Edited by David Mizejewski, National Wildlife Federation Naturalist
Think about your yard. Is it mostly lawn? Maybe you have a few established trees scattered here and there. While a neat expanse of green has its aesthetic appeal, you could be missing out on an opportunity to create a vibrant, multi-layered ecosystem teeming with wildlife – all by strategically planting native trees and weaving in a tapestry of other native plants. If that’s not enticing enough, consider the maintenance costs of that lush green lawn. Take back your time and make environmentally-friendly choices with a more natural landscape.
Understanding the Power of Vertical Habitat
Trees aren't just solitary giants; they are vertical habitats, offering a diverse range of spaces from their towering canopies to the shaded understory and the ground beneath. By understanding and utilizing this vertical structure, you can dramatically maximize the habitat space in your own backyard, turning it into a haven for a variety of creatures. Trees alone can have a tremendous impact but the magic truly unfolds when you complement them with a variety of native flowering perennials, grasses, and shrubs.
Trees as Wildlife Cafes: Fueling the Food Web
Imagine the difference between just a turf grass lawn with a single maple tree versus a landscape thoughtfully designed with layers of trees, shrubs, and flowers. The lawn, while providing some open space for people and their pets, offers no structural diversity and no habitat for wildlife. Adding a large canopy tree species such as an oak or maple is a great start, but you can do so much more by layering different types of native plants. This creates lots of cover and safe places for wildlife to raise their young. Most birds, from the familiar cardinal nesting in dense branches to chickadees and woodpeckers raising their families in tree cavities, rely on this structural complexity.
Beyond shelter, trees themselves are also primary food sources. They are the caterpillar host plants – the essential food source for the larval stage of many moths and butterflies. The oak tree, in particular, stands out as a powerhouse, supporting an astounding 550+ species of moth and butterfly caterpillars. This is critical because 96% of birds (virtually all our backyard birds) feed their young caterpillars. These juicy larvae are packed with protein and fat, vital for growing nestlings. While adult monarch butterflies rely on the nectar of flowering perennials like milkweed, asters, and coneflowers, their caterpillars depend entirely on milkweed – often thriving in sunny spots that complement the structure of nearby trees.
And let's not forget the direct food trees provide: seeds, nuts, berries, and fruits are all offered by various native trees and shrubs, attracting a wide array of birds and small mammals. Some trees and perennials even offer nectar-rich flowers, providing an early season boost for pollinators.
Now that we've explored how trees serve as vital food sources for a variety of wildlife, let's ascend to the highest layer of this vertical habitat and discover the unique roles played by canopy trees, understory trees, and other native plants.
The Upper Story: Canopy Trees and Their Inhabitants
At the top, the canopy trees reach for the sky. Think of majestic oaks, maples, and hickories. These giants provide essential resources and shelter high above. Warblers, for example, are often found flitting through the upper branches, with different species preferring various heights within the canopy. Some sing their intricate songs from the very top, while others forage in the mid-levels.
The Middle Ground: Understory Trees for Added Diversity
But the story doesn't end there. Beneath these lofty branches, an understory can flourish. This layer, composed of smaller trees that thrive in partial shade, adds another crucial dimension to your wildlife habitat. Consider planting beautiful native options like flowering dogwood (Cornus florida) and eastern redbud (Cercis canadensis). These not only offer stunning ornamental value with their spring blooms but also provide valuable food, cover and places to raise young for wildlife. Their lower stature creates vital layers of habitat, offering refuge and foraging opportunities for species that prefer the mid-levels such as cardinals, nuthatches and jays.
The Ground Floor: Perennial Flowers, Grasses, and Shrubs
Let's not neglect the ground floor—the foundational layer of native plants that thrive between 1 and 6 feet tall. This layer plays a crucial role in creating a diverse and balanced ecosystem.
Flowering perennials are magnets for a whole host of pollinators. Native wildflowers offer vital nectar and pollen resources for bees, butterflies, moths, and even hummingbirds. By selecting a variety of species that bloom throughout the growing season, you can provide a continuous buffet for these essential insects. Remember that milkweed is the sole host plant for monarch butterfly caterpillars, making its inclusion absolutely crucial if you want to support this iconic species.
Native shrubs act as a crucial mid-level layer, bridging the gap between the understory trees and the ground. They offer dense cover for birds to escape predators, build nests, and forage for berries and insects. Shrubs like viburnums, elderberries, and serviceberries provide valuable fruit for birds and small mammals. Their twiggy structures also offer excellent winter shelter.
Native grasses, often overlooked, play a significant role in a healthy ecosystem. While grasses won’t grow in the shade of a tree, they make excellent borders for your garden and provide habitat for various insects, including grasshoppers and crickets, which in turn become food for birds and other small animals. Native bunch grasses create excellent nesting sites and winter cover for ground-nesting birds and small mammals. Their root systems also help to improve soil health and prevent erosion. For similar benefits at the base of your trees, consider planting shade tolerant native sedges or ferns.
Additional Benefits of Native Landscapes
Beyond providing food and cover, incorporating native trees and other native plants into your landscape offers a wealth of additional benefits. They offer welcome shade for both wildlife and our homes, helping us rely less on AC during hot summer months. Planting a line of dense trees, especially evergreens, can serve as effective windbreaks, helping to lower your energy costs by reducing wind chill in the winter. A well-planned mix of trees and shrubs can even create a beautiful and functional living fence or natural border.
On a larger scale, trees and plants play a vital role in our environment. They absorb carbon dioxide and release oxygen, a crucial process, especially in urban areas where air quality can be a concern. While tropical forests are often highlighted for their oxygen production, our local urban forests are critically important for the health of our communities. Trees also respire, releasing moisture into the air, which can help to humidify and cool down our cities and towns, mitigating the urban heat island effect.
Interestingly, research suggests a connection between green spaces and community well-being. Researchers noted, “the positive impact of nature and green space on human health and well-being has been documented by over 100 studies.” They reviewed 45 papers on the subject and concluded that parks and green spaces in urban areas may help reduce crime due to increased opportunities for social interaction and recreation, improved community perception, and stress reduction through connection with nature.
Several studies have indicated that neighborhoods with more trees and green spaces often experience lower crime rates. In Baltimore, Maryland, a study found a 12% drop in outdoor crimes in neighborhoods with 10% more in tree canopy. Other studies in Portland, Oregon and Philadelphia, Pennsylvania have yielded similar results.
With all these compelling reasons, from supporting local wildlife to enhancing our communities and even lowering crime, the question isn't if you should plant native trees and plants, but when you should start.
Let’s Get Growing: The Time to Plant is Now
The best time to plant a tree was 20 years ago, the second best time is today. Don't wait to transform your yard into a thriving wildlife sanctuary and reap the numerous benefits that native trees and other native plants provide. By creating these vital layers of habitat, you're not just beautifying your landscape; you're making a tangible investment in the future of our local biodiversity and the health of our planet. Start planning your native plant additions today – your local wildlife will thank you for it!