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Forests are critical to the health of the Chesapeake Bay. Large stands of trees can protect clean water and air, provide habitat to wildlife and support the region’s economy. But human activities have altered the watershed’s forests, reducing tree cover and fragmenting forests that still exist. Conserving and expanding forest cover is a critical, cost-effective way to reduce pollution and restore the Bay.

Why are forests important?

Forests are critical to the health of the Chesapeake Bay. Large stands of trees perform ecological functions that can benefit all plants and animals, from cleaning our water and air to creating valuable habitat.

Forests protect clean water

Forests act like giant sponges, keeping our rivers and streams clean and protecting our drinking water. Forests capture rainfall, trap polluted runoff and stabilize soils that might otherwise wash into waterways.

  • Streamside forests, also known as riparian forest buffers, can reduce the amount of nutrient pollution entering waterways, sometimes by as much as 30 to 90 percent. Forests currently buffer about 60 percent of the streams and rivers that flow into the Bay.
  • Mature trees have deep root systems that can hold soil in place, stabilizing streambanks and reducing erosion.

Forests protect clean air

Through a process known as attenuation, tree roots and leaves and forest soils can absorb and trap the pollutants in our air.

  • Forests can capture more than 85 percent of the nitrogen that falls onto them from the air, keeping the pollutant from flowing into our groundwater, rivers and streams. Excess nitrogen in our waterways can fuel the growth of algae blooms, which block sunlight from reaching underwater grasses and, during decomposition, create low-oxygen “dead zones” within which marine life cannot survive.
  • In urban areas, tree cover can lower summertime temperatures, counteracting the decline in air quality that can occur when pavement and buildings replace plants.

Trees also produce the oxygen we breathe.

Forests create habitat

Forests provide food, shelter, nesting sites and safe migration paths for critters in the water and on land.

  • “Interior” forests, or those that are mature and separate from other land uses, provide interior forest dwelling species with the moderate temperatures and light levels that are integral to their summertime habitat. Just 40 percent of Chesapeake forests can be considered interior habitat.
  • Streamside forests shade the water that runs beneath their leafy canopies, maintaining cooler water temperatures and reducing stress on sensitive fish. The leaf litter, seeds and other plant materials that fall into streams from these forest buffers also form the foundation of the freshwater food chain, and fallen branches, logs and woody debris can create habitat for underwater critters.
  • Standing dead trees, also known as snags, provide habitat to owls, woodpeckers, squirrels and other animals that nest in tree cavities, and a number of insects, small mammals and birds can be found foraging and living among the decomposing logs, stumps and leaves on the forest floor.

Forests support the region's economy

Forests contribute billions of dollars each year to the region’s economy. Forests support the region’s economy by: 

  • Protecting clean air and water
  • Creating wood and paper
  • Generating jobs and income
  • Increasing property values
  • Lowering residential and commercial energy use
  • Improving physical and mental health
  • Providing opportunities for recreation

Forestry is the second largest industry in Pennsylvania and Virginia and the fifth largest in Maryland. The forest industry supports many of the region’s small cities and towns, and provides 140,000 jobs, $6 billion in income and $22 billion in industry output to the Bay watershed’s economy each year.

Forests support outdoor hobbies and recreation 

Forests provide us with places where we can reflect and experience natural beauty and solitude. Forests also foster outdoor recreation, through activities like hiking, biking, camping and bird-watching.

What does a healthy forest look like?

A healthy forest is a complex community of plants, animals and soil. Healthy forests contain multiple layers of vegetation, each of which performs a unique function. This diversity of structure allows forests to protect clean water and provide wildlife with a range of critical habitats.

  • The top layer of the forest is known as the canopy. The canopy shades and protects the plants and animals below it, while intercepting and slowing rainfall.
  • Below the canopy is a layer of smaller trees and shrubs known as the understory. Here, young trees begin to grow, replacing older trees as they die.
  • Below the understory is the forest floor, where vines, grasses, mosses, worms, insects, fungi, bacteria and other small plants and animals can be found. Here, leaves, wood and other organic material decompose into a nutrient-rich soil that will feed other plants.
  • The litter on the forest floor protects the underlying soil, which often contains more living biomass than what can be found above the ground.

How are forests harmed?

Human activities—including sprawling development and the introduction of invasive species—have altered the composition of forests across the Chesapeake Bay watershed, reducing tree cover and fragmenting those forests that still exist.

Historic deforestation

When Europeans arrived to the Bay region in the seventeenth century, they discovered diverse forests that stretched across 95 percent of the watershed. European settlers viewed the removal of these forests as integral to economic development, and European settlement had dramatic and long-lasting effects on the region’s forests and water quality. By the late 1800s, 40 to 50 percent of the watershed’s forests had been cleared of trees, as land was repurposed for agriculture and trees were cut down for fuel, fencing and timber. Throughout the twentieth century, “new” forests grew up on abandoned farmland. But our forests are now more homogenous in age, size and species composition than before Europeans settled the region.


Between 1982 and 1997, the Bay watershed lost more than 750,000 acres of forestland to development—a rate of about 100 acres per day. While this rate fell in 2006 to an estimated 70 acres per day, it remains unsustainable.

As trees have been replaced with roads, buildings, farms and houses, 60 percent of the watershed’s forests have been divided into disconnected fragments. These fragmented forests are less resilient to disturbances and more prone to negative influences like wildfires and invasive species.


Parcelization describes the breakup of large land ownerships into smaller ones. Over the past decade, the number of family forest owners in the Bay watershed has increased by nearly 25 percent—a rate of about 23,000 new family forest owners per year. But close to 70 percent of all family forest owners hold less than 10 acres of land.

The parcelization of forests often corresponds with a decline in the percentage of forestland that is managed for wildlife, timber, recreation or other uses; this increases the risk of fragmentation and conversion to other land uses.

Overabundant deer

In forests across the watershed, white-tailed deer have become an increasing threat to forest health. As forests are fragmented, deer have found food on farms and in suburban gardens and safe refuges in areas where hunting is prohibited. But locally high deer populations can harm forest growth and alter forest composition, as deer eat large amounts of seedlings and young trees and selectively browse for food.

Invasive plants, insects and diseases

Invasive plants are harmful to forests for several reasons. Invasive plants:

  • Grow and reproduce rapidly, killing and out-competing other species in the process
  • Lower the quality of available food sources and shelter options for wildlife
  • Eliminate the native host plants of insects
  • Compete with native plants for pollinators

Kudzu, English ivy and Japanese honeysuckle are three invasive plants that have become permanent residents of Chesapeake forests.

Invasive pests and diseases can also alter forest conditions. Gypsy moths, emerald ash borers, chestnut blight, Dutch elm disease and beech bark disease have all had long-term, devastating impacts on the region’s forests.

How are forests being restored?

Retaining and expanding forests is a critical, cost-effective way to reduce pollution and restore the Bay. An investment in forests is an investment in clean water and air, and sustainable forestry will help address sprawling development, climate change and energy independence.

Current restoration goals

As part of the 2014 Chesapeake Bay Watershed Agreement, Chesapeake Bay Program partners committed to two goals related to trees. The riparian forest buffer goal is to restore 900 miles per year of streamside forest buffers and conserve existing buffers until at least 70 percent of the areas along streams throughout the watershed are forested. The tree canopy goal is to expand urban tree canopy—the layer of trees covering the ground when viewed from above—by 2,400 acres by 2025, providing air quality, water quality and habitat benefits throughout the watershed.

Take Action

For Chesapeake Bay restoration to be a success, we all must do our part. Our everyday actions can have a big impact on the Bay. By making simple changes in our lives, each one of us can take part in restoring the Bay and its rivers for future generations to enjoy.

To support forests in the Bay watershed, consider planting trees and shrubs to create more wildlife habitat. You can also choose and use native plants to support the plants and animals that have adapted to this region.



Chesapeake Bay News

In The Headlines

Bay Watershed Forest Cover

In the 1600s, forests covered 95 percent of the Chesapeake Bay watershed. According to high-resolution land cover data collected in 2013 and 2014, just 57 percent of the watershed—about 24 million acres—is forested.

Planting Forest Buffers

Between 2014 and 2015, about 64 miles of forest buffers were planted along the Chesapeake Bay watershed’s rivers and streams. This is 7 percent of the Chesapeake Bay Program’s goal to plant 900 miles of forest buffers each year. It brings the total amount of forest buffers planted since 1996 to 8,216 miles.

Protected Lands

Data collected between 2015 and 2016 show that, since 2010, approximately 1,004,577 acres of land in the Chesapeake Bay watershed have been permanently protected from development. While some increases in acreage can be attributed to improvements in data collection—for instance, by reporting previously protected but newly digitized, corrected or refined parcels of land—other increases can be attributed to newly protected parcels of land. The total acreage marks an achievement of 50 percent of the land conservation goal adopted in the Chesapeake Bay Watershed Agreement and brings the total amount of protected land in the watershed to 8.8 million acres.

Bay 101: Healthy Forests

December 15, 2010

Healthy forests clean our air and water, support industries and economies, and provide us with a place to relax. Craig Highfield, Forestry for the Bay Program Manager, explains how a healthy forest works and why they are so important to the Chesapeake Bay watershed.


Protecting the Forests of the Chesapeake Bay Watershed - A Response to Directive 06-1

Publication date: December 05, 2007 | Type of document: Directive | Download: Electronic Version

In 2006, the Chesapeake Executive Council recognized that retaining, expanding, and sustainably managing forest lands is essential to restoring a healthy Chesapeake Bay by signing Directive 06-01. This implementation document responds to…

The State of Chesapeake Forests

Publication date: September 01, 2006 | Type of document: Report | Download: Electronic Version

This first-of-its-kind report synthesizes more than a decade's worth of data from public and private sources, highlights current forest conditions, forecasts future trends, and outlines key goals and strategies necessary to conserve and…

Chesapeake Bay Riparian Handbook: A Guide for Establishing and Maintaining Riparian Forest Buffers

Publication date: June 01, 1998 | Type of document: Report | Download: Electronic Version

The purpose of this handbook is to provide professional land managers and planners with the latest information on the functions, design, establishment and management of riparian forest buffers.

Forestry Best Management Practices and Water Quality in the Piedmont and Ridge and Valley Provinces of the Chesapeake Bay Watershed

Publication date: July 01, 1997 | Type of document: Report | Download: Electronic Version

A literature review was conducted to determine the effectiveness of forestry best management practices (BMPs) in reducing water quality impacts of forestry management operations within the Piedmont and Ridge-and-Valley of the Chesapeake Bay…

Forest & Riparian Buffer Conservation: Local Case Studies from the Chesapeake Bay Program

Publication date: August 01, 1996 | Type of document: Report | Download: Electronic Version

This publication is a collection of case-studies that highlight accomplishments of local governments and citizen organizations to recognize the importance of forests to their communities and to take action to retain and restore those…

Water Quality GIT BMP Review Protocol

Publication date: | Type of document: Policy Document | Download: Electronic Version

July 13, 2015 version.

From Around the Web

Bay FAQs

  • How do forest buffers benefit the Chesapeake Bay?


Bay Terms

  • Attenuation
  • Canopy
  • Deforestation
  • Erosion
  • Forest fragmentation
  • Forest parcelization
  • Forest-interior species
  • Riparian forest buffers
  • Understory


Bay-Friendly Tips

  • Plant Trees and Shrubs
  • Plant a buffer of trees and shrubs around the edge of your property to capture polluted runoff.
  • Use Native Plants
  • Native flowers, shrubs and trees often require less water and can provide food and habitat for birds, butterflies and honeybees.


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