birch collection: https://3dsky.org/collection/shared/5081280 
Birch forest part 10
Polygons:
Birch_forest_17.1m – 321 158
Birch_forest_15.8m (2) – 157 430
Birch_forest_16.8m – 135 664
Birch_forest_15.9m – 221 213
Birch_forest_18.2m – 157 432