The Chinese family tree is a little bit more complicated than your typical American family tree. For an expanded version of the above image from the great people at Off the Great Wall, click here. If you would like to watch an animated video of the above image, you can check it out here as well: http://www.youtube.com/watch?v=nCFRoILS1jY
The reason for all of these different titles is a result of the importance of family relationships in traditional Chinese culture. All of your uncles are not equal; your uncle who is older than your father has different responsibilities and expectations than your uncle who is your father's younger brother. This may not be as significant in today's mainland China, due to the ever-expanding influence of the One Child Policy. It is still very relevant in Taiwan and many Chinese American families however.