Important Trees for Wildlife Diversity in the United States
Regardless if you are a hiker, photographer, hunter, or birdwatcher; understanding the biome you visit is a crucial step in finding wildlife in that area and tree species often from a cornerstone of that habitat. While I am by no means an expert I have spent the past few months looking at various tree species around the United States that seem to be particularly beneficial in promoting wildlife diversity. This list is no where near exhaustive but I hope it can at least help you identify trees in your area or places you may visit and perhaps gain a little more understanding and appreciation for their pivotal role in supporting wildlife.
15.) Douglas Fir (Pseudotsuga menziesii)
Native to the western United States, the Douglas Fir can be identified easily by its distinctive cones with pointed bracts pointed out of the side. On younger trees or those without cones, the first step will be to look at the needle extending from the branch. Is there more than one needle? If so it is a pine. If not pull one needle off and place it between your fingers, can you roll it or is it flat and wide? If flat and wide look at the needle itself, it should be about 1 1/2" long and have two pale white stripes running down the needle. If it meets these criteria, you probably have a Douglas Fir. Two varieties exist, the coastal and the rocky mountain. The trees can live up to 1,000 years or more and are the second tallest conifer in the world (behind the coastal redwood). These trees are the primary habitat for the threatened Spotted Owl and their seeds and branches are grazed upon by Blacktail Deer, Moose, and Elk. In areas with dense populations of these animals you will often observe stunted Douglas Firs as the deer will continually feed off the top shoots thereby preventing growth.
14.) Mangrove (Rhizophora mangle)
The Red Mangrove is a critical tree in maintaining the health of estuary systems in Florida, Louisiana, and Texas. Easily recognizable by its aerial prop roots, mangroves provide protection and habitat for a variety of species including juvenile fish, birds, mammals, and the endangered Florida Manatee, Key Deer, and American Crocodile. In fact the Florida Fish and Wildlife department notes that around 1,300 species of animals rely upon mangroves for their survival. In addition, mangroves improve the quality and clarity of the water by capturing sediment from upstream, stabilizing the bank, acting as a filter, and perhaps most importantly: the roots themselves become prime habitat for detritus eaters such as shrimp, snails, bivalves, barnacles, and worms which themselves help improve water quality.
13.) Dogwood (Cornus drummondii & Cornus sericea)
Dogwood's are an undervalued resource for wildlife. Generally they are found in transition zones between forests and grassy areas or underbrush areas with adequate light. While it may grow up to 20 ft tall and 15 ft wide, dogwoods are often shrublike in the wild. The fruit which ripens in early fall is excellent forage for songbirds, grouse, quail, pheasants, and turkey--often lasting until early winter. Twigs are often food for rabbits and deer. Younger dogwoods can create dense thickets when grown closely together which provides necessary cover for small mammals and birds.
12.) Smooth Sumac (Rhus glabra)
With its distinct shape and unique fruit, Smooth Sumac is perhaps one of the most recognizable plants you never paid attention to. Preferring a forest edge and often one of the first plants to pioneer a freshly burned field, Sumac commonly grow up to 9 ft tall and 15 ft wide and are easily identifiable by the 4 to 9"panicle on which the fruit develop. Flowers in midsummer. Cottontail's and Deer will eat the twigs and the fruit is a favorite of bobwhite quail, pheasant, chipmunks, turkey, and dove.
11.) Cottonwood (Populus deltoides)
Cottonwood Trees provide a dynamic and vital roll in providing ecological diversity within prairie biomes. This may be surprising as most think of the prairie as a singular expanse of grass and wildflowers. Thinking this would be partially right, indeed prairies are mostly grasslands, but that is only part of the story. For a view of the prairie in my area look here at my hike through Konza Prairie in the Flint Hills, in some directions all you will see is grass for miles and in other directions you will see quite a few trees. You see the prairie is a battlefield and the boundaries between pockets of woodland and the expanse of grass are continually waxing and waning. This battle is the story of the Cottonwood and I find it fascinating. To understand this let us begin with an area that is entirely grass and has a small creek running through. Miles away in early summer a Cottonwood releases thousands of small seeds with cotton like strands which allow them to be carried great distances in the wind. A fraction of those may find themselves in a creek and are carried downstream where they wash ashore and begin to grow on a muddy bank in open prairie. As this lone tree grows it begins to establish a more secure bank and outcompete grasses for light. More Cottonwoods establish themselves and in the process this pioneer plant provides suitable conditions for other trees to begin growing there, notably Ash and Elms. Since Cottonwoods grow poorly in shade unlike Ash and Elms, increasingly the Cottonwoods will begin to be found only on the fringe of this micro forest slowly combating the grassland and expanding into the prairie. As it develops into a woodland it begins to increase biodiversity: amphibians seeking shelter from the harsh sun will multiply on creek banks, Prairie Elk and Mule Deer will seek shelter from the prairies' quintessential harsh thunderstorms and snow and will forage on the leaves and twigs of the trees, and birds, squirrels, and small mammals will make their homes in the canopy. It would seem this woodland is unstoppable and the prairie will lose this battle. Perhaps this would be the case but the grassland has its own unique weapons to combat the woods--fire and water. Fire is frequent on the prairie and if intense enough may kill most or all of the trees. In addition, while Cottonwoods have a high tolerance of wet conditions, other trees in the prairie often are not, being more drought resistant than water tolerant. In years where a stream may run especially high or years with atypical rain these species suffer. Thus you can see how this tiny woodland will constantly grow and shrink, Perhaps it may even disappear all together and the process will begin anew.
10.) Hawthorn (Crataegus crusgalli, Crataegus viridis, & Crataegus phaenopyrum)
While many people undoubtedly curse the Hawthorn after being stabbed by its it's impressive thorns, this tree plays an important role for wildlife despite its malicious nature. They are an important source of nectar for insects. The fruit is an important source of winter forage for fox, thrush, waxwings, deer, turkey, pheasant and turkey. In addition many songbirds under the protection of it's thorns build nests within it. Typically the species grows up to 40 ft tall and is most often found in well drained soil in full sun. Despite its thorny nature, Hawthorns easily compete for the title of most beautiful trees no matter the season.
9.) Cedar (Thuja occidentalis and Juniperus virginiana)
Cedar's provide excellent roosting areas for Turkey at night and when searching for them if your area has some it is a great place to start looking. Also look for deer rubs on Cedar tree's as male deer will often use their trunks for shedding their velvet and Bucks marking their territory. Perhaps most importantly the Northern White Cedar, native to the upper reaches of the US and Canada, serves as an important emergency food source for deer during harsh winters, no doubt saving many from starvation. Young cypress have branches close to the ground thus serving as a natural shelter from predators, wind, and snow for many species.
8.) Wild Plum (Prunus americana)
A small tree native to the central United States. Easily identifiable by the fragrant white flowers which develop prior to the leaves in early spring and the small fruit The suckers which develop from the root system are quite beneficial in aiding in the stabilization of banks near rivers and creek beds. In addition the tendency for wild plums to grow from root suckers often means they form dense wind breaks in the wild. Often located on the edge of forests they are excellent habitat for quail. The fruit is eaten by many birds and budding twigs by both Whitetail and Mule Deer.
This is not Socrate's poison hemlock, Conium maculatum. Eastern Hemlock is a coniferous tree native to the eastern US. The dense foliage provides excellent winter protection for grouse, turkey, and deer. The branches provide excellent nesting habitat for a variety of songbirds which also feed off the seeds. The twigs are also browsed by deer and rabbits.
6.) Aspen (Populus tremuloides)
Growing in dense homogeneous forests in high elevation mountain habitats. Aspen are a crucial species for deer, moose, and elk which both use them for shade and also consume the bark and twigs. Bark is smooth and white to gray colored. While Aspens produce seeds, new tree growth occurs primarily through root sprouts, thus entire groves are often clones of the same tree. Increasing Elk populations have severely limited Aspen growth in Yellowstone National Park for several decades by eating the new shoots before they can reach maturity. The somewhat recent introduction of wolves into the park area seems to have reversed this trend. As a result total biodiversity has notably increased within the park as more Aspen trees means more habitat for all wildlife.
5.) Bald Cypress (Taxodium distichum)
A large tree typically growing on saturated soil or swamps. Characterized by a main trunk with a thick knee at the bottom and leaves which shed every winter. Root system stabilizes swamp systems and aids flood control. Waterfowl and songbirds consume the seeds and use the branches for perching areas. Bald eagles often make nests in the crowns.
The state tree of Arizona, the Desert Ironwood grows in valleys in the Sonora Desert. The tallest trees in the desert they may reach 25 feet, though this is small compared to many trees it is enough to provide shelter from the heat for many of the deserts inhabitants, cooling temperatures by as much as 15* with its shade. Nicknamed the nursery plant, the Ironwood provides necessary protection for a variety of wildflowers and cacti which are often found underneath its branches. Trees bloom from April to June and produce 2 inch long bean like seedpods, which are an excellent source of food for a variety of wildlife. The Desert Ironwood is a keystone species for Jack Rabbits, Desert Bighorn Sheep, Mule Deer, and Sonoran Pronghorn in the desert landscape.
3.) Balsam Fir (Abies balsamea)
Medium sized evergreen characterized by numerous resin blisters. Cones stand erect are are dark grey in color. Found throughout the northern US the Balsam Fir provides winter food for Moose, Red Squirrels, Porcupine, and White Tailed Deer as well as shelter for Snowshoe hares, and Ruffled Grouse.
2.) American Chestnut (Castanea dentata)
Perhaps the ultimate food source for Whitetail deer in the eastern US, an American Chestnut forest is able to produce 2,000 lbs of nuts per acre and generates more carbohydrates per acre than corn. In addition, Chestnuts begin bearing nuts within 3-5 years unlike oaks which can take up to 20 years to produce a quality food source. Rapidly growing to heights up to 100 ft tall, the American Chestnut once accounted for 25% of the trees in the Appalachian Mountain range but after introduction of a fungus in 1904 (Chestnut blight) native populations were decimated. New strains which are 15/16's American Chestnut and 1/16 Chinese Chestnut are proving to be resistant to the fungus and the species is making a comeback.
1.) White Oak (Quercus alba)
The monolithic and long lived White Oak, these trees may be up to 150 ft wide and 100 ft tall. The Acorns which drop in the fall provide an incredibly valuable food source for deer, black bears, wood ducks, turkey, squirrel, pheasant, and rabbits. Unfortunately the White Oak doesn't begin acorn production until it is 20 years old and won't reach full productivity until the age of 50, but unlike other Oak trees the White Oak will produce acorns yearly. Find a White Oak in the fall or winter and you most likely have found a key food source for the wildlife in the area.