East Indian Walnut or Siris, as it's known in India, is a deciduous landscape, timber and fodder tree originating in the Indian subcontinent and Southeast Asia, its natural range extending from Pakistan, through India to Bangladesh and Burma.
In natural forests, it may reach up to 30 m (100 ft) tall with a straight trunk and narrow crown but on open sites is more commonly 10 to 20 m (30 to 60 ft) tall with a short trunk supporting a large, round and wide-spreading crown. The bark on young trees is light brown and smooth, on mature trees becoming fissured and rough.
The leaves are up to 25 cm (10 in) long and twice-feathered, made up of deep green lance-shaped leaflets arranged in pairs along each leaf branch. At the start of the dry season, they fall to the ground, leaving the branches bare until the rainy season when the new leaves emerge and grow to cover the branches again.
The flowers resemble powder puffs with long greenish filaments and are sweetly fragrant. They come into bloom at the transition between the dry and rainy seasons, coinciding with new leaf growth. They are followed by flat, papery seedpods that turn light brown when mature and persist on the tree for many months, well into the next dry season.
The heartwood is attractive, resembling that of brown walnut with its characteristic black and grey streaks. However, its weight, durability and general quality varies significantly between trees that have grown at different rates, with slow-growing trees producing a heavier, more durable, high-quality wood than fast-growing trees.
Tree growth rates are strongly influenced by the availability of moisture, with growth rates generally increasing with increasing rainfall. As a result, wood density and natural resistance vary considerably, ranging from 500 to 800 kgs per cubic meter (31 to 50 lbs per cubic ft) and from non-resistant to moderately resistant.
Well-formed logs are sawn into planks used for joinery work, flooring, furniture and cabinets. Selected logs are sliced for decorative veneer and the small roundwood and branchwood is used as a fuelwood, both for firewood and making charcoal.
Although rich in nectar, the structure of the flower makes it difficult for honeybees to gain access, which limits its importance as a honey plant.
The fresh leaves and seedpods are used as a livestock feed and have a reported crude protein content of about 20% of their dry weight.
It is commonly planted to shade coffee and tea crops and to contribute environmental services such as soil erosion prevention and land reclamation, on account of its nitrogen-fixing abilities and its tolerance to adverse growing conditions. It is also sometimes cultivated in gardens and landscapes for the shade it gives and for its showy, fragrant flowers.
Grows naturally in sub-humid to humid subtropical and tropical climates, generally in areas with annual lows of 16 to 25 °C, annual highs of 27 to 35 °C, annual rainfall of 400 to 2500 mm and a dry season of 2 to 9 months. However, it reaches its best development as a timber tree in areas with annual rainfall of 1300 mm or more.
New plants are usually started from seed, which are pretreated before sowing by immersing them for a few seconds in boiling water that is then allowed to cool. It performs best on moist to dry, free-draining loam and sand soils of a slightly acid to alkaline nature, generally with a pH of 5.0 to 8.5. It has good tolerance to drought, seasonal flooding, soil salt and limestone soil conditions.
The seedpods are produced in large quantities and are easily dispersed by wind and water. It is listed in more than one reference publication as a serious weed and is assessed as a high weed risk for Hawaii and Florida, respectively by the Hawaii Pacific Weed Risk Assessment project (HPWRA) and by the IFAS Assessment of Non-Native Plants in Florida's Natural Areas. Root-suckering also contributes to its weediness.
Pollen released by the flowers is reported to cause hay fever in some and the dust from sawn wood is an irritant to the nasal passage.
Adams, C. D. 1972, Flowering plants of Jamaica, University of the West Indies, Mona, Greater Kingston
Allen, O. N. & Allen, E. K. 1981, The Leguminosae : a source book of characteristics, uses, and nodulation, University of Wisconsin Press, Madison, Wisconsin
Barwick, M., et al. 2004, Tropical & subtropical trees : a worldwide encyclopaedic guide, Thames and Hudson, London
Chevallier, A. 2000, Encyclopedia of herbal medicine, 2nd American ed., Dorling Kindersley, New York
Chudnoff, M. 1984, Tropical timbers of the world, Forest Service, U.S. Department of Agriculture (USDA), Washington, D.C.
Dey, S.C. 1996, Fragrant flowers for homes and gardens, trade and industry, Abhinav Publications, New Delhi, India
Doran, J. C & Turnbull, J. W. 1997, Australian trees and shrubs : species for land rehabilitation and farm planting in the tropics, 2nd ed, Australian Centre for International Agricultural Research (ACIAR), Canberra, Australian Capital Territory
Duke, J. A. 1983, Handbook of energy crops (unpublished), Center for New Crops & Plants Products, Purdue University, West Lafayette, Indiana
Fawcett, W. 1891, Economic plants, An index to economic products of the vegetable kingdom in Jamaica, Jamaica Government Printing Establishment, Kingston
Francis, J. K. 1998, Tree species for planting in forest, rural, and urban areas of Puerto Rico, U.S. Department of Agriculture, Forest Service, International Institute of Tropical Forestry, Piedras, Puerto Rico
Francis, J. K. and Liogier, H. A. 1991, Naturalized exotic tree species in Puerto Rico, General technical report SO-82, USDA Forest Service, Southern Forest Experiment Station, New Orleans
Francis, J. K. et al. 2000, Silvics of Native and Exotic Trees of Puerto Rico and the Caribbean Islands, Technical Report IITF-15, USDA Forest Service, Rio Piedras, Puerto Rico
Gohl, B. 1981, Tropical feeds : feed information summaries and nutritive values (Revised edition), Food and Agriculture Organization of the United Nations (FAO), Rome
Hocking, D. 1993, Trees for drylands, International Science Publisher, New York
Howes, F. N. 1949, Vegetable gums and resins, Chronica Botanica Company, Waltham, Massachusetts
Jensen, M. 1999, Trees commonly cultivated in Southeast Asia : an illustrated field guide, 2nd ed., Food and Agricultural Organisation of the United Nations (FAO) Regional Office for Asia and the Pacific (RAP), Bangkok
Krishen, P. 2006, Trees of Delhi : a field guide, Dorling Kindersley Publishers, Delhi
Letourneux, C. 1957, Tree planting practices in tropical Asia, Food and Agriculture Organization of the United Nations (FAO), Rome
Liegel, L. H. 1987. A technical guide for forest nursery management in the Caribbean and Latin America, U.S. Dept. of Agriculture, Forest Service, Southern Forest Experiment Station, New Orleans
Luna, R. K 1996, Plantation trees, International Book Distributors, Dehradun, Uttarakhand
Macmillan, H. F. 1943, Tropical planting and gardening : with special reference to Ceylon, 5th ed, Macmillan Publishing, London
Nair, P. K. R. 1993, An introduction to agroforestry, International Centre for Research in Agroforestry (ICRAF), Kluwer Academic Publishers, Dordrecht
National Research Council (Board on Science and Technology for International Development) 1980, Firewood crops : shrub and tree species for energy production (Volume 1), The National Academies Press, Washington D. C.
Parrotta, J. A. 2001, Healing plants of peninsular India, CABI Publishing, Wallingford, Oxfordshire
Porter, T. 2012, Wood : identification & use, Compact edition, Guild of Master Craftsman Publications, Lewes, East Sussex
Randall, R. P. 2002, A global compendium of weeds, R.G. and F.J. Richardson Press, Melbourne
Scheffer, T. C & Morrell, J. J. 1998, Natural durability of wood : a worldwide checklist of species, Forest Research Laboratory, Oregon State University, Corvallis, Oregon
Schubert, T. H. 1979, Trees for urban use in Puerto Rico and the Virgin Islands. U.S. Department of Agriculture, Forest Service, Southern Forest Experiment Station, New Orleans
Singh, R. V. 1982, Fodder trees of India, Oxford & IBH Publishing Company, New Delhi
Vázquez, Y. C. 1999, Potentially valuable Mexican trees for ecological restoration and reforestation, Institute of Ecology, Database SNIB-REMIB-CONABIO, Project J084, Mexico
Webb, D. B. 1984, A Guide to species selection for tropical and sub-tropical plantations, 2nd ed., Unit of Tropical Silviculture, Commonwealth Forestry Institute, University of Oxford, Oxfordshire
Dagar, J. C. & Singh, G. 2007, Biodiversity of Saline and Waterlogged Environments: Documentation, Utilization and Management, NBA Scientific Bulletin, (9), 78.
Morton, J. F. 1976, Pestiferous spread of many ornamental and fruit species in south Florida. In Proceedings of the Florida State Horticultural Society (Vol. 89, pp. 348-353).
Morton, J.F. 1964, Honeybee Plants of South Florida, Proceedings of the Florida State Horticultural Society, Vol 77:415-436.
Nair, P. K. R., Fernandes, E. C. M., & Wambugu, P. N. (1985). Multipurpose leguminous trees and shrubs for agroforestry. Agroforestry systems, 2(3), 145-163.
This website is provided for general information only. Iplantz makes no statements, representations or warranties as to the accuracy or completeness of the content of this website and does not accept any liability to you or any other person for the information which is provided or referred to on this website.
In particular, Iplantz does not represent or warrant that any dataset or the data it contains is accurate, authentic or complete, or suitable for your needs. Changes in circumstances after the time of publication may impact the accuracy of datasets and their contents.
To the maximum extent permitted by law, Iplantz accepts no liability whatsoever to any person arising from or connected with the use of or reliance on any information or advice provided on this website or incorporated into it by reference, including any dataset or data it contains. No responsibility is taken for any information or services that may appear on any linked websites.