1. Introduction

1.1 Description

Large deciduous tree up to 30 m high and 100 cm or more in diameter at breast height. Long straight cylindrical bole up to 2/3 of the height of the tree. the bole is often buttressed and may be fluted, Spherical crown.  Deep tap root system.  Bark pale brown, grey, striate, fibrous, peeling off in thin strips.  Branch lets are quadrangular and channelled. Fruit is a drupe with 4 chambers and may contain 0-4 seeds. Inflorescence:-large dichotomously branched terminal cymose panicle. T. grandis Teak is 96-100% self-incompatible. The species is hermaphroditic and pollinated by insects such as black ants, horse flies, and particularly by bees.

1.2 Varieties of Teakwood  

Below are some of the typical varieties of Teak wood cultivation in India.

1) Nilambur (Malabar) teak 2) South and Central American teak 3) West African teak 4) Adilabad teak 5) Godavari teak 6)Konni teak.

1.3 Distribution

Teak occurs naturally occur between 10⁰N and 25⁰N on the Indian subcontinent, especially in portions of India, Burma, Laos, Indonesia(mainly Java) and Thailand also Introduced in many countries of Asia and Africa. In India, it is naturally distributed in the peninsular region, but has also been planted in non-traditional areas in northern and northeastern states.

1.4 Uses 

It has been extensively used for decking, deckhouses, rails, bulwarks, hatches, weather doors planking, furniture, boat building, and construction and boat building.

2. The factor making Teak a favourable choice for Agroforestry

• Deciduous species remain leafless for a considerable period during a year.
• Fast-growing species in the early years
• Easy to manage
• Fire tolerant
• High timber value
• Can be raised with most of the arable crops-wheat, paddy, sugarcane, soybean, mustard, groundnut, vegetables, medicinal plants etc.
• Kharif crops in rainfed areas and rabi crops in irrigated areas can be easily raised with teak during the initial 3-4 years without any drastic reduction in crop yields.
• Teak based agroforestry systems are highly economic. A study carried out by Mutanal et al., 2002 at Karnataka Teak is intercropped with Sorghum, Groundnut, Sorghum + Grass, Sorghum + Subabul, Groundnut + Grass, Groundnut + Subabul and found that B: C ratio is maximum for Sorghum + Teak (2.96) followed by Sorghum + Teak + Grass(2.96) and Groundnut + Teak (2.32) as compared to the sole crop (1.90 for sorghum; 0.96 for Groundnut).

3. Teak Agroforestry System

• Agri-silvicultural models (Teak + casuarinas with agricultural crops maize, cotton, turmeric, tomato and chilly),
• Agri-Silvi-horticulture model (Teak + coconut with agricultural crops plantain, turmeric, vegetables, maize and cotton)
• Silvihorticulture model (Teak-Gauva, Annona)
• Under irrigated lands, the silvopasture model was developed with Teak and Casuarina as tree components and Napier and Guinea as pasture components.

4. Site factors

• Climate: Teak prefers a moist, warm tropical climate. It can withstand extremes of temperature, but maximum and minimum shade temperatures of 39 – 44 ⁰C and 13- 17 ⁰C respectively are the most favourable for its growth. It grows well in rainfall zone of 1200-2500 mm and altitude range of 600 m to 1200 m MSL.
• Soil: Their most suitable soil is deep, well-drained, fertile alluvial-colluvial soil with a pH of 6.5-8 and a relatively high calcium and phosphorous content. Teak does not tolerate waterlogging or infertile lateritic soils.

5. Propagation techniques

It is one of the easiest species to propagate through almost all the common methods viz. direct sowing, entire transplanting, stump planting and vegetative propagation.

5.1 Regeneration through Seed

Seed collection and storage

• Viable seeds were obtained from the age of 5-6years.
• Seeds should be collected underneath the trees during January-March.
• Seeds cleaned and dried are collected in gunny bags and stored in dry areas.

Pre-sowing treatment                      
· Seed germination in the untreated seeds is totally absent or very in-significant
· Following treatments require to break the dormancy of the seed

Alternate wetting and drying

Freshly collected seeds are put in gunny bags which are then submerged under flowing water for four days. The gunny bags are taken out and spread over in the strong sun for four days. It is again submerged in water for 3-4 days following drying. It is repeated for 3-4 times until the endocarp and mesocarp gets easily cracked.

• Pit method
  Seeds are put in alternate layers of seeds and straw and daily watered for seven
  days then dried and stored till the time of sowing
• Soaking in water
  Immersion of seeds in water for a number of days has hastened germination
• Biological method

         Burying the seeds for one year near the anthill is reported to give better results.

Chemical treatment

• Soaking the seed in concentrated H2SO4 for 20 minutes and thorough washing
  in running water hasten germination
• Scorching
  Scorching the seeds in light running fire of leaves of grass or alternatively
  seed picked from the plantation after a light ground leaf-fire is a useful method
• Cow-dung
  Soaking the seeds in the mixture of cow dung and water enhance germination.

Nursery technique    
· Nursery beds are prepared one year in advance of planting         
· Beds of 12 m × 1.2 m size are prepared     
· In moist localities raised beds are prepared while in dry localities sunken beds are helpful for germination.          
· Seeds are sown in the nursery bed from February-June.    
· 2.5-3 Kg seeds are required per bed.          
· About 1200-1500 seedlings are expected

5.2 Preparation of stumps  

Stumps with 1cm to 2cm diameter at collar level with about 25cm root portion and 2.5cm stem portion are most suitable. 

6. Plantation technique

• Direct sowing
  · It is practised very limited scale due to heavy causality.    
• Entire transplanting
  · Dona plants are preferred in place of trees in place of pre-sprouted or normal teak stumps.
  · The soil in Dona retains moisture for a comparatively longer period and keep the plant alive.
  · Dona plants are 4-6 months old at the time of planting or casualty replacement in JulyAugust
• Stump planting         
  · This is the most useful and economical method for teak plantation.         
  · Stumps are plated in crowbar holes and generally buried up to the collar.           
  · In Odisha and the drier part of Tamil Nadu stumps are buried up to the tip.   
  · In Madhya Pradesh in hard soil stumps are planted in 15cm diameter hole and about 30cm deep.
  · While planting the stumps the collar is flushed with ground level.  
• Pre-sprouted teak stumps   
  · In very dry locality pre-sprouted stump planting give satisfactory results 
  · The stumps are planted 4-6 months in advance and put in a container raised on a
  platform in shade and watered daily  
  · These stumps after sprouting are planted at the onset of monsoon.                       
  · The planting of sprouts is done with the ball of Earth intact in cylindrical holes. 

7. Vegetative propagation                  

• Teak can be propagated by grafting, layering and rooting branch cutting.
• Among the grafting method used bud grafting is preferred as it is easy, economical
  and more suitable for grafting on stumps.
• Grafting success depends upon the age of the mother plant, time of grafting and method used.

8. Management

Irritation: – irrigation during the stress period boosts the growth of the plants.

Weed Control: - Teak is a light-demanding species and its growth and development is reduced sharply under poor light conditions. Hence, intensive weeding is very necessary during the early establishment of the plantation, i.e. 1-3 years. Carry out weeding operations on regular basis. Weeding may be carried out at 3 operations in the first year, 2 operations in the second year and one operation in the third year.

Thinning Operations: – The first thinning is conducted in Teak wood farming at 5-10 years after planting of teak, depending on-site quality and the size of initial spacing. Generally, under good site and close spacing (1.8×1.8 m and 2×2 m), the first and second thinning (mechanical thinning) are conducted at 5 and 10 years respectively. About 25% of the trees are left for further growth and development after the second thinning.

Insect pest and diseases:- Teak defoliator (Hyblaea puera) and leaf skeletonizer (Eutectona machaeralis) are considered to be the major pests in teak and occur on seedlings in nurseries and also in grown up trees in plantations. H. puera feeds on tender foliage’s during the early part of the growth season and E. machaeralis feeds on older foliage towards the end of the season and can be controlled by spraying of the foliage with the chemicals like monocrotophos or endosulfan 0.05-0.075% or neem-based formulations (Neem azal 1%) at 10-12 days intervals. A virus (NPV) based formulation (biocide) is also available for management of the defoliator H. puera.

Root rot due to Polyporous zonalis is also common in teak plantation. Pink disease fungus causes cankers and bark flaking. Powdery mildew caused by Olivea tectonae & Uncinula tectonae leads to premature defoliation.