Is there any benefit to pruning lower branches on mature (40 years +) trees? I suspect I still have 10-15 years before harvest and was wondering if it would help growth (girth) or increase the marketable length of logs?

These trees probably should have been more carefully pruned 20 years ago, but … they weren’t. :) anything I should do now?

Thanks!

Thanks for the great question! Unfortunately, pruning older and larger diameter trees for the sake of producing more clear lumber (or increasing sawlog grade) is NOT a good "return on investment."

As you correctly surmised in your second paragraph -- that boat has already sailed. However, you may still have an opportunity to add diameter growth to these trees via selective thinning (crop tree release).

For more information on crop tree release, please refer to this excellent publication from Univ. of Kentucky Extension Forestry:

http://www.uky.edu/~jmlhot2/Resources/Technical%20Guide%20to%20Crop%20Tree%20Release%20in%20Hardwood%20Forests_Miller%20et%20al%202007.pdf

Best of luck!