Garden

Growing Tips: Let’s talk trees

Trees are much more than attractive components of a landscape. They provide numerous other benefits which we sometimes overlook or take for granted. Let's consider some of the ways humans and other living creatures, as well as the environment as a whole, benefit from trees.

Shade

One of the first things that comes to mind when thinking of trees is often the shade they provide. With the exceptionally hot weather our area has experienced over the past few summers, shade is even more important than ever. A shady outdoor area is often several degrees cooler than a sunny spot. Shade trees can make an entire neighborhood feel much cooler. Shaded sidewalks and paved areas absorb less heat. Trees that shade the side or roof of a home can help it stay cooler inside as well, making the home more comfortable and reducing cooling costs.

Windbreaks

Groups of evergreen trees, positioned correctly, can be used to create windbreaks that decrease the amount of cold winter winds affecting a house and thereby reduce heating costs.

Oxygen

Trees pump oxygen into the atmosphere. Like other plants, trees use sunlight, carbon dioxide and water to produce the food they need through a chemical reaction called photosynthesis. Oxygen, a byproduct of photosynthesis, is released through a tree's leaves. Humans and most other living creatures need oxygen to survive.

Water

Trees help to mitigate flooding, decrease erosion and filter water. Tree roots absorb water and aid in infiltrating it into the ground, where it is filtered as it moves through layers of soil. Some of that water makes its way to underground aquifers which many humans depend upon. Tree roots also help to hold the soil in place, preventing soil particles from entering waterways and degrading them. Rain hitting the leaf canopy of a tree is slowed as it falls through layers of leaves, making it less likely to fall on the soil with enough force to erode it.

Habitat

Small mammals, birds and insects often make their homes in trees. Hollowed out spots, called tree cavities, are home to squirrels, chipmunks, raccoons, owls and several species of songbirds, just to name a few. Trees also provide places for birds to make their nests. Tree branches serve as perches from which birds can sing or scout for food. Tree bark provides

shelter for a variety of insects. All of these creatures are part of the circle of life and need safe places to live and raise their young.

Food

Many of the fruits and nuts enjoyed by both humans and wildlife grow on trees such as apple, pear, peach, plum, cherry and walnut. In addition, flowering trees provide pollen and nectar for bees, butterflies and other pollinators. According to Dr. Douglas Tallamy of the University of Delaware, a single native oak tree can support over 500 species of insects. These insects in turn support birds because insects in the caterpillar stage are a primary source of food for young birds who are not yet able to eat the seeds enjoyed by adults.

Native trees are of particular importance when it comes to sources of food for wildlife. While an exotic tree from another continent may be a beautiful sight, it will have little or no value for wildlife.

Beauty

Trees, with their graceful branches, lush canopies and interesting bark add beauty to our landscapes. Some bloom in spring while others provide splashes of fall color. Others stay green all year, giving us some welcome color during cold, gray winters. We sometimes use their branches and pine cones to make holiday decorations. The presence of trees has been found to increase residential property values by 3% to 15% according to the Arbor Day Foundation (www.arborday.org/perspectives/8-reasons-plant-tree-arbor-day).

With so many benefits to offer, are you thinking of adding a tree or two to your landscape? Think carefully before making your selection and include native trees whenever possible. Not only will they add beauty, shade and oxygen, they will also provide food and habitat for wildlife.

To help you get started, University of Maryland Extension has tips for selecting trees at www.extension.umd.edu/resource/tips-choosing-trees-and-shrubs/. Information on native trees for Pennsylvania landscapes is available at www.extension.psu.edu/early-spring-blooming-native-trees-a-delight-to-us-and-to-pollinators and through PA Enflowered at www.paenflowered.org/AdvancedPlantSearch-treesshrubs.

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Debra C. Burrows, PhD, is a retired Penn State Extension Educator and a certified Master Gardener. She can be reached at dcb3@psu.edu.