Abstract. Mursidah, Lahjie AM, Masjaya, Rayadin Y, Ruslim Y. 2020. The ecology, productivity and economic of swiftlet (Aerodramus fuciphagus) farming in Kota Bangun, East Kalimantan, Indonesia. Biodiversitas 21: 3117-3126. Swiftlet nest is a high-value non-timber forest product produced from the saliva of swiftlet birds. While the demands for this commodity continue to increase in global market, careless harvesting techniques have diminished the swiftlet population and the production of swiftlet nests, threatening its sustainability. One effort to solve this problem is by developing swiftlet farming which involves building swiftlet. This research aimed to analyze the ecology, productivity, and financial feasibility of swiftlet farming of different-sized swiftlet houses in Kota Bangun Subdistrict, East Kalimantan, Indonesia. This research used qualitative and quantitative analysis methods. Data were collected using purposive sampling to determine the location, sample of swiftlet houses, and interviews with respondents. Quantitative analysis on the financial performance of swiftlet farming was analyzed using the net Benefit-Cost Ratio (net B/C), Net Present Value (NPV), Internal Rate of Return (IRR) and Payback Period (PP) methods. The results showed that swiftlet nest production in Kota Bangun begins in the third year and ends between 27 and 45 years later, depending on the age and size of the house as well as the quality of the timber. The swiftlet house with a size of ​​512 m2 had the net B/C of 4.06, NPV of IDR 1,403.79 million, IRR of 30%, and PP of 5.44 years. The swiftlet house with a size of ​​1,600 m2 had the net B/C of 2.27, NPV of IDR 1,774.83 million, IRR of 24.09%, and PP of 9.4 years. Our study suggests that swiftlet farming is financially highly feasible, especially for the swiftlet house with a size of 512 m2.

Gnetum gnemon L. (Gnetales) forms hardwood-like secondary xylem in its trunks and branches although it is a gymnosperm. The present study tested the surface growth stress in relation to anatomical and chemical properties of the secondary xylem in inclined and vertical stems of G. gnemon using morphological and chemical composition analyses. Secondary growth was promoted on the upper half of the cross section in an inclined stem; at the same time, tensile growth stress increased on the upper side and decreased on the lower side of the inclined stem. However, formation of reaction wood fibers was not detected on either side. The microfibril angle was associated with differences in tensile growth stress. Thus, we conclude that negative gravitropism in G. gnemon is caused by a synergistic effect of increased tensile growth stress as well as the promotion of secondary growth on the upper side of the inclined stem. Our results are comparable to the negative gravitropism observed in the family Magnoliaceae, which does not form gelatinous fibers in its tension wood.

Winarni B, Lahjie AM, Simarangkir B.D.A.S., Yusuf S, Ruslim Y. 2018. Forest gardens management under traditional ecological knowledge in West Kalimantan, Indonesia. Biodiversitas 19: 77-84. Local wisdom of Dayak Kodatn people in West Kalimantan in forest management shows that human and nature are in one beneficial ecological unity known as Traditional Ecological Knowledge (TEK). Former cultivation forest areas are managed in various ways, including planting forest trees, fruit-producing plants, and rubber trees until they transform into the forest garden. This research used three models, monoculture rubber cultivation (Model 1), combined rubber and camphor cultivation (Model 2), and combined rubber and durian cultivation (Model 3). This research intended to: (i) analyze the production of rubber latex and durian fruit; (ii) analyze the growth increment of camphor and durian trees; (iii) analyze the financial feasibility of rubber tree plantation, combined rubber and camphor tree plantation, and combined rubber and durian trees plantation; (iv) formulate the model of rubber cultivation. This research also used measurement methods other than field measurement, which were tree diameter and height, rubber latex and durian fruit weight, and questionnaire interviews. The maximum productions of rubber latex from three models were achieved at the age of 17 years, while maximum production of durian fruits was achieved at the age of 55 years. The maximum growth increment of camphor and durian trees were achieved at the age of 40 years. Based on NPV analysis and IRR, those three models were worthy of being cultivated. Financially, the combined rubber and durian cultivation (Model 3) was the most profitable, followed by monoculture rubber cultivation (Model 1), and lastly the combined rubber and camphor cultivation (Model 2).

Abstract. Kristiningrum R, Lahjie AM, Masjaya, Yusuf S, Ruslim Y. 2019. Species diversity, stand productivity, aboveground biomass, and economic value of mangrove ecosystem in Mentawir Village, East Kalimantan, Indonesia. Biodiversitas 20: 2848-2857. Mangrove forest is one of the important ecosystems. It provides a variety of benefits both ecologically and economically. There are many biodiversity values of mangrove ecosystems that it can be evaluated economically. This study aims to: (i) identify the species diversity of mangrove forest; (ii) analyze the mangrove productivity and aboveground biomass; (iii) analyze the ecosystem value of mangrove forest in Mentawir Village, Penajam Paser District, East Kalimantan Province. The research used systematic random sampling method by establishing two plots with extent of one hectare for each plot in which each plot was divided into 20m x 20m subplots. The volume and mean annual increment (MAI), as well as current annual increment (CAI), were calculated. Economic value of mangrove ecosystem was calculated using Contingent Valuation Method (CVM) to reveal the total margin between Willingness to Pay (WTP) of wood produced by mangrove forest and Willingness to Accept (WTA) of fisheries catches. The results showed that there were 12 species of mangroves in the studied areas in which Rhizophora apiculata was the dominant species. Total aboveground biomass in Plot I and Plot II were respectively 127.46 tons ha-1 (62.61 tons C ha-1) and 79.26 (38.85 tons C ha-1) and dominated by Rhizophoraceace family with 76.80%, while 23.22% of the biomass was contributed by other mangrove families. The mangrove forest had a maximum average volume increment at 48 years and 42 years with MAI of 2.97 ha-1yr-1and 2.12 m3 ha-1yr-1 at Plot I and Plot II, respectively, with the total volume reached 127.5 m3 ha-1 and 79.60 m3 ha-1. The calculation of total margin between WTP and WTA indicated that in economic value of mangrove ecosystem in Mentawir Village with an extent of 2,300 ha was between IDR 207,000,000 yr-1 and IDR 345,000,000 yr-1. Our findings suggest that a good mangrove ecosystem will result in high economic value and biodiversity values cannot be separated from economic benefits in order to protect its sustainability.

The Kenyah Dayak people began to migrate from the isolated area to the Mahakam basin in the early 1950's. As the Kenyah people migrate downstream, infiltration of monetary economy into the village increases, which leads to changes of life style, social structure such as work organization and mutual aid system in daily life, and so on. In the course of a series of such changes, sustainable swidden agriculture system is also changed to a less sustainable one. The Benuaq Dayak people, however, practice sustainable 'swidden (paddy) -rattan forestry' system while they can earn much income. The Buginese way of land utilization, 'swideen (paddy) -pepper production' system, is the least sustainable though the pepper production is the most profitable in the region. The land utilization by the transmigrated Javanese is not so sustainable at present, but there is a possibility of its getting more sustainable because of acquisition of the land ownership.