The Bilar Manmade Forest in Bohol was of the earliest batches of South American mahogany propagules introduced to the Philippines on a large scale.


Using mahogany in our reforestation programs may be ecological suicide

It's not only about how many trees we should plant, but also what kind. We may be inadvertently propagating dead zones.

  • September 17, 2018

  • Written by Judith Torres

  • Photographed by Ed Simon

Editor’s note: Because ecolodges are often built along the edges of or within rich, bio-diverse ecosystems, ecotourism advocates like Hitesh Mehta insist that ecolodge owners and developers plant only native species within the area. During the workshop, Anthony Abrias of the Philippine Native Plant Conservation Society spoke about the urgency of propagating only native plants, and the dangers of introducing and promoting exotic plants.


READ MORE: Find out what makes an authentic ecolodge

Name some of the most popular trees in our cities. Most people would include in their list the acacia, fire tree, mimosa and golden shower. Most people below 30—if they know the tree names—might also mention the African tulip, traveller’s palm and neem tree.

Majestic acacias give rest to the eyes of the traffic-weary driving through Mckinley Road in Makati. Along Carcar avenue in Cebu, alternating with century-old acacias are centenarian mimosa or rain trees that flash fiery red, signaling summer to Carcaranons coming home for vacation. Rockwell would be unrecognizable if all the giant palms planted along its islands were suddenly gone. And there would be a huge public outcry if the spreading acacia and fire trees in UP Diliman campus were removed.

People driving to and from Carcar and Cebu City are welcomed by 100-foot tall acacia and fire trees lining the National Highway in Brgy Perrelos. The trees, planted circa 1912, are not native to the Philippines, but have since become “naturalized” and much loved for their magnificent canopies.

But these trees shouldn’t have been planted in the first place, as none of them are native to the Philippines. Neither are 80 to 90 percent of the trees planted under the national greening and reforestation programs, which is pulling out all the stops to meet its target of 1.5 billion trees planted in 1.5 million hectares by 2016, when President Aquino’s term ends.

Hundreds of thousands of mahogany seedlings were planted over 857 hectares in Bilar, Bohol, in the 1960s and are now a forest of majestic trees–and sadly for the ecosystem of Bilar and Loboc towns, very little of the native wildlife.

What’s the big deal?

After getting over the initial surprise that many of the trees we are familiar with are not native at all, people tend to dismiss native species advocates as hardline and extremist. Those who do may argue, as the Department of Environment and Natural Resources (DENR) does, that the exotic species being planted, such as coffee, cacao, rubber and langka, will generate economic security for farmers.

They may point out that quick-growing exotics will help us regain much-needed forest cover faster, stabilize our watersheds and reduce downstream flooding. They may also say that we need wood for fuel, and for wood and paper products. What is wrong with planting exotics?

Biodiversity hotspot

The answer is, native plants support our native wildlife, and exotic plants don’t. Exotics, particularly alien invasive species, enfeeble our already endangered biodiversity, and weaken our food web. The Encyclopedia of Earth says the Philippines is one of the few countries on the planet that is “in its entirety, both a hotspot and a megadiversity country.” That means our islands harbor one of the most diverse collection of living things on Earth, and also one of the greatest number of endangered and threatened species.

What makes our situation critical is that a high proportion of our life forms—at least one third of vascular plants, for example—are unique or endemic to the Philippines. If these endemic species were to cease existing in our country, unless they are successfully propagated elsewhere, they will become extinct.

The case for dipterocarps

The rich plant and animal life of our country took millions of years to evolve, each adapting to and dependent on another and another in an intricate web of survival and balance.
Our lowlands were carpeted with rainforests dominated by towering yakal, tanguile, lauan, apitong, bagtikan and 40 more species of the same family called dipterocarps. Dipterocarps are the backbone of biodiversity in Southeast Asia. Hundreds of species of insects, moss, fungi, etc., can be found in a single dipterocarp tree, according to the ASEAN Biodiversity Information Sharing Service.

Unfortunately, dipterocarps were the most logged trees in our country at the height of our timber trade in the 1980s, comprising over 90% of the total volume of wood exported by the Philippines. And yet, despite being the most exploited trees in our country, they are rarely used in land rehabilitation and reforestation efforts. Instead, the government has favored exotic tree species like mahogany, acacia and ipil-ipil, and recently, falcate and gmelina.

Up until 2011, mahogany was the most planted tree of the National Greening Program (NGP). In 2012, in response to urgings by native plant conservationists, mahogany slid down to second place, giving way to the native narra tree. Still, the DENR’s list of ten most planted trees does not include any dipterocarps.


A Dipterocarpus keruing seed

DIPTEROCARP NUMBERS

Source: Soil and Water Conservation Foundation, Bohol

The dipterocarp family gets its name from the two (di) winged (ptero) fruits (karpos) of the tree.

• 45 species of dipterocarps exist in the Philippines
• 20 are endemic
• 40 to 80 meters in height
• Up to 2 meters in diameter
• The tree starts producing flowers, fruit and seeds at the age of 17-18 years
• They flower every 7-8 years


READ MORE: Notes from a metaphysical site analysis

The case against mahogany

Mahogany is not indigenous to the Philippines, but to the forests of Central and South America. Says Anthony Abrias of the Philippine Native Plant Conservation Society: “We just think they are native because at the height of the timber industry in the Philippines (mid 1960s-1980s), the dealers in the lumber trade, to simplify everything [and to ride on the demand worldwide for the prized Honduran mahogany] decided to call all our hardwoods ‘Philippine mahogany,’ whether they were white lauaan, red lauaan, apitong, mayapis, tanguile, almon, yakal, bagtican, etc.” So all these trees became known simply as “Philippine mahogany,” even though these dipterocarps bear no relation to the mahogany species.

The most planted tree of the National Greening Program in 2010 and 2011 was mahogany. Out of 392 million trees planted from 2010-2014, less than 20% of them were native.

Conservationists contend that the DENR did not do their homework. Says Abrias: “The DENR’s preferred seedling species is mahogany. But they did not specify that we should plant ‘Philippine mahogany.’ So here we are with good intentions, buying and planting mahogany without asking where these seedlings come from.”

Using mahogany to replenish our forests is ecological suicide. One of the most vocal opponents to planting exotic trees is Dr. James LaFrankie, author of Why Native Trees? He says: “Native species [have] a relationship to the land, water and other organisms that have developed over a million years. Certain fungi live with the roots, certain insects feed on the plant parts, while others pollinate the flower. Birds and mammals live along the branches and feed on the seeds. No such relationship exists for the newcomer.

“The result is ten hectares of mahogany in a biodiversity-dead zone. There are no birds, no insects, only a nearly dead soil due to the lethal chemicals that leak from the rotting leaves. There is no future for ten hectares of mahogany. It will remain as it is, until cut and replaced.”

Tarsier versus mahogany

One of Bohol province’s tourist attractions, the Bilar Manmade Forest, is an 857-hectare biodiversity dead zone. Thousands of mahogany trees were planted in the 1960s to 1970s, a government reforestation effort aimed at stabilizing Bohol’s watershed which had been severely affected by rampant logging, harvesting of firewood, and slash-and-burn for crop growing.

The successful project has been and still is hailed as a model of public and private sector cooperation and volunteerism. The result is an eerily beautiful stand of soaring trees, albeit entirely inhospitable to Bohol’s most beloved icon, the endangered tarsier. Tarsiers prefer dense thickets. They cling to slender branches of secondary growth around two meters off the ground, and eat insects, small lizards and birds. They cannot cling to massive mahogany tree trunks, and mahogany trees repel the tarsier’s prey.

Now it would be unfair to claim that the mahogany forest displaced the tarsier. The land had already been barren, uninhabitable for the tiny mammal. But the existence of the Bilar mahogany forest now precludes the possibility of recovering the tarsier’s natural habitat in the area.

In order to ensure the survival of the tarsier, the government of Bohol together with the Philippine Tarsier Foundation has earmarked 134 hectares of secondary forestland as a tarsier sanctuary where they can roam undisturbed. This is hardly enough room for the specie to flourish, however. Tarsiers are territorial, and their home ranges average 2.45 and 6.45 hectares for females and males, respectively. They certainly could use the 857 hectares now occupied by mahogany.

Dipterocarp trees such as yakal, tanguile, guisok-guisok, bagtikan, guiho, almon, hagakhak, etc., are the backbone of Philippine lowland rain-forests. Without them, the ecosystem collapses.

The best time to plant a tree

The bottom line is, indigenous trees and plants support biodiversity. Exotics don’t.

Abrias says that native plant conservationists are not extremists: “We recognize that exotic plants have economic uses for us, such as pineapples, which are from South America. But if we’re not in the food industry, if we’re in tourism and development, then let’s develop responsibly. Since we have already lost 80 percent of our forest cover, and our wildlife are dependent on forests, then let’s plant trees that are native to our country.”

Abrias concludes: “There’s a Chinese saying that goes, ‘The best time to plant a tree was 100 years ago.’ To that we add: ‘The next best time to plant is to plant a native tree today.’” 

This article was originally published in BluPrint Volume 3 2015. Edits were made for BluPrint online.