Mr Trump has blamed the fires on forest mismanagement, and while visiting California over the weekend, the US President added an eyebrow-raising solution to the mix.
He said: "You gotta take care of the floors".
"And they don't have a problem", Trump said. And when it is, it's a very small problem.
Niinisto said their conversation focused on the California wildfires and the surveillance system Finland uses to monitor forests for fires.
The U.S. leader has faced mockery from Finns after suggesting that Finnish people take care of their forest floors by "raking" them.
Twitter quickly learned of the raking comments, with many from Finland ridiculing Mr. Trump by tweeting images of themselves or others raking in the forest.
Some even argue that Finland has too few forest fires, from a biodiversity point of view.
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Add Donald Trump as an interest to stay up to date on the latest Donald Trump news, video, and analysis from ABC News. Trump said. "I mean, with this stuff, you never know what's going to happen".
Trump made the comments as he visited Northern California to see the wildfire damage on Saturday, and by the next day, droves of Finns were ridiculing him online. "And they're raking them - they're on fire", Trump said.
Strong winds were still complicating efforts to contain the deadliest forest fires in California's history as the death toll rose to 76 with nearly 1,300 unaccounted for. "You wouldn't have the fires".
Many Finnish citizens have been mocking President Donald Trump for claiming that they stop forest fires in their country by raking leaves.
Ah yes, raking leaves!
Seemingly placing the blame once more he insensitively said about seeing firefighters clearing dried brush: 'This should have been all raked out'.
"I was with the President of Finland. But the reality is, to manage every little bit of fuel with a rake is not practical".
California's problems are complicated, she said - a combination of hot, dry climates, poor community design and "100 years of fire suppression" that helped turn forests into tinder boxes. "And if you don't know this, if you really don't know this, man, everybody needs to start rethinking what you're saying and how you're saying it because you sure don't give a damn about the people in California".
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