Based on the Regional Physical Framework Plan (RPFP) 2002–2020, most of the lands in the province are categorized as rolling to very steep slopes. Lands classified under 0–3 percent slope or level to nearly undulating lands cover only 17,415 hectares, which represent only 10 percent of the total land area. Lands under the 3–8 percent slope or with gently sloping to undulating cover 9,998 hectares, which is equivalent to only 6 percent. Undulating to rolling (8–18 percent) slopes cover 14,093 hectares, while rolling to moderately steep eat up 37,676 hectares, or 22 percent. The steep to very steep slopes combined have the biggest share of 94,298 hectares, or an equivalent of 54 percent.
The slope distribution shows that only about 27,413 hectares or 16 percent (0–8%) belong to the relatively developable range, while the bigger chunk of 146,067 hectares (84%) falls under the protection slope range.