Cocoa: Pruning

The growth of the cocoa tree has a distinct pattern and differs at different ages. This is illustrated diagrammatically in Fig. 3.

1-4, Stages of the growth of cacao, Theobroma cacao L., Storculiaceae, from Tropical America. -1, Seedling of cacao (copied from Dyant-Najad, 1968). -2, Seedling before the first branching, note the rhythmic branching. 3-, Formation of the first plaglotropic stages. 4-, Adult Cacao. 5-, Base of plaglotropic axes, and the mechanism of the relay in the growth in height, note the parenchymatous dome that terminates the caulomare of the trunk. 6-, Plan of a tier 3 m in diameter, note the articulated structure, the rhythmic growth, and the axillary position of the flowers.

After germination, the seedling grows in height with regular flushes of growth until about 1m to 2m high when upright growth is stopped.

4 to 5 lateral branches (fan branches) are then formed at the jorquette. After a phase of growth, the elongation of growth of the trunk recommences when a new chupon grows out of lateral bud below the jorquette. This new growth is usually vigorous, traverses the whorl of branches and gives rise to a new tier of branches 1m to 2m higher than the first tier or even higher if light is limiting.

If uncontrolled, the above pattern of upright growth can continue for 5 to 6 tiers growing to nearly 10 m high. To make the bushes easier to manage and also to improve yields, it is necessary to control the growth of cocoa by pruning it.

The subject on pruning has been discussed by many authors (Hardy, 1960; Cook, 1966; Chan, 1980 and Jelani et al. 1984)

Pruning requirements differ according to the age and stage of development of the trees and may be briefly described as initial pruning when the trees are establishing, shape pruning to develop a strong well-balanced framework of branches, maintenance pruning to be carried out to maintain a balance between vegetative vigour and fruit production and rejuvenation pruning when vigour and yield of the bushes drop as a result of disease or pest damage.

At all times, pruning should be for a definite purpose as it may be expected that excess removal of foliage will seriously delay growth in young trees and reduce yields in mature cocoa.

The major objectives of pruning are:-

  • Height control
  • To produce strong/well-balanced framework of branches
  • To maintain balance between vegetative vigour/fruit production
  • To rejuvenate disease/pest damage bushes
  • To promote aeration
  • To facilitate access

The above objectives could be achieved through various types of pruning tailored to specific need. The main types of pruning carried out in Malaysia are:-

  • Height control pruning
  • Number of fan branches pruning
  • Water shoots pruning
  • Periphery pruning
  • Within canopy pruning
  • Pest/disease pruning
  • Rehabilitation/rejuvenation pruning

For practical reasons, it is necessary to restrict the growth of the cocoa bushes to a manageable height. In Malaysia, the standard practice is to restrict the growth of cocoa to one storey only. However, if the first storey is too low as to hinder field operations, a second storey is allowed to grow. The storey is removed eventually when the second storey is fully developed. Strong dominant branches that grow vertically upward on the fan branches are also removed to restrict height increment (height control pruning).

Some planters prefer to restrict the main fan branches arising from the jorquette to four only. Usually, there are 4-5 main fan branches when the cocoa branches at a jorquette and it is really not necessary to control the number of main fan branches unless they are not balance (number of fan branches pruning).

To cut down unnecessary growths and improve the usage of assimilates, all water shoots arising from the main trunk should be pruned regularly (monthly). It is important that water shoots are pruned at an early stage of growth. They should be pruned as close to the main trunk as possible. Unless they are pruned flush with the trunk, there is a tendency for numerous water shoots to grow from the base of the improperly pruned water shoots pruning could damage flower cushions and reduce fruiting (water shoots pruning).

Once the cocoa bushes are fairly well developed with self-shading canopy, all the low hanging/droopy branches within 1.00 m to 1.25 m from the ground should be pruned to facilitate access and to encourage more upright growths (perihphery pruning).

Finally, the within canopy/shape pruning is carried out produce an ideal bush growth form having the following characteristics:-

  • Strong/well-balanced framework of branches
  • Minimal unproductive branches i.e. slender/droopy branches with foliage receiving little/no direct sunlight and badly diseased/moribund branches.
  • Foliage concentrating mainly close to canopy surface
  • Well aerated canopy
  • Minimal obstruction to access/harvesting

Once a desired growth form and canopy is achieved, maintenance pruning should be carried out regularly to maintain a balance between vegetative vigour and fruit production.

Sometimes it is necessary to rehabilitate/rejuvenate a mechanically damaged (eg. falling timber when the shade trees are poisoned) or disease damage bushes (eg. advance stage of VSD infection).

In such cases, a basal chupon near the collar region may be allowed to develop into a full bush to replace the damaged/diseased bushes. Budding of such bushes with high yielding clones have also been tried with satisfactory results.

For best results, pruning should be properly timed. The unwanted branches and water shoots should be pruned in their early stage of growths.

For shaping and maintenance pruning, pruning should be carried out before the main flushing and flowering seasons.

It is advisable to practice monthly or even more frequent water shoots pruning when required. The other types of pruning may be carried out at quarterly intervals.

Always maintain a continuous canopy. Never overprune or expose the jorquette.

Pruning to control VSD is a much debated and controversial subject in Malaysia and will be dealt with under pest and disease.

Ooi L.H. and Chew P.S. 1985. Some important agronomic and agricultural practices in cocoa  estates. TDMB Plantation Management Seminar, Kuala Trengganu

Note: The full list of references quoted in this article is available from the above paper.