Trees and crops can easily burn but they can also stop wildfires from happening in the first place, say researchers in the Philippines.

Wildfire has been a major issue in the Wahig-Inabanga River Basin, Philippines at sites under the Integrated Natural Resources and Environmental Management Project (INREMP).

Ivy Joy R. Barbante, the monitoring and evaluation officer of the Provincial Project Management Office in Bohol, says that wildfires had already burned a total of 125.7 hectares of INREMP sites in 2020 alone and posed a major threat to INREMP’s goal of restoring watersheds and delivering ecosystem services to forest-based communities.

Unsustainable practices such as slash-and-burn, which were previously practised by farmers in the River Basin, have left forest lands degraded and covered with grass. These degraded grasslands can ignite easily from both human activities and natural causes. In this context, wildfires could be considered a ‘disease’ and water naturally the cure.

However, an old proverb says that ‘prevention is better than cure.’ In this case, farmers need to find preventive measures to reduce the risk of wildfires.

One measure that has already been adopted in INREMP is establishing agroforestry systems. Agroforestry restores degraded forests, minimizes the likelihood of erosion in sloping areas, and improves the productivity of farms by integrating trees, crops and livestock. Through covering a given piece of land with these components, flammable grass will be unlikely to take over and wildfires will be avoided.

Fire-proof agroforestry systems

Grass species, such as ‘cogon’ (Imperata cylindrica (L.) Raeusch) and ‘themeda’ (Themeda spp) are the dominant species found in the INREMP sites. They can easily take over a whole farm if left unchecked for several months. These grasses are highly combustible during the dry season. They grow in exposed, open areas under hot temperatures.

To reduce the chances of wildfires, farmers in the River Basin have filled open spaces with crops and trees, including maize, sweet potatoes, taro, cassava and banana, which are harvested at varying times throughout a year. The fruit trees include cacao (Theobroma cacao), rambutan (Nephelium lappaceum), ‘lanzones’ (Lansium parasiticum, also known by many local names, such as ‘duku’ in Indonesia), durian (Duro spp) and ‘guyabano’ or soursop (Annona muricata), which when fully grown can prevent infestation by grasses. As the trees grow, they restrict light reaching the ground and, hence, the growth of the grasses.

Agustin Mercado Jr, ICRAF’s agroforestry and conservation farming specialist, explained that, ‘Grasses are shaded out by the trees; when the amount of transmitted light is less than 40% the grasses tend to be shaded out and eventually die.’

INREMP is an ambitious, seven-year initiative of the Philippine Government, implemented by the Department of Environment and Natural Resources with funding from the Asian Development Bank.

ICRAF provides technical assistance and capacity building to establish sustainable land-use systems. Four types of agroforestry systems have already been established in Wahig-Inabanga River Basin: three in Diis Kauswagan in the municipality of Trinidad and one in Concepcion in the municipality of Danao.