Ruddy, sapling bows were probably the preferred bow stock with the Native Americans. They didn't have the tools or desire to chop down a mature tree.
Look for the straightest, limb free sapling you can find. Cut it as long as you can, determine which side should be the back and reduce the belly from the handle out each limb. If larger than 3", split the sapling down the center.
Almost any wood will work. Look for hickory, oak, crabapple, ERC, etc. a 40#+ bow is possible.