What do trees provide habitat for

By Josie Miller

Urban trees are valued for the ecosystem services that they provide, such as energy conservation, carbon sequestration, air quality enhancement, and stormwater mitigation. Additionally, urban trees are valued for the social services they provide, including their effects on the health and wellness of humans. As more people become interested in supporting wildlife, urban trees are increasingly valued for their habitat potential.

What is a wildlife habitat tree?

Habitat trees have been defined as “standing live or dead trees providing ecological niches (microhabitats) such as cavities, bark pockets, large dead branches, epiphytes, cracks, sap runs, or trunk rot” (Bütler, R., Lachat, T., Larrieu, L., & Paillet, Y., 2013). These microhabitats are used by a number of animals, plants, and fungi as a place to live, forage, and breed. On living trees, cavities may be formed naturally, such as when a large branch breaks and the exposed wood begins to rot, or they may be excavated by primary cavity nesters such as pileated woodpeckers or northern flickers. Bark pockets may be associated with a particular tree species, such as shagbark hickory that has naturally peeling bark, or they may occur on a dead tree on which the bark has begun to slough off as part of the decay process. Overall, standing dead trees, also known as snags, and dying trees are thought to benefit hundreds of species.

Habitat tree residents

Urban residents of habitat trees include birds, small mammals, amphibians and reptiles, arachnids, and insects. Each of these animals finds shelter from predators and weather in the insulated nooks of a habitat tree. Additionally, plants, lichens, and fungi may use a tree as a growing substrate or food source. Birds may use dead branches on the tree as a perch from which to sing or hunt, or use a cavity as a place to roost or nest. Secondary cavity-nesters, such as bluebirds and flying squirrels use natural cavities, or the vacant cavities previously excavated by woodpeckers (primary cavity-nesters.) Birds, such as brown creepers, and bats may also inhabit the protected spaces behind loose or sloughing bark. Amphibians and reptiles take advantage of cracks as both a safe hiding place and hunting grounds for insects. All of these animal residents add to the ecological function of the urban forest. By welcoming birds, bats, and other insectivores, humans and trees alike benefit from the resulting insect pest control.

Incorporating wildlife trees into an urban setting

Although habitat trees are common in unmanaged forests, they are lacking in the urban environment. Due to safety and aesthetic concerns, habitat trees are often removed from these settings. In order to encourage urban wildlife, more people are choosing to keep, or even create wildlife trees. Maintaining an urban wildlife tree requires a commitment to manage the tree, but rewards the manager with myriad opportunities for wildlife viewing.

Because wildlife trees may be potentially hazardous, it is important to consult an ISA Tree Risk Assessment Qualified Arborist when deciding whether or not to keep or create a habitat tree. If a habitat tree is unadvisable for your situation, the arborist may recommend leaving a large stump as an alternative. Cavities and roosting slits may be artificially created by the arborist in order to enhance the stump habitat. Because dead and dying trees are not always recognized as habitat trees, installing signage is an effective way to share your intentions with your community.

Photography

1. Declining elm tree (Ulmus americana) in meadow provides habitat for animals with minimal risk to humans. (Josie Miller)
2. Shaggy bark of white oak (Quercus alba) behind which bats may hide. (Josie Miller)
3. Pileated woodpecker (Dryocopus pileatus) nestlings in excavated cavity. (“Woodpecker” by Charles de Mille-Isles is licensed under cc by 2.0)
4. Black cherry (Prunus serotina) snag protected by homeowner. (Josie Miller)

About the Author

Josie Miller is a field technician at Floracliff Nature Sanctuary, a 287-acre forest and ecological preserve in the palisades region of the Kentucky River in southern Fayette County, Kentucky. Email @ 

Resources

Bütler, R., Lachat, T., Larrieu, L., & Paillet, Y. (2013). Habitat trees: key elements for forest biodiversity. In In Focus—Managing Forest in Europe (2.1). Retrieved from http://www.wsl.ch/info/mitarbeitende/buetler/publications/InFocus-Integrate-chapterHabitat_trees-final.pdf

The Cavity Conservation Initiative (2016). The value of dead trees. Retrieved from http://cavityconservation.com/value-of-dead-trees/

French, B. (2015). Features of habitat trees. http://www.arboriculture.international/environmental-1#environmental

Harper, C. Improving your backyard wildlife habitat. Agricultural Extension Service, the University of Tennessee PB1633I. Retrieved from http://www.slideshare.net/Sotirakou964/tn-improving-your-backyard-wildlife-habitat

National Wildlife Federation. (1997). Turning deadwood into homes for wildlife. Retrieved from https://www.nwf.org/News-and-Magazines/National-Wildlife/Gardening/Archives/1998/Turning-Deadwood-into-Lively-Homes-for-Wildlife.aspx

Torsello, M. & McLellan, T. (2004). There’s life in hazard trees. Retrieved from http://na.fs.fed.us/spfo/pubs/uf/wl_haztrees/haztrees.htm

Washington Department of Fish and Wildlife. (2011). Snags—the wildlife tree. Retrieved from http://wdfw.wa.gov/living/snags/snags.pdf

Writter, S. (1997). Dead trees and living creatures: the snag ecology of Idaho. Idaho Wildlife (Vol. 17 No. 4). Retrieved from https://fishandgame.idaho.gov/public/wildlife/nongame/leafletSnag.pdf

Trees are not only vital for humans, but they’re important for animals as well. By planting a tree in your yard, you’re not only making it more beautiful, but you’re also helping local wildlife out too. Even when a tree is only just a seedling or has just been planted, all different kinds of animals begin to benefit from it. Animals both big and small depend on trees.

From trees, animals receive many of the things they need to survive, and in return, animals help trees pollinate and reproduce. Animals and trees rely on each other for support. Here are some ways in which animals use trees.

For Food

One of the most important tree uses that foster the tree-animal relationship is through food. Some trees grow flowers or leaves that animals eat. Other trees produce seeds and fruits that animals (and sometimes humans) can eat too. Here are seven trees that will help to attract birds to your yard.

For instance, the Pacific dogwood produces orange and red berries that birds enjoy. The red alder yields seeds that birds, such as the pine siskin and common redpoll, like to eat so much that they come back each year. Squirrels, porcupines, and other mammals enjoy acorns, pine nuts, and a variety of other nuts.

For Shelter

Trees serve as homes for many animals. Birds may be the most common animal that comes to mind when you think of tree-living, but they’re not the only ones. In North America, you’re likely to find bats, raccoons, squirrels, mice, opossums, bears, and maybe even a lynx. Around the world, animals such as koalas, sloths, pandas, orangutans, lemurs, geckos, and many more are all adapted to tree-top living. Many of these animals spend the majority of their days sleeping, playing, eating, and raising their babies all in the trees.

In your own yard, you can choose to plant certain trees that will attract birds and mammals alike. For instance, you can give birds that are threatened or endangered the shelter that they need to survive, all while keeping your yard beautiful. Choosing coniferous, deciduous, and fruit tree options to plant in your yard will help to attract birds.

The two of the best options are Douglas firs and western hemlock trees. These trees attract marbled murrelets and northern spotted owls, which are two of Portland’s most imperiled birds. Marbled murrelets will use the branches of these trees to lay their eggs, rather than in birds’ nests. Northern spotted owls will use these two trees as well as grand firs, incense cedars, and ponderosa pines as their habitat. You might even provide a home for a bald eagle nest.

For Shade

Like humans, animals sometimes need a break from the sun. Whereas some animals live in trees, other animals just need a tree for some shade, especially during the summer on those hot, sunny days. Popular trees that provide shade to humans can provide shade to animals too. The pagoda dogwood is a good example. Not only do they have fruit that attracts local wildlife, but the great shade that they provide is also enjoyed by birds and mammals.

If you’re considering a tree that will provide shade and protection for your yard and home, remember this option will also be helping local wildlife with more than shade. During times of bad weather, whether extreme rain, winds, or heat, animals can be safe in trees and not far from their source of food.

For Reproduction

Trees are used by animals as a place where they can reproduce safely. For some animals, such as birds, they also serve as a place where they can lay their eggs and raise their young and keep them safe until they’re ready to leave the nest. Because of this, a tree is a very important aspect of the life cycle for some animals.

Animals however also aid in the health and reproduction of trees. Many animals fertilize trees and others work to disperse seeds and pollen from the plants into different areas, allowing more to grow.

Other Uses

In addition to all the above uses, there are some other ways animals rely on trees. Rather than living in trees, some animals just use them as resting points. Additionally, trees can help some animals to hide or help them to hunt and capture their prey.

Animals use trees for an array of purposes, and trees are vital for many animals’ survival. Some examples of wildlife that need trees to survive are birds, owls, frogs, salamanders, bats, raccoons, red foxes, snowshoe hares, the American beavers, and bears. Just to name a few! By planting trees, you’re helping to create a wonderful wildlife habitat in your community and helping to make sure our ecosystem thrives. Isn’t that great?

If you’re looking for the best types of trees to plant to attract certain animals to your yard, look no further than Mr. Tree. We know which trees work best to attract a variety of birds and furry friends, big or small, to your yard. Or maybe you want to provide a food source or shelter to an animal already living in your yard. We can help with that too. We’re happy to guide you in your decision and help out with all aspects of planting.

Contact us today. We’d love to hear more about your yard and what you’re looking to plant. We are also happy to chat more with you about how animals use trees and how your yard can be a haven for them. The relationship that a tree and animals have is an important one, and you can help foster that just by simply planting a tree or two.