Casuarina

High-yielding varieties and improved silvicultural practices for Casuarina

Casuarina is an important multipurpose short rotation tree widely cultivated in Peninsular India. The main uses of casuarina are pulpwood, poles and fuel wood. It fixes atmospheric nitrogen into the soil in association with the bacteria Frankia. This ability enables casuarina to grow well even in nutrient poor sites. It also tolerates salt-laden winds in the coast and hence widely preferred for establishing shelterbelts and stabilizing sand dunes. Casuarina also functions as an efficient windbreak species not only protecting agricultural crops but also improving microclimate for enhancing yield from the crops.

Casuarina is cultivated by a large number of farmers mainly in the States of Andhra Pradesh and Tamil Nadu. They normally plant around 4000 trees per acre and harvest at the age of 4 to 6 years. These plantations yield on average 40 tonnes of wood per acre. The major end user of casuarina wood is paper industries followed by the market for poles.

The Institute of Forest Genetics and Tree Breeding (IFGTB) has developed genetically improved varieties and improved silvicultural practices of casuarina. The new high-yielding varieties and silviculture techniques help the tree growers to increase productivity of casuarina plantations significantly.

Genetically Improved Varieties of Casuarina

In India, Casuarina equisetifolia is the widely cultivated species for over a century. IFGTB introduced a new species called C. junghuhniana in 1996 through systematic field testing. A long-term breeding programme has been undertaken for both the species and new varieties possessing desirable characteristics like wide adaptability, fast growth, good stem form and wood properties were developed. The salient features of the new varieties are provided in Table 1.

Table 1. Salient features of high-yielding varieties of casuarina developed by IFGTB.

Species	Variety	Salient Features	Productivity (tonnes per acre per year)	Pulpwood Production in 4 years (tonnes per acre)
Casuarina equisetifolia (CE)	Seed Orchard seeds	Low tree to tree growth variation; faster growth than unimproved seeds; suitable for coastal areas; straight stems for use as poles.	12	48
Casuarina junghuhniana (CJ)	Seed Orchard seeds	Low tree to tree growth variation; faster growth than CE seeds. suitable for inland areas; highly drought-tolerant; suitable for rainfed cultivation.	14	56
	Clone CJ9	Suitable for inland areas; faster growth than CJ seeds; straight stems for use as poles; highly drought-tolerant; suitable for rainfed cultivation.	16	64
Casuarina hybrids (CH)	Clone CH1, Clone CH2, Clone CH5	Suitable for both coastal and inland areas (except clay soils and waterlogged sites); faster growth than all other varieties; straight stems for use as poles; drought-tolerant can be grown under rained conditions from the second year.	18	70

It is necessary to choose the most appropriate variety suitable for the planting location and desired duration of cultivation and end use for obtaining maximum productivity. Seeds / plants of the above-mentioned varieties can be obtained from IFGTB or from the paper industries and private nurseries who have taken license from IFGTB for supplying these varieties. The contact details of nurseries that supply the varieties are given in Table 2.

Table 2. Name of contact details of sources that supply high-yielding varieties of casuarina.

S. No	Name of the Organization	Address	Contact Number
1	Institute of Forest Genetics and Tree Breeding	Forest Campus, R.S. Puram, Coimbatore 641002, Tamil Nadu	Seed: 0422-2484 Clones: 9488450674
2	Andhra Paper Limited	Rajahmundry – 533105 East Godavari Dist. Andhra Pradesh	8498094339
3	Tamil Nadu Newsprint and Papers Limited	Kagithapuram 639 136 Karur District, Tamil Nadu	9442591419
4	Seshsayee Paper and Boards Limited	Pallipalayam, Namakkal District, Erode 638 007, Tamil Nadu	9443214628
5	Dr. S. Makesh	Mithravayal village , Karaikudi Taluk, Sivaganga District, Tamil Nadu, PIN 630 108	9943901055
6	Santhi Clonal Nursery	P. Sakthivel, Kullanchavadi Main Road, Vegakollai Post, Panruti Taluk, Cuddalore District, Tamil Nadu	9159705868
7	Sangeetha Hitech Nursery	S. Senthilkumar Chinna Pattanur village Vanur Taluk, Villupuram District, Tamil Nadu, PIN 605 11	9843500990

Image: A 28-month old plantation of high-yielding clone CJ9

Improved Silvicultural Practices

It is essential to adopt the most suitable silvicultural practices for realizing the full potential of the high-yielding varieties. Farmers often practice the same methods adopted for the low productive material even when using new fast growing varieties. This results in non-realization of expected wood production from the new varieties and also causes other problems.

1. Land preparation and pitting: The land should disc ploughed twice and planting done in pits of 30x30x30 cm. In particular the clones have to be planted in pits for proper root development and to prevent lodging of saplings.

Image: Faster growth of clone CH-5 (center) compared to other clones at three years age

2. Spacing between trees: The spacing to be adopted for different types of planting material and duration of cultivation is provided in Table 3. Clonal plantations should be planted with wider spacing compared to seedling plantations. The optimal stocking of clonal plantations is 2100 to 2400 trees per acre for a rotation period of three to four years. A higher stocking of trees, particularly in areas with clay soils and waterlogging, diseases and lodging of trees will occur. Table 3. Spacing to be adopted for different types of planting material and rotation period and the estimated yield.

Variety	Spacing (ft)	No. of trees per acre	Pulpwood Yield (tonnes per acre)
Unimproved Seed	3 x 3	4000	30 - 40
Seed Orchards Seed	4 x 4	2700	40 - 50
Clone (up to 3 years)	6 x 3	2400	50 - 70
Clone (more than 3 years)	6 x 3.5	2100	70 - 80

3. Weeding: Saplings of the high-yielding varieties put up fast growth once they are established and it is essential to keep the plantation free from weeds to obtain maximum early growth. It is recommended to carry out mechanical weeding two to three times during the first six months after planting. The canopies of trees close between six months to one year after which no weeding is necessary.

4. Irrigation: Providing irrigation facilitates fast growth and maintaining the original stocking of the trees in the plantation. However keeping the field always wet may cause disease infection and lodging of trees especially in clay soils. It is recommended to adopt drying-wetting-drying approach of irrigation. Most of the new varieties possess high level of drought tolerance and were found to grow well with irrigation give once in a month.

5. Pruning of side branches: Removing side branches helps in maximum diameter growth and also increases the pole quality of the trees. Pruning may be taken up at 12 months and between 18-24 months during dry season to prevent disease infection.

6. Fertilizer application: The composition and amount of fertilizer to be applied to casuarina plantations should be decided for a given site after conducting soil tests. A basal doze of 10 g of super phosphate per pit is recommended for early establishment and root nodule development. A general recommendation for post-planting fertilizer application is provided in Table 4. Applying the fertilizers in holes made in between trees helps in effective absorption by the trees. The response of trees to fertilizer reduces after 24 months due to competition among trees for space and light.

Table 4. General recommendation for fertilizer application. Quantity mentioned in kg per acre

Fertilizer	3 months	6 months	12 months	18 months	24 months	Total
Urea	7	10	12	14	0	43
Super Phosphate	12	12	12	12	12	60
Muriate of Potash	7	10	14	14	14	59
Total	26	32	38	40	26	162

7.Controlling insect and disease attack: Casuarina is attacked by the bark-eating caterpillar which digs up deep tunnels in the main stem making the stems weak and prone to breaking during heavy wind. It can be controlled by spraying of Monocrotophos (1.25 ml/litre) at 0.5% over the feeding area or by injecting 0.5% (1 ml/litre) Dichlorvose into the bore holes and sealing with mud. Biological control by application of Beauvaria bassianais an eco-friendly option and commercial formulations are available in the market.

Image: Attack of bark-eating caterpillar in casuarina

Image: Attack of collar rot disease in casuarina

In clayey soils, trees may die due to of root / collar rot caused by fungal pathogen. The affected trees show yellowing of leaves followed by drying up of the entire tree. The disease can be managed through an integrated approach involving measures such as sanitation, cultural practices and use of fungicides. Keeping wider spacing between rows of trees (e.g. 6 x 3 feet) ensures adequate sunlight and air flow in the plantation apart from facilitating adequate root development for anchorage. Application of biocontrol agents like Trichoderma viride and Pseuodomonas fluorescence in the pits while planting prevents infection. Irrigation should be provided only when necessary by following wetting and drying method. Weeding and pruning should be taken up periodically. The disease incidence can be controlled by application of fungicidal solution (SAFF-2 @2 % or FOLICURE @ 1 %.) as soil drenching.

8. Harvest and marketing: Harvesting should be carried out when the rotation period is completed since growth increment reduces thereafter. Paper industries are the major end users of casuarina wood and most of them buy directly from the farmer. Their contact details may be obtained from the website of the respective industries or from the authorised nurseries from where the planting stock was procured. Casuarina wood can also be sold to local traders for poles and other uses.