Melina is a species with broad natural distribution in southeast Asia, and grows form sea level to 1,000 m above sea level. It has been introduced in tropical countries and has been very successful under a wide range of climatic conditions. In Latin America, the species has been planted mainly in Costa Rica, Brazil, Venezuela and Guatemala. The species grows in the following life zones: Very Humid Tropical Forest, Humid Tropical Forest, and Dry Tropical Forest in sites where the average annual precipitation is between 1,000 and 3,000 mm, from sea level to 500 m of elevation and with average temperatures between 24 and 35 °C (Murillo and Valerio 1991). In Costa Rica it has been observed growing well up to 600 m above sea level with average annual precipitation of up to 2,500 mm and 2 - 4 dry months per year.
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A SUCCESSFUL CASE OF MELINA-BASED INDUSTRIAL DEVELOPMENT Maderas Cultivadas de Costa Rica S.A. (Cultivated Woods of Costa Rica S.A.) pioneered the establishment of melina plantations in northern Costa Rica. Its first plantations were established in August 1986 using Costa Rican State forest incentives offered for the activity. The company currently has 6,550 ha of plantations (12.2% of the area planted in Costa Rica). In addition, it has established a sawmill to process the raw material. The company has been a beneficiary of the Costa Rican Reforestation Incentive Program since 1979. The company began harvesting in 1992. The product of the first thinning was used to make pallets and focused on supplying the pallets needed by the fruit industry (mainly banana) in the country's northern and Atlantic zones. Currently the wood from the final cut is processed in the company's sawmill and sold for furniture-making and construction purposes. The company has installed a drying oven that provides dry boars for the national market as well as for exportation. More and more, the Costa Rican wood market is beginning to accept melina for construction (framework) purposes and for furniture-crafting. This company sells sawn, dry wood to furniture factories, as is the case of Muebles de Coronado, at approximately US$200/m3 (Leon 1998). The company is identifying new international markets and has during 1998 exported samples of "green" sawn wood to the Japanese company, SHOUEI LTD. Wood prices in these first efforts were US$225/m3 of boards (CCF 1998a). |
For good development the species requires deep, well-drained soils, with a lime to lime-clay texture and flat to hilly topography. Some strong limiting factors to its development are wind, clay, flooded or compact soils, and weed competition.
The species has had great success in some Central American countries. Preliminary yield tables have been made on melina by Hughell (1991). These are applicable to the Central American region (Table 2). Site Index (SI) of 28 represents a high productivity site, while SI of 21 is moderately productive and SI of 14 illustrates low productivity. These tables present a management model for the production of wood that will primarily be destined for the lumber industry.
There are other management alternatives in Costa Rica for plantations whose objective is to produce wood chips for pulp and paper. Information on these models is not available but it is known that they work on a rotation of 6 years and produce total volumes of approximately 240 m3/ha.
The initial plantation spacing is 3m x 3m (1,111 trees/ha) in the case of lumber production and it is for this reason that the yield tables show the plantation evolution starting at this density. Lower densities are not used since the species branches out at low heights and the thick branches it produces affect tree formation.
Pruning is one of the main silvicultural activities applied in the management of this species. The experiences generated in Costa Rica suggest that three prunings in a 12 year cycle are recommendable. The first cutting of branches should be made when the plantation trees reach an average height of 5 meters, to 50% of the trees' height. The second should be made when the average tree height reaches 10 meters, cutting back the branches to 50% of the trees' height and the last pruning should be made when the trees reach a height of 16 meters and then they should be pruned to a height of 10 meters. Carrillo (1997) estimated that a pruning program that guarantees 10 meters of knot-free wood, would represent approximately 80% of the commercial volume extracted from the plantation without knots.
Hughell (1991) recommends a thinning program for the species, applicable according to the Site Index (SI). For SI of 28, 3 thinnings are recommended. The first thinning should be made at age 4, the second at age 8 and a third thinning at age 12. In those areas with SI of 21 or 14 only 2 thinnings are proposed at 6 and 10 years in the first and at 8 and 12 years in the second, respectively.
Nevertheless this thinning schedule depends on the rotation age of the species. According to experiences generated in Costa Rica, the age of the final cut for melina plantations oscillates between 10 and 14 years depending on the site conditions. Currently the 12 year rotation is used more to do species production projections.
The Mean Annual Increment (MAI) in total volume that appear in the Table 2 and 3 oscillate between 6.6 and 30 m3/ha/year at 12 years of age for the lowest and highest site indexes, respectively. The average site index 21 shows an MAI in volume of 17.7 m3/ha/year. Nevertheless, experience generated in Costa Rica with the species show that higher volume increments can be achieved. Zeaser (1998) reported an MAI in total volume between 30 and 50 m3/ha/year in southern Costa Rica with plantations established with genetically improved seed with the appropriate fertilization and weed control programs.
Vallejos (1996) established a yield and production classification system for melina (Table 3). The study included plantations from 1 to 15-years old. With this information it was possible to estimate that at 12 years of age sites with an average productivity will have diameters (dbh) oscillating between 34.9 and 43.2 cm and total volumes between 184 and 294 m3/ha.
Table 2. Preliminary yield table for Gmelina arborea management in Central America for site indexes 28, 21 and 14m with planting densities of 1,111 trees/ha
|
Age |
Remnant Trees |
Trees Extracted |
Vol. Acum. |
MAI |
CAI |
|||||||
|
N |
H |
D |
G |
Vol |
N |
G |
D |
Vol |
||||
|
SI=28 |
|
|
|
|
|
|
|
|
|
|
|
|
|
2 |
989 |
7,9 |
11,0 |
9,5 |
28,9 |
|
|
|
|
28,9 |
14,4 |
14,4 |
|
4 |
549 |
14,7 |
19,4 |
16,2 |
72,8 |
440 |
9,5 |
16,5 |
49,1 |
121,9 |
30,5 |
46,5 |
|
6 |
549 |
19,3 |
23,7 |
24,1 |
154,5 |
|
|
|
|
203,6 |
33,9 |
40,9 |
|
8 |
399 |
22,4 |
29,9 |
28,0 |
177,0 |
150 |
5,9 |
22,4 |
43,9 |
270,0 |
33,7 |
33,2 |
|
10 |
399 |
24,4 |
31,6 |
31,3 |
239,3 |
|
|
|
|
332,3 |
33,2 |
31,2 |
|
12 |
299 |
25,7 |
36,8 |
31,8 |
221,5 |
100 |
5,5 |
26,6 |
45,6 |
360,0 |
30,0 |
13,9 |
|
14 |
299 |
26,4 |
39,9 |
32,0 |
258,1 |
|
|
|
|
396,7 |
28,3 |
18,3 |
|
SI=21 |
|
|
|
|
|
|
|
|
|
|
|
|
|
2 |
989 |
5,9 |
8,3 |
5,3 |
12,9 |
|
|
|
|
12,9 |
6,4 |
6,4 |
|
4 |
989 |
11,0 |
13,6 |
14,4 |
58,6 |
|
|
|
|
58,6 |
14,6 |
22,8 |
|
6 |
609 |
14,5 |
18,9 |
17,1 |
76,6 |
380 |
7,3 |
15,7 |
38,0 |
114,6 |
19,1 |
28,0 |
|
8 |
609 |
16,8 |
21,0 |
21,2 |
120,7 |
|
|
|
|
158,8 |
19,8 |
22,1 |
|
10 |
409 |
18,3 |
25,3 |
20,5 |
109,6 |
200 |
6,4 |
20,1 |
39,6 |
187,3 |
18,7 |
14,2 |
|
12 |
409 |
19,2 |
25,9 |
21,5 |
135,4 |
|
|
|
|
213,0 |
17,7 |
12,9 |
|
14 |
409 |
19,8 |
29,5 |
24,6 |
157,8 |
|
|
|
|
235,4 |
16,8 |
11,2 |
|
SI=14 |
|
|
|
|
|
|
|
|
|
|
|
|
|
2 |
989 |
3,9 |
5,5 |
2,4 |
4,1 |
|
|
|
|
4,1 |
2,1 |
2,1 |
|
4 |
989 |
7,3 |
9,1 |
6,4 |
18,8 |
|
|
|
|
18,8 |
4,7 |
7,3 |
|
6 |
989 |
9,7 |
11,8 |
10,9 |
40,0 |
|
|
|
|
40,0 |
6,7 |
10,6 |
|
8 |
639 |
11,2 |
14,9 |
11,2 |
40,7 |
350 |
4,1 |
12,2 |
17,1 |
57,8 |
7,2 |
8,9 |
|
10 |
639 |
12,2 |
15,8 |
12,5 |
55,0 |
|
|
|
|
72,1 |
7,2 |
7,2 |
|
12 |
439 |
12,8 |
18,4 |
11,7 |
46,7 |
200 |
3,3 |
14,4 |
15,3 |
79,1 |
6,6 |
3,5 |
|
14 |
439 |
13,2 |
18,5 |
11,7 |
54,4 |
|
|
|
|
86,8 |
6,2 |
3,9 |
|
Vol |
= Volume in m3/ha without bark up to 10cm |
G |
= Basal area in m2/ha |
|
N |
= Number of trees per hectare |
V. Acum |
= Accumulated Volume accumulated (remnant trees + extracted trees |
|
H |
= Total average height in m |
MAI |
= Mean Annual Volume Increment |
|
D |
= Diameter to 1,3 m in cm |
CAI |
= Current Annual Increment |
Source: Hughell (1991).
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STON FORESTAL’S GENETIC IMPROVEMENT PROGRAM Gmelina arborea that includes studies on site classifications, plant nutrition, weed control, intensive silvicultural management (pruning and thinning) and the Genetic Improvement Program. The objective of the latter is to improve melina for paper pulp production. One of the company's main results has been the identification of the species’ limiting edaphic parameters such as high aluminum content in the soil. On the other hand, nursery production has become specialized and is now done on a large scale. In 1989 the company began selecting 6-years or older Plus trees from the Costa Rican melina population based on 3,000 ha located in the country's northern and dry Pacific regions. In 1992 the company had 3,400 selected clones located in a 15 ha farm and that same year they began with progeny tests. In 1993 seed production with some degree of improvement was started in the Farm Seed Orchard. In 1994 the Farm Seed Orchard produced 3,000 kilos of seed and established the first 200 ha of plantations to use this seed. The result was a volume increment 22% greater than that obtained using seed from a Seed Stand established in the country's dry Pacific. In 1995 melina from Thailand, Burma, India and a plantation in Brazil were introduced with the objective of broadening the company's genetic collection. The idea was to improve production and tree form. Since 1995 the company has used only seed from the Farm Seed Orchard to establish new plantations. The annual plantation area is 1,000 ha and the level of improvement has increased as now there is more information available on the best sites for developing the species as well as on intensive silvicultural management technology. The investment necessary for the genetic improvement program is approximately US$100,000 annually and it is estimated that around US$1.2 - US$1.5 million has already been invested. According to CAMCORE reports the seed produced by the company showed the best growth results in melina proveniences trials both within Costa Rica as well as in Colombia, Venezuela and Indonesia (CAMCORE 1996). These used three test seed samples from Thailand (coming from Kanchanaburi, Chantaburi and Nakonratchasima) and one test seed sample taken from the Ston Forestal company plantations in Costa Rica. The results were:
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Comparing the information from Vallejos (1996) and Hughell (1991) yield tables it is evident that the yields obtained in Costa Rican melina plantations are superior to all others reported in Central America.
Table 3. Production and yield classification for Gmelina arborea in Costa Rica
|
Range |
MAI dbh |
MAI height |
MAI Basal Area |
MAI Volume |
|
Excellent |
> 4.63 |
> 3.91 |
> 4.64 |
> 37.78 |
|
High |
3.61 - 4.62 |
3.21 - 3.90 |
3.40 - 4.63 |
24.50 - 37.77 |
|
Medium |
2.91 - 3.60 |
2.33 - 3.20 |
2.21 - 3.39 |
15.34 - 24.49 |
|
Low |
1.91 - 2.90 |
1.23 - 2.32 |
1.54 - 2.20 |
6.79 - 15.33 |
|
Marginal |
< 1.90 |
< 1.22 |
< 1.53 |
< 6.78 |
Source: Vallejos (1996).
In Costa Rica there has been significant progress made in the identification of the factors which limit species development. Vazques and Ugalde (1995) studied 28 sites located in Costa Rica's north Pacific and found that:
Vallejos (1996) recommended planting melina in sites protected from wind with slopes of less than 20% and soil calcium contents superior to 18cmol(+)/L. Ston Forestal is producing improved melina seed which is certified by the National Seed Office of Costa Rica. The seed is sold on a national and international level.
