THE MANAGEMENT OF TEAK PLANTATIONSJulio César Centeno, PhD Growth Patterns Establishment Phase Stand Dynamics Thinning and Pruning Rotation Teak [Tectona grandis L] is a tree originally from an area encompassing parts of India, Thailand, Myanmar and Laos. It seems to have been introduced to Java, Indonesia, in the 14th century. Some scientists consider the island of Java as part of the natural range for the species. It has performed well in plantations, not only in its Southeast Asian range of origin, but also in other parts of Asia, as well as in Africa and Latin America. Teak has been cultivated in the tropics for centuries. There are references to plantations established in India in the early 1800s, and in tropical America about 100 years later. Although it is not devoid of silvicultural and management difficulties, it may be fairly said that it is a well-known timber species, relatively benign and successful in plantation environments in the tropics. The total area under teak plantations today is estimated at 3 million hectares. Good growth and high quality is associated with deep, flat, and well drained alluvial soils, rich in calcium; a mean annual temperature between 22 and 27 degrees centigrade; and an annual precipitation from 1,500 to 2,500 millimeters, with a marked dry season of 3 to 5 months with a maximum of 50 millimeters of rain. Dry site conditions are usually associated with stunted growth. Very moist conditions may lead to faster growth, but also to a thick sapwood and poor overall quality, including lower average density, less attractive color, poor texture, and loss of strength. Growth Patterns The rate of growth and the quality of teak from plantations are largely dependent on the type and quality of the seeds; the physical and chemical characteristics of the soil, including topography and drainage; on environmental variables such as rainfall, temperature and humidity; and on management techniques. Although a significant variety of growth patterns have been recorded in different part of the world, the best managed and most productive plantations tend to fall within a well defined range [Figure 1]. Nevertheless, there are many cases of poorly established and managed plantations, with rates of growth below the lower estimate indicated in this figure. Myanmar Forest Service: Myanmar's Mighty Teak Tree. except when teak is planted on . 1996]. suppressing the development of weeds. In comparison. and to manage them to reach a good average height before flowering sets in. A larger number of trees may be considered desirable to close the canopy quickly. there is limited conclusive evidence in this regard. the largest standing teak tree. making branching more profuse. The usual 1. An important aspect of plant competition may be sought in the relatively large need for aeration of the root system. while keeping a large enough basic stock on which to mold a good final crop. with closure of the canopy commonly taking place between the third and fourth year. An early first thinning would then become necessary to prevent stunting. Pure stands have been associated with the deterioration of the soil and with erosion. The light requirements of teak are those of a pioneer species.4 meters in diameter and 46 meters high in April of 1996 [Ref.Figure 1: Yield Potential of Teak Plantations Teak trees grown in plantations on good soils may reach an average of 60 centimeters of diameter at breast height [DBH]. However.200 to 1. and in the requirements for light and nutrients. to decrease the problems caused by weeds and the size of lateral branches.600 plants per hectare is a good range. while forcing the live crowns high up along the stems in a shorter time. and 30 meters in height in about 50 years. to promote rapid development of the saplings. Spacing should be relatively wide. Establishment Phase Teak establishes best on terrain cleared of competing vegetation. located in the Baw Forest Reserve of Myanmar. measured 2. A viable option for the production of high volumes of quality teakwood is to establish pure plantations on well-prepared and well drained soils. unable to stand much competition from other plant species. or from trees of the same species. 5 meters. with the loss of growth potential. and the second when the dominant height reaches 17 to 18 meters. the stand is affected by stagnation. Each site has a certain carrying capacity. This also implies a loss of growth potential. since the purpose is to produce as much timber in the main stem as possible. on the other hand. The dominant height and the cumulative basal area are parameters normally not affected by the initial stocking or by thinning regimes. coupled with the number. Erosion is a further threat when thinning is too strong. It is also useful to guide thinning operations. This generates a dynamic within the stand. where undergrowth has been systematically cleared. Often the age at which the first thinning is practiced is determined by the dominant height. where healthy growth is present. Trees within a stand also interact and compete with each other. which strongly influences its patterns of growth. with a profound effect on production. when these are of 0. If. These are fundamental decisions. The thinning regime may thus be designed to concentrate the basal area carrying potential of the site in a minimum number of trees. and intensity of thinnings.05 hectares in size. If thinning is practiced late. the stand is thinned too early or too strongly. A guiding rule is to allow the mean basal . It may also be estimated from the average height of the five largest diameter trees in permanent sample plots. nutrients and light available to each. The basal area of a stand is the average cross-sectional area of all trees per unit of stand surface. particularly when the undergrowth contributes to the fixation of nitrogen. teak should be planted only on the best site classes. preferably free of knots and defects. attack by defoliators is less frequent and intense. particularly during the latter stages of development of the plantation. with reactions controlled mainly by their genetic base. The initial spacing of planting. with the first thinning taking place when the dominant height reaches 9 to 9. measured in terms of basal area. which can be influenced by management decisions to achieve desired production objectives. especially when planted on unsuitable soils. Among these options is the space made available to each tree. normally measured at breast height. Within determined limits of thinning. the trees tend to produce more side branches and epicormic shoots. Dominant height is the average height of the 100 largest diameter trees per hectare. and by the space. poor in nutrients. total production per ha should not deviate significantly from the carrying capacity of the site. tends to avoid the deterioration of the soil.steep slopes. and therefore the overall yield of the plantation. and can be further reduced with the maintenance of a suitable understorey. Stand Dynamics A series of options are available to influence the development of a plantation. largely determine the space made available to individual trees as they develop. The management of pure stands where a protective understorey is maintained after canopy closure. On the best sites. which in turn is determined by site quality. timing. where only small and temporary canopy gaps are created. as well as the quality and quantity of the timber produced. Epicormic shoots may also be related to the genetic imprint of the seeds. As a general rule. or where excessive burning has taken place. Pure teak plantations are often prone to attack by defoliators. Thinning and Pruning Thinning and pruning operations are closely inter-related. but varying in numbers of trees. . pruning should be done selectively. when rapid height growth occurs. coordinated with the intended method of thinning. The trees then must have larger individual crowns to keep the canopy closed. to facilitate peeling. finishing. which thus will be thicker than in stands with higher numbers. and improved through experience and experimentation. pruning becomes an attractive silvicultural operation and a fruitful investment. and for the uniformity of strength. and the wood volume produced will be concentrated on lower numbers of trees. and seasoning. The management strategy can be designed to encourage the formation of clear boles. To minimize damage. as long as the canopy remains closed. which should be perceived as an investment to improve the quality of the final product. age and site quality. among other uses. It is also desirable to improve working properties of the timber. to clear 2 to 3 meters of stem at a time. A common strategy to grow long boles. depends largely on the thinning schedule. is to keep the stand quite closed and high in number of trees during the first years of development. How much wood goes into the branches of the crown. and consequently the branches relatively small and thin. tearing a strip of bark from the stem as it falls. For cost effectiveness. there may exist various provenances with genetic predisposition for small or broad crowns. and to facilitate access to the stand. To prevent the development of epicormic shoots. using a pruning saw. decorative veneer and plywood. the operation should be carried out just after the period when most new leaves are produced. Pruning also serves to reduce the chances of ground fires reaching the crowns. clear of knots. furniture. This prevents the branch from breaking when the saw cut is nearly complete. Even within a tree species. with a strong influence on the quality of the wood and on production performance. The removal of branches up to a desired height is done first near the time of canopy closure. Nonetheless. It is a costly operation.area to build up to between 20 and 22 square meters per hectare after the second thinning. it is better to sever the main branch about 30 cm from its connection with the stem. and how much goes into the valuable part of the stem. before cutting the stub flush with the trunk of the tree. As much self-pruning as possible should be provoked through stand architecture. since both the demand and the price for high quality tropical timber tends to increase. by pruning the trees that will yield commercial timber. Theoretically. the amount of all wood formed per hectare will be more or less the same for stands of the same provenance. The thinning schedule has thus to be adapted to the provenance used. and then thin the stand again to bring the mean basal area proportionately down to between 13 and 15 M2 per hectare. Thinning regimes are dictated by the development of the trees in height and basal area. while keeping the stand low in the number of stems. This is meant to keep crowns small. Knot free timber is desired to improve the quality and appearance of high-grade construction material. It is therefore justifiable only when the extra revenues involved out-balance the costs. The combination of reliable information on dominant height and cumulative basal areaprovides one of the best approaches to the successful management of teak plantation in tropical environments. teak has the propensity to produce adventitious branches and epicormic shoots next to the scars caused by pruning. and the need to prevent a slowing down of growth due to an excessive reduction of the crown. At such ages. Rotation Based on a weighed assessment of economic and silvicultural considerations. Julio César Centeno. thinning operations will provide returns at intermediate stages. In Asia. the stem length pruned at a time. During this rotation period. The mean annual increment at such ages may vary from 10 to 20 cubic meters per hectare.Nevertheless. teak trees are often allowed to develop for 60 years or more before harvesting. they would register similar mean annual increments as those in Asia for the same age. usually from 20 to 30 years. This does not mean teak grows better or faster in America. easing the economic burden related to the long-term nature of the operation.ula. Most plantations in tropical America are managed with far shorter rotations. A balance is necessary between the need to produce knot free timber. Were these plantations allowed to develop for 60 or 80 years.ve . a rotation of 25 years to 40 years may at present be considered as the optimum cycle to achieve a viable balance between financial returns and the production of market quality timber. the mean annual increments may vary from 3 to 10 cubic meters per hectare per year. and making the investment financially attractive. PhD Apartado 750 Mérida-VENEZUELA Tel / Fax: +58 74 714576 Email: Jcenteno@ciens.