As normally shown, a family tree "grows" down from the top, from the oldest generations at the top to the newer generations at the bottom.
A tree showing the descendants of an individual (illustration right) will more closely look like a tree in shape.
One showing the ancestors of an individual (illustration below in "The Family Tree of Sigmund") will be wider at the top than the bottom.
When looking at the bottom of the tree, it will show more recent generations, and when looking farther up, there will be older generations.
Family tree Facts for Kids. Kiddle Encyclopedia.