Safed Siris (Albizia procera)
Natural Habitat and Classification
The tree is commonly found on alluvial ground along streams, and in moist even swampy places. It is particularly common in low lying moist Savannahs.
The species is found in the sub-Himalayan tracts from Yamuna eastwards to West Bengal, Satpura range, Gujarat, South India and in the Andamans. It has good adaptability for growing in moist as well as fairly drought conditions. The tree is classed as a light demander although it stands moderate shade in the pole stage. It is fairly drought resistant but frost-tender. It produces root suckers when the stem is mutilated or the tree becomes old.
Albizia procera occurs in tropical semi-evergreen forests, tropical moist deciduous forests, dry tropical forests and northern sub-tropical broad-leaved forests. In the areas of its natural distribution, the absolute maximum shade temperature varies from about 36°C to 46°C, the absolute minimum from -1°C to 18°C and the normal annual rainfall from about 1,000-5,000 mm. Its common name is White Siris and trade name Safed Siris.
The tree belongs to family the Leguminosae, sub family Mimosoideae.
As a Plantation Tree
Being a fast growing species and having an immense potential for introduction in different types of soils and climatic conditions, it is planted in various states by the Forest Departments and also by farmers under Agro-forestry programmes. This is an important fast growing species in Assam and other eastern states, particularly Tripura. It is also planted in Bihar and Uttar Pradesh. Albizia procera has been used in experimental planting in saline and alkaline areas with considerable success. Being a legume, it fixes nitrogen through symbiotic bacteria present in root nodules and thus enhances and soil fertility.
Planting Site and its Preparation
The species prefers alluvial soils although it also comes up in clayey or moderately alkaline and saline soils, where it attains a smaller size. The planting site is cleared of undesirable growth by cutting and burning; 30 cm x 30 cm x 30 cm pits are dug before the summer season. The soil gets weathered during the hot months. It is also raised as a shade tree in tea gardens and planted in mine spoils. Since the species is vulnerable to browsing by cattle etc. the plantation areas have to be well protected generally by providing barbed wire fencing.
Entire plants as well as stumps are generally put in previously prepared planting pits with the break of the monsoon showers. Small as well as large 1 year to 15 months old saplings can be successfully planted depending upon the climatic conditions; success with smaller plants is however, achieved in moist areas
In Assam and North Bengal, in case of line sowing, 2-3 m spacing between lines is adopted. The seedlings are spaced about 0.5 m in the lines at the end of the first growing season. Spacing of 2m x 2m or 3m x 3m are recommended for planting of entire transplants or stumps. Around the agricultural fields the species can be planted in a single row at 3m or 4 m spacing.
In the tarai and bhabar tract of Uttar Pradesh, Safed Siris has been raised by sowing in admixture with other species like khair, sissoo, semal etc., in continuous ridges 4m apart. In areas subject to strong wind it is mixed with other wind firm species in plantations. In multi row strip plantations along roads, rail lines and canals, this species is planted in the middle row.
Application of 5 ml rhizobium broth and 75 g single super phosphate per plant in the year of planting significantly increases the growth and development, and establishment of plantation.
In moist localities irrigation is not done. However, in drier and refractory sites, irrigation during summer months and winter, if there are no rains, is needed for ensuring the survival as well as better growth. As many waterings as possible should be done. Mulching has a very good effect in retention of moisture. In agroforestry plantations watering may not be required as the plants get sufficient moisture from the irrigation of agriculture crops. Where sufficient moisture is not available the plants die-back during the first and second year in summers, and resprout in the following rainy season.
Three weedings are carried out in the first and second year in high rainfall areas, elsewhere two in the first and second year and one in third year, irrespective of whether the plantation is raised by direct sowing, entire transplants or stumps. Climbers and bushes likely to shade the plants are also cut. In the case of direct sowing, thinning of the plants is done to reduce competition.
Cleaning and Thinning
These operations are carried out depending upon the development of the crop and its silvicultural requirements
Trees are generally harvested from December to May. Collection of pods is done before they split on the tree otherwise the fallen seeds are quickly infested and damaged by pests. For fodder, the leaves are best collected from October to December when the availability of foliage is maximum.
Timber and fuelwood are main marketable products which are sold in almost all the timber markets and fuelwood depots throughout India. The wood is also used for making paper pulp and chipboards in industries along with other species. Bark finds commercial use in the tanning industry
Indian Council of Forestry Research and Education, Dehradun. Safed Siris (Albizia procera). Dehradun, Forest Research Institute. 12p.