fruits on cherry trees dying
There is similar story like on https://ask.extension.org/questions/186445. There is too late make photos with small cherries at least on my two cherries Royal Ann and Rainier, where a lot of cherries drop off. Also attached is photo of North Star Sour cherry which behave strange .For Royal Ann is second year when a lot of fruits dropped. 3 years ago tree had a lot of fruits even relatively very young. These year I added horse manure under all trees and watered a lot of my trees as May was very dry in British Colombia (Canada). All trees generally growing strong but problem with fruits. By the way, the Manure works very good in vegetable garden. Do you have some advise and reason fruits dropped out.
P.S. How big fruit will grow before fall down if pollination is a problem? There should be not pollination problem as I have Yet Stella and Montgomery cherries in neighborhood. Also, there were not cold during bloom of flowers only maybe too rainy.
First two pictures are Royal Ann whereas last picture on house background is North Star cherry.
Outside United States
Thank you for your question. An excellent article on this phenomenon is found at this source. Perhaps you can compare its advice with your plant care.
As to using horse manure as fertilizer, this source observes:
"Organic materials such as compost and manures are natural slowrelease sources of nutrients. Because they contain a low percentage of nitrogen they must be used in relatively large quantities to supply the desired levels of nutrients. Animal manure varies in its nutrient content but typically contains less than one percent of each nutrient. One drawback to using either natural or synthetic slow-release fertilizers is that most of them are complete fertilizers and may result in overapplication of phosphorus."
The manure may be adding organic matter to the soil, but is not particularly rich in the three main fertilizers: nitrogen, phosphorus and potassium.
How have you pruned your trees over the last few years? According to this Extension article, pruning has an impact on fruit production.
I hope these help you gain some insight into your trees' problem. Good luck!