Mr. Arsenio B. Ella
Forest Products Research & Development Institute (FPRDI), LAGUNA
Philippines
Introduction
In the Philippines, cutting of almaciga (Agathis philippinensis Warb.) for timber and lumber production is banned. Hence the utilization of this species is limited to the resin, known in the world trade as almaciga resin or Manila copal. Almaciga resin is used in the manufacture of varnishes, lacquer, soap, paint, printing inks, linoleum, shoe polish, floor wax, plastic, water proofing materials, paper sizing and many other products. Locally, it is used as incense in religious ceremonies, as fuel, torches, caulking substances and smudge for mosquitoes. Although regarded as a minor forest product, it is one of the country's leading dollar earners. In 1997, the Philippine Forestry Statistics reported that 381,000 kg of almaciga resin valued at US$303,000 were exported.
There are two kinds of almaciga resin: the ground or fossil resin, and the surface or tapped resin. Fossil resin is the amber-coloured exudation from the roots. It is obtained by digging into the ground where the almaciga once grew. In contrast, surface resin is extracted by tapping a living almaciga tree. It is soft when fresh, but hardens over time as it flows freely and later turns to amber-coloured like the fossil resin. Between the methods, tapping is the easier way to produce Manila copal.
However, traditional methods employed by Filipino tappers to harvest the resin, which include deep tapping, overtapping and frequent rechipping is endangering the industry.
Traditional tapping methods
The more common methods of almaciga tapping in the Philippines are:
Deep tapping. The cuts are deliberately extended to include sapwood, destroying the vascular cambium responsible for the tree's continuous radial growth and healing of wounds;
Overtapping. Oversized cuts or too many cuts are made around the tree circumference. The law requires that the distance between cuts around the girth should be twice the length of the tapping cut. Violations result in impaired growth and eventual death of the tree; and
Frequent rechipping. This introduces impurities into the exuded resin instead of increasing the flow rate. Chips of bark, wood and foreign materials lower the resin grade. Resin must be collected at least every 2 weeks to give ample time for the accumulation of large, easily-removed lumps of hardened resin.
In this study, FPRDI aims to establish guidelines for the proper tapping that will help prolong the life span of almaciga trees thereby maximizing resin production.
Materials and Methods
Various R and D studies have been conducted by FPRDI, including: (a) determination of the effects of four diameter classes (20–30cm, 40–50 cm, 60–70cm and 80 cm above) and sulfuric acid (H2SO4) at four concentrations (0%, 40% and 60% by volume) on resin production of almaciga trees; (b) survey of improper tapping practices of almaciga resin in the Philippines; and (c) identification of other factors affecting resin production. The investigations were designed primarily to improve the conventional methods of tapping almaciga trees so as to attain sustained yield productivity.
Results and Discussion
Earlier studies have shown that resin production is affected by:
Vigor of the tree. Vigor is seen in tree size and tree crown density. Since the leaves manufacture the resin, a tree with a heavy, well-proportioned crown produces more resin than one with a sparse crown. Also, a large tree with a bigger bark surface and a heavier crown produces more resin than a smaller tree;
Location. Certain site characteristics presumably influence resin production. Resin production has been observed to be poor in Zamboanga, a province in Mindanao about 826 km south of Manila. In Abra, a province in Luzon, around 325 northwest of Manila, trees at lower elevations produce more resin than trees at higher elevations; and
Inherent capacity. Resin production is also affected by heredity. Given nearly the same tree size and crown density, resin production of trees in the same location has been found to differ.
Proper Tapping Methods
Owing to the detrimental effects of traditional tapping methods, FPRDI laid down the following guidelines for the proper tapping of almaciga trees. This tapping method was based on the results from the R &D studies FPRDI had conducted: (a) resin yield increased with increasing diameters up to 60 cm, but decreased at higher diameter classes; (b) resin exudation directly increased with increasing acid concentrations up to 50%, but either leveled off or decreased at higher concentrations; and (c) diameter and sulfuric acid acted independently on resin exudation of almaciga trees. The guidelines are:
Tap only trees with a diameter at breast height of at least 40 cm;
Remove loose bark, dirt and other foreign materials and lightly scrape the portion to be tapped. Start the first tapping at a point not more than 30 cm above the ground;
Make a horizontal cut about 2 cm wide and 30 cm long and not beyond the bark, using a razor-sharp broad-bladed bolo or a large knife. Tapping more than twice around the tree circumference is permitted, but the distance between tapped portions should be about 60 cm or twice the length of the cut. While cutting, take utmost care to avoid damaging the cambium;
Spray a mist of 50% sulfuric acid solution about 6 inches from the cut portion to stimulate resin flow, using one pass of a pint size capacity plastic squeeze sprayer. Since all acid-damaged tissues are removed in rechipping, the right amount of acid prolong the tree's tapping life; and
After a week when resin exudation stops, a fresh cut may be made immediately above the previous one of the same length but lesser width (0.4 to 1cm wide). Apply acid as before. Tap vertically upward.
Conclusions
FPRDI had established guidelines for the proper tapping method of almaciga trees. The application of such guidelines would require a good working knowledge about the basic structure of the stem, nature of resin production, and biological factors in relation to tapping process in order to: (a) prolong the life span of almaciga tree; b) increase production of quality almaciga resin; (c) increase income of tappers; and (d) help in the conservation program of the government.
