The best way to use tree chippings is to compost them. They are likely to be PERFECT carbonaceous material. Mix them with horse manure, cow manure etc. (providing the nitrogenous material) as you mix.
Trial and error will tell you the best ratio, depending on the type of tree, freshness of the chips, freshness of the manure etc.
For starters try 2 parts chippings, to one part manure (approximately). If your pile doesn’t heat up, try another pile of equal parts chip to one part manure.
Trial and error!
My advice would be to turn the piles twice, and let the compost mature for 3 to 6 months.