Many who plant irregularly-shaped fields with trees lining the fields, often with a woods behind them, discovered that the area under the drip line was softer soil this spring. Pushing the envelope even in early June to get crops in the ground, that soil under trees in many fields was wetter.
If it dries out later and the summer turns dry, will it be the first to suffer from competition form the trees? That remains to be seen. What is known is that especially if it's soybeans, there may be competition from wildlife early in the season, eating off the tender soybeans, especially near the field borders.
That tendency is so pronounced that one farmer won't even plant soybeans in a heavily-populated wildlife county. He's fought deer and other wildlife too many years, seeing them chew off so many soybeans that it wasn't economic to plant small patches of land to soybeans, assuming the patches were lined with trees.
The fact that fence rows can zap yield for several rows out, not just for the row or two next to the trees, was documented in Farm Progress Corn Illustrated studies a few years ago. In a very dry year, 12 rows out from a tall, brushy fence row, not even a woods, were so affected that yield was about half what it was away from the trees. The yield decreased row by row starting with the last yield near the trees, but with 12 rows out still showing reduced yield compared to the rest of the field. Shading may be one of the factors involved in limiting performance of rows along tree lines.
What are you paying for that land near the trees? Are you paying the same high cash rent you pay for the rest of the field? Is it a cost of doing business, or is it something you should take into account when making cash rent offers?
There have been scenarios in the past, such as in the Corn Illustrated plot a few years ago, where it actually cost the farmer money to plant the outside 12 rows near the fence row. That doesn't even include the rent he was paying to a landlord for the field. Gross return from the corn harvested didn't even cover expenses due to the reduction in yield.