As an example of a different approach to thinning I would suggest looking at the decission of what to do with so-called "Wolf Trees". Wolf Trees are individuals that are particularly fast growing, that have very large and widespreading canopies and very thick branches. Their vigour supresses the growth of nearby trees. (Their thick coarse branches means they are of very low value as timber trees - produce wood with large knots)
From a timber production perspective they reduce the potential maximum yield of timber from a given area - by shading many trees around them. From a different perspective in a recently planted area, or area of natural regeneration following clear felling - these individuals relativley rapidly produce large diameter trees so valuable to certain specialist woodland invertebrates that may have persisted in a state of decline in the abscence of large trees in that area - and are effectively on borrowed time until more suitable habitat is restored that enables them to flourish again.
A professional forester would probably suggest removing such a tree when thinning but from a biodiversity point of view it might be beneficial to favour such a tree - giving it even more light to grow even more quickly.
I'm not suggesting any wrong answers just that there isn't only one way to select trees for thinning - it always depends on what your aim is and why you are motivated to thin
