'dem Apples

We went out to the Dacha this Saturday for the first time in forever. We were greeted by forest of ragweed and thistles as tall as our heads. (Alister is my witness that I am NOT exaggerating). I quickly located our neighbor's (AKA guy we are buying the property from) scythe and got to work clearing a path to the door and to all my trees and plants.
Sadly, my rhubarb, which I had labored so long over and saved from the evil mouse is missing. It was there in April - and I was ecstatic as I thought it had died in the winter. It had 5 healthy leaves and was safely surrounded by bricks to mark it as special. No rhubarb. No bricks. Very odd.
Another oddity is that there are no apples. None. Alright, out of the 3 healthy apple trees on our property, I can count the total number of apples on both of my hands. Natasha, a neighbor who also goes to our church said this is normal. In Ukraine you harvest every other year. Last year there was a bumper crop and this year nothing.
I wonder if I missed some lesson in agricultural absorption as a child growing up on the farm. i remember fruit, apricots, apples, and cherries coming every summer. We never harvested a lot - except form the apple sauce tree in our yard - but we always harvested.
Is this an oddity of Ukraine vs America? My explanation of the lack of apples would be that something happened while the apples were in blossom - I.E. strong rain or frost, But Natasha says that Apples come every other year.
This isn't the only "fruit cycle" in Ukraine. Huckleberries are apparently every three years. Last year was a bumper for them too. If I had known that they wouldn't be as plentiful this year I would have conserved my freezer stash through till this December at least - But before we went stateside I made it a point to use things up to make way for the new harvest. I'm guessing that the walnuts might be cyclical too because our tree also seems to lack a single nut.

I'm finding my knowledge about farming slightly defective.
Among the list of things I wish I knew more about is pruning. I know there are ways to prune to make trees more productive - but how is that exactly - and when do you do it. I did internet searches - but somethings are just better to know from people.
Also - how can I keep misletoe from killing my apple trees? Which is worse - letting the misletoe stay or severely pruning? How densely can trees productively coexist?