How much of the tree are we talking about?

If you must you can spray it with insecticide.

Maybe you can get away with spraying the tree down with water and washing em off for awahile.

That looks like an inch worm. They like maple leaves.Natural predators are birds, wasps and yellow jackets. http://www.asktheexterminator.com/garden_pests/Inchworms_printer.shtml

'So how do you get rid of these things? Well, they do have a few natural predators like birds, paper wasps and yellow jackets. One of the most common methods of limiting the number of inchworms in a given area involves allowing more wasps to survive there. Wasps like to feast on inchworms. Of course, for many people, wasps are not really a good idea for obvious reasons. The inchworm can also be managed using various chemicals or non-toxic “green†products. Try to find their main areas of infestation. If it is in a fruit tree, you may be able to spray the tree and nuke the entire infestation."

Thank you toronado3800 and avamom2012! There is a wasp nest (not my favorite) in another tree out there. It is maybe 1/8 - 1/4 of the tree but I see it is getting the new growth as well. I guess I will get some good green spray and see what I can do for it. Thanks again!