About a third of the contiguous United States is covered in trees. The most widely cited estimate puts tree canopy cover at 34.2 percent, based on analysis of aerial photographs taken around 2005. That single number, though, papers over enormous variation: North Dakota sits at roughly 2.6 percent tree cover while New Hampshire reaches nearly 89 percent. The story of American tree cover is really a story of where you look, who owns the land, and what forces are pushing forests to grow or shrink.
Where the Trees Are and Where They Aren’t
The 34.2 percent figure comes from a nationwide assessment using photo interpretation of thousands of random points across the lower 48 states, yielding a picture of how canopy and impervious surfaces are distributed at the state and national level.1Landscape and Urban Planning. Tree and impervious cover in the United States The broad pattern is what you’d expect from a road trip: heavily forested states cluster in New England, the Southeast, and the Pacific Northwest, while the Great Plains and desert Southwest are comparatively bare.
State-by-state numbers illustrate the extremes. New Hampshire’s nearly 89 percent tree cover puts it at the top, followed by other northeastern states like Maine and Vermont. At the other end, North Dakota manages just 2.6 percent, reflecting a landscape dominated by agriculture and grassland.2Environmental Pollution. Tree and forest effects on air quality and human health in the United States The midpoint states, those hovering around the national average, tend to be places with a mix of farmland and scattered woodlots, like parts of the Midwest and the mid-Atlantic.
One counterintuitive finding is that in several predominantly grassland states, urban and community areas actually have significantly more tree cover than surrounding rural land. In Kansas, urban areas carry about 17 percentage points more tree cover than rural areas, likely because people plant and maintain trees in towns that would otherwise be open prairie. In more forested states like Kentucky, the pattern reverses: rural land has nearly 38 percentage points more tree cover than urban areas, because cities displace what was once dense forest.1Landscape and Urban Planning. Tree and impervious cover in the United States
What Counts as “Tree Cover” Depends on Who Is Measuring
That 34.2 percent figure describes tree canopy cover, meaning the area of ground shaded by tree crowns when viewed from above. This is different from “forest land,” which the USDA Forest Service defines based on a combination of tree density, land area, and land-use designation. A narrow strip of trees along a suburban street contributes to canopy cover but would not meet the Forest Service’s definition of forest. Conversely, a recently clear-cut parcel might still be classified as forest land if it is expected to regenerate, even though its current canopy cover is zero.
Different agencies and international organizations use different definitions, and those differences matter more than you might think. The United Nations Food and Agriculture Organization (FAO) has its own forest definition that emphasizes minimum area and canopy density thresholds, which do not line up perfectly with how the USDA Forest Service counts forest land. A recent review found that these interconnected monitoring frameworks rely on different definitions and address different goals, creating real challenges for comparing numbers across reports.3Trees, Forests and People. Forest definitions applied for national United States forest reporting: Status, gaps, and opportunities When you see headlines claiming the US has “lost” or “gained” forest, it is worth asking which definition the number is based on.
The measurement technology itself is evolving. Satellite instruments like NASA’s ICESat-2 now provide detailed information on canopy heights and density from space, using laser pulses to map tree structure along narrow tracks and then extrapolating across broader areas with statistical models.4PubMed Central. A spatially comprehensive canopy cover dataset derived from NASA’s ice, cloud and land elevation satellite-2 (ICESat-2) for the state of Alabama, USA These tools improve resolution and accuracy, but each new method introduces its own assumptions and limitations. The overarching point is that “how much of the US is covered in trees” is a simpler question than the measurement apparatus behind it.
Who Owns America’s Forests
Ownership of forested land in the US splits dramatically along an east-west line. In the western states, over two thirds of forest land is publicly owned, with the majority managed by the US Forest Service as National Forests. Cross the Mississippi, and the picture flips: more than 80 percent of eastern forest land is in private hands.5Treesearch. Map of forest ownership in the conterminous United States
This ownership divide shapes everything from wildfire management to conservation policy. Public forests in the West are subject to federal land-management plans, controlled burns, and timber harvest restrictions. Private forests in the East are managed by millions of individual landowners whose decisions about logging, development, and replanting are driven by economics, estate planning, and personal preference. Any national strategy to protect or expand tree cover has to reckon with these fundamentally different governance structures.
Trees in Cities and the Inequality Gap
Urban tree cover gets outsized attention relative to its total land area because that is where most people live and where trees provide the most immediate benefits. A nationwide enhanced dataset covering all Census-defined urban areas found that these urbanized zones collectively span about 274,000 square kilometers, a small fraction of the country but home to the vast majority of the population.6Scientific Data. An enhanced national-scale urban tree canopy cover dataset for the United States
Urban trees are not distributed equally across neighborhoods. A study of more than 5,700 communities found that the least affluent neighborhoods had a median tree cover of about 20 percent, while the most affluent had about 35 percent.7PLOS ONE. The tree cover and temperature disparity in US urbanized areas: Quantifying the association with income across 5,723 communities The relationship between income and tree cover appears roughly linear: for every step up in relative income, tree cover nudges higher. A separate analysis across multiple cities confirmed that high-income neighborhoods consistently have more canopy cover, though the racial dimension of this gap varied by city.8PLOS ONE. Trees Grow on Money: Urban Tree Canopy Cover and Environmental Justice
Race also plays a role. On average across the country, neighborhoods where the majority of residents are people of color have about 11 percentage points less tree canopy and 14 percentage points more impervious surface than predominantly white neighborhoods.9npj Urban Sustainability. Current inequality and future potential of US urban tree cover for reducing heat-related health impacts These gaps have direct consequences for temperature: the existing tree canopy reduces air temperatures by an estimated 1.0°C in white neighborhoods compared to 0.8°C in neighborhoods with majority people of color. The difference sounds small until you consider it compounds during heat waves, when even a fraction of a degree affects hospitalization and mortality rates.
How Trees Cool Cities and Save Lives
The practical value of urban tree cover shows up most vividly in heat. Field measurements with temperature loggers found that the likelihood of temperatures exceeding about 32°C was more than twice as high in spots with no tree canopy compared to those with 50 percent cover, and more than five times as high compared to locations under full canopy.10Scientific Reports. Street trees provide an opportunity to mitigate urban heat and reduce risk of high heat exposure Street trees, in particular, shade sidewalks and buildings during peak afternoon hours, reducing not just air temperature but the radiant heat bouncing off asphalt and concrete.
Scaled up to the national level, the heat-reduction services provided by urban trees carry real economic weight. Across 97 US cities studied, researchers estimated that about three quarters of urban residents live in neighborhoods with less than 20 percent tree cover. The existing canopy still helps avoid an estimated 245 to 346 heat-related deaths per year. When avoided illness and reduced electricity use for air conditioning are factored in, the total annual value runs between roughly $5 billion and $12 billion for the entire US urban population.11Ecosystems. The Value of US Urban Tree Cover for Reducing Heat-Related Health Impacts and Electricity Consumption
Wildfire Is Reshaping Western Forests
The biggest ongoing threat to tree cover in the western United States is wildfire. In California, substantial gains in tree cover during the 1990s have been more than erased by fire-driven declines since 2000, with the losses concentrated in southern mountain regions where post-fire regrowth has not kept pace.12AGU Advances. Losses of Tree Cover in California Driven by Increasing Fire Disturbance and Climate Stress Tree cover losses generally occurred where summer temperatures exceeded about 17.5°C, and net gains happened in cooler areas, a pattern that points directly to climate warming as a driver.
Fires are not just burning more area; they are burning more severely. Across western US forests between 1985 and 2022, annual area burned increased roughly tenfold, while the area burned at high severity, meaning fires that kill all or most trees, increased fifteenfold.13PubMed Central. Intensifying Fire Season Aridity Portends Ongoing Expansion of Severe Wildfire in Western US Forests That disproportionate rise in severe fire is the critical detail. A low-severity burn can leave a forest largely intact, clearing underbrush and even promoting regeneration. A high-severity burn can convert forest to shrubland or grassland for decades.
California’s data reveals an especially troubling feedback loop. The amount of tree cover lost per unit of area burned rose by about 70 percent from the late 1980s to the early 2020s. Part of this is because fires are increasingly reaching into denser forests that were historically resistant to burning: the pre-fire tree cover within fire perimeters increased by roughly 41 percent over the same period, while fire severity rose by about 30 percent.14Environmental Research Letters. Rising forest exposure and fire severity from climate warming amplify tree cover losses from wildfire in California Warmer summers and drier winters are driving all three trends. Dense old-growth forests that once shrugged off low-intensity burns are now vulnerable to fires that did not historically reach them.
Invasive Pests and Eastern Forests
While fire dominates the western threat picture, invasive insects are quietly reshaping eastern forests. The emerald ash borer, a beetle native to East Asia, has caused rapid and widespread mortality of ash trees across North America.15PubMed Central. Effects of Late Stages of Emerald Ash Borer (Coleoptera: Buprestidae)-Induced Ash Mortality on Forest Floor Invertebrate Communities The beetle’s larvae feed beneath the bark, carving winding tunnels through the tissue that carries water up the trunk. As these galleries expand, the tree’s water supply is progressively choked off, leading to canopy thinning and eventual death.16Forest Ecology and Management. The relationship between the emerald ash borer (Agrilus planipennis) and ash (Fraxinus spp.) tree decline
Ash trees are particularly common in riparian forests, the strips of woods along streams and rivers, where they often make up a large share of the canopy. High ash mortality in these areas opens gaps that alter light levels, moisture, and the composition of the understory plant community.17Forest Ecology and Management. Legacy effects of emerald ash borer on riparian forest vegetation and structure In some cases, invasive shrubs and vines rush in to fill the openings, fundamentally changing the character of the forest. The emerald ash borer is the most dramatic current example, but it follows a pattern: other non-native pests like the hemlock woolly adelgid, the Asian longhorned beetle, and various bark beetles are each attacking specific tree species and altering local canopy cover. The nonnative tree species that sometimes fill in can also shift forest composition in unexpected ways over time.
Four Centuries of Shifting Species
Even setting aside outright loss of tree cover, the composition of American forests has changed dramatically since European colonization. A study of northeastern US forests used pre-colonial land survey records and modern Forest Inventory data to track shifts over roughly four centuries. Beech, once the dominant tree in the region with an average relative abundance of about 22 percent, has dropped to roughly 7 percent. Oaks declined from about 18 percent to 11 percent. Maples, meanwhile, surged from about 11 percent to 31 percent of the canopy, becoming the most common group across the region.18PubMed Central. Four Centuries of Change in U.S. Forests
These shifts reflect centuries of selective logging, land clearing, fire suppression, and changing wildlife pressures. Oaks, for instance, historically benefited from periodic fire, which cleared competing species from the understory. When fire was suppressed, shade-tolerant species like maples gained the advantage. The result is a forest that may have similar total tree cover to the pre-colonial era in some areas but is composed of very different species in very different proportions. From a distance, the canopy looks green. Up close, it is a different forest.
Climate Change and the Slow Migration of Trees
A warming climate is expected to push tree species’ habitable ranges northward, and in some models, that looks like a coherent wave of migration toward cooler latitudes. Reality is messier. An analysis of multi-decadal inventory data across the contiguous US found that rather than shifting poleward as a group, tree species showed idiosyncratic responses: some moved north, some shifted in other directions, and some barely moved at all over a roughly 28-year period.19Basic and Applied Ecology. Latitudinal range shifts of tree species in the United States across multi-decadal time scales
Process-based modeling work fills in the mechanisms. Species are projected to lose habitat at the southern edges of their ranges primarily because of increased drought stress and reduced ability to reproduce successfully. At the northern edge, warmer conditions can help seeds ripen and reduce frost damage to flowers, opening new territory. But the pace of northward colonization is limited by how fast seeds actually disperse, which for most trees is painfully slow compared to the rate of warming. Models project that something like a fifth of a species’ current southern range could experience local extinction under moderate warming scenarios, with slightly larger losses under more aggressive warming.20Journal of Ecology. Tree species range shifts at a continental scale: new predictive insights from a process‐based model The mismatch between climate velocity and seed dispersal means that even if suitable habitat exists farther north, many species will lag behind the climate for generations.
Reforestation Ambitions and Carbon Math
The US currently has about 1.4 trillion trees on its forest land, and those forests, along with harvested wood products, absorb the equivalent of more than 14 percent of the country’s total carbon dioxide emissions each year.21PubMed Central. Tree planting has the potential to increase carbon sequestration capacity of forests in the United States That is a substantial climate service, and it is one reason tree planting gets so much political enthusiasm. Analysis of national forest inventory data suggests that fully stocking all understocked productive forest land could boost carbon uptake by about 20 percent per year, an additional roughly 188 million metric tons of CO₂ annually.
Getting there is harder than it sounds. One widely discussed reforestation scenario envisions planting 30 billion trees across about 64 million acres of natural and agricultural land by 2040, at an estimated cost of around $33 billion. That would require increasing annual seedling production by about 1.7 billion, or a 2.3-fold jump over current nursery output.22Frontiers in Forests and Global Change. Challenges to the Reforestation Pipeline in the United States The bottleneck is not just money. Seed collection infrastructure, nursery capacity, trained planting crews, and post-planting care all need to scale up simultaneously. And none of this accounts for the ongoing losses from wildfire, pests, and development that chip away at existing cover. Planting trees is easy to champion and genuinely difficult to execute at the scale the numbers demand.
There is also a question of what kind of forests to build. Simply maximizing canopy cover is not the same as restoring ecological function. A monoculture pine plantation increases tree cover but does not support the same biodiversity, soil health, or resilience to disturbance as a mixed-species native forest. The push toward reforestation is encouraging, but the details of species selection, site matching, and long-term management matter as much as the headline number of trees planted.