Answer: If you carefully dig down to the main root you should be able to twist the sucker off cleanly while it is still small, otherwise you will have to cut it off. There are also sucker stopper products (growth regulators) you could apply to the cut ends when the sprouts are till small. It is important to remove them promptly while they are small.
You might be able to net the tree to exclude the chipmunks, however they are difficult to exclude. A spray on repellent labeled for rodents and squirrels might help or you might be able to install a baffle on the trunk to prevent them from climbing the tree.
I hope this helps.
Q&A Library Searching Tips