Hi John,

I'm sorry to hear your trees are not doing good. Are we talking about Douglas-fir trees? Is this a managed forest and if so, how old is the stand? What signs & symptoms do you notice that let you know the trees are not doing well? I've listed some things to look for below. Are you able to send photos that show the whole tree and also any close-ups of the signs & symptoms? 

Things to look for:

Is the crown thinning? Are there yellowing needles? Is the problem happening from the top down, bottom up, or randomly throughout the crown?

Do you see any signs of insect damage, such as exit holes in the bark or woodpecker damage? 

Any swelling on any branches or oddities/deformities/bulges/etc?

Once you give me some more information and send a few photos over, I would be happy to help you figure out what's going on with your trees.