“This is Heidi’s cottage, ‘Elaman Puu’, which means Tree of Life. It’s built with a variety of natural building techniques with a rubble trench, earthbag stem walls dressed in stone, birch bark damp-proof membrane beneath the straw bales on the northern walls with cob and cordwood to the south and a reciprocal roof on a roundwood frame. All of the materials were harvested locally.
Heidi began her natural building journey by investigating what natural materials were available on the land where she wanted to build her tiny house. Set in the forests of southern Finland the choice of roundwood timbers with a reciprocal roof was easy and obvious. Heidi also dug several pits on the land to search out the clay she would later use to plaster the interior of the home.…”
From naturalhomes (a really nice website)