Here is a copy of The Treasure Trove of the Sun by M. Prishvin and illustrated by Feodor Rojankovsky.
From the inside flap:
This is a modern European story but it has the earthy quality of a folk tale, for the action takes place in a country village in Russia where the peasants still live by habits and traditions of many hundreds of years.
The story is about two orphaned children who live all by themselves: twelve-year-old Anna, golden-haired, friendly, and calm: her younger brother, Peterkin, stalwart, stubborn and excitable. One spring day Anna and Peterkin go off in search of sweet spring cranberries, and their search takes them to the Wandering Swamp, a “treasure trove of the sun” – so called because of the rich layers of peat formed there by the warm sunlight working on the decomposing plants.
Anna wants to go the sensible way along the well-trodden path used by the other cranberry pickers. But Peterkin wants to follow a narrow, dangerous trail past the Blind Break Quagmire to a secret moor that his father had once told him about.
The action takes place in just one day, but it is a fateful, unforgettable day, full of hope, fear, despair, finally a little wisdom. Woven into the children’s story is the tale of the old forester, Antip, and his hound dog, Tress, the adventures of the villagers on a wolf hunt, and the wild, weird life of the swamp itself with the calls of birds and animals echoing back and forth.
The result is a fascinating, many-colored tapestry, and Feodor Rojankovsky has caught the colors of this tapestry in brilliant, glowing pictures.