40 acres is a relativley small area. It is possible that deer are not hanging in that area, but more or less only cruising through. If the overwhelming majority of your trail camera photos are at night, I'd say that is a confirmation. If you have not yet, try planting a food plot. A long narrow of of about an acre or two shuold do the trick.

For sure find the food that the deer might be coming to and from. This time of year acorns should be dropping. Be sure to ease in to your 2 stands only when the wind is right to do so. If you 40 acres is wooded, try a self-climber so that you can relocated easily.

Good luck.