Q.Pruning magnolia trees
Our magnolia trees where starting to grow very tall. I decided to cut about one foot off both trees from the top. They are about 2 metres tall. Since i cut them the leaves started to fall off. What have i done. Have i stressed the trees, are they going to die.

Cutting off the top of a tree is called topping. Unfortunately, it is damaging to the tree and encourages unhealthy growth. Your trees will probably survive, but will be stressed for a while, and their future growth won't look very good unless you repair the damage with careful pruning. An arborist may be able to help.
Please see these articles for help:
https://www.gardeningknowhow.com/ornamental/trees/tgen/tree-topping-information.htm
http://hort.ifas.ufl.edu/woody/topped.shtml
https://extension.psu.edu/natural-resources/forests/urban-community/publications/pruning-landscape-trees