When we think of trees, what comes to mind? Swaying limbs and fluttering leaves in the breeze? A hammock? Shade? This imagery is true for many trees, but their forms vary widely. There are shrubs shown here that are trained as small trees, and other trees when small look like shrubs until many years of growth produces a multi-trunk tree. That is another difference; multi-trunk trees have, as the name suggests, multiple trunks coming from their bases, as olive trees will naturally do on their own. Some trees that grow into multi-trunk specimens can be trained early on in the nurseries to become what the industry calls "standards", a single-trunk tree as we are all familiar with in the landscape. Certainly, numerous trees naturally grow as standards, which require little to maintain single trunk forms. Attempting to make them into a multi-trunk will end with a badly formed tree. What all this means is that designers should consider how a tree naturally forms and work with that form in their designs. Forcing only means higher maintenance, and few clients desire the compounding cost impact over time.
Speaking of maintenance, another designers' practice that causes higher maintenance as trees mature is placing them in the wrong place. Remember the mantra, "the right tree in the right place" and your design will be golden. The wrong places include planting trees too close together. Pay attention to their mature sizes, and place them accordingly so not to heavily overlap limbs with each other creating conditions for excessive pruning. If density is desired, consider using understory trees and large shrubs that will not crowd tree canopies but provide greater canopy at a lower level. Planting where the canopy does not have sufficient space, such as too close to a structure, has other ramifications leading to excessive pruning close to buildings, roots compromising foundations, and trees leaning away from said structures creating poor tree forms. When these situations occur, it is of no wonder why clients become frustrated when trees need excess corrective pruning, treatments due to stress, or outright removal. If designers want to create a design legacy, thinking about the long-term growth of trees should be a priority.
The trees listed here are primarily categorized as evergreen (keeping their leaves all year round while shedding old ones), deciduous (loosing their leaves in a season, which includes both summer and winter dormancies), and conifers, such as pines and redwoods. What is missing are palms. I and other arborists do not consider palms as trees but grasses due to their monocotyledon classification and by extension their performance. For example, they do little to contribute to forest canopy unless planted in tightly placed groves, which I encourage as a designer for the right project. For the purpose of this blog, see palms and other monocotyledons under grasses in the plants menu below.