Surprisingly enough, I find a crowbar lying on the ground.  I think that if I can get an end of the crowbar in a space between the tree and the shovel, I should be able to pry the shovel loose.

 

Should I pick up the crowbar?

Or should I try to pry the shovel with my hands?

                     Title: Tree, shovel and crowbar - Description: A picture of the tree with the shovel leaning against the trunk. There is a blue sky and green grass. The crowbar is lying to the right of the tree in the grass.                                   Title: Pry the shovel myself - Description: A picture showing the tree with the blue sky and the green grass. The shovel is leaning against the tree and I am reaching with my mittened hands to pry the shovel away from the tree.