|SILVICULTURE OF EUCALYPTUS
WITH REFERENCE TO THE PRACTICES BEING FOLLOWED BY
AP FOREST DEVELOPMENT CORPORATION LIMITED
Eucalyptus is an Australian genus comprising of about 500 and odd species and most of which are found in Australia and some in Tasmania, New Guinea and other islands. This species is a native of Australia and is grown in varied climatic conditions.
The Eucalyptus was introduced in India during the time of Tippu Sultan in Nandi Hills of Mysore in late eighteenth century. Subsequently, the British have introduced Eucalyptus globulus in the Nilgiris as a firewood species. About 170 species, varieties and provenances of Eucalyptus were tried all over India, out of which the most outstanding were Eucalyptus tereticornis, Eucalyptus grandis, E. citriodora, E.globulus and E.camaldulensis. Eucalyptus has attracted the attention outside their home in early part of nineteenth century. They were planted in the southern Europe for ornament. Their economic value was realized due its fast growing nature and plantations were formed extensively throughout the world wherever they are suitable to grow.
In Andhra Pradesh, the species Eucalyptus globulus was said to have been introduced in Horsley hills of Chittoor district in the nineteenth century. In 1934, Eucalyptus rudiana was introduced again in Palamanair of Chittor district. In 1948, E.tereticornis, E.rostrata plantations were raised in Sriharikota of Nellore district. In 1953, Eucalyptus hybrid was introduced in Zaheerabad of Medak district. However, largescale plantations were commenced with the formation of APFDC from 1976. So far, the APFDC has raised over 48,000 hectares of seed origin plantations up to 1994. Thereafter, the Corporation has switched over to Eucalyptus clonal plantations by converting the old seed origin plantations. So far, by 2011, the Corporation has raised about 40,500 Ha of clonal Eucalyptus plantations which is the largest by a single organization.
Besides the APFDC, the Forest Department through VSS has embarked upon raising large scale clonal Eucalyptus plantations in degraded reserve forests. Further, the farmers from Prakasam, Nellore, West Godavari and Chittoor districts have started growing large scale Eucalyptus clonal plantations. M/s.ITC Badrachalam, M/s.JK Paper Mills, M/s.BILT have also been promoting the large scale Eucalyptus clonal plantations.
Species: Eucalyptus camaldulensis, Eucalyptus tereticornis, clones developed from these species.
Vernacular names: Nilagiri, Jamail in Telugu in different regions
Description of the tree: Eucalyptus is an ever green species, more or less aromatic and containing oil glands in their leaves. Oil distilled from leaves is of medicinal value. The species is a fast growing and the leaves are in varied shapes from sickle shape (E.camaldulensis) to dagger shape (E.tereticornis) etc. Bark exfoliating, falls in flakes during early summer.
The rainfall requirement for raising Eucalyptus plantations is about 500 to 2000 mm per annum. Better growth is seen in the areas with rainfall ranging from 1000 to 1200 mm. In high rainfall zone, the growth is found to be not spectacular.
The Eucalyptus grows in varied climatic conditions tolerating extreme temperatures to some extent. The maximum temperature is 300 C to 42 0C and minimum temperatures are 18 0 C to 22 0 C.
Geology, rock and soil:
The Eucalyptus comes up in various types of soils. It prefers sandy loam with good drainage and the growth is found to be excellent is these soils. However, on alkaline and black cotton soils, the growth is stunted and poor.
Leaf fall and growth:
The leaf fall is seen in February-March though some leaf fall is observed throughout the year.
The growth is vigorous during the monsoons though growth is observed throughout the year.
Flowers are seen in July-August.
Fruits appear in January-March. The seeds are minute. The number of seeds per gram is about 400 to 1000.
The Eucalyptus generally is a light demander. To some extent, it tolerates shade in its younger stages in the misc coppice shoots. However, coppice cutting is done to facilitate high light to the growing plants under traditional method.
Resistance to wind damage:
The Eucalyptus develops long roots in the initial stages and can withstand moderate to heavy gales. However, in high winds or gales, the surface roots and branches tend to break and the plants fall to the ground. It is also observed that the clones are more prone to wind damage.
It is a drought hardy species.
It is fire tender species. During fire accidents, the tender bark is burnt and the stem develops epicormic branches resulting in stunted growth.
The mature plants can withstand mechanical injury to certain extent. The young plants are damaged by grazing animals in the initial stages. Normally not eaten by cattle.
REGENERATION OF THE SPECIES:
The Eucalyptus exhibits natural regeneration in the natural habitat in Australia and neighboring islands. The natural regeneration is not widely seen in India as the conditions are not favourable.
However, the natural regeneration was observed on a very limited scale at Nilgiris where continuous moisture is available. The natural regeneration is also seen in certain parts at Bapatla, near the coast where the moisture availability is for longer period.
The species is not regenerated through natural regeneration in AP or in India.
The artificial regeneration is resorted on a large scale throughout India except in temperate regions. The artificial regeneration involves the following:
Raising of Nursery stock:
The nursery technique is varied from place to place and time to time. The nursery technique under traditional method of planting is raising of primary seedlings sown in the raised primary beds and transplanted into polythene bags filled with soil and maintained for 6 months. The grown up seedlings are planted in the pits duly removing the polythene bag.
The nursery technique under the advanced technology is – the clonal plants developed are vegetative cuttings (propagules), rooted under controlled atmospheric conditions and maintained for 6 months are used for planting. For this, the mist chambers and the clonal multiplication areas are established for production of clonal plants throughout the year.
Earlier CMAs were raised for obtaining the propagules and transferred to the tubets. Sand bed technology was developed to get the propagules from the Mist chamber site itself to get quick propagules from the apical shoots of clones planted in the sand beds.
Under traditional method, the site is cleared of miscellaneous growth and burnt. The planting points are marked by fixing the stakes at fixed espacement. The espacement followed earlier was 2 x 2m, 3x1.5 m, 3x2m, etc. This method was followed up to 1986. Thereafter, the site was uprooted manually and inter-ploughed the area after planting. This method was followed up to 1994.
From 1994 onwards, the Corporation has taken up large scale clonal Eucalyptus plantations under the scheme aided by the World Bank. As per the programme, the site is cleared of all the stumps through semi-mechanical uprootal using poclainers and tilling the soil to 45 cms depth. Thereafter, the site is leveled and ploughed the area with heavy duty tractors once before planting and once after planting.
Digging of CCTs, construction of RFDs is taken up as part of soil and moisture conservation measures to conserve all the moisture and prevent soil erosion. Digging of cattle proof trench, brushwood fencing is taken up wherever required.
Planting is taken up at a fixed espacement after fixing the stakes. The espacement followed was 3x3 m , 3x2m and 2.8x1.4 m. Presently, the Corporation switched over to 3x1.5 m. The plants are planted in 30 cms cube pits. The pits are pre-treated with anti termite chemical and super phosphate for better growth.
Before planting season commences, a detailed Planting Plan is prepared, with the objective of completing the planting work within the prescribed time, by making best use of men and materials. Care is taken to complete the entire planting by about 25th July in S-W monsoon areas and by about 30th November in N-E monsoon areas. Since there will be a break in monsoon after commencement of planting, a provision for watering is given for about 10% of population. For the purpose one water storage cistern is constructed in each 10 ha. of area.
After completion of planting, all the planting points are enumerated row-wise and are posted in Registers for further monitoring. After planting is completed in each of the sectors, the casualties are enumerated on day-to-day basis and are recorded planting point and planting row-wise in the Registers. After replacement, the dates of replacements are recorded. The casualties are replaced in (3) phases over a period of 15 to 20 days after planting. The replacements taken up in each of the phases are marked with different coloured stakes for effective management. It ensures 98 to 100% survival by the end of the monsoons.
Since the yields from the plantations mainly depend on the overall survivals adequate care is being taken in the raising year to have maximum survivals. The APFDC Board has also approved a scheme for awarding the staff who have successfully raised plantations under Categories of 95 to 97%, 97.01 to 99% and 99.01% and above.
During the raising year the following cultural operations are taken up.
The weeding-cum-soil working is taken up with the cessation of monsoons.
Misc growth removal:
This is taken up along with inter ploughing after establishment of plants.
One inter ploughing is taken up after establishment of the plants, before the cessation of rains.
Fire tracing is taken up during February to March to avoid fire damage to the tender plants.
Maintenance of the plantations:
Coppice cutting of misc species, weeding-cum-soil working, fire tracing were taken up as part of maintenance of plantations during the first year maintenance. During the subsequent years, only fire tracing was taken up.
1st & 2nd Year maintenance:
One inter ploughing, fertilizer application with Urea at 75/100 gms per plant is given for vigorous growth. Fire tracing and desilting of CCTs are taken up.
3rd Year to 6th Year Maintenance:
One inter ploughing in alternate rows and fire tracing are taken up.
First Cut: at the end of the 7th year
Second Cut: at the end of the 13th year
Third Cut: at the end of 19th year of raising.
Eucalyptus Coppice plantations maintenance:
After harvesting, the Eucalyptus stumps throw numerous coppice shoots and there will be lot of competition among the coppice shoots. To encourage better growth of the coppice shoots, singling of coppice shoots is taken up within 6 months of harvesting. Normally, 2 to 3 coppice shoots which are vigorously growing and are in opposite directions are allowed and the remaining less vigorous shoots are culled out.
The coppice plantations in the 2nd and 3rd rotations are maintained duly inter ploughing the areas on alternate rows and giving fire protection every year.
PESTS OR DISEASES:
The Eucalyptus clonal or seed origin plantations are highly susceptible to Pink disease caused by Corticium salmonicolor and gall insect caused by Leptocybe invasa.
The plantations were damaged completely due to pink disease and such plantations were harvested. E.camaldulensis was found to be highly susceptible to this. As such, this species was not planted subsequently.
The Eucalyptus clones such as clone No.10 is highly susceptible to the gall pest and planting was discontinued with this clone.
Clone No.7 is more resistant and the level of infestation was noticed to be minimal and this clone is being planted. New clones such as 413, 316, 411, 2306 are being tried which are found to be resistant to the gall pest.
Initially the propagules were treated with 2 ml per litre concentration of Rogar. Subsequently the propagules are treated with Acephate at 3 gms per litre. After the seedlings are brought into shade house and then into open nursery, they are sprayed with Rogar (2ml/6ml), Confidar (2ml) and Endopsulfan (2 ml) per litre concentration alternatively at (15) days interval. Later Metacystox at 2 ml per litre in the 1st application followed with Imdiacloprid at 1 ml per litre concentration at 15/20 days intervals are given.
It is observed that various prophylactic measures taken as above had no or very negligible effect on control of the pest. The Clone 10 is found to be most susceptible in the nursery followed with Clone 27. The infestation is found to be less in Clone 3 and least in Clone 7. In view of above future nursery activity is limited to ITC Clone 7 only. What is needed is identification of more pest resistant varieties and introduction of biological control methods
However, the gall pest disappears with the onset of next monsoons and the growth of the plants is found to be normal.
Statistics of growth:
The Corporation has harvested seed origin plantations and the produce varies from 10 to 25 MTs per hectare in the first cut and in the 2nd and 3rd cuts the yields were varying from 0 to 15 MTs per ha. The yields of the plantations varying due to low survival, fire damages and pest incidence like Pink disease.
The APFDC has raised very successful clonal plantations. Owing to high survivals, these plantations have yielded pulpwood in the range of 60 to 105 MTs per ha depending upon the rainfall pattern. In the high rainfall zone such as Paloncha, Maredumilli, the highest yields recorded are to the extent of 110 MTs per ha whereas in the low rainfall zone such as in Rangareddy and Medak districts, the yields are to the extent of 30 to 50MTs per Ha. The pulpwood is supplied to the buyer within 24 to 48 hours of harvesting with the moisture content intact.