Hello,
From the look of your photos this is a Sassafras albidum- the common sassafras tree. Look at the tree again and search for some older leaves- the close up leaves your picture shows are all at the tip of a branch, and are young leaves. Sassafras leaves can have 3 different shapes- leaves like the ones your picture shows, leaves shaped like a 'mitten', and leaves with 3 lobes--- that is, like a mitten with a thumb on either side.
Here is a link to pictures--
http://www.hort.uconn.edu/plants/s/sasalb/sasalb1.html

Your picture of the whole tree shows some 'mitten' shaped leaves. If these mitten shaped leaves belong to the tree you are asking about, it is a sassafras tree.
 
Or, if the mitten shape is from a trees that has a limb reaching over into the canopy of this tree is the case, please take some pictures of your tree's branch, showing how it branches off, and a close up of the buds. Also a picture of the back side of a leaf will help.

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