Why do boreal forests sometimes naturally exist near the equator?

Most of the Boreal forest is very sparse when it comes to human population density. There is however a pattern in human population density when comparing different latitudes of the Boreal forest. The most southern parts of the Boreal forest have a much higher concentration of people, and the more the forest continues north, the less people are found. This is not just a pattern found in one spot in the world, it actually is very consistent around all places the Boreal forest exists. For example, three of the biggest cities in these forests are as follows: Oslo in Sweden, Helsinki in Finland, and Yekaterinburg in Russia. All of these major cities are located at the most southern part of the Boreal forest in that region. There are a handful of major cities found in the Boreal forest, but both the cities and the population density are concentrated all at the southern parts of the forest.

Explanation:

Going from north to south the first climate type that exists is the tundra which can be found in the Northeast corner of Russia, Northern Finland, Iceland, and North Quebec with also the Yukon (both in Canada). The next climate type in the Boreal forest is the subarctic which appears in the majority of Canada and Alaska, as well as occupies most of Russia, Finland and Sweden. Continuing to go south, the next climate type is the humid continental which appears only in southern Russia as well as part of southwestern Sweden. The final climate type that exists is the marine climate which only appears on the west coast of Norway and the south coast of Iceland. The climate type I chose to define was the subarctic because it was the climate type that dominated most of the Boreal forest. The subarctic is the region just south of the Arctic circle, categorized by its warm, but short summers and its bitter cold winters. Little vegetation exists, because of the extreme climate.