100 foot square LZ and 50 feet of trees, surrounding, is a serious situation. It's not a death sentence, but the pistol's certainly cocked- I would not operate routinely from such a pad (I fly EMS). If and when something happens, you will have nowhere to go, except the trees or vertical into the hover hole. Worse, the smallish LZ makes distractions and error particularly unforgiving. If I had a penny for all the trees I've seen hit...
Specifically:
First, a 100 feet is not a lot of room, in spite of how it looks on the ground, It is small from the air.
Next, the trick to surviving a power failure from 50 feet is having the opportunity to hit the ground a glancing blow, and use aircraft structure to absorb energy. You can't do that in a hover hole. You're going to hit the ground vertically (bad), or tumble through the trees.
Power failures are what we all worry about, but urgent situations, and emergencies, come in zillions of varieties. You have no space to develop options in your planned base- you have up, down, and into the trees.