Feeding maple trees

Q: I have several young maple trees that I planted four years ago. When I planted them they were about a foot high. I live in southern Interior BC, (West Kootenays). Each year the trees grow healthy looking leaves, but the woody parts of the trees are not growing. The best of them is now perhaps 18 inches tall and the stem is smaller than my little finger. What should I feed the trees? So far I have been giving them a commercial steer-manure product that I pour out onto the soil surface around the stem.

The maple trees might be overfed with commercial steer manure since most maples tend to be fast growers. There is no mention if the manure is composted (aged) or whether the previous fertility of the ground is in question (what was grown there before the maples were planted). Some summer pruning by shortening the tree truck and branches, “root pruning” to limit the spread of the tree roots, or apply a complete granular fertilizer as directed on the label.