When Mount Pinatubo in Pampanga, some 90 kilo-meters (55 miles) north-west of Metro Manila, erupted for nine hours on June 15, 1991, after dormancy for over 500 years, it was considered as the sec-ond largest eruption of the 20th centu-ry, second only to the 1912 eruption of Katmai-Novarupta in Alaska.

The impacts were staggering: over 800peoplewerekilled,andover100,000 more were left homeless; property and economic damages reached over $1.5 billion; and the discharging of between 15 to 30 million tons of sulfur dioxide gas in the atmosphere, resulting in a decrease in the global temperature by an estimated 0.73oCelsius. The damages, of course, didn’t stop when the eruptions ceased – it is mainly because of the lahar (mixture of ash, volcanic debris, and water) flows that buried homes in the months after the eruption, so much so that the then home of the US military in Asia Pacific, the Clark Air Base, was then turned over to the Philippine government.

While the region continues to recover from the disaster, lahar has, interestingly, become a source of livelihood for some 30,000 Pampagueños (Pampanga locals), not to mention earning local government units (LGUs) considerable amounts, what with lahar now used as quarry material, and as tourists flock to the province to see how lahar re-created the landscape.

Making good of the bad.

At least so it seems, as Menandro N. Acda, Ph.D., and associate professor at the College of Forestry and Natural Resources and currently chairman of the college’s Department of Forest Products and Paper Science of the University of the Philippines in Los Baños, Laguna found yet another use for the lahar as a cost-effective physical barrier to protect wooden structures from subterranean termites.

It was in 2004, when Acda visited a furniture plant in Pampanga, that the academician noted how lahar, a “sandy aggregate,” buried such towns as Bacolor, but that it “could be put to better use as an alternative method of termite control,” he says. With this awareness, he decided to give it a closer look – boosted, fortunately, by funding from the Charles Lindbergh Foundation, and the Ford Conservation and Environmental Grants.

Acda’s interest in termites was because in the Philippines alone, “termites cause (an estimated) hundreds of millions of dollars worth of property damage every year.” And of the kinds of termites (grouped according to feeding behaviour), it is subterranean termites that are primarily responsible for damage to wooden structures.

Of course there are existing methods of termite control, including the injection of chemical termiticides into the soil, not only costly but also deemed hazardous because these are carcinogenic that can pollute the environment; and using termite baits, which costs twice as much as chemical termiticides, even if these are outside of the Philippines, the use of physical barriers did not, for a while, exist in the Philippines – until Acda’s use of lahar for the same purpose.

And why lahar?

Three years of study enabled Acda to come up with a study, Volcanic Debris to Prevent Termite Invasion into Homes and Timber Structures in the Philippines, that verified the earlier conviction that lahar can be an effective termite barrier. The effectivity of lahar is because, on one hand, it is the “right particle size (dependent on the mandible and head capsule dimensions of the target termite species) effective for preventing the destructive activities of all of the four most pernicious termite species (Coptotermes vastator Light, Macrotermes gilvus Hagen, Nasutitermes luzonicus Oshima, and Microcerotermes) in the Philippines;” and, on the other hand, lahar actually has sharp edges that can cut and kill termites attempting to burrow through a layer of lahar.

In Acda’s estimation, a small house with a 60-square-meter floor area will require about 10 to 12 cubic meters of screened lahar particles for installation beneath its floors and along its foundation walls.

The use of lahar is not only “cheaper than the cost of conventional at the College of Forestry and Natural soil poisoning methods and termite Resources and currently chairman baits, (but it) is also environment-of the college’s Department friendly, and can (even) provide ad-of Forest Products ditional income opportunities for peo-Paper Science of the ple in the lahar areas of Pampanga University of the Phil-and Albay,” Acda ends.