Cherries productive despite adverse conditions

Each year I marvel at my 18-year-old cherry-laden trees. Growing on my wet ground, they stopped putting on new growth about 8 years ago. Now at 10 feet, they are nettable and, because no new growth, they do not need to be pruned. You can vaguely see from pic that they have consecutive growth rings only 1 mm apart.

I wonder if this a common occurrence with cherries grown under adverse conditions? Anyone else see this? I know these conditions shorten the tree’s lifespan but I’m still harvesting plenty of cherries in my lifespan.