Biophysical Characterization of Degradation in Mt. Makulot, Cuenca, Batangas

Abstract

The study provided a limited biophysical characterization of the degradation in Mt. Makulot, Cuenca, Batangas which can be used as a baseline data for future researchers, planners and natural resource managers in management intervention and rehabilitation plans. The general objective was to characterize the evidences of degradation of Mt. Makulot and to relate these with physical and biological conditions in the area, present land use, human activities and socio-economic conditions.

Anthropogenic factors that may have contributed to the site degradation (number of mountain hikers and present land use by local residents) were determined via registration logbooks, informal interviews and previously published research materials. Degraded areas (erosion, compaction, gullies, pedestals and trees with exposed roots) were identified via photographs. Erosion extent was quantified for observed degraded sites by numerical measurements of length of exposed tree roots, length of pedestals, depth and width of gullies and soil profile. The biological component of the mountain was determined by performing terrestrial vegetation analysis using the point centered quarter method (forest ecosystem) and the point sampling technique (for grassland ecosystem). Existing data like climate, rainfall, slope, topography were gathered from various institutions that have conducted research in the area. Mt. Makulot with its biophysical characteristics of sloping terrain, high elevation and loam soil type is prone to degradation due to anthropogenic and climatic factors. The climate type of the area which shows heavy rainfall and high temperature make the area for recreation and agroforestry is taking its toll. The recreational use has attracted a huge number of hikers. This number of hikers, frequency and annual distribution has caused trampling of soils in wet condition resulting to compaction, erosion and loss of vegetative ground cover.

Physical degradation signs which are mostly caused by erosion are evident in the form of gullies, exposed tree roots, pedestals and landslides. The degradation status of the mountain has led to less number of visitors over the years due to decline of the scenic value. The numerical values for eroded sites show that most of the A horizon is 100% eroded. Most of the B horizon is 12% to 98% eroded. Both the A and B horizon contains the tree roots and its erosion renders these roots exposed. Presence of gullies shows a massive severity of erosion extent of the mountain.

Vegetation analysis showed that in the forest ecosystem, the species diversity is only 22.5% which is one indication of low plant diversity. The dominant tree species was coconut (Cocos nucifera Linnaeus) based on the highest important value. The coconut tolerates a wide range of climatic conditions and both strongly alkaline and acidic soils. The mountain was used as an agricultural area and is now a secondary forest dominated by fruit trees. The change from primary forest to secondary forest decreased the tree vegetation diversity. This reduction in diversity is one indication that the site is degraded.

In the grassland ecosystem, the plant diversity is only 3%. This low diversity is an indication of degradation of the grassland area. Analysis showed that the dominant species is talahib (Saccharum spontaneum) with the highest recorded values for summed dominance ratio. Talahib loves moist and fertile soils. Cogon (Imperata cylindrica) showed the highest recorded value from summed dominance ratio. Cogon thrives in acidic soils. This indicated that the soil in the grassland area are becoming acidic due to leaching during heavy rainfall. The presence of grasslands and increasing acidity of the soil indicate land degradation. However, the grasslands in the study area are kept that way so as not to obstruct the scenic views.