Taken from the wiki page:
"Biochemistry
Like apricots and apples, the seeds of black cherries contain compounds that can be converted into cyanide, such as amygdalin.[16][17] These compounds release hydrogen cyanide when the seed is ground or minced, which releases enzymes that break down the compounds. These enzymes include amygdalin beta-glucosidase, prunasin beta-glucosidase and mandelonitrile lyase.[18] In contrast, although the flesh of cherries also contain these compounds, they do not contain the enzymes needed to produce cyanide, so the flesh is safe to eat.[19]
The foliage, particularly when wilted, contains cyanogenic glycosides, which convert to hydrogen cyanide if eaten by animals.[20] Farmers are recommended to remove any trees that fall in a field containing livestock, because the wilted leaves could poison the animals. Removal is not always practical, though, because they often grow in very large numbers on farms, taking advantage of the light brought about by mowing and grazing. Entire fencerows can be lined with this poisonous tree, making it difficult to monitor all the branches falling into the grazing area. Black cherry is a leading cause of livestock illness, and grazing animals' access to it should be limited."
I can also say that the leaves from the cherry when shredded and added to the compost heap have the distinctive smell of almonds.
