You should NEVER prune your trees like this!

Topping a tree is not a good idea. Most of the time, topping is done to reduce the size of the tree's crown without regard to its health. Sadly, despite research and best management practices discouraging the practice, it is still common in landscapes today. Instead, if you want to reduce the size of your tree, consider hiring a knowledgeable arborist to do a "crown reduction prune". This method slowly reduces the tree's crown in a way that's much easier for the tree to handle. For more information about why topping a tree is not a good idea, visit these resources:
https://extension.psu.edu/tree-toppin...
https://www.johnson.k-state.edu/lawn-...

Topping varies from pollarding in a few ways. Pollarding a tree:
usually starts at a young age, when the tree is more vigorous and more tolerant of stressors.
involves the continued maintenance and care of resprouts, and the formation of nubs at the end of the heading cuts. These nubs are allowed to seal and they are not removed.
Whereas, topping a tree:
usually occurs when a tree is mature and is typically too old to handle a stressor of this scale.
involves no follow up or maintenance of resprouts.
is usually done to reduce the size of the tree instead of abiding to a specific pruning system.