About 16 football fields of trees per minute were lost to wildfires in 2021, according to a new report.
Data from Global Forest Watch shows that around the world, the amount of trees burning has almost doubled in the last 20 years.
Climate change is a key driver of the increase as it leads to warmer temperatures and drier conditions.
Of the 9 million hectares of trees consumed by fire in 2021, more than five million were in Russia.
The new data allows researchers to distinguish between trees lost to wildfires and those destroyed for agriculture, logging or during deliberate burns.
In 2021, the second worst fire year on record, an area the size of Portugal was lost.
“It’s shocking,” says James MacCarthy, an analyst at Global Forest Watch.
“It’s about double what it was just 20 years ago. It’s kind of amazing how much fire activity has increased in such a short period of time.”
The effects of fire-related losses are felt primarily in forests in more northern countries such as Canada and Russia.
While fire has long been a natural part of how these forests function, the scale of the devastation seen in Russia in 2021 was unprecedented.
Of the 9.3 million hectares (23 million acres) burned worldwide, Russia accounted for more than half.
“What’s more worrying is that fires are becoming more frequent, more intense and have the potential to unlock a lot of the carbon that’s stored in the soils there,” said James McCarthy.
Trees and soils store carbon dioxide – one of the key gases warming our atmosphere – and experts say it is vital to tackling climate change.
Climate change is seen as a key driver of these fires, with rising temperatures creating drier conditions in which more trees burn.
Northern regions of the world are warming at faster rates, leading to longer fire seasons.
In Russia, a 31 percent increase in fire losses in 2021 was partly due to prolonged heatwaves that experts believe would be virtually impossible without human-induced warming.
“Climate change is increasing the risk of hotter, faster and bigger fires,” said Dr. Doug Morton, head of the Biosphere Sciences Laboratory at NASA.
“And nowhere is this more visible than in forests and woodlands where you have plenty of fuel to burn.”
In other parts of the world, the impact of deforestation is also leading to more fires.
In the Brazilian Amazon, which recently saw the number of trees cut down rise to a six-year high, losses due to agricultural clearing and logging are having a negative effect.
“Deforestation changes local and regional climates and removes much of the evapotranspiration that helps keep temperatures cooler and wetter,” said James McCarthy.
“So cutting down these forests actually makes them hotter and drier and makes them more prone to fire.”
While many of the trees that burn will regrow over a period of about 100 years, there are significant associated impacts of these losses on biodiversity, water quality and soil erosion.
The UN says the outlook for forest fires in the coming decades is bleak. A 50% increase in extreme fires is expected by the end of this century.
To tackle this problem, scientists say rapid and deep cuts in global carbon emissions are key.
World leaders at the COP26 climate change conference in Glasgow last year pledged to end deforestation, but the promise must be kept if it is to make a difference.
There needs to be an even greater focus on preventing bushfires, rather than fighting them, according to Mr MacCarthy.
“About 50% of national fire budgets go to fire response and less than 1% is actually for preparation and planning,” he says.
Follow Matt on Twitter @mattmcgrathbbc.