For a while I was completely mystified by this card, but a little Googling gave me at least part of the answers. It was sent by someone who lives in the small town of Kuhmo in eastern Finland on the border with Russia.
According to both the sender and Wikipedia, tar used to be burnt in Kuhmo. It was of great economic importance. I couldn't understand what they meant by tar burning but it turns out to be because of a basic difference in understanding the meaning of the word "tar". In northern Europe tar means a substance produced by the slow heating heating of pine wood, whereas in other some other countries it means a substance produced from coal, and that was what I was thinking of. The tar in tar pits is yet another meaning and refers to asphalt.
The picture shows a boatload of barrels of tar being rowed along the river. Apparently men rowed the boats all the way to Oulu, a distance of several hundred kilometres. It could take weeks. The tar was sold and the return journey brought salt, sugar and textiles to the home town.
A further mystery of sorts comes from the lines written. They are part of a poem, I think, by Ilmari Kianto. Google failed me on this and translated only a few words. I'll give the original here in the hope that a Finnish speaker will pass by and translate for me.
Mun purteni - se kehtoni
ja tuuli tuutijain,
yön taivas yksin äitini
ja aalto armahain!