By: Chris V. Panganiban
Inquirer Mindanao Bureau
SAN FRANCISCO, Agusan delSur — Agusan del Sur recorded about 140,000 hectares of tree-cover loss from 2001 to 2025, placing the province among areas with the largest declines in tree cover in the Philippines, based on satellite data from Global Forest Watch (GFW).
The recorded loss represents about 18% of the province’s tree-cover area in 2000, according to GFW data, which track changes in vegetation using satellite imagery.
The findings highlight continuing pressure on one of the country’s most important forest landscapes, home to major watersheds, biodiversity areas, and the Agusan Marsh, one of the Philippines’ most significant wetland ecosystems.
However, the figure does not mean that all 140,000 hectares represent permanently destroyed forests.
Data limits
GFW defines tree-cover loss as the removal or death of tree vegetation at least five meters tall detected through satellite monitoring. The data show where tree canopy has disappeared, but they do not automatically determine whether the affected areas were natural forests, commercial plantations, or other tree-covered lands.
Tree-cover loss can result from permanent land conversion, timber harvesting, fires, storms, disease, or other disturbances. Some areas may recover naturally, while others may be replanted.
Because satellite images measure changes in vegetation cover rather than land history, additional ground verification is needed to determine the actual cause of each recorded loss.
According to Reymar Ballescas, a forestry and mapping specialist who uses geographic information systems (GIS) for local land-use planning, satellite-based forest monitoring provides an important overview of landscape changes but requires ground validation to determine what actually happened on the ground.
Ballescas said GFW is useful in tracking changes in tree cover, but its satellite-based system cannot automatically distinguish between natural forests and other tree-covered areas such as commercial plantations and perennial crops. Areas planted with falcata, mahogany, rubber, durian, marang, and other tree crops may register as tree-cover loss when their canopy is removed, even if the land remains under forestry or agricultural production.
He said interpreting Agusan del Sur’s forest changes also requires looking at the province’s logging history. Ballescas noted that the period from 2000 to 2011 coincided with the final years of some Timber License Agreements (TLAs) and the transition from traditional logging concessions toward other land uses, including plantations and agricultural expansion. He said this period showed significant forest changes that require further assessment to determine whether losses were linked to timber extraction, land conversion, or other activities.
Ballescas added that recent tree-cover loss figures should be examined alongside official land-cover data from the National Mapping and Resource Information Authority (NAMRIA) and field-based GIS validation. He said separating plantation forests from natural forests is necessary to accurately assess the condition of Agusan del Sur’s remaining forest landscapes.
Falcata cycle
The interpretation of satellite-based tree-cover loss data requires consideration of the presence of commercial tree plantations, including falcata (Falcataria moluccana) farms.
Falcata is a fast-growing timber species cultivated in many parts of Southeast Asia, including the Philippines, because of its suitability for wood production. Its timber is used for products such as plywood, veneer, pulp, and other wood-based materials.
In plantation areas, mature falcata trees are periodically harvested and the land may be replanted for another production cycle. When a mature plantation is harvested, satellite images can detect the sudden disappearance of tree canopy, which may be recorded as tree-cover loss.
However, GFW data alone cannot determine whether a recorded loss occurred in a natural forest, a commercial plantation, or another type of tree-covered area. Establishing the exact cause requires additional ground-based information, such as plantation maps, land-use records, and field verification.
This distinction is important because a harvested falcata plantation and a cleared natural forest may appear similar in satellite monitoring, but their ecological consequences are different. While plantations provide livelihood opportunities and timber supply, they generally do not perform the same biodiversity and watershed functions as natural forests.
.Main drivers
According to GFW data, about 63% of Agusan del Sur’s recorded tree-cover loss occurred in areas where the dominant drivers were associated with deforestation and land-use changes.
Permanent agriculture was identified as the largest driver, accounting for about 86,000 hectares of tree-cover loss. These areas were converted into long-term agricultural production.
Shifting cultivation accounted for about 43,000 hectares, involving temporary farming activities where vegetation is cleared and may later recover. Logging activities were associated with another 7,300 hectares of recorded loss.
The figures show the major pressures affecting the province’s landscapes, but satellite data alone cannot determine whether individual activities were legal or illegal. Such determinations require field investigations and review of government records.
Local losses
Within Agusan del Sur, five municipalities accounted for nearly 59% of the province’s total recorded tree-cover loss from 2001 to 2025.
Loreto recorded the highest loss at about 19,000 hectares, followed by Trento with approximately 18,000 hectares. Bunawan recorded about 16,000 hectares, while La Paz and Esperanza each recorded around 14,000 hectares.
These municipalities experienced the largest changes in tree cover during the 25-year period, based on satellite monitoring.
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