Environmental Factors Affecting Agarwood (Aquilaria malaccensis Lamarck, 1783) Forests of BhutanRabgay, Tenzin .; Gurung, Dhan. ; , Jambay.; , Penjor.; Thinley, Pema .; Tshering, Bep .; Dorji, Tshering.; Tshering, Karma.; Sitaula, Bishal.K; Raut , Nani .;
Aquilaria malaccensis Lam., commonly referred by its trade name Agarwood, is highly sought for perfume, incense and medicine; and is an endangered species. Even though it is found growing naturally in southern Bhutan, its distribution and ecology are sparsely known. So, this study aimed to understand the ecological requirements and model suitable habitats for the growth of A. malaccensis in the country. Purposive-non-probability sampling was adopted for the study in the natural A. malaccensis habitats in Jomotsangkha and Manas regions where Agarwood is found growing naturally. The plot size of 20 x 20 m for trees, 5 x 5 m for understory and 2 x 2 m for groundcover were used to collect vegetation data. Soil samples were collected from the centre of groundcover plots. A total of 168 plant species under 67 families were recorded from the entire study area. Lauraceae and Euphorbiaceae were found to be the most dominant and co-dominant families in the natural Agarwood stand. A cluster analysis using PC-ORD revealed that Agarwood prefers habitat with warm-moist evergreen broadleaved forest. The Pearson and Kendall correlation in NMS ordination showed the strongest correlation between Agarwood growth and mean annual rainfall (r = 0.90) followed by average soil pH of 6.15 (r = 0.82). However, the slope and aspect of the area exhibited a negative correlation with the growth and distribution of Agarwood (r = -0.46). An area of 6,490.8 km², which accounts to 16.9% of Bhutan, was found to be suitable for the growth of Agarwood. This could support Agarwood regeneration and plantation to conserve and protect the species from extinction in the wild.
KeywordsAgarwood, Bhutan, ecology, distribution, habitat
Ahmed, F. (2010). Study of Agar production in two selected areas of Bangladesh (Unpublished master's thesis). Bangladesh Agricultural University, Mymensingh.
Akter, N. and Neelim, A.Z. (2008). Agarwood plantation at BRAC Tea Estate: introduction, environmental factors and financial analysis. .
Bruggeman, D., Meyfroidt, P. and Lambin, E.F. (2016). Forest cover changes in Bhutan: Revisiting the forest transition. Applied Geography, 67: 49-66. doi: https://doi.org/10.1016/j.apgeog.2015.11.019
Chamling, K. (1996). Traditional paper, essential oils, rosin and turpentine. .
Choden, K. (2012). Bhutan’s aromatic tree potential. The Bhutanese, pp. 1 . Accessed 5 March 2019.
Chowdhury, M. (2014). Production of agarwood through aeration method into the agar tree (Unpublished master's thesis). Bangladesh Agricultural University, Mymensingh.
Department of Forests and Park Services. (2019).. Accessed 10 January 2019.
Dorji, U., Olesen, J.E., Bøcher, P.K. and Seidenkrantz, M.S. (2016). Spatial variation of temperature and precipitation in Bhutan and links to vegetation and land cover. Mountain Research and Development, 36(1): 66-80. doi: https://doi.org/10.1659/MRD-JOURNAL-D-15-00020.1
Dorji, U., Olesen, J.E. and Seidenkrantz, M. (2016). Water balance in the complex mountainous terrain of Bhutan and linkages to land use. Journal of Hydrology: Regional Studies, 7: 55-68. doi: https://doi.org/10.1016/j.ejrh.2016.05.001.
Elias, M.F., Ibrahim, H. and Wan, R. (2017). A review on the malaysian Aquilaria species in karas plantation and agarwood production. International Journal of Academic Research in Business Social Sciences, 7(4): 1021-1029. doi: 10.6007/IJARBSS/v7-i4/2911
Ellenberg, D. and Mueller-Dombois, D. (1974). Aims and methods of vegetation ecology. New York: Wiley.
Faridah-Hanum, I., Mustapa, M., Lepun, P., Tuan Marina, T., Nazre, M., Alan, R. and Mohamed, R. (2009). Notes on the distribution and ecology of Aquilaria Lam.(Thymelaeaceae) in Malaysia. Malaysian Forester, 72(2): 247-259.
Hashim, Y.Z.H.-Y., Kerr, P.G., Abbas, P. and Salleh, H.M. (2016). Aquilaria spp.(agarwood) as source of health beneficial compounds: A review of traditional use, phytochemistry and pharmacology. Journal of Ethnopharmacology, 189: 331-360. doi: https://doi.org/10.1016/j.jep.2016.06.055.
Holdridge, L.R. (1967). Life zone ecology. San Jose, Costa Rica: Tropical Science Center.
Kaka, Gurung, D.B., Khandu, Y., Katel, O., Chhetri, P.B. and Wangda, P. (2014). Population Structure of Cupressus tortulosa Griffith along the Altitudinal Gradients of Tsendenanag Ridge in Punakha, Bhutan. Bhutan Journal of Natural Resources and Development, doi: 10.17102/cnr.2014.04
Kumar, A., Marcot, B.G. and Saxena, A. (2006). Tree species diversity and distribution patterns in tropical forests of Garo Hills. Current science, 91(10): 1370-1381.
Kundu, M. and Kachari, J. (2000). Desiccation sensitivity and recalcitrant behavior of seeds of Aquilaria agallocha Roxb. Seed Science Technology, 28(3): 755-760.
Lok, E. and Zuhaidi, Y.A. (2010). Cultivation And Management Practices Of Aquilaria For Agarwood in Malaysia. Paper presented at the Seminar on Reclamation, Rehabilitation and Restoration of Disturbed Sites: Planting of National and IUCN Red List Species.
Mat, N., Rahman, S.A., Ngah, N., Mahmud, K., Rosni, N.A. and Rahim, K.A. (2012). Growth and Mineral Nutrition of Aquilaria Malaccensis (Karas). In Two Habitats As Affected By Different Cultural Practices. Journal of Nuclear and Related Technologies, 9(1): 6-16.
Nakashima, E.M.N., Nguyen, M.T.T., Le Tran, Q. and Kadota, S. (2005). Field survey of agarwood cultivation at Phu Quoc Island in Vietnam. Journal of Traditional Medicines, 22(5): 296-300. doi: 10.11339/jtm.22.296
Norbu, L., Dhital, D.B. and Wangda, P. (2008). Reforestation in Bhutan—Accomplishments and prospects. Keep Asia Green, 3: 67-109.
Ohsawa, M. (1987). Life zone ecology of the Bhutan Himalaya: Laboratory of Ecology, Chiba University Chiba, Japan.
Pelzang, W. (2009). Assessing the status of Aquilaria malaccensis in Bhutan. . Accessed 15 February 2019.
Peng, C.S., Osman, M.F., Bahari, N., Zakaria, R. and Rahim, K.A. (2015). Agarwood inducement technology: A method for producing oil grade agarwood in cultivated Aquilaria malaccensis Lamk. Journal Of Agrobiotechnology, 6: 1-16.
Reddy, C.S. and Ugle, P. (2008). Tree species diversity and distribution patterns in tropical forest of Eastern Ghats, India: a case study. Life Science Journal, 5(4): 87-93.
Saikia, P. and Khan, M. (2014). Ecological features of cultivated stands of Aquilaria malaccensis Lam.(Thymelaeaceae), a vulnerable tropical tree species in Assamese Homegardens. International Journal of Forestry Research, doi: 10.1155/2014/140926
Shulka, G., Subba, M., Dey, T., Rai, P., Puri, A. and Chakaravarty, S. (2014). Tree Diversity Pattern in Sub-Humid Tropical Foothill Forest of Indian Eastern Himalayas, Journal of Tree Sciences. 33(1): 69-77.
Soehartono, T. and Newton, A.C. (2000). Conservation and sustainable use of tropical trees in the genus Aquilaria I. Status and distribution in Indonesia. Biological Conservation, 96(1): 83-94. doi: 10.1016/S0006-3207(00)00055-0.
Suharti, S., Pratiwi, P., Santosa, E. and Turjaman, M. (2011). Feasibility study of business in agarwood inoculation at different stem diameters and inoculation periods. Indonesian Journal of Forestry Research, 8(2): 114-129.
Wangchuk, S. (2003). CITES Management Authority of Bhutan, in litt. to TRAFFIC Southeast Asia. . Accessed 11 March 2019.
Wangda, P. (2003). Forest Zonation Along The Complex Altitudinal Gradients in a Dry Valley Of Punatsang Chu, Bhutan. (Masters thesis), Course of Natural Environmental Studies, Graduate School of Frontier, Sciences, Laboratory of Biosphere Functions, The University of Tokyo, Japan.
Wangda, P. and Ohsawa, M. (2006). Gradational forest change along the climatically dry valley slopes of Bhutan in the midst of humid eastern Himalaya. Plant Ecology, 186(1): 109-128. doi: 10.1007/s11258-006-9116-5
Wangda, P. and Ohsawa, M.J.P.E. (2006). Gradational forest change along the climatically dry valley slopes of Bhutan in the midst of humid eastern Himalaya. Plant Ecology, 186: 109–128.
Zich, F., Oceania, T. and Compton, J. (2001). The final frontier towards sustainable management of Papua New Guinea's agarwood resource. .