In the Philippines, it’s not surprising to see mountains and hills that look like green or yellow-green mounds. Some are entirely green, some have only patches of greens. Upon closer inspection, the green expanse is due to cogon grass (Imperata cylindrica). More often than not, trees are sparse, or not present at all.
Usually, mountain grasslands are products of kaingin or slash-and-burn cultivation. If the forest land is frequently burned or grazed, pyrophytic (regenerates after fire) grasses like cogon invades and replaces the formerly dominant woody plants and trees in the area. Easily dispersed by wind, Imperata flourishes with lots of sunshine and can tolerate poor soil in erosion-prone areas.
Grasslands are for grazing or cropping using traditional farming and/or shifting cultivation. Studies show that over-cultivated upland areas result to extreme soil loss which threatens the sustainable productivity of the upland.
According to Dr. Canesio D. Predo of Leyte State University (LSU) and Dr. Herminia A. Francisco of UP Los Baños (UPLB), “the Philippine government is concerned with rehabilitating vast areas of grasslands in the country through reforestation and other tree-based plantation establishment, including agroforestry.” This land use system can increase income and improve water supply, carbon sequestration, reduce soil erosion, and enhance biodiversity.
Based on this premise, the team conducted a survey to evaluate the environmental and economic benefits of alternative land use options in some grasslands in Claveria, Misamis Oriental in Mindanao.
Results indicate the benefits from carbon sequestration in tree-based farming systems. “Carbon sequestration,” Predo and Francisco explained, “refers to the process by which trees use carbon dioxide that otherwise could pollute the atmosphere.” By reducing carbon dioxide in the atmosphere, trees can mitigate global warming or climate change.
Predo and Francisco also clarified that it is important to provide farmers with incentives to encourage them to adopt tree-based farming.
Alternative land-use systems
The study used six models of land use systems to rejuvenate Imperata grasslands. These were:
* IMPLUS Imperata land use for animal pasture or grazing system
* FPLUS farmers’ current practice of annual maize cropping system (100% of the area devoted to corn); soil is cultivated before planting corn; inorganic fertilizers were applied
* TIMPLUS timber trees with Imperata for animal pasture or silvopastoral system; 85% is allocated to Imperata while 15% is planted to trees
* TCLUS timber trees planted in hedgerows with annual maize cropping system at the alley areas; 85% is devoted to corn and 15% to timber
* TCSFLUS social forestry model of agroforestry system wherein the bigger areas are devoted to timber trees in hedgerows with annual maize cropping at the alley areas; 40% devoted to timber while 40% is devoted to corn
* TPLUS timber plantation land use system
The tree species used were the Gmelina arborea (non-nitrogen fixing tree) and Acacia mangium (nitrogen-fixing tree). In all of the systems, 60% of the tree component is Gmelina arborea and 40% Acacia mangium. In the TCSFLUS system, the tree components were equally distributed (20%-20%).
Results showed that it was profitable to retain Imperata grassland for animal grazing purposes; however, it was not the most efficient type of land use,” the research team said. “Conversion of Imperata grassland into tree-based systems were more efficient than other land use systems.”
TPLUS (timber plantation system) was the most efficient land use system among the tree-based systems because of the high value of harvested timber, lower predicted soil loss, and high level of soil nutrients sustained. From data collected over 20 years, the researchers concluded that TPLUS system had the highest NPV over 20 years, followed by TCSFLUS system. Losses in the FPLUS system increased due to lowering yields from high soil erosion.
If tree-based systems are profitable, why do farmers insist on the traditional farming system (FPLUS)? The researchers explained that smallholder farmers do not want to risk their income from crops with the projected income from trees.
Benefits from trees
So how will farmers adopt tree-based farming if it’s too risky and the benefits are not immediate? The study showed the potential of the TCLUS system where farmers can get income from corn while waiting for timber to grow. Predo and Francisco projected that farmers can get their money back from timber in seven to ten years.
There are also environmental benefits of tree-based systems. Soil erosion can be reduced by 20% – 91% compared to farmers’ practice, with soil loss up to 75%.
Tree-based farming was introduced by the World Agroforestry Centre (ICRAF) in Mindanao in cooperation with LGUs, farmers associations, and other government institutions. In the Visayas, ICRAF, and LSU/Cornell University are involved. “In Northern Luzon, farmers are planting trees because of the demand for wood by a private company,” the team reported.
“Farmers like tree-based farming systems. It makes the soil fertile, the environment cooler, and it increases their income,” Predo and Francisco replied. The farmers also said this system is a good investment for their children. However, some farmers are hesitant to adopt this system because of small farm size, lack of capital, and lack of access to planting materials.
But with proper policies, good governance, and support, it’s not impossible for farmers to plant trees for a better future.
References: Predo, C.D. and Francisco, H.A. Bioeconomic Analysis of Land Use Options for Grassland Areas in Claveria, Misamis Oriental. 2002; Masipiqueña, A.B., Person, G.A. and Snelder, D.J. The Use of Fire in Northeastern Luzon (Philippines): Conflicting Views of Local People, Scientists, and Government Officials. Cagayan Valley Program for Environment and Development. http://www.lucy.ukc.au.uk/Rainforest/Workingpaperspublic/Fire/fire_9.html; Mueller-Dombois, D. Biological Invasion and Fire in Tropical Biomes. January 2002. University of Hawaii. http://www.nif.gov/joint_fire_sci/invasive%20publications/ Hrs_22pr_10_112_121_c.pdf
Article by Likha Cuevas- bar.gov.ph, January-March 2003 Volume 5 No. 1