Grafting is the process of combining scion wood--the young branches--from one tree with the stump of another to promote growth of a new tree. In oak trees, blue oaks are considered a viable species to graft. When grafting oak trees, the best method to use is the modified bark graft.
Obtain scion wood from the desired oak trees. Scion wood are the young branches on trees, roughly 1/4 inch in diameter and 8 to 12 inches in length. Place the wood in a refrigerator for storage if it will not be used immediately.
Find a viable stump and saw at least 3 inches off of the top to provide a fresh grafting location. A viable stump will be free of diseases and boring insects.
Use a grafting knife to cut an upside down "T" in the bark of the stump, just below the stump's top. The T should be roughly 2 inches long and 1 inch wide at the bottom. Do not cut too deeply, just through the hard, outer layer of the bark. This will provide the budstick with the correct placement next to the nutrient-providing portion of the tree.
Trim the scion wood so that the tip forms a diagonal. Push the diagonal end into the "T" cut in the stump's bark until it remains firmly in place.
Paint the entire grafting area and the top of the stump with asphalt sealant to prevent moisture loss and disease as the plant's graft heals. New growth will appear within 6 weeks of grafting if the graft was successful.