How many trees are in Yellowstone National Park?

Estimating how many trees are in Yellowstone National Park is not as simple as counting individual trunks, but scientists can make reliable approximations by combining forest coverage data, tree density studies, and long-term ecological monitoring. Yellowstone covers more than 2.2 million acres, and forests occupy roughly 80 percent of that land. Based on forest structure surveys and average tree densities for Rocky Mountain ecosystems, ecologists estimate that Yellowstone contains several billion individual trees, making it one of the largest intact forest systems in the lower 48 states.

Quick Reference Table: Number of Trees in Yellowstone National Park

Tree Category	Estimated Numbers	Key Visitor Insight
Total Trees (All Species)	Hundreds of millions	Yellowstone’s forests cover about 80% of the park, making exact tree counts impossible
Lodgepole Pine	Well over 200 million	Dominates nearly all forested areas and defines Yellowstone’s landscape
Engelmann Spruce	Tens of millions	Common in cooler, higher-elevation forests and moist valleys
Subalpine Fir	Tens of millions	Often grows alongside spruce in mature, shaded forests
Douglas Fir	Several million	Mostly found in the northern range and lower elevations
Whitebark Pine	Millions, declining	High-elevation tree critical for wildlife but threatened by disease
Aspen Trees	Millions (clonal stands)	Fewer individual trees, but large interconnected root systems
Juniper & Limber Pine	Hundreds of thousands	Sparse, scattered trees in dry or rocky areas

The overwhelming majority of these trees are lodgepole pines, which dominate Yellowstone’s forests more than any other species. Lodgepole pine forests are often extremely dense, especially in areas that regenerated after historic wildfires such as those in 1988. In many of these stands, densities can reach thousands of trees per acre. Because lodgepole pine covers nearly all of Yellowstone’s forested landscape, it likely accounts for well over half, and possibly as much as two-thirds, of all trees in the park, translating into billions of individual lodgepole pines alone.

Engelmann spruce and subalpine fir make up the next largest share of Yellowstone’s trees, particularly in higher elevations, colder valleys, and areas with deeper, more developed soils. These species tend to grow more slowly and in less dense stands than lodgepole pine, but they form extensive forests across mountain slopes and sheltered basins. While their overall numbers are far lower than lodgepole pine, they still represent hundreds of millions of trees combined, contributing significantly to Yellowstone’s forest diversity and long-term ecological stability.

Douglas fir is another important tree species, though its numbers are much smaller in comparison. It is primarily found in the park’s northern range and lower-elevation areas where conditions are warmer and drier. Douglas fir forests are patchier and less widespread, meaning their total population is likely in the tens of millions rather than hundreds of millions, yet these trees play an outsized role in providing winter cover and food for wildlife.

Along rivers, streams, and wetlands, willows, cottonwoods, and aspens form narrow but ecologically critical corridors of trees. Individually, these species do not contribute massive numbers compared to conifer forests, but collectively they still account for millions of trees across the park. Aspen stands, in particular, fluctuate dramatically over time due to fire, climate, and grazing pressure, making their total numbers highly variable from decade to decade.

Smaller populations of trees such as whitebark pine, limber pine, and juniper exist mostly at high elevations or in specialized habitats. While their overall numbers are relatively low, these species are essential for wildlife, especially birds and mammals that depend on their seeds. Together, they likely make up a small but ecologically crucial fraction of Yellowstone’s total tree count.

Taken as a whole, Yellowstone National Park likely contains several billion trees spanning more than a dozen native tree species. Rather than a static number, this total constantly changes as fires, insects, disease, climate shifts, and regeneration reshape the landscape. Yellowstone’s forests are dynamic and ever-renewing, and the sheer scale of its tree population reflects one of the largest and most resilient forest ecosystems in North America.