Suede is a type of unfinished leather. This means that the leather surface is actually the inside of the animal's skin. Suede is a sensitive material that can be damaged if it comes into contact with the wrong cleaners. Never use water or liquid cleaners, which will darken and spot the suede permanently. This restriction can make cleaning tough stains, such as tree sap, counter-intuitive.
Pick as much of the the tree sap off with tweezers as you can. Pull the sap straight up and be careful not to let it drag or drip on clean areas of the suede as you work.
Wipe the tweezers off after every retrieval with clear water to remove all residue.
Work with the tweezers until you remove the bulk of the tree sap residue.
Brush the stained area with a pencil eraser. Remove as much of the residual sap as possible.
Sand the stained area lightly with a piece of fine-grit sandpaper if it is still noticeable. This grinds away the top layer of the suede, so be careful not to rub too hard or you could wear a hole in the suede.