Linda From Maine wrote:
To keep the early buds from freezing, yes. Once there is fruit on the trees, the weather is warm enough to not need; however, then there is always a slight chance of hailstorm to bruise and damage!
And for the cherries - if it rains and is warm just before cherries are ripe and ready to pick, they will burst, rendering them useless for commercial sales. Just a crazy way to earn a living, but I'm sure glad some do tackle it!
Some cherry orchards a couple hours from here have black shadecloth suspended about 2 metres above the whole orchard.
Protects from frost, hail and sunburn.