Again, sorry for the delay. I will have a couple of posts for you this time again. Firstly I wanted to report that the bur oak sapling that I was given in Olds has grown a fourth leaf and is doing fine. I mention this because I have learned a little about bur oaks while at the farm. Quite often on the oak you will find the little nodules or burs growing. These are caused by the rough bulletgall wasp (Disholcaspis quercusmamma) laying its egg in the bark of the tree. The sap flows out to cover it and forms the gall protecting the egg. This kills the twig or branch end, but it doesn't harm the tree itself. Also, the wasp has been known to pick off other dangerous insects, thereby preserving the health of its host, albeit indirectly, but not without some cost.
For us, it means that we have to trim off the affected parts, simply to preserve saleability. People often think that the tree is diseased and not want to buy it, and with today's natural cynicism any attempt to explain the matter can be interpreted as disingenuous. Thankfully, the wasps only seem to inhabit young trees. By the time it matures the wasps will move on.