UNITED STATES—There are an immeasurable variety amongst trees. Evergreen trees retain their foliage through the seasons. Deciduous trees defoliate in autumn, and regenerate new foliage in spring. Small trees are comparable to large shrubs. Large trees can get big enough to be prominent features in neighboring gardens. Some densely foliated trees make dark shade. Sparsely foliated trees produce lighter shade that other plants can live with.This time of year, many deciduous trees get impressively colorful before going bare. Some trees have bronze, purple, yellowish, reddish, blue, gray or variegated foliage through summer. Many trees provide appealing bloom. Some provide fruit. Trees can be exploited for shade, privacy or aesthetic appeal. Even unwanted or deteriorating trees make good firewood.
In order to conform to garden situations, most trees need some degree of maintenance. Falling limbs that would not be a problem in the wild are hazardous in landscapes, around homes, or anywhere that they can hurt anyone or anything. Trees that develop dense canopies or accumulate dead branches and foliage can become hazardously combustible, especially near chimneys.
Just as there are many different kinds of physicians who specialize in different aspects of health care, there are different kinds of horticultural professionals. Large trees are the most substantial plants in any landscape, so are beyond the reach or capabilities of gardeners who are proficient with lawns and shrubbery. Trees therefore need to be maintained by those who know them best.
Arborists are horticulturists who specialize in arboriculture, or the horticulture of trees. They can assess the health, stability and structural integrity of trees to identify potential problems before they get too serious. Arborists can also prescribe arboricultural procedures that may partially alleviate or even correct certain problems. Most arborists work with crews who are qualified to execute their recommended procedures accordingly.
Arborists who are certified by the International Society of Arboriculture, or ISA, have demonstrated proficiency with arboriculture by passing a certification examination, and maintain their certification by continued participation with the ISA. The website of the ISA at www.isa-arbor.com features a roster of ISA certified arborists that can identify arborists within particular locations. The site also provides information about trees and why proper arboriculture is so important.
Highlight: Camphor Tree
Within the native range through Japan, Korea, Vietnam and southeastern China, the wood of the camphor tree, Cinnamomum camphora, has historically been used like incense cedar was used in California; to construct chests and closets. It is aromatic enough to repel insects from vulnerable fabrics. Here in California, it is known as a strikingly sculptural shade tree with a rounded and dense canopy of glossy light green foliage. Individual leaves are about two or three inches long. The minute pale flowers that bloom in spring are not much to look at, but can make a sawdust-like mess as they fall. Mature trees get about fifty feet tall and slowly spread even wider. The bulky roots are resilient to drought, but sensitive to excessive moisture.
By Tony Tomeo