Current data suggests there are more trees in Canada's boreal forest than stars in the Milky Way galaxy.
In 2015, Nature published a study estimating the global tree population at more than three trillion trees. According to data collected by the study's 38 researchers, about 750 billion trees are located in boreal forests in North America and Eurasia. Canada's reported share is 318 billion trees. The estimate was formed using data from international forestry databases and peer-reviewed studies reporting large international inventories published in the preceding 10 years. The study only included trees thicker than 10 centimeters in diameter at breast height.
In contrast, the most cited estimate of stars in the Milky Way, conducted by the The European Space Agency by measuring the luminosity of the galaxy, is 100 billion.
NASA noted that while 100 billion is the most commonly cited figure, estimates of 400 billion and greater exist.