I have a 5 yr old tulip tree that has a few cracks at its branch angles. I attached a picture below of one of these cracks. This crack is facing north. These cracks did not exist until the tree started growing this year. The tree appears healthy and has grown 4 to 4.5 feet this year. It looks like the old outer layer of bark was not flexible enough to expand with the rapidly growing trunk and just started cracking. Everything within the crack is alive growing wood. This tree was also protected when it was small and is now growing up into a more wind driven area with height. I noticed the trunk really getting quite a bit larger this year than in past years as well. So I want to say it is nothing more than growing pains for this sapling but what do you think?

Thanks,

Jon