Blistering summer temperatures partnered with Monsoon humidity can make your wood move and groove like you have never seen before…..
Proper lumber storage requires ensuring your bundles are banded tight and placed so the units lay flat on stickers to prevent them from bowing, crooking, kinking, cupping or twisting.
Did you know that lumber actually breathes in and out? 
The lumber sucks in the moisture with rain and humidity and then it dries out with the heat/low humidity. This is what causes the movement in your lumber.
Mold is a dirty word!
Paper wrapped material has the potential to mold.
If you will be storing wood for a while, consider cutting the paper off of the ends to let the air get to the wood. A lot of times moisture caused by rain will get in through a hole or cut in the paper and that will start the mold process. This can happen with the heat and the wood sweating as well.