fox squirrel’s diet. American beech (Fagus grandifolia) feeds mice, squirrels, chipmunks, bears, deer and foxes. American hazelnut (Corylus americana) bears within a few years and gives squirrels, foxes and deer a nut from July, weeks before any acorn. Allegheny chinquapin (Castanea pumila) feeds squirrels, chipmunks, opossums and deer, and the Chinese chestnut we grow for food feeds deer and squirrels too, though it is not a native.

Mast years and the boom and bust behind them

Oaks do not bear evenly. White oak has a good crop every 4 to 10 years by one account and every 3 to 5 by another, and yields swing from nothing to 202,000 acorns per acre. The leading explanation is predator satiation: a failure starves the seed eaters down, and the next flood of acorns is more than the survivors can eat.

In 13 years of records from New York, white-footed mice and chipmunks tracked the previous year’s acorn crop, and black-legged tick nymphs tracked the rodents a year after that; deer numbers had no predictive power. When a gypsy moth outbreak wiped out the acorn crop in Shenandoah National Park, pregnant bears went to den a week earlier and came out a week later.

Two things follow for a planter. Mast comes from big crowns: substantial yields are rare from oaks under 25 years old and best from large trees with well-developed crowns. And the two oak groups fail in different years. A March 1955 freeze in east Texas and Louisiana all but wiped out the white-group crop while the red group had a good year. Plant both; the split is the whole point.

White oak acorns are eaten, red oak acorns are buried

White-group acorns hold about 2 percent tannin and 5 to 10 percent fat, and they sprout the autumn they fall. Red-group acorns hold 6 to 10 percent tannin and 18 to 25 percent fat, and they stay dormant until spring. Gray squirrels offered artificial acorns picked the low-tannin ones in autumn and the high-fat ones in winter, tannin and all. In tagged-acorn experiments, small mammals ate the white oak acorns on the spot and buried the red oak ones, which keep in the cache. A gray squirrel that does want to keep a white acorn bites the embryo out of the tip first, and the excised acorn stays sound for up to six months.

On the ground, white oak seedlings clump within a few yards of the parent while red oak seedlings spread much farther, planted by squirrels, flying squirrels and mice that never came back, and by blue jays that carry small red-group acorns more than half a mile.

Soft mast from June to March

Soft mast is fleshy fruit, and a calendar. Downy serviceberry (Amelanchier arborea) ripens from June; bears eat it, and squirrels, chipmunks, rabbits, mice, foxes and deer eat the fruit or browse the plant. Red mulberry (Morus rubra) fruits from June to August for opossums, raccoons and both tree squirrels. Black cherry (Prunus serotina) ripens through the summer and is a favorite of black bears; red foxes, raccoons, opossums, squirrels and rabbits take it too. American plum (Prunus americana) ripens in August and September and its thickets are shelter as well as food. Pawpaw (Asimina triloba) goes from August into October to foxes, opossums, raccoons and squirrels, and black gum (Nyssa sylvatica) feeds bears and foxes.

American persimmon (Diospyros virginiana) ripens from September into November and is the fall fruit for everything at once: squirrels, foxes, skunks, deer, bears, coyotes, raccoons and opossums. At persimmon trees watched by camera in one study, deer made 93 percent of the visits, but a deer’s rumen destroys the seed; the raccoons and coyotes that pass it whole plant the next tree. Hackberry (Celtis occidentalis) ripens in fall and hangs on the tree until winter or spring. American holly (Ilex opaca) holds fruit through most of the winter, for birds first and deer and squirrels after. Nannyberry (Viburnum lentago) and blackhaw (Viburnum prunifolium) feed mammals as well as birds, and American beautyberry (Callicarpa americana) holds fruit into winter for raccoons, foxes, opossums and deer.

The low fruit matters as much. Eastern box turtles eat mayapple (Podophyllum peltatum), black cherry, elderberry (Sambucus canadensis), black huckleberry (Gaylussacia baccata), blueberry, mulberry, blackberry, grape and pokeweed, and pass the seeds; fungi are 10 to 55 percent of what they eat.

Browse, and what it means for a planting

Browse is twigs, buds and bark, and in the North it is 74 to 91 percent of a deer’s winter diet. Deer reach about 5 feet up, so a sapling is at risk and a tree is not. In the Northeast their preferred woody foods include maple, dogwood, hawthorn, holly, black gum, black cherry, oak, sumac, basswood (Tilia americana), hemlock and viburnum. Rabbits take twigs, buds and bark once the green is gone and can girdle a young oak.

Some natives are largely left alone. Shagbark hickory is seldom browsed unless nothing better is around, beech is poor deer food, and the University of Maryland’s deer-resistant list includes pawpaw, spicebush (Lindera benzoin), sweet pepperbush (Clethra alnifolia), American holly, sweetbay magnolia (Magnolia virginiana), blackhaw, black elderberry and eastern red cedar (Juniperus virginiana), with the warning that there is no deer-proof plant. Where deer are overabundant they strip the palatable species, the unpalatable ones take over and tree diversity falls; hemlock can stop regenerating altogether. So cage every young tree from the first day, and put the browse-favored species inside the fence and the resistant ones at the edge. Protecting young trees from animals has the hardware.

Bark, cavities and the big old tree

The endangered Indiana bat spends its summers under the loose bark of dead and dying trees, and the peeling plates of a live shagbark hickory make what the Forest Service calls an excellent alternate roost. It prefers big trees that get direct sun for more than half the day and forms nursery colonies of up to 100 females. The northern long-eared bat, listed as endangered in November 2022, roosts alone or in maternity colonies of 30 to 60 under bark and in the cavities and crevices of live trees and snags. The moths they hunt come from the same trees; see the butterfly and moth article.

In Pennsylvania 35 species of birds and 20 species of mammals use tree cavities, and only the squirrels and one or two bats cannot do without them. A raccoon den cavity averages 11 by 14 inches and sits 10 to 39 feet up; southern flying squirrels pile into an old woodpecker hole 15 to 20 at a time in winter, and screech owls use them too. In Shenandoah National Park 84 percent of pregnant black bears denned in live tree cavities, most often in a northern red oak (Quercus rubra), in trees averaging 38 inches through with the entrance 32 feet up. Fungus is not a death sentence for a big tree, and a hollow one away from any target is the most valuable tree on the property; old growth is largely a matter of having them.

Leaf litter, logs and the pool under the canopy

The animals in the litter outnumber everything else. In a Missouri Ozark oak forest, careful counts found 7,300 to 12,900 southern red-backed salamanders per hectare, two to four times the 1975 Hubbard Brook estimate. Rotting logs shelter salamanders, snakes, mice and shrews; at least 19 kinds of salamander and 26 reptiles use logs, stumps, bark and slash piles in Pennsylvania alone.

Eastern box turtles sleep in a shallow form dug in moist litter, burrow under a log in hot weather, and from October or November until March hibernate in stump holes and hollows filled with deep litter, digging deeper as the cold comes down. They range over about 4 to 20 acres and die by the thousands on roads and under mowers every year. Wood frogs winter in rotting logs and stumps or under moss and leaves and freeze solid there, protected by glucose in their tissues. In early spring they and the spotted, Jefferson and blue-spotted salamanders walk to a vernal pool, a fish-free hollow that fills in spring and dries by summer, and breed in a few nights. They spend the other eleven months in the surrounding woods, usually within 600 yards of the pool, under logs, stones, deep litter and canopy shade. Leaf litter, not wood chips and the habitat around a tree cover the litter and the stick pile.

Winter cover, water and the way between

Evergreens are winter shelter. Deer in the North gather in yards under closed conifer canopy that cuts wind and snow depth; one Michigan yard held 43,000 deer, and 11,000 died in one hard winter. Eastern hemlock (Tsuga canadensis) is thermal cover, snow interception and a highly preferred winter browse, which is why it fails to regenerate under heavy deer. Dense eastern red cedar is escape cover for deer and small mammals, and rabbits, foxes, raccoons, skunks and opossums eat its blue cones. Rosebay rhododendron (Rhododendron maximum) thickets are winter and escape cover for deer, cottontails, bears and grouse; mountain laurel (Kalmia latifolia) does the same on drier ground, and American holly is the broadleaf evergreen for a yard.

Water sets the map: the old guidance keeps raccoon den trees within a quarter mile of it, and beavers cut within about 300 feet of it, aspen and willow first. Animals also need a way between the pieces: a hedgerow of hazelnut, plum and staghorn sumac (Rhus typhina) along a fence, a strip left unmown between the woods and the neighbor’s, a brush pile at the edge.

Why native, and what the ornamentals do instead

The hard mast species are all natives, and no maple, pear, zelkova or crape myrtle makes a nut. The soft-mast natives feed the animals that plant them; the ornamentals that have escaped mostly feed ticks. In Connecticut, forest under Japanese barberry (Berberis thunbergii) held 166 ticks per acre infected with the Lyme bacterium against 20 per acre in adjacent barberry-free forest, and the litter under barberry weighed 2.3 tons per acre against 5.0 on plots without it. Around St. Louis, deer used stands of Amur honeysuckle (Lonicera maackii) more than uninvaded woods, infected lone star ticks were more numerous there, and cutting the honeysuckle out reduced both. Deer then carry the seed: more than 70 plant species, several of them invasive introductions, germinated from deer droppings collected over one year in New York. White mulberry (Morus alba) hybridizes with the native red mulberry, one more reason not to plant it. Invasive vines and shrubs covers the removal.

The species that matter most

Ranked, with the gaps in our catalog named.

1. Oaks, both groups. Ours: swamp chestnut oak (Quercus michauxii) and overcup oak (Quercus lyrata) for wet ground, cherrybark oak (Quercus pagoda) for the red group, dwarf chinquapin oak (Quercus prinoides), which bears within a few years, and bear oak (Quercus ilicifolia) for small or poor sites. White oak, northern red oak and chestnut oak (Quercus montana) are the common natives to add.
2. Hickories. Shagbark for the nuts and the bat bark, northern pecan (Carya illinoinensis) for bottomland. Mockernut (Carya tomentosa) and pignut (Carya glabra), which we do not grow, are preferred squirrel mast and rarely sold anywhere.
3. American beech and black cherry. We sell neither. Beech is the third hard mast and deer mostly leave it alone; black cherry is the summer fruit for bears, foxes and raccoons.
4. Black walnut, American hazelnut, Allegheny chinquapin. Early nuts.
5. American persimmon, pawpaw, black gum, the serviceberries, red mulberry, American plum. The fruit calendar, June to November; hackberry carries it to March, and arrowwood viburnum (Viburnum dentatum), gray dogwood (Cornus racemosa) and deerberry (Vaccinium stamineum) feed mammals as well as birds.
6. Evergreens. Eastern red cedar and eastern hemlock, which we do not sell, and American holly, rosebay rhododendron and mountain laurel, which we do.
7. Shrubs. Spicebush, nannyberry, blackhaw, black elderberry, black huckleberry, staghorn sumac, American beautyberry, black chokeberry (Aronia melanocarpa), Washington hawthorn and American crabapple.

How to plant for wildlife

Plant a mast orchard with a fruit understory and a shrub edge. Give the oaks and hickories room to grow the wide, sunlit crowns that bear. Plant the two oak groups in equal numbers so a spring freeze cannot take the whole year, and add a hickory even though you may not see nuts for decades. Under and around them put the fruit trees in the order they ripen, serviceberry to persimmon, then the shrubs. Cage everything young; the deer and rabbits you are planting for will otherwise eat the planting.

Keep the dead wood: a snag that is not over a house or a path stays, and a hollow oak is a bear den or a raccoon den in the making. Keep water on the place, and if a low spot under trees floods in spring, leave it. Do not use anticoagulant rodenticides: a poisoned mouse takes days to die and is eaten by foxes, raccoons, skunks, hawks and owls; New York’s wildlife health program logged more than 325 such poisonings from 2012 to 2024. Keep cats indoors; free-ranging cats kill an estimated 6.3 to 22.3 billion mammals a year in the United States. Mow high where box turtles live. Pull the barberry and honeysuckle.

What to do this fall

• Plant acorns of both oak groups the week they drop, under hardware cloth, and a hickory nut or two beside them.
• Order a persimmon, a pawpaw and a serviceberry for the understory, and a holly or a rhododendron for winter cover.
• Cage every sapling before the first frost.
• Rake nothing under the trees; pile the prunings; leave the snag.

Sources

• Oak dispersal syndromes: do red and white oaks exhibit different dispersal strategies?: Steele, Smallwood and others, USDA Forest Service General Technical Report SRS-73 (2004): acorns feed more than 150 wildlife species, the tannin and fat figures for the two oak groups, squirrels eating white acorns and caching red ones, embryo excision, seedling spacing and jays carrying acorns over a kilometer.
• Quercus alba, Fire Effects Information System: USDA Forest Service: white oak acorn crop intervals and yields per acre, which mammals eat the acorns, animals taking 72 to 83 percent of the crop, rabbits girdling stems and acorn fall in September or October.
• Carya ovata, Fire Effects Information System: USDA Forest Service: which mammals eat shagbark hickory nuts, the fox squirrel’s preference months, hickory nuts as 5 to 10 percent of a chipmunk’s diet, dispersal by squirrels and chipmunks, and deer seldom browsing hickory.
• Odocoileus virginianus, Fire Effects Information System: USDA Forest Service: acorns above 70 percent of the fall diet, browse as 74 to 91 percent of northern winter diets, the 5-foot reach, preferred browse species in the Northeast, mast from large crowns and trees over 25 years, the 1955 freeze, deer as keystone herbivores, conifer yards and the Mead Deer Yard losses.
• Ursus americanus, Fire Effects Information System: USDA Forest Service: 26 of 28 Massachusetts females producing cubs after good mast years and 10 of 10 producing none after poor ones, Shenandoah bears denning a week earlier after the acorn failure, 84 percent of pregnant bears denning in live tree cavities, and the bear’s soft mast.
• Procyon lotor, Fire Effects Information System: USDA Forest Service: acorns as the raccoon’s most important winter food, cherries, apples and persimmons in the diet, den cavities of 11 by 14 inches at 10 to 39 feet, and den trees within a quarter mile of water.
• Terrapene carolina, Fire Effects Information System: USDA Forest Service: the box turtle’s fruits and fungi, seed dispersal, forms in litter, hibernation dates and litter-filled hollows, home ranges and deaths on roads and under mowers.
• Climate, deer, rodents, and acorns as determinants of variation in Lyme-disease risk: Ostfeld, Canham, Oggenfuss, Winchcombe and Keesing, PLOS Biology 4 (2006): mice and chipmunks tracking the prior year’s acorns and tick nymphs tracking the rodents a year later, with deer adding no predictive power.
• Myotis sodalis, Fire Effects Information System: USDA Forest Service: Indiana bats roosting under loose bark of dead and dying trees, shagbark hickory as an excellent alternate roost, roost tree size and sun, and nursery colonies of up to 100 females.
• Northern long-eared bat (Myotis septentrionalis): US Fish and Wildlife Service: roosting under bark and in cavities and crevices of live trees and snags, maternity colonies of 30 to 60, the moth-heavy diet and the November 2022 endangered finding.
• Dead Wood for Wildlife: Penn State Extension (Hassinger and Payne): 35 bird and 20 mammal species using cavities in Pennsylvania, squirrels and bats as the obligate cavity users, screech owls, and the salamanders, reptiles, snakes, mice and shrews that use rotting logs.
• Abundance, biomass production, nutrient content, and the possible role of terrestrial salamanders in Missouri Ozark forest ecosystems: Semlitsch, O’Donnell and Thompson, Canadian Journal of Zoology 92 (2014), hosted by the USDA Forest Service: 7,300 to 12,900 southern red-backed salamanders per hectare in Ozark oak forest, two to four times the 1975 Hubbard Brook estimate.
• Vernal Pools: University of New Hampshire Extension: the obligate pool breeders, eleven months spent within 600 yards of the pool, why fish-free pools matter, and keeping logs, stones, deep litter and canopy shade.
• Controlling Japanese barberry: alternative methods and impact on tick populations: Ward, Williams and Worthley, USDA Forest Service GTR-NRS-P-78 (2011): 166 infected ticks per acre under barberry against 20 in barberry-free forest, and litter of 2.3 tons per acre under barberry against 5.0.
• Seed dispersal of Diospyros virginiana in the past and the present: evidence for a generalist evolutionary dispersal syndrome: Rebein and others, Ecology and Evolution 7 (2017), full text at PubMed Central: deer made 93 percent of the camera detections at persimmon trees, and only the raccoons and coyotes passed viable seed.
• Seed dispersal by white-tailed deer: implications for long-distance dispersal, invasion, and migration of plants in eastern North America: Myers, Vellend, Gardescu and Marks, Oecologia 139 (2004): more than 70 plant species, several of them invasive introductions, germinated from deer droppings collected over a year in New York.
• Invasive honeysuckle eradication reduces tick-borne disease risk by altering host dynamics: Allan and others, PNAS 107 (2010), abstract at the University of Missouri-St. Louis repository: deer used Amur honeysuckle stands more, infected lone star ticks were more numerous there, and removing the honeysuckle reduced both.
• Managing Hardwood Stands for Acorn Production: Mississippi State University Extension: an even split between the two oak groups guards against a total acorn failure in any one year.
• Rodenticide Toxicity: Cornell Wildlife Health Lab: the days between a rodent eating an anticoagulant bait and dying, the foxes, raccoons, skunks, hawks and owls poisoned by eating it, and the more than 325 New York cases from 2012 to 2024.
• The impact of free-ranging domestic cats on wildlife of the United States: Loss, Will and Marra, Nature Communications 4 (2013): free-ranging cats kill an estimated 6.3 to 22.3 billion mammals a year in the contiguous United States.