The sweet variety of cherries and cherry trees require at least 2 cherry trees to properly pollinate and produce fruit.
If you only have one of the sweet variety of cherry trees then the cherry tree will not produce any fruit.
So if you plant the sweet variety of cherry trees and cherries then you need to plant at least 2 cherry trees so that they produce fruit.
Some other types of cherry trees do not require more than one cherry tree to produce fruit but some do.
It depends on the types of cherry trees.
Montmorency cherry trees live on average of between 16 to 20 years before they die and no longer produce any cherries.
When it comes to lifespan of trees the Montmorency cherry tree has a pretty short lifespan which is about on par with some dogs lifespans.
Other types of trees can live as long as 100 years to even as long as 500 years to 1,000 years.
So a tree living to only 16 years to 20 years is pretty short.
It's not only Montmorency cherry trees that live from 16 to 20 years but also it goes for other types of cherry trees.
All cherry trees live at most 20 years which is a pretty short time for a tree to live.