Predicting sustainability of agroforestry in a customary forest (Hutan Marga) in Lampung Province, Indonesia

Lampung Province has a critical forest encroachment problem that has to be solved immediately. One way to solve this problem is to ensure the sustainability of the hutan marga or customary forest as one kind of private forest which can provide farmers their daily needs. It belongs communally to the indigenous people of Buay Belunguh in West Lampung District. The community manages the hutan marga in West Lampung by agroforestry. To be able to meet the needs of the community, it should be managed in a sustainable manner. Unfortunately, the factors that affect the sustainability of agroforestry in the customary forest and priority ranking on the factors that significantly affect the sustainability have not been recognized until now. This research was conducted in three villages (Bakhu, Bedudu, and Sukarame) where the communities manage the forest communally. The result of the logit analysis showed that the most influential variables on hutan marga sustainability are the availability of labor and the soil condition. From the analysis results, the level of farming index is moderate with a score of 65.6. This means that on average, there are three types of agricultural activities in the customary forest because the communities practice intercropping vegetables, trees, coffee, and cacao. In addition, they also raise chickens and goats as well as maintain fish ponds. Thus, it is not surprising that 72.33 percent of the respondents have incomes above IDR 3,600,000 per month. With so many kinds of agricultural activities that are carried out in the hutan marga, such require a sufficient number of laborers. The analysis showed that the number of laborers is an influential variable to the sustainability of the customary forest. The soil condition (i.e., soil nitrogen and soil texture) also have an effect on sustainability. The soil fertility condition is from fair to good. Also based on the analysis results, the level of the communities' social acceptability index in the three research sites is high with a score of 74.92. Thus, SAI is considered an influential variable in the sustainability of the customary forest. The length of residence in the three villages is also a significant variable such that a person's skills, knowledge, and attitude are affected as he or she resides longer in the community.