trees providing shade at middle branch park

Shade trees provide a cool respite from urban heat, Middle Branch Park, Baltimore.

Updated: April 18, 2022

Key points

  • Planting trees, mostly native ones, and taking good care of them are key actions individual gardeners and communities can take to limit the impacts of climate change and create beautiful, resilient homes and neighborhoods.
  • Trees provide shading, cooling, cleaner air and water, habitat for wildlife, and stormwater management -- many essential benefits in our natural and built environments.
  • Trees are “carbon sinks”-- they capture and store carbon dioxide, the primary climate-changing greenhouse gas. 
  • Maryland has a goal of planting 5 million native trees by 2031. Residents can receive support for purchasing and planting trees. The Maryland Department of Natural Resources and many Maryland county governments and organizations offer tree rebate programs. 

The benefits of trees in our changing climate

In our changing climate, trees play an essential role both in mitigating climate-warming greenhouse gasses as well as supporting and improving the quality of life in our natural and built living spaces. These are the many benefits of planting and maintaining trees:

Shade & cool your living spaces. Trees help reduce the urban “heat island effect” - the higher temperature of cities due to the prevalence of hard surfaces like roads, parking lots, and buildings, all of which absorb and re-emit heat. In Baltimore City neighborhoods with no trees, for example, summer temperatures have been recorded as much as 10°F to 16°F hotter than surrounding areas that have abundant green spaces and parks. Trees make it cooler by providing shade and releasing water vapor.

Save energy. Trees that shade your home in the summer and block cold winds in the winter can help you reduce the costs of air conditioning and heating. Planting with energy conservation in mind can lower your energy bills by 3 to 30 percent, depending on the size of the tree, its location, and other factors such as home construction.

Increase property value. Various studies of single-family properties have shown that the presence of trees and neighborhood tree cover increase property value by 2% to 15%.

Sink carbon. Trees are champions when it comes to holding carbon out of the atmosphere. All plants use carbon dioxide (CO2) to generate their own food and energy. In trees, a portion of this energy builds wood which stores carbon for a long time. Trees are “carbon sinks.” They hold carbon inside while they are alive. When they die, some of the carbon gets stored in the soil through roots and decomposition, and some is released back into the air. 

Improve health and well-being. Trees contribute to cleaner air by absorbing some air pollutants and capturing particles of dust and ash. Children living in communities with trees have less asthma. Trees improve community walkability, which is connected to a reduction in obesity. Studies also have shown that being around trees reduces stress and anxiety, lowers blood pressure, and increases feelings of calmness. More tree cover has even been associated with less crime.

Provide habitat. Do you enjoy birds? Butterflies? Fish? Trees provide nesting places as well as food for birds, butterflies,and small animals. Native bees and other insects and birds have evolved with native plants, which provide the specific food and habitats they need for survival. Twenty-seven percent (27%) of Maryland bees are pollen specialists, meaning they must have pollen from specific native plants to survive and raise their young. For fish: Tree roots stabilize stream banks, reduce erosion, and keep water clear; their canopies provide shade to regulate water temperature and dissolved oxygen – all important conditions for healthy populations of fish and other aquatic wildlife.

Reduce stormwater runoff. Trees help to intercept and soak up rainwater, stabilize the ground, reduce erosion, and keep water clean. Tree planting in urban and suburban areas is especially important to help minimize the amount of stormwater running over paved surfaces to storm drains and carrying pollution to streams, rivers, and the Chesapeake Bay. 

Selecting trees with climate change in mind

All tree species have a natural habitat range where they can survive and thrive. As climate change accelerates, more severe weather (floods, droughts), higher temperatures, earlier springs interrupted by freezes, and new pest and disease pressures will put stress on trees in our forests and landscapes. By 2080, summer temperatures in Baltimore, Maryland may feel more like they do in Cleveland, Mississippi, about 6°F warmer. Some tree species will fare better than others in the future. Some tree populations will be able to adapt or migrate gradually to new habitat ranges, while others will not be able to. People can facilitate migration by planting a different palette of trees with climate change and species adaptability in mind. For more on this, refer to Native Plants and Climate Change.

Researchers are working on models to help predict which types of trees will be most adaptable to future climate conditions. These are several examples:

  • The USDA Forest Service’s Climate Change Tree Atlas explores traits, habitat suitability, and adaptation potential for 125 tree species. The trees were given an “adaptability rating” to indicate how likely they will adjust to climate conditions in 2100 under low and high greenhouse gas emissions scenarios. In the Lower Chesapeake area, for example, oaks, red maple, black gum, and loblolly pine are among the species that are expected to be more adaptable.
     
  • (PDF) Climate Change Projections for Individual Tree Species: Greater Baltimore, Maryland. This list provides a summary of tree adaptability for the Baltimore region, based on the Forest Service’s Climate Change Tree Atlas.
     
  • (PDF) Climate Change Vulnerability of Urban Trees, Washington, DC is a similar assessment of tree adaptability for the nation’s capital. [Note: This list also gives ratings to some non-native species. Invasive ones (denoted with an *) should not be planted.]

Research is also underway on sourcing, trialing, and breeding new trees that will be suitable for our region’s hotter summers but still able to survive Mid-Atlantic winters. Some trees that are native to the Southern USA: Florida sugar maple (Acer saccharum ssp. floridanum), Florida anise (Illicium floridanum), and Mexican flowering dogwood (Cornus florida subsp. urbiniana), for example, have captured the interest of ornamental plant breeders at the University of Pennsylvania’s Morris Arboretum.

There will be trade-offs when it comes to selecting species from outside of our region vs. using regionally adapted native species. In urban areas with high heat, air pollution, and limited planting space, a non-native, non-invasive species might be tougher and better able to survive and provide benefits such as shading and cooling, but it may not support native wildlife as well as a native species, for example.

Questions to consider 

With climate change in mind, how do you decide which trees to plant for the best chances of survivability and benefits provision? A piece of general guidance is: Plant mostly native trees. Choose ones best suited to your site and goals. And take good care of them. If you can only plant one tree, think about multiple benefits you could gain with your choice. Here are some questions to consider:

Why choose a native tree?

Maryland native trees are ones that have evolved here naturally. They are adapted to our region’s soil and climate conditions and support native wildlife such as pollinators and other beneficial insects, birds, and small mammals. They are essential to the normal functions of an ecosystem. Will climate change put stress on some native trees? Yes. Therefore, it is prudent also to consider “near native” trees whose natural range of habitat includes our nearest southern seaboard state: Virginia. Native and “near native” will be the better choices for supporting native wildlife and a resilient ecosystem in the year 2100. Non-native trees do provide some benefits too, but trees that are non-native and invasive (e.g. Norway maple, mimosa) should be avoided.

Do some trees sequester carbon better than others?

Yes, but there is a lot of variation in carbon dioxide (CO₂) absorption rate based on species, age, and health condition of a tree. In general, CO₂ absorption is associated with growth rate, with younger trees taking up CO₂ at a faster rate than older, slower-growing trees. The bottom line: planting any new tree that is suitable for your site conditions (soil, sun/shade, moisture) will be beneficial when it comes to carbon sequestration. It is important to keep old trees healthy too; they store carbon as long as they stay alive.

Can I plant trees for energy conservation around my home?

Planting trees can lower your home energy bills by 3 to 30 percent. The amount of savings will vary by size of the tree(s), their location, and other factors such as home construction (e.g., insulation). Shade trees provide cooling in the summer and allow sunlight to pass through for passive solar heating in the winer. Rows of evergreen trees (and shrubs) can provide a protective windbreak in the winter, resulting in lower heating costs. Refer to the section below: Tree placement for home energy conservation.

Which trees can handle tough conditions near city streets and sidewalks?

Small to medium-size native trees recommended for urban areas include: Serviceberry (Amelanchier sp.), Washington hawthorn (Crataegus phaenopyrum), sweetbay magnolia (Magnolia virginiana), and American Hornbeam (Carpinus caroliniana), among others. For additional recommendations, refer to:

Are some trees better for stormwater management?

Yes. Some trees can tolerate saturated soil for a limited period of time, but others are intolerant of wet areas. Rain gardens are typically planted with herbaceous plants and shrubs that can handle short periods of flooding. If you are considering a tree for an area that tends to stay moist, sweetbay magnolia, red maple, blackgum, and river birch are among the species that are tolerant of wetter conditions. Refer to these resources: The Right Tree for Your Lawn and Rain Gardens Across Maryland (PDF).

Are some trees better for supporting wildlife than others?

Yes! Native trees are the best choice when it comes to supporting wildlife. Research by University of Delaware scientist Dr. Doug Tallamy has shown that oaks, willows, cherries, birches, crabapples, maples, and elms are some of the top choices when it comes to supporting native butterflies and moths. Native blackgum, crabapple, hawthorn and serviceberry are great choices for supporting bees.

What are some trees that will provide food?

Fruit trees like persimmons, pawpaws, and figs can be grown in Maryland with less pesticide use compared to other tree fruits like apples, peaches, and cherries, the latter being susceptible to more disease and pest pressures. Beginner gardeners might first want to try growing perennial berry plants such as blueberries, blackberries, or raspberries, which are easier to maintain than tree fruits. Perennial berry plants keep soil in place and store carbon too - great for a climate-resilient garden.

Purchasing your trees

The state of Maryland and many Maryland county governments and some nonprofit organizations offer rebates to support residents with tree planting. These programs have specific guidelines for applying, selecting approved trees, and planting requirements.

  • At the state level, check the Marylanders Plant Trees program for information on how to receive a $25 rebate.
  • The Chesapeake Tree Canopy Network has an online map of tree planting initiatives in Maryland.
  • Contact your local government office (usually the environment or public works department) to inquire about local tree planting programs and rebates.

Refer to our Planting a Tree or Shrub page for information on preparing your soil and how to plant your tree correctly. 

Planting trees for home energy conservation

Shade trees

  • Planting a shade tree on the west side of a home, to provide shade during the hottest summer afternoon hours, will provide the greatest cooling benefit and conserve energy needed for air conditioning. 
  • Planting on the east side of a home (to shade during the morning hours) has the second greatest benefit for energy savings.
  • Trees placed at the south side will cast shortened shadows in the afternoon when energy demand is the greatest. If planting on a south side, place the tree at a distance from your home that is 2.5 times the expected mature height of the tree to minimize winter shading.
  • To shade a two-story home, choose a tree that will grow to 30’ tall or higher.
  • Plant to provide shade over paved surfaces such as driveways and sidewalks. This will reduce heat that is absorbed and radiated. Small trees (under 20’) should be at least 10’ away from a driveway; large trees (>20’) should be 20’ away from a driveway.
  • Planting to shade an air conditioning unit: Research shows that planting to shade an air conditioning condenser has a minimal effect on improving efficiency, resulting in an estimated savings of <3%.  Vegetation should be at least 3’ away from the unit so that air flow is not obstructed. 

Evergreens for windbreaks

  • Plant evergreen trees on the northwest, north, or west sides of your home, to provide protection from the prevailing winter winds. This can help to reduce heating costs in the winter months. Eastern redcedar (Juniperus virginiana), Eastern white cedar/arborvitae (Thuja occidentalis), and American holly (Ilex opaca) – evergreens that retain their leaves down to the ground – are some options to provide a windbreak.

Guidelines for tree placement near buildings and utilities

  • Near a building foundation: Plant small trees a minimum of 15’ away from the foundation. A specific way to calculate spacing is to find out the expected mature canopy size of your tree, and cut that number in half. For example, if the mature width of a tree is 40’, plant it 20’ from the foundation.
     
  • Under power lines: Choose trees that are 25’ tall or lower at maturity. Tall shrubs are another option for spaces near power lines. (When Plants and Powerlines Collide: Native Shrubs Under 10 Feet, Clemson)
     

Maintaining trees: preventing tree risks & hazards

Correct planting and ongoing care are essential for maintaining your tree(s) in optimal condition, preventing hazards, and achieving maximum benefits for years to come. Erratic weather patterns are anticipated as climate change progresses, and this will put more stress on trees. It has been estimated that 80 percent of trees that fail in storms were ones that have some type of defect such as cracks, dead branches, weak branch unions, or root problems.

Monitor your tree(s) regularly for early signs of trouble. Do a visual inspection of your tree(s) at least annually and after storms. Look for:

  • Branches with no leaves
  • Hanging or fallen branches
  • Leaves that are unusually yellow in color and smaller than normal size
  • Rotting wood or loose bark on the trunk
  • Cracks where the branches meet the trunk
  • Mushrooms at the base of the trunk
  • Encircling (girdling) roots visible at the base
  • Tree leaning to one side
  • Tree has had construction/soil compaction near the base, roots were cut or paved over
  • Vines clinging to and growing up the trunk (e.g. English ivy should be removed)
  • Refer to Tree Health Assessment and Risk Management (MSU Extension)

Some early warning signs of trouble may be remediated by corrective pruning and/or soil health improvement. Send your questions and photos of tree symptoms to Ask Extension. We may recommend that you contact a certified arborist to conduct an onsite inspection of your tree for a complete evaluation of risks. You can find a certified arborist at TreesAreGood.org. Make sure the person you work with is a Licensed Tree Expert.

References and Resources

Brandt, Leslie, et.al. 2016. A Framework for Adapting Urban Forests to Climate Change, Environmental Science & Policy, 66, pp. 393-402

Chesapeake Native Plant Center | Online tool to search for native trees

Chesapeake Tree Canopy Network | Find tree canopy initiatives in Maryland

Climate Change Vulnerability of Urban Trees, Washington, DC (PDF) | ForestAdaptation.org

Climate Resilient Trees for Anne Arundel County | Watershed Stewards Academy

Fowler, Jarrod and Sam Droege. Pollen specialist bees of the Eastern United States, 2020. 

How Choosing the Right Tree Can Help Adapt to Climate Change | Chesapeake Bay Program

Kuhns, Michael. Planting Trees for Energy Conservation: The Right Tree in the Right Place, Utah State University Forestry Extension.

Lovasi, G.S. et. al. 2008. Children Living in Areas With More Street Trees Have Lower Prevalence of Asthma. J Epidemiol Community Health; 62(7): 647-649  

Mach, Bernadette and Danil Potter. 2019. Woody Plants for Urban Bee Conservation. University of Kentucky

Parker, D.S. et.al. (1996). Measured Impacts of Air Conditioner Condenser Shading, presented at The Tenth Symposium on Improving Building Systems in Hot and Humid Climates, Texas A & M University, Fort Worth, TX, May 13-14, 1996.

Sawka, Michelle, et.al. (2013). Growing Summer Energy Conservation Through Residential Tree Planting. Landscape and Urban Planning, vol 113, pp 1-9.

Soak Up the Rain: Trees Help Reduce Runoff | United States Environmental Protection Agency

Stimpson, Ashley, Green health: a tree-filled street can positively influence depression, study finds, The Guardian, March 2021.

Tallamy, Douglas W. Bringing Nature Home: How You Can Sustain Wildlife With Native Plants, Timber Press, 2009.

Trees for Energy Conservation | Extension Foundation

Trees for Our Changing Climate | Casey Trees

Tree Health Assessment and Risk Management | Mississippi State University Extension

University of Wisconsin-Madison. 2019. Trees Are Crucial to the Future of our Cities. ScienceDaily 

Urban Tree Selection Guide: A Designer’s List of Appropriate Trees for the Urban Mid-Atlantic (PDF). (2015). Casey Trees.

Using Trees and Vegetation to Reduce Heat Islands | EPA

Use Vegetation to Increase Energy Efficiency | Landscapes for Life

Wolf, Kathleen L. 2007. City Trees and Property Values. Arborist News 16, 4: 34-36.

Yeager, Ray, et. al. 2018. Association Between Residential Greenness and Cardiovascular Disease Risk. Journal of the American Heart Association, Vol 7, Issue 24 

Author: Christa Carignan, Horticulturist & Coordinator, University of Maryland Extension Home & Garden Information Center. Reviewed by Jon Traunfeld, Director, Home & Garden Information Center, and Dr. Mitchell Pavao-Zuckerman, Associate Professor of Urban Ecosystems and Sustainable Built Environments, University of Maryland. 2022