It is the second breeding area, meaning you'll be able to breed dragons in the Breeding Mountain as well.
If you buy the Ultra Breeding Tree, it's good to have a Hatchery which has the upgrade 3 or 4.
Ultra Breeding Tree 2
On 14/5/2015, Social Point released the second version of the Ultra Breeding Tree as the forth breeding area along with the Breeding Mountain. The upgrade will cost 150 and you will earn 75,000 .
For more info about breeding, please visit the Breeding page.