Burundi's government has banned the cutting down of trees to be used for Christmas festivities.
The influx of foreigners had led to a boom in Christmas tree sales
A senior official in the environment ministry told the BBC those found violating the order could be fined as much as $50 or face two months in jail.
Alexis Niyonzima urged people to use artificial trees instead.
The country had lost enough of its forest cover and could not afford any more trees to be cut down, he said.
Correspondents say many trees were cut down for fuel during Burundi's 12-year civil war, which officially came to an end this year with the election of Pierre Nkurunziza as president.
The influx of foreigners working for organisations overseeing the peace process has led to a boom in selling Christmas trees in urban areas.
The majority of Burundi's mainly Christian population lives in the countryside, where trees are not used for Christmas decorations.