Trees age differently than people, ontogenetically as opposed to chronologically, but trees still have to pass through many of the stages people do - embryonic, juvenile, sexually mature. To get a sense of how trees age, think of their age in terms of the number of cell divisions it has taken for the most recent wood on the tree to form. Ontogenetically, the newest wood on the tree (branch tips) is the oldest because it took many more cell divisions for that wood to form. So, trees from seed, seedlings, often must persevere for many years before they become sexually mature and produce blooms/fruit.
OTOH, propagules/scions retain their ontogenetic age, so a rooted branch cutting or scion (specially prepared cutting grafted to understock) taken from a sexually mature part of the parent tree will be capable of producing blooms/fruit very quickly. Not so for seedlings, unfortunately. I have a Hawthorn tree I collected from a wild landscape. It was collected 21 years ago, this spring, and I'm still waiting for it's first flush of blooms. Maybe next year.
Al
