Do all trees form flowers at some point in the growing season and pollinate?
Trees do some sort of flowering, though the flower may be practically unnoticeable. Even oak trees have flowers that are male and female. Dogwoods have flowers that are more noticeable and beautiful. The flowers of any type of tree will produce the pollen that must be spread from flower to flower so that seeds can be produced. The seeds of an oak are acorns. The seeds of the dogwood are the berries you have seen. This is basically how things work for almost all plants – some sort of flowering, spreading of pollen, then fruit and seeds form so that more of the plant can be grown.
