Trees provide shade, a natural setting for a home, and walls and ceiling for outdoor areas. Trees enhance a garden, soften the lines of building, give a neighborhood character, and hold the color of the skyline.
Trees serve many purposes, both aesthetic and practical. They can absorb noise, filter the air, and frame attractive views or screen unattractive ones. They also often enhance property values.
UNDERSTANDING THE TREE
.Trees are complex organisms whose many parts function together so that the tree can grow and thrive. Understanding how the parts of a tree work together will aid you in caring for trees.
A protective layer of bark covers the trunk of the tree. Beneath this outer layer of bark is the inner bark (phloem) that is part of the tree's vascular system, carrying nutrients to where they are needed. Between the inner bark and the sapwood is a thin layer called the cambium layer that produces the new cells for both. Growth in the diameter of a tree's trunk is by cell division and expansion from this cylinder of cambium cells. The inner sapwood, or xylem, carries nutrients and water from the roots to the leaves.
Beneath the sapwood is the heartwood, an inactive region of sapwood. Heartwood gives the tree strength and rigidity and serves as a depository for stored food and wastes.
The root system of a tree can be quite extensive, depending on the depth and texture of the soil in which it grows. As a tree matures, relatively shallow horizontal roots develop and predominate. Lateral roots form at the base of the trunk and spread to build an extensive network that anchors the tree. Lateral roots also store food. Feeder roots grow from the lateral roots and transport water and nutrients absorbed by the root hairs (microscopic appendages to feeder roots). Root caps produce a continuous supply of new cells that are sloughed off and serve to lubricate the advance of the growing root tip through the soil.
Pruning can do much to enhance the health and appearance of a tree. At planting time, light pruning helps compensate for the root loss of bare-root plants and improves the water balance in container-grown trees. Pruning can be used to encourage strong branch structure and handsome form. Regular maintenance pruning, such as removing dead wood and crossed branches, lets light into the interior of the trees and will improve overall growth and vigor. Pruning is particular useful for controlling tree size.
On mature trees, pruning can be used to maintain a balance between vegetative growth and flowering. Stagnated trees can sometimes be revived through pruning.
A knowledge of how trees develop and how they respond to pruning is essential to knowing when and how to prune.