Birch tree dripping fluid / branches turning black

[Sapling]

I have a question regarding a Birch tree....
All of the lower branches are turning black in color on a large birch tree. There are splits along truck of the tree and knots are weeping clear fluid that is running from one large branch and dripping onto ground. Any ideas what might be wrong.....?

 

[kennertree]

Can you post a pic?

 

[Sapling]

Here are a few pics.
I have been reading about the sap flow issue which is common for this time of year but why does the tree have so many cracks and why is it leaking so much if there are no fresh cuts?