The tree row economics has been broken down on here before. We have several quarters of land that have tree rows spaced from 30 rods to 45 rods. The last few wet years we have had to leave several acres in areas we normally plant becasue the trees caught a lot of snow and caused low areas to connect and block access to several acres on each quarter.
On a couple of quarters we have lost 30% of acres we normally farm in these wet years when other fields with no trees averaged half that.
As I mentioned to KDM you can thank the Federal govt for sloughs being torn up because of prevent plant rules in Federal crop insurance. Dry years those sloughs are where your bushels come from that add to your proven yield which in turn is the basis of everything the FSA does.
Yes that same prevent plant pays for acres that are mentioned above, but not having a crop planted on those acres increases alkali and increases the odds of not getting it planted the following year as well. Combine that with larger and larger equipment and tree rows end up costing in over laps more than one thinks unless you have sectional control.