Old grouth forests are full of sick, diseased and decadent trees?

That is false. An old-growth forest — also termed primary forest, virgin forest, primeval forest, late seral forest, or (in Britain) ancient woodland — is a forest that has attained great age without significant disturbance and thereby exhibits unique ecological features and might be classified as a climax community.

No because the eaeht is on a 23.5 degree axis tilt and so when it is winter the northern hemisphere is pointing away from the sun and the soutubern hemisphere is pointing toward the sun

Your gonna need to upload an image with the question : )