I find it hard to believe that those, thawed, could resemble these:
But that’s what the text suggests.
The snowy “sentinels” are obviously conifers (my best guess is black spruce, if the flora of Finland is like Alaska), and are also much more widely spaced than the green trees in the summer photo with mixed conifer/deciduous cover. The summer photo looks a lot like where I live, in the (sub-arctic) boreal forest in Alaska at about 65 degrees North.
AND IT’S SUMMER NOW!!! 
(It’s been a long, hard winter and I’m really glad it’s over.)
The sun sets at night (well, actually in the wee hours of the morning) and then rises again a couple hours later, but it’s all civil twilight until sometime in August.
Sarah