The best way to examine growth rates is viewing a cut stump that exposes the whole history of the tree in two dimensions.  Every time you cut a tree for harvest or thinning, look at the information displayed.  Look for growth rates over the years, indications of injury, finally focusing on the last ten years of growth.  Fire scars, grazing injury, drought, harvests, logging damage, and other signs can tell you  details of past events around that tree.  Seeing what has happened to this cut tree over the years can help you decide how to manage the standing trees around this stump.

Both photos of tree disks show the typical pattern of growth of in an unthinned stand.  Each tree grew well at first, putting on a  1/4" ring every year.  After the stand becomes crowded, diameter growth falls to about 1/32"per year.  Thinning is needed on a regular basis.

In the photo above, the hollow stump in the fore-ground tells the story of a ground fire that  passed by here 50 years ago.  By examining this stump when this tree was removed, you can make a better decision regarding the crop tree left for future growth.