In Indonesia, ulin (Eusideroxylon zwageri Teijsm. et Binnend.) is found naturally only in Sumatra and Kalimantan. Nowdays, exploitation of this species is still happening and therefore it tends to become distinct. At the other hand, there are still a lot of aspects that need to be studied. This study focused on morphological diversities, ecology, mother trees, and conservation of ulin in Kalimantan. Result of the study indicates that ulin has a very high diversity in morphological characters, both vegetatively and generatively (especially on shape and size of the fruits or seeds). Ecologically, ulin trees grow well in humid tropical forests, non innundated lands up to 500(-625) m above sea level, on flat areas surrounding the streams and rivers, on undulating lands, slopes and ridges. Regarding to thesoil conditions, the habitat of ulin is usually sandy, low pH and low macroscopic chemical elements (N,P,K). The potency of ulin as mother trees in nature vary from 22.11% to 32.30% of the total existing population. In connection with the conservation efforts, the in-situ and ex-situ conservations have been implemented; however, security and control for the conservation areas (mainly in-situ) need to be more improved.

ABSTRAKJasa lingkungan berupa ekowisata pada kawasan hutan mangrove di Tanjung Batu, Kabupaten Berau, Provinsi Kalimantan Timur merupakan salah satu potensi sumber daya alam yang belum banyak dimanfaatkan. Penelitian ini bertujuan untuk menganalisis potensi pengembangan ekowisata mangrove di Kampung Tanjung Batu berdasarkan penilaian kondisi obyek daya tarik wisata alam, persepsi wisatawan dan masyarakat, serta potensi nilai ekonomi yang dimiliki. Metode penelitian yang digunakan melalui observasi, wawancara terstruktur, dan studi pustaka. Analisis data obyek daya tarik wisata alam dilakukan melalui skoring dan pembobotan, persepsi wisatawan dan masyarakat dilakukan secara deskriptif, sedangkan potensi nilai ekonomi berdasarkan pada nilai kesediaan membayar (Willingness to Pay/WTP). Hasil penelitian menunjukkan bahwa kawasan hutan mangrove Tanjung Batu prospektif untuk dikembangkan sebagai destinasi ekowisata dengan skor total daya tarik wisata alam berada pada kategori tinggi. Persepsi wisatawan dan masyarakat sekitar mendukung penuh upaya pengembangan ekowisata dengan potensi nilai ekonomi diperkirakan sebesar Rp. 1.423.914.894 tiap tahun. ABSTRACTEnvironmental services in the form ecotourism at mangrove forest of Tanjung Batu, Berau District, East Kalimantan Province is one of the natural resources that have not been used. The aim of this study was to analyze the potential of ecotourism development in mangrove forest of Kampung Tanjung Batu which is based on rating natural tourist attraction object, the perception of tourists and local community, as well as potential economic value. Data were collected through observation, interviews, and study of related literature. Natural tourist attraction object analysis was conducted by the scoring, whereas the perception of tourists and local community by descriptive method, and economic value based on willingness to pay. The result of study showed that mangrove forest area of Tanjung Batu prospective to be developed as an ecotourism destination with a total score of natural attractions that were in the high category. The perception of tourists and the local community fully supports the efforts of ecotourism development with potential economic value was estimated at Rp. 1.423.914.894 per annum.

Mangrove is known as a unique and complex ecosystem, located in the intertidal zone vulnerable to anthropogenic pressures. In this study, we analyzed the floristic composition and relationship between species density and soil properties of mangrove forests in Teluk Adang Nature Reserve (TANR), East Kalimantan, Indonesia. Data were collected by establishing 6 transects placed perpendicular to the sea. The results showed that there were 14 species of mangroves in TANR. The current remaining stand has not been disturbed by human intervention. Rhizophora apiculata dominated all growth strata (seedlings, saplings, and trees) with the Important Value Index (IVI) of 98.22%; 127.73%, 144.03%, respectively. Ecologically, the density and distribution of Rhizophora apiculata correlated with soil texture conditions such as silt and clay. The tree density of mangroves in TANR was classified as low with an average of 606.67±147.230 ind ha-1. The average values of diameter, height, and basal area were 18.16±2.119 cm; 12.24±2.667 m; 42.56±2.255 m ha-1 , respectively. The Margalef species richness index and Shannon Wienner diversity index in TANR were in the low-to-moderate category. To improve the condition of the disturbed mangrove forests, it should be immediately restored by considering the result of the analysis of the current composition and structure of mangrove vegetation.

The purpose of this research was to know about some ecological aspects of nyamplung tree (Calophyllum inophyllum L.). This research was conducted at Tanah Merah coastal forest, Taman Hutan Raya Bukit Soeharto, East Kalimantan in June 2009. Data collection were using purposive sampling plot of 20 x 20 m, which the total area of 0,44 ha. The result showed that the stand,beside at the tree stage with the IVI of 90,11%, nyamplung is also dominant at the pole stage (IVI=140,06%) and seedling stage (IVI= 85,85%). Only at the sapling stage Dillenia suffruticosa (Griff.) Martelli is dominant (IVI =135,98%). Pouteria obovata (R. Brown) Baehni has the highest value of association index to the nyamplung tree based on Ochiai, Dice, and Jaccard indices. In connection with the physical environment where the nyamplung stand found, the habitat indicated by the air temperature of 25,4-31,7 0 C, the air humidity of 75-97%, and rainfall average of 2.000-2.500 mm/year. Meanwhile composition of soil was dominated by sands, and the acidity of 6,1-7.3.

Authors' Contribution MYH, DK and MFH conceived this study. MAR, MAI and HUH analyzed the data. DK, ZM, MRH and SNS wrote and edited the manuscript.