We didn't prune any of our trees all these years, and its been 5 years since we planted them. Somehow the thought never occurred to us, and we were so happy just to see them grow, that we didn't think we should reduce their size in any way. Only in the summer of 2016, did we start looking at our trees carefully because of a few reasons.
1. Many had developed a big canopy on a small trunk, and were keeling over in a storm. We lost some trees like this.
2. The canopy has become so thick and unwieldy, that hardly any light or breeze reached the interiors of the tree
3. Many of the trees were grafted, and we noticed that the non-hybrid desi trunk was growing thicker, and taking over the main tree.
4. Some trees were growing at odd angles, and in odd shapes
After the mango season had passed, we spent an entire day pruning our trees. We cut of big branches that were growing at strange angles.
We cut off the big trunk of the 'non hybrid' plant in a grafted tree. We should perhaps have done that several years ago, but we never noticed it.
We took of extra branches from trees to open up the tree a bit and allow more sunlight and air to drift through.
And we cleared our the lower branches of groves, so that the trees would rise more vertically, and we could walk under them to collect the fruit.
This was a long overdue exercise, but the trees look better shaped and healthier now. We think this would lead to spurt of growth in the spring and better fruit production next season. We generated a huge quantity of firewood in the process which will come in handy during the winter for burning fires, and cooking food.