Rejuvenation Pruning Cut canes to about 6 inches above ground FIGURE 19–9 Renewal pruning and rejuvenation. Renewal pruning Before Remove 1/3 of shrub canes FIGURE 19–10 Renewal pruning of an old tree removes old and unproductive or damaged branches and heads back limbs to encourage new growth. Cut away in the process. Homeowners who request or undertake this procedure themselves feel their trees are overgrown and pose a hazard. Because of the severe reduction in the canopy, the tree is deprived of most of its photosynthetic surface, leading to stress from inadequate food supply. The tree trunk is weakened and predisposed to disease and insect attack, as well as bark splitting from sunburn. The stubs are prone to decay and also produce many rapidly growing weak new shoots. Topping reduces the life of the tree and is expensive, since a weakened tree is prone to weather-related damage and often needs pruning after a few years. 19.8 PRUNING ROOTS Unlike the pruning of aboveground plant parts done as part of the plant management operation, roots are pruned once during the plant establishment process. Roots of large plants are pruned immediately or shortly before transplanting (Figure 19–11). If pruned long before transplanting, the roots have the opportunity to develop a new mass of secondary roots for better establishment when transplanted. Sometimes pruning is necessary to reduce the root size in order to fit the hole for transplanting. Tractormounted mechanical root pruners are used by large commercial nurseries that produce and sell large plants. 19.8 Pruning Roots 579
FIGURE 19–11 Root pruning is accomplished by using a spade for a small plant or using commercial tree augers for large plants. Bare-root plants may be pruned before planting to remove damaged roots. 19.9 TRAINING PLANTS Training A system of plant management that involves pruning and tying to create and maintain desirable plant size and shape. Training, a horticultural activity performed while the plant is young, entails laying the basic architectural framework for the shape the plant will assume at maturity. Further, it is easy to manipulate the limbs of young plants with little danger of breaking them. Plants are trained according to a predetermined strategy to accomplish specific purposes. A successful program combines a good understanding and application of the practices of pruning, plant nutrition, and the use of physical supports in some cases. Plant training requirements vary according to the determined objectives. Hedge plants are rarely trained. Small fruits such as grapes require elaborate training for good production. Sometimes it is best to allow plants to grow and develop to assume their natural shapes and forms without any interference. Certain species cannot tolerate limb manipulation without adverse consequences. After developing the foundation for the adult plant shape and form, the gardener must prune or reposition limbs periodically to maintain these characteristics. 19.10 TRAINING AND PRUNING ORNAMENTAL TREES The primary goals of training ornamental trees are to develop a strong tree trunk, develop an attractive plant form, and establish a heading height. Central Leader The main upright shoot of a tree. 19.10.1 DEVELOPING A STRONG TRUNK The training strategy for developing a strong trunk is called the central leader. One strong, upward-growing branch is identified and encouraged to grow to become the central axis of the tree. One way of developing a strong trunk is as follows: 580 Chapter 19 Pruning 1. Cutting back (heading back) the plant in the first year will allow new growth to occur just below the cut. Unless a young tree is weak, it should not be staked. If required, staking should be loose to allow the trunk free movement in the wind in order to develop strength. 2. A strong, upward-growing branch is identified in the second year, and other branches (competing leaders) below the selected leader are removed or pruned back. Water sprouts will develop as a result.
This books ( Financial Accounting: Practice and Principles ) Made by Jan Bebbington
The successful systems based formula for teaching financial accounting that gained such academic acclaim in its first and second editions, is back! Financial Accounting remains the student s favourite! The third edition is more streamlined, more user friendly and even more accessible. An in-depth, worked example from an actual partnership, brings alive for students the accounting issues involved in partnerships, a required topic of accreditation. Financial Accounting is based on a threefold approach: an organizational flow-model is used to locate financial accounting in its organizational context; this model is then used to derive a systematic logical approach to financial accounting and the construction of the financial statements; and the text attempts to forge a firm link between the traditional diet of introductory financial accounting and the wider issues of accounting theory. Financial Accounting is the ideal text for undergraduate Accounting students.
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