Q.cedar trees
I have a wind break of cedar trees. Many of the lower branches are dead. I have started trimming them off but I was wondering if there is a way of stopping it or if they are all dying.

Browning of Cedar Trees could be due to low moisture levels, disease or pests.
I would check with your County Extension Office to see if Cedars are suffering from any diseases in your region.
They can also refer you to a qualified Arborist to seek professional advise.
Pruning should be done in fall, when the trees are dormant.
https://www.gardeningknowhow.com/extension-search/
https://www.gardeningknowhow.com/ornamental/trees/cedar/growing-cedar-trees.htm
https://www.gardeningknowhow.com/ornamental/trees/cedar/pruning-cedar-trees.htm