Ficus callosa: Unheralded species shows promise as livelihood source for coastal communities

Preliminary studies on a heretofore relatively unknown species indicate potential use in boat making and a possible alternative source of income for coastal communities. Further studies are required to develop and determine acceptability and viability of propagation, harvesting and processing technologies.

By Lito Osmeña, Calixto E. Yao and Roberto Ybañez

icus callosa (kalukoi in most dialects, or hindang in Leyte and Surigao and taloot in Cebu and Negros Oriental) belongs to the Family Moraceae, the same family to which Anthocarpus integra (nangka) and Ficus balete (balete) belong. The tree is highly prized in the Visayas and Mindanao for its lightness and resistance to marine borer, qualities that make it a good material for boat making.In spite of its economic potential, however, kalukoi is virtually unknown because of its sparse distribution and indistinct appearance in the open. In San Isidro, Leyte, the species is thriving well, but only in limited numbers as the trees are harvested for boat making.Among foresters, a big reason for the lack of interest has been the fact that the species belongs to the Ficus group, in which balete and tibig (Ficus nota ), both known for their low quality wood, are also included.

Recent interest in the species stems from three specific physical characteristics of kalukoi -- the nearly cylindrical bole, appropriate height, and fast growth, which indicate a potential as material for electrical posts. Tests and planting trials conducted by the Forest Research and Development Institute (FPRDI) at Los Baños showed however that kalukoi  wood falls short of the standards for wood strength for electrical posts. Other uses -- such as for furniture making and boat making -- may be more appropriate for commercial purposes.

This article can serve as a formal documentation of the species for possible technology dissemination.

Kalukoi is a large tree with a diameter at breast height (dbh) reaching a maximum of 55cm, and with merchantable height (mh) and total height of 17 meters and 29 meters, respectively. It is widely distributed in the Visayas and Mindanao, but in a limited number. The tree is typically found along roadsides and in urban areas, usually solitary, rarely in groups. The crown is conical to spreading, especially in the open. Inside forests, the tree is generally taller, nearly cylindrical, with a narrow crown concentrated at the top.

The species can be distinguished by the following characteristics:

Leaves -- the species has several developmental stages. The juvenile leaf (one-year-old seedlings or coppice) is long (8cm x 60cm), elliptic and serrated along the whole margin. As the tree matures, the serration disappears except at the lower half. Leaves are simple, forming a whorl with a cordate (heart-shaped) base and the margins almost touching each other.

Flowers/fruits -- the round fruit measures 2cm in diameter, is greenish gray and powdery, and emanates from the leaf axis in pairs from a slender individual peduncle measuring 3cm in length. The inner portion of the fruit, including the fleshy seed covering, is pinkish. A medium size fruit has 220 tiny (1.5 mm in diameter) brown seeds resembling the seeds of malambingan (Allaenthus luzonicus), a related species. The seeds turn brown when mature. Propagation is aided by giant bats, which eat the ripe fruit and drop it minced with the seeds.

Bark -- the bark is khaki in color, 1 cm thick, with prominent leaf/branch abscission layers. The inner bark is whitish and, unlike most other species of the Moraceae family, produces a colorless sap that causes skin irritation and burning, depending on the degree of contact. (This may account for the tree. s resistance to marine borer or termite attack.)

The tiny seeds of kalukoi germinate within 10 days but tend to go through a grass stage, taking two months to develop bigger leaves. Growth accelerates when leaves grow to about 3cm x 6cm. Seeds collected from rotting fruits collected under the canopy germinate at a 40%-50 % rate. The seeds can be refrigerated up to five months, but with germination decreasing to 10% over time.

The species is susceptible to damping off (fungal infestation due to overcrowding, limited sunlight and over watering). To prevent this, use a seed box filled with fine sand. Using the broadcast method, sow the seeds at appropriate distances to avoid overcrowding. For higher germination and more robust seedlings, allow more sunlight by using semi-transparent plastic shade. Seedlings are ideally potted at 2cm height.

Growth Rate

Field observations have confirmed that kalukoi is a fast-growing indigenous species, increasing 4-5 cm in diameter and 2-3 meters in height every year in good sites. At four months, a plantation in San Isidro, Leyte established on a level ground topsoil, had an average height of 1 meter and a dbh of less than 1cm. In another site, on a slope made of felled material, two-year-old trees in the open were found to have an average dbh of 8cm and total height of 7m. Two trees under shade, which were planted at the same time as those in the open, were only 3 meters tall and 3.5cm in dbh. An eight-year-old tree growing among coconuts and mango trees had a straight bole measuring 25 cm in dbh, and was 10m and 14m in mh and total height, respectively.

Another big tree (reckoned to be about 20-25 years old) within an old acacia (Samanea saman) stand had a dbh of 55cm, mh of 16 meters and total height of 29 meters. As with the tree within the coconut-mango plantation, the bole is nearly cylindrical. In contrast, trees in the open were not as tall or as cylindrical, exhibiting generally wider crowns, shorter boles and denser foliage.

The species appears to be shade tolerant, surviving under heavy canopy and then shooting up rapidly when its  reaches canopy level.

Phenology

A prolific seeder, kalukoi starts to bear fruit at 2-3 years old and continues to produce seeds regularly for many years. In Cebu, seed fall is March-April and July-August. The tree is deciduous and sheds off in November-December. As in many deciduous species, fruiting follows leaf development and varies from area to area. 

Natural regeneration

Despite having two fruiting seasons, kalukoi has a very poor regenerating capacity. Wildlings rarely grow under the canopy of mother trees. The few solitary regeneration volunteers are usually found along roadsides, far from the mother trees. These wildlings must have sprung from seeds dropped in flight by bats, as there are no trees nearby where the mammals could have roosted.

The poor regeneration could be attributed to the generally dense underbrush (due to the fact that the high crown permits enough sunlight for other plants to grow) and thick litter fall, which reduce the chance for the tiny seeds to reach the ground. Often, the fleshy fruit remains intact on the ground or above the litter fall until its rots, along with the seeds.

It is worth noting that the species seems to have a very limited distribution range as far as elevation is concerned. So far the highest elevation at which kalukoi has been sighted is about 100 meters. Another interesting fact about the tree is that it is seen more often in built-up areas along roadsides (an urban tree?) than in the hinterlands.

To determine the suitability of kalukoi for electrical post and other potential uses, wood samples consisting of two sticks (representing butt and top) each from three trees were sent to the Forest Product Research and Development Institutue (FPRDI) at Los Baños, Laguna. The source trees ranged from 20 cm to 55 cm in dbh and 10 meters to 28 meters in total height. The results are listed in Table 1:

*  Samples from the three different trees with corresponding diameter: Sample I . 55cm, II-20cm, and III-50cm

1    Determined in accordance with ASTM D143-52: Standard Methods of Testing Small Clear Specimens of Timber.

2    I, II and III confirmed/verified by FPRDI as Ficus callosa.

3    Based on oven-dry weight and volume at test.  The metric term for specific gravity as stated in the Metric System Board Metrification Circular No. 1-80 dated August 7, 1980.

4   Mpa=145 pounds per square inch (psi).

5   Load required to embed a 1.1 cm steel ball to ½ its diameter.

6   kN=225 pounds.

7   Joule=8.853 inch-pounds.

8    Tested by the Physical and Mechanical Properties/Structural Design and Engineering Sections, FPRDI

According to the FPRDI test results, kalukoi failed to meet the standard for modulus of rupture (MOR) in static bending, an important requirement for poles and piles. Kalukoi wood has only 35-42MPa, way below the minimum requirement of 50 MPa. This puts kalukoi in the same category as ilang-ilang, binuang, bagalunga, and other fast-growing species, which are all considered low-strength wood. Surprisingly, balete and dita, long regarded as belonging to the same class as kalukoi , showed higher hardness values -- 63-80 MPa and 40-50 MPa, respectively. (The difference may be a function of differences in fiber lengths between species.) Based solely on strength, in fact, balete meets the requirement for electrical posts; unlike kalukoi, however, it does not have a straight bole, and it is difficult to propagate.

The FPRDI suggests that kalukoi, assuming high treatability (the samples were not tested for treatability), may be used as material for service drop posts. Service drop posts have very limited demand, however, and thus may not warrant the establishment of a large plantation.

* Tesoro et al, 1990, modified

Ilang-ilang (Cananga odorata), balete, dita (Alstonia scholaris) and other species with characteristics (wood grain, density, strength) similar to kalukoi have been shown to have high treatability, indicating that kalukoi may have the same property and thus may be a good material for furniture plywood and veneer. White to creamy with a distinct wood grain, kalukoi wood may be used for light construction (sash door, panel cores, pulp and paper making, wall board, pencil slat and matchstick) where strength, hardwood and durability are not critical requirements. Further studies on finishing workability, seasoning and veneering characteristics must be done to assess its commercial potential, however.

How kalukoi compares with other species

To better appreciate the potential of the species for furniture and other uses, it may be good to compare its wood properties with other species of a similar class as well as with some hardwoods as extreme yardstick. Such comparison will provide some safe assumptions on those physical properties of kalukoi that have not been determined. As already pointed out, although kalukoi has not been tested for treatability, the fact that woods with similar wood properties (specific gravity, etc.) exhibit high treatability may indicate that kalukoi is easy to treat as well.

Table 3.  Other wood properties of kalukoi compared to other low strength wood

S.G. . Specific Gravity

MOR . Modulus of Rupture (strength)

Earning from kalukoi

Given the big demand for kalukoi for boat making, the planting of the species may be promoted as a means of livelihood among coastal communities, especially people's organizations under the Community Based Forest Management (CBFM) Program of the Department of Environment and Natural Resources (DENR). The CBFM is a shift from DENR's traditionally regulatory mode to harnessing people empowerment to eliminate the open access system of resource use and, with the community's involvement, ensure the protection, sustainable use and management of forest resources. Under this program, the community, through an accredited people's organization, is given a 25-year tenurial instrument called the Community Based Forest Management Agreement (CBFMA), which may be renewed for another 25 years.

In Bohol, kalukoi timber (about 40cm in diameter) from Surigao is presently selling at Php3,000 apiece, mainly for boat making. Even at current prices, a people's organization that begins a kalukoi plantation today has the potential to generate a big income in 8-10 years, the time it takes for the trees to mature. Harvesting may be shortened by appropriate silvicultural technology.

Community members have a number of farm systems, involving either communal or individual management, to choose from. With farm systems such as the Tree Farm Leasehold (TFL), a people's organization may lease land for 10-15 years under a sharing arrangement (usually 20%-80% or 30%-70%, depending on the proximity, slope, and productivity of the area) and operate it as a communal management area. Backyard or boundary tree farms under the management of individual community members are also a viable option.

Recommendations

·  Determine other wood chemical and physical properties to identify other possible uses of kalukoi.

·  Conduct research studies on the effect of fertilizer and spacing, pruning, thinning, intercropping and elevation on the growth and survival of the species.

·  For DENR and DA-BFAR: Promote kalukoi for boat making among the coastal people's organizations

 

Tesoro, F.O. and J. U. Aday, 1990. Properties and Uses of Some Philippine Woods. Forest Product Research and Development Institute, DOST, College, Laguna.

Yao, C.E. 1998.  Tree Farming: Sourcebook, Provincial Government of Bohol in association with the Governance and Local Government (GOLD ) Project

1995 Malambingan for Dogout Canoe, Philippine Lumberman, July-August, 1995

___________ In the Press, Tree Farm Leasehold

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