Saving the forest in order to save the tiger is a method of in-situ conservation.
If you recall from the chapter, when you want to save the tiger from extinction, you need to conserve the natural habitat of the tiger. More tigers are prone to extinction as they find it difficult to hunt, to survive and reproduce when their habitats are encroached upon. Therefore, by saving the forest as a whole, by conserving trees and by decreasing urbanisation, we can save the natural habitats of several organisms including the tiger. This approach is known as in situ conservation.