Counties Going Bald: Tree Cover Loss Over 20 Years

An aerial view of a missing square of trees in the middle of a heavily forested area

Which U.S. counties have lost the most tree canopy coverage?

To mark June as Great Outdoors Month, LawnStarter ranked Counties Going Bald: Tree Cover Loss Over 20 Years.

We compared over 3,100 U.S. counties based on the net percentage and net change in tree cover (in kilo hectares) between 2000 and 2020 using data from Global Forest Watch.

1 kilo hectare (kha) = 2,471 acres

Get lost in the woods of our ranking below. To learn how we ranked the counties, see our methodology.

County Rankings
Top 5 Close Up
Key Insights
Methodology
Final Thoughts: What’s Causing the Nation’s Canopies to Recede?

County Rankings

See how each county fared in our ranking:

Top 5 Close Up

Check out the slideshow below for highlights on each of our 5 counties with the highest rates of tree cover loss between 2000 and 2020.

Key Insights

700 counties in our ranking have lost 1 kilo hectare (or about 2,471 acres) of tree cover or more between 2000 and 2020. However, over half of the counties in our ranking — 1,794 of them — experienced a net gain in tree cover between 2000 and 2020.

Alaskan territories bookmarked the top and bottom of our ranking, with some of the largest recorded tree canopy losses and gains. 5 regions finished with high rates of canopy degradation, including Yukon-Koyukuk Census Area (No. 1) which is over 7X bigger than the largest county of the lower 48 states, San Bernardino County, California (No. 112).

Millions of acres of Alaskan wildlands have been impacted by wildfires, and since 2016, 2 million acres of spruce forest area have been devastated by spruce beetle infestations.

5 Rhode Island, 12 Maine, and 23 Wyoming counties landed near the top with higher rates of tree loss.

Tree mortality in Rhode Island can be attributed to gypsy moth caterpillars — which are responsible for killing over 45,000 acres of forest. Damage has also been caused by environmental stress, other pests, and diseases such as beech leaf disease, discovered in 2012. The state is working to “future-proof” some forested areas by planting more resilient species like southern pines.

Many of Maine’s trees are succumbing to invasive threats such as emerald ash borers and hemlock woolly adelgids, which are degrading forests of native beech, ash, and hemlock trees. Coastal spruce trees are also under environmental threat from pests and harsh weather conditions.

Estimates show that the mountain pine beetle epidemic impacted over 3.3 million acres of federal forest areas in Wyoming. The state is also removing many dying cottonwoods.

Arid counties with less tree cover to begin with have some of the most dramatic net percentage increases and decreases in tree cover. Several Texas counties sprouted along the bottom of our ranking near Lea County, New Mexico, in last place. These regions don’t naturally have heavily forested environments but have had comparatively large canopy gains.

Explore more regional insights below.

Methodology

First, we determined the factors (metrics) that are most relevant to rank the Counties Going Bald: Tree Cover Loss Over 20 Years. We then assigned a weight to each factor based on its importance and grouped those factors into 1 category: Tree Loss. The categories, factors, and their weights are listed in the table below.

For each of the 3,132 U.S. counties with available data, we then gathered data on each factor from the sources listed below the table.

Finally, we calculated scores (out of 100 points) for each county to determine its rank in each factor, each category, and overall. A county’s Overall Score is the average of its scores across all factors and categories. The highest Overall Score ranked “Most Tree Loss” (No. 1) and the lowest “Least Tree Loss” (No. 200).

Note: Some location names (Census Area, Borough, or Municipality) are considered counties or their equivalents by the U.S. Census Bureau.

Sources: Global Forest Watch

Final Thoughts: What’s Causing the Nation’s Canopies to Recede?

United Nations members (and the U.S. by executive order) have committed to a 30X30 conservation goal, aiming to conserve 30% of their land and seas by 2030. Maryland has already met this goal.

Unfortunately, even conserved canopies can be decimated by problems like pests and diseases.

Tree cover loss can have many root causes.

Extreme weather events can weaken or destroy trees: Tornadoes, hurricanes, flooding, ice storms, drought, derechos, landslides, and acid rain are known to damage or kill trees.
A report found that wildfires were to blame for 26%–29% of total global forest loss from 2001 to 2019.
Pests — especially invasive defoliating species like the spotted lanternfly and spongy moth — can weaken or kill native tree species.
Trees can be impacted by various diseases — such as blight, oak wilt, annosus root rot, and other fungal diseases — which can be exacerbated by harsh weather conditions and pests.
Across the globe 17,000 tree species are at risk due to human development. Forest fragmentation from road development, pipelines, and sprawl can also disrupt local ecology.

Deforestation leads to decreased biodiversity, impacting wildlife like lizards and birds, and the ecosystem overall. Habitat destruction can also increase disease transmission, such as rabies outbreaks.

Trees can sprout as climate heroes as we deal with unprecedented levels of carbon dioxide, with the ability to hold high amounts — over 48 pounds per mature tree — of CO2.

Conservation efforts like the Forest Legacy Program, sustainable forestry practices focusing on maintaining biodiversity, and widespread awareness about tree care and invasive threats can help keep our canopies green and growing.

Tree Care Tips

Trees are not only beneficial to the environment, but they can increase your property value and lower your energy bills. They also add some outdoor shade and an element of privacy.

Do your part and plant a tree. Keep it alive with the help of our guides below.

Hire a local LawnStarter crew to help grow your backyard canopy or revamp your landscape with native plants and trees.

Media Resources

Valdez-Cordova Borough, Alaska (No. 3,130), had the highest net gain in tree cover, 117 kilo hectares, followed by Alaskan territories Lake and Peninsula Borough (No. 3,129) and Matanuska-Susitna Borough (No. 3,125).

Spacious counties like Idaho County, Idaho (No. 4), Aroostook County, Maine (No. 10), and Navajo County, Arizona (No. 11) — each among the nation’s 50 largest counties — scored near the top of our ranking with over 47 kilo hectares of canopy loss over 2 decades.

8 Idaho counties — like Idaho County (No. 4), Valley County (No. 6), and Custer County (No. 12) — scored among the 100 counties with the most tree cover loss. Canopies in the Gem State have been devastated by dwarf mistletoes, bark beetles, and other defoliators.

Only 13 out of 58 California counties finished in the bottom half of our ranking. A statewide survey reported around 36.3 million dead trees in 2022. California forests struggle with drought, disease, and pests, in addition to warmer temperatures and overcrowded forests.

Out of 11 California counties that exist entirely within the Sierra Nevada, 9 counties — such as Butte (No. 20), Madera (No. 139), and Placer (No. 197) — finished in the balding half of our ranking. Only Mono (No. 1764) and Kern (No. 2077) landed toward the bottom, with tree cover gains of 1.2 and 2.3 kilo hectares, respectively.

Every year residents of Custer County, South Dakota (No. 33), set fire to an effigy of a mountain pine beetle at the Burning Beetle festival. The region has battled with this beetle on and off since the 1890s, and it is responsible for a 1996–2016 epidemic that damaged 450,000 acres of the Black Hills.

Main Photo Credit: Andrii Chagovets / Adobe Stock / License