I also create wood chips, then use them to maintain access trails.
The big concern is GHG (Green House Gas) release during storage. The internal temperature of woodchip piles goes through a typical cycle. As the pile warms, CO2 is released. After 5 to 10 days, the temperature increases and peaks. This indicates that aerobic decomposition is starting to taper off, while anaerobic decomposition is ramping up. Now you start to get methane release. You also get a bit of nitrogen oxide.
To minimize the GHGs, keep the pile spread thinly - 1/2 meter to 1 meter. Try to let the branches dry for a few months if possible then chip them in the fall when they are drier and the temp is cooler. Well ventilated storage helps to allow as much oxygen as possible into the pile. Turn the pile with a pitchfork at the first sign of it getting hot.
All of these strategies maximize exposure to fresh air and keep the wood chip temperature cool. If you can do these two things, then you minimize the anaerobic stage which is when methane is produced.
