First, cuttings can occur for a variety of reasons, such as nest building, seeking moisture, or seeking food. If you have a bird feeder and have removed it, squirrels may be overpopulated and seeking alternative food sources. (Never use an unmodified bird feeder as you will only create problems down the road; see Bird Feeders Not Squirrel Feeders for more information on bird feeders and their modification.)
Second, you have some options. Consider spraying your trees with a taste repellent such as Ropel, cinnamon/cinnamon oil, or capsaicin. Be sure that the label allows its use on plants. (Be doubly sure to follow directions, and never use the product on plants intended for human consumption.)
Third, fence the plants so that squirrels can’t get to them. Use 1/4-inch weave galvanized hardware cloth. Don’t use any wire “fabric” with holes larger than 1/2-inch weave, and don’t use chicken wire because it isn’t strong enough. If your trees are relatively isolated from neighboring trees that you don’t own, consider wrapping the trunks with aluminum flashing at least 18 inches high. With this method, squirrels can’t get a grip on the trunk to climb. Place the flashing at least 4 feet off the ground so they can’t jump over it. If you must use multiple sheets to wrap, be sure the overlap is always on the top over the sheet below, like shingles. Otherwise, squirrels will use the edge to climb. Also, be sure to trim branches up to at least 5 feet above the ground so that squirrels can’t leap up and access the tree.
Fourth, employ population reduction through trapping. Check state and local laws to be sure that it’s legal in your state. Visit Tree Squirrels on how to effectively trap them.
Don’t think that translocation of wildlife is necessarily more humane (even if your state allows it) than simply euthanizing the animal. An animal that is moved from its native area encounters great challenges. It has to: 1) find a new home, 2) find new food and water sources, 3) accomplish items 1 & 2 while avoiding unfamiliar predators, and 4) do all of the above before nightfall or daybreak (depending on species) so that it doesn’t die of exposure, etc. Translocation also stresses the resident population because you’ve now introduced a newcomer that has to fight for territory, not to mention any potential diseases that the newcomer may bring to the locale or contract from the new area. See Relocating Problem Wild Animals for further information on relocating animals.
Remember, there is no magic in this business. So don’t bother with ultrasonic gadgets. Most animals can’t hear in the ultrasonic range anyway.