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 and 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 360 to 460, the absolute minimum
from -1 0C to 18 0C and the normal annual rainfall
from about 1,000 to 5,000 mm. Its common name is White Siris and trade name
Safed Siris.
The tree belongs to family the Leguminosae,
sub family Mimosoideae.
(c) Growth Statistics
A large deciduous tree with a tall, erect or
more often somewhat curved stem with pale yellowish or greenish white bark
and light crown. In some localities it may reach 36 m in height and 2-3 m in
girth with a clear bole of 12 m, but is usually 18 to 24 m in height. In the
drier regions, such as Madhya Pradesh, the Satpura, Gujarat and parts of
Tamil Nadu, the trees are commonly found up to a girth of 1.2 to 1.5 m. The
bark is about 1.2 cm thick, peeling off in thin flakes often with horizontal
lines. Leaves are bipinnate with rachis 25 – 26 cm long with a large oblong
gland near the base. Flowers are greenish yellow in peduncled heads arranged
in large lax terminal panicles.
The rate of growth is rapid. In northern India
it attains a girth of 1-1.3 m in twelve years and upto 2 m in thirty years
giving a mean annual girth increment of 4-10 cm. In Tripura plantations of
this tree attain a average height of 10.66 m in 10 years.
The leaf fall takes place in January-February
and the new leaves appear in April-May. In favourable localities, the tree
is rarely leafless. Out of the climatic factors, temperature is more
important than rainfall and humidity, affecting leaf fall and leaf
initiation. The pods are formed soon after the flowering, develop rapidly to
attain full size by November – December and ripen from February to May;
under north Indian conditions the pods ripen from January to March. Ripe
pods are dark reddish brown,10-20 cm long, 6-12 seeded and dehiscent. The
seeds are smooth, greenish brown with a leathery testa.
(d) 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.
The sapwood is white with a yellowish cast,
subject to sap-stain; weight at 12% moisture content about 641 kg/cum and
the specific gravity 0.579 for timber of Dehradun origin; heartwood golden
brown with lighter and darker streaks; straight or broadly and shallowly
inter-locked grained; very coarse and even textured. The timber is strong,
elastic, tough and hard. Tests at Dehradun show that is stronger than Burma
teak. Young’s modulus for Burma teak is 18,30,000 against 20,71,000 for
white siris. The relative suitability of the wood in terms of Teak taken as
100 is, strength as a beam, 88; stiffness as a beam 85; suitability as a
post 88; shock resisting ability, 128; retention of shape, 80; shear, 111;
hardness, 97; refractoryness, 71; nail or screw holding property, 98.
The timber is moderately refractory to
seasoning. Conversion from green logs gives best results. If the timber is
left in the log, hard-shake is liable to result unless ends are coated with
a suitable covering such as cowdung and mud, tar, or other special
preparations. The timber is about two and half times harder than teak.
(b) Use as Timber,
Poles, Pulp and Paper etc
It is a valuable timber and is used in general
construction (house posts, beams, scantlings, planks, boards), carriage and
carts, motor-lorry and bus bodies, agricultural implements, tool handles,
packing cases and crates, etc. It is a high grade furniture timber, though
not so decorative. It is used for a variety of other purposes such as well
construction, canoes and dug-outs, oars, cane-crushers, oil presses and rice
pounders. It is largely used in Assam and Tripura. Due to the more broadly
interlocked nature of the grain, it is more suitable for use in large
sections where a bolder effect is desired, such as in large-sized panels,
table-tops, etc. The wood is resistant to termites.
It is not an easy timber to treat with
preservative as the heart wood is only partially treatable; but treatment is
commercially profitable and feasible. It is hard and somewhat difficult to
saw, as the grain is broadly interlocked. With care, it works to a smooth
surface and takes a good polish. It is preferable to use the poles of Safed
siris after treatment as mine props and for other purposes.
Fibre length varies from 0.70 to 1.65 mm,
average being 0.90 mm. Similarly the minimum diameter of fibres is 0.014 and
maximum 0.028 mm with an average of 0.021 mm. The proximate chemical
analysis of the wood indicated that it is a suitable material for paper
pulp. Bleached pulp in satisfactory yields (50.3%) can be prepared from
white siris wood by the sulphate process. The fibre length being short, its
pulp is required to be mixed with long fibre pulp such as bamboo in suitable
proportion for paper manufacture on a commercial paper machine. The pulp is
suitable for writing and printing paper.
(c) Use as Fodder
The leaves are readily eaten by cattle, sheep
and goats. The branches from favourite fodder for elephants. In plantations,
deer browse the saplings to almost bare sticks, the tree is lopped for
fodder in Maharashtra, Orissa, Punjab, Tripura and Uttar Pradesh. It
contains 18.9% protein, 3.3% fat, 39.7% carbohydrates, 1.51% calcium, 0.30%
phosphorus, 31.9% fibre and 6.2% ash (minerals).
(d) Use as Fuel
The calorific value of dried sapwood is 4870
Kcal per kg and that of heartwood 4865 Kcal/kg. Excellent charcoal (39.6%)
can be prepared from the wood. It is widely used by the people as fuel. The
wood is an excellent fuel. Wood having 6.84% moisture contains 89.56% carban
and other organic matter, and 3.6% ash; its calorific power is 86.9 compared
to pure carbon 100; and 13 litre of water is evaporated by 1 kg wood at 1000
C.
(e) Use for
Environmental Conservation
The species finds favour in plantation
programmes especially in poor, marginal, dry and degraded lands due to its
varied adaptability. Its resistance against drought has made this species
popular in dry zones. Albizia procera has been extensively used in
experimental planting in saline and alkaline areas. Besides its good soil
binding capacity due to fast growth it has excellent power to fix the
nitrogen and thereby enrich soil status. It is often grown in gardens and
avenues for ornamental purposes.
(f) Other Uses
White siris alongwith
other forest wastes has been found to be useful for making chipboards of
satisfactory strength properties. The leaves are valued as insecticide and
for the treatment of ulcers. All parts of the plant are reported to show
anti-cancer activity. The roots contain alphaspinasterol and a saponin. The
saponin has been reported to possess spermicidal activity at a dilution of
0.008 per cent. The tree gives a copious gum. The bark is used for tanning
as it contains about 12-17 per cent tannin. In times of scarcity the bark is
ground with flour and eaten. A decoction of the bark is given in rheumatism
and haemorrhage. It is used as a fish poison. The seeds of Albizia
procera contain Proceranin A, which is toxic to mice and rats when
administered parenterally and orally. The intraperitoneal LD 50 for mice is
15 mg/kg body weight. The branches (twigs) are used by tea-planters as
stakes for laying out tea-gardens. These are found to split well.
The natural regeneration of Albizia procera is good. The conditions
for natural regeneration are quite favourable. It produces an abundant crop
of pods almost annually. The pods ripen from December to May. They fall from
the trees for most part for the hot season, dehiscing before or about the
time of falling. The pods are blown by wind to considerable distances.
Germination of the seeds take place readily, provided there is sufficient
moisture; in the forest, seedlings may be found in quantity in the
neighbourhood of seed-bearers during the rainy season from seed which
germinated early in the rains. Some of the seeds may lie ungerminated till
the second rains. The factors favourable to natural reproduction are good
moisture and bare loose soil where the seed gets buried with the early
showers. Thus on new soft alluvial ground near rivers, seedlings in all
stages may often be seen in abundance. Natural seedlings may also be found
in some quantity in moist grassy tracts.
Under natural conditions, the seedling reaches a height of
10-20 cm by the end of the first rains. It is capable of struggling through
low grass and weeds. Its rate of growth is slow but increases considerably
later, when it overtops the weeds. The sudden removal of weeds around
seedlings, previously unweeded, is however, not advisable, as they are
liable to die due to sudden exposure to the sun. Vigorous seedlings produce
long stout tap roots which may reach a length of 60 cm in 3 months from
germination. The lateral roots are usually covered with nodules. Under
natural forest conditions, if left unweeded in full sunlight, the seedlings
reach a height of 15 cm by the end of the first season and 60 cm by the end
of the second season. In the third year the height ranges from 70 cm to 2.5
m, and in the fourth year up to 5 m.
During weeding, the soil
should not be unduly exposed; only weeds actually interfering with plants
should be removed, the remainder being left to shade in the ground during
the hot weather. Climber cutting should be done when necessary. Thinning of
the crop is done according to the silvicultural requirements.
In the mixed deciduous forests generally coppice system is
adopted with about 40 years of rotation. In Kerala, this tree is worked
under the selection system. In Assam and some eastern
States the forests containing this species are worked under the clearfelling
system with artificial regeneration on a sixty year rotation.
The nursery beds are
prepared on well drained sites. The sandy loam soil with pH around 7 is
ideal. The nursery beds are prepared in unshaded space.
(b)
Seed Collection and Storage
Seeds usually ripen from
January to May, depending on the locality. Ripe pods are dark coloured. The
seeds may be collected from ripe pods. It is advisable to collect the pods
from the tree without waiting for them to drop down. Pods are dried in the
sun till they open up. The seeds can be extracted by hand or by gentle
thrashing. The seeds are cleaned of pod fragments and defective ones by
winnowing. These are dried thoroughly under the sun. One kilogram of dry pod
yields about 250-375 gram of seeds. One kilo of dried seed contains
approximately 20,000 seeds.
The seeds retain
viability for a long time. Seeds kept in a gunny bag for 2 years, germinate
as freely as fresh seeds. The seeds should be kept carefully in sacks in a
dry well-ventilated shed. It is advisable to spread the seeds out on mats
occasionally to air, otherwise they may become mildewed. It has been
observed that seeds stored for 15 years showed a germinative capacity of
20%.
(c) Sowing
The sowing is done in
April-May under irrigated conditions in the nursery. The seed is put in
cooling boiled water and allowed to soak for 24 hours to soften the seed
coat. It results in quicker and more even germination. Sowing is done in
lines about 8 cm apart and the seedlings are spaced about 5 cm in the lines.
About 30 g seed is sown per square meter of nursery area. The seed rate in
West Bengal is about 8g/m2 for a spacing of 7.5 x 7.5 cm. The
germination of the treated seed commences in about 3-4 days and takes about
2-3 weeks to complete. A germination percentage of 50-90 can be expected.
The seedlings raised from April-May sowing attain a height of about 15 cm by
July-August when these are planted out in pits in the field. In case the
seedlings do not attain plantable size by July, these are retained in the
nursery for one more year. In drier areas 15 month old seedlings only
planted in the field.
(d)
Vegetative Propagation / Clonal Techniques
Stumps prepared from one or two year old plants give very
good success and are used for planting new areas or for filling the gaps. In
Bihar, seeds are
sown close in drills 15 cm apart, in March-April and watered well. When
about 7.5 cm high, the seedlings are pricked out to 38 cm x 38 cm apart if
the plants are required for stump planting in the following year. A spacing
of 15 cm x 15 cm is adopted if the plants are to remain in the nursery only
till the first rains. Stumps can be prepared from either 3 months old or 15
months old seedlings; the later give better results. They should be put out
at the break of monsoon rains. For still better results the stumps made from
one year old seedlings i.e. in March-April are planted in polythene bags
filled with a mixture of soil, sand and FYM in equal proportions. These are
regularly watered. With the onset of rains these develop into healthy plants
which give almost 100% success in the field.
(e)
Pricking Out
The pricking out of germinated seedlings is done either in
nursery beds or in polythene bags. In case stumps are aimed at to be made
from 15 month old plants, the seedling when 7.5 cm high are pricked out at
38 x 38 cm spacing. A spacing of 15 x 15 cm is adopted if the plants are to
remain in the nursery till the first rains only. Pricking out of seedlings
with two pairs of leaves are also done in polythene bags filled with soil,
sand and farm yard manure. In Dehradun conditions polythene bags of 23 x 13
cm and potting mixture soil, sand and FYM in the ratio of 3:1:1 have been
found to be the best. The seedlings raised in polythene bags are planted out
in the field in the next rainy season. Since the seedlings develop strong
tap roots, the polythene containers are shifted periodically to avoid the
root from striking and penetrating into the ground. This is done to avoid
shock to seedlings and their drying which results due to damage to roots at
the time of lifting and transportation for planting out in the field.
(f)
Fertilization
Application of leaf mould
manure is helpful but not essential. Albizia procera nodulates well
through the native strains of rhizobium which fix enough atmospheric
nitrogen needed for growth. The nodules are solitary or in groups and are
rounded to dichotomously branched. Cultures of rhizobium are easily prepared
on yeast mannitol agar medium. The inoculation is done by pelleting the
seeds with lignite based culture or drenching the seedlings with broth
culture. The nodule development is miximum from October to February.
Artificial inoculation improves the growth and development of seedlings.
Application of nitrogen at the rate of 10-20 kg N/ha of soil as a starter
dose helps in early establishment of seedlings without suppressing the
development of nodules. Phosphorus application at the rate of 20-40 kg P/ha
enhances the growth and development of seedlings. Application of VAM culture
develops resistance in seedlings against drought conditions.
(g)
Irrigation
After sowing the seed in
beds they are covered with straw and daily watering with rose can is done.
The straw is removed after germination and watering is continued.
Regular watering in the
nursery to keep the pricked out seedlings in beds or in polythene bags is
necessary to keep the soil moist. The watering should preferably be done in
morning or evening hours. After the seedlings get fully established,
watering is recommended on alternate days. In case the seedlings are
maintained in pricked out beds for another year watering is done, through
flow irrigation in channels made around the beds. In polythene bags, however
watering by rose can is preferred.
(h)
Weeding
Regular weeding of nursery beds or polythene containers is
very essential to keep the seedlings free from any weed competition.
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 on suitable sites; 30
cm x 30 cm pits are dug before the summer season. The soil gets weathered
during the hot months. In U.P. in alkaline and saline soils larger size pits
such as 60 cm x 60 cm x 90 cm, 60 cm x 60 cm x 120 cm or even 120 cm x 120
cm x 120 cm are dug out which are refilled with imported non-saline and
non–alkaline soils. Vermiculite, gypsum and farmyard manure are also mixed
in the imported soil. 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 has to be well protected generally by
providing barbed wire fencing. In wet climate as in Assam, pit digging is
not necessary as stump planting in crowbar holes is fairly successful.
(b) Planting
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
plants can be successfully planted depending upon the climatic conditions;
success with smaller plants is however, achieved in moist areas. Albizia
procera is susceptible to break in gales hence this species should be
planted in blocks or in central row in road, rail or canal side strips. The
methods followed in some of the states is given below:
Assam and Other Eastern States: In these
States, it is generally raised by premonsoon sowing in parallel
continuous lines 2.3 m apart from centre to center. Stumps
made out of one year old nursery plant and
planted in field in crowbar holes give about 60-75 survival
and on the average a height of 75 cm. Planting
out of small naked root plants from nurseries planted out in
August also give up to 70% survival. Stump
planting any time between April-December gives best results
provided that the peak rainy season and the
early summer drought are avoided.
Bihar: Stumps made from 15 months old
seedlings are planted in 30 cm x 30 cm x 30 cm dug up and refilled
pits. This is the usual planting practice. Although direct
sowing in prepared lines with the break of the
monsoon is also done.
Uttar Pradesh:
This species is raised through direct sowing in mechanized plantations in
the tarai and
bhabar tract. Elsewhere entire plants and stumps are planted.
Entire plant planting is superior to stumps as
far as height growth is concerned. In alkaline and saline
lands Albizia procera gives better survival and
growth as compared with other species such as neem, sissoo,
eucalyptus, mahua, karanj, bahera, arjun,
khair etc.
(c)
Spacing
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.
(d)
Mixed Plantations
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.
(e)
Fertilization
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 Jabalpur conditions
having soils of Typic Ustorthent.
(f) Irrigation
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.
(b)
Cleaning and Thinning
These operations are carried out depending upon the
development of the crop and its silvicultural requirements.
Five species of insects
bore the seeds, out of which Bruchus bilineatopygus causes up to 80%
damage. It is a light brown, about 4.45 mm long beetle that lays oval, light
yellowish eggs on young pods. The eggs hatch into small grubs, which enter
fleshy pods. The damage can be seen in the form of oozing of gummy fluid on
the outer surface of the pods. The grub turns into pupa and then beetles
emerge out of pods. These beetles again lay eggs on fresh pods and stored
seeds. There are five generations in a year. The pest is controlled by
spraying of 0.05% monocrotophos on the tree in the first half of September.
Mixing of folidal 2% dust with seeds in the ratio of 1:100 is recommended
for protecting seeds from damage.
Eurema blanda,
a butterfly, that migrate in large swarms, lay eggs in clusters on the lower
surface of the leaves. The larvae after hatching out from eggs feed
gregariously on the leaves. Eurema hecaba, Cusiala raptaria, Hyposidra
successaria, Semiotthisa emersaria, Ascotis selenaria and other
Lepidopterous insects also feed on the foliage and other soft tissues of
seedlings. For controlling all these pests, collection and destruction of
conspicuous clusters of pupae, and spray of 0.05% water emulsion of
malathion, endosulfan or sevin is recommended. Another insect Oxyrhachis
mangiferana (Hemiptera) lays eggs in V-shaped slits in thin bark of
shoots. After the eggs have hatched, a broad oval scar is left, which
distorts the growth of the shoot or kills it. The pest may be controlled by
application of 0.04% monocrotophos.
Seedling wilt is caused
by Fusarium oxysporum. The lower leaves initially turn yellow and
then fall off. The yellowing proceeds towards the growing shoot and within a
month the seedling dies. The roots of affected seedlings get discoloured. It
is controlled by application of 0.3% Dithane M-45 or 0.2% Bavistin. Treating
the seed beds with 0.2% Bavistin before sowing prevents the occurrence of
damage.
Leaf spot disease is
caused by attack of foliage by Collectotrichum dematium. The disease
manifests on older leaves of seedlings as a small water soaked yellowish
spot which later develops into a circular light brown lesion with a distinct
yellowish margin. The spot hole develops in the advanced stages of infection
causing premature defoliation. The disease is aggravated under high humid
conditions. The tender shoots of seedlings are also infested and damaged.
The disease can be controlled by spraying 0.2% captaf fungicide. Little leaf
disease caused by Mycoplasma like organisms is often observed in seedlings
after the germination of seeds. The cotyledons and first pair of leaves turn
yellow. Later on the foliage becomes bunchy with much reduced sized of
leaves. Ravenelia clemensiae attacks leaflets of the seedlings.
Profuse development of postules takes place on the leaf surface adversely
affecting the metabolic activity of plants resulting even in death. The
disease is controlled by application of 0.2% diathane M 45 or sulfex.
(b) In Plantations
The larvae of
Xystrocera globosa bore into the inner bark and sapwood and may hasten
the death of injured or sick trees. A heavy infestation may kill less
resistant trees in one season only. Spraying a mixture of
Paradichlorobenzene 1 part and kerosene 10 parts kills the larvae and
callous quickly, covers the wound. The larvae of Indarbela quadrinotata
bores in the wood of standing green trees. They are minor pests. Removing
the silken mat and then brushing the eaten bark with any insecticidal
emulsion, kills this borer. The larvae of a number of moths of families
Geometridae, Eucosmidae, Noctuidae, Lycaenidae, Pieridae and Pyralidae
defoliate the tree.
The young trees of Siris
15-20 years old are subject to attack by a highly virulent bark and stem
disease which produces a grayish black canker on the stem. The disease is
called pit canker disease and it is caused by the fungus Fusarium solani.
The canker seems to start where the branches are broken off by wind, and to
extend upto 2-4 m in length and sometimes to cover three quarters of the
diameter of the trees. Either the crowns die above canker or the stems break
off at the place where the canker is deepest. It can be controlled by
application of 0.3% Fytolon solution. Ganoderma lucidum cause root
rot and Ganoderma applanatum as well as Polyporus gilvus cause
heart rot but these are of minor importance only.
It is a fast growing species. The mean annual girth increment has been
recorded from different regions varying from 2.5 to 12.4 cm. In Tripura,
plantations of average height of 10.66 m and average diameter of 17.8 cm in
10 years have been reported. In Allen forest, Kanpur, in a group of three
trees growing close together, at the age of 14 years the largest was 21.3 m
high and 173 cm in girth at breast height. Albizia procera under
silvipastoral system in association with Cenchrus and Stylosanthes pasture,
in Jhansi,
U.P. gave a mean height of 10.75 m and 30.60 cm diameter at breast height in
8-9 years. The average dry matter production of tree parts (kg/tree) was,
main bole 87.54, branches 62.72, total wood 150.26, leaves 18.39, pods 2.45
and total biomass 174.07 in the above mentioned silvipastoral system. Annual
wood production of about 10m3/ha has been recorded in Java.
The mixed deciduous forests where this tree occur, are
managed generally under the coppice system with a rotation of about 40
years. In Kerala
State, this tree is worked under selection system. Although natural
reproduction is generally good near seed bearers, artificial reproduction
would be necessary for completing the stocking. In southern West Bengal, where plantations are raised for fuel supply, a
rotation of 20 years is indicated. In Assam and some eastern
States the forest containing this species are worked under the clearfelling
system with artificial regeneration on a sixty year rotation.
Harvesting and its
Calender
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
Market and Marketable
Products, used as Raw Material in
Forest Based Industries
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.
