Q.I Have Two Huge Magnolias In My Backyard Next To One Another, One Lost All Of Its Leaves The Other Not
The tallest one lost absolutely all of it’s leaves, the branches all look brown. The other retained most of its leaves and has green branches. It has been a month and nothing has happened. Is my tree dead?

Certified GKH Gardening Expert
You can give it a scratch test to see if it is still alive. Here are the instructions below. I see it was topped at some point and there are a bunch of water sprouts. I may also see some insect borer holes. Sometimes a tree will drop its leaves due to environmental stress, but I would think new leaves would have grown back by now.
These articles may help you pinpoint the problem. You can also contact your local extension agent. I've included a form to locate the office.
https://www.gardeningknowhow.com/ornamental/trees/tgen/tree-scratch-test.htm
https://www.gardeningknowhow.com/ornamental/trees/magnolia/magnolia-tree-diseases.htm
https://www.gardeningknowhow.com/plant-problems/disease/verticillium-wilt-treatment.htm
https://www.gardeningknowhow.com/ornamental/trees/tgen/tree-borer-insects.htm