Dissertation – Pruning

In coffee cultivation, the balance between vegetative growth and reproduction is vital for ensuring both the health of the plant and the quality of the coffee seeds. The relationship between these two processes is complex and, in many ways, not entirely understood. However, what is evident is that achieving the right balance is fundamental for long-term productivity and consistent, high-quality yields. One of the most effective ways to manage this balance is through pruning, a practice that plays a central role in coffee farming, particularly in large-scale plantations. Pruning is the selective removal of certain parts of a plant, such as branches or roots, to improve its health, growth, or productivity. It helps shape the plant, enhance fruit or flower production, and prevent disease by improving air circulation and removing dead or overbearing branches.



Stimulating New Growth for Future Yields

A crucial aspect of coffee growing is that flower buds are only initiated on the same wood once. This means that the amount of vegetative growth produced in one season directly impacts the crop yield in the following season. Without sufficient new growth, the tree will have fewer sites for flower bud initiation, resulting in reduced yields. Pruning stimulates the production of new, healthy branches—often referred to as “new fruiting wood”—that will be the site of flower and fruit development in the future.


Beyond simply encouraging new growth, pruning also plays a key role in regulating the plant's fruit load. Without intervention, coffee plants can overbear, producing more fruit than their nutrient reserves can support. This not only leads to smaller and lower-quality seeds but can also cause the plant to suffer from resource depletion, ultimately resulting in overbearing dieback. By managing the number of fruit-bearing branches through pruning, farmers can reduce the risk of overbearing, allowing the plant to focus its energy on producing fewer but higher-quality fruits and avoid biennial bearing.



Maintaining Plant Health and Preventing Biennial Bearing

One of the challenges many coffee farmers face is biannual bearing, where the plant produces a heavy crop one year followed by a light crop the next. This fluctuation is largely due to the depletion of the plant’s energy reserves during heavy fruiting years, leaving insufficient resources for the following seasons flower buds. Pruning helps to mitigate this by ensuring a more consistent balance between vegetative growth and fruit production, reducing the extreme variations in yield from year to year.


In addition to stabilizing yield patterns, pruning also contributes to the overall health of the plant. By improving airflow and sunlight penetration within the canopy, pruning reduces the risk of fungal infections and other diseases that can compromise the quality of the seeds. The enhanced light exposure also promotes photosynthesis efficiency throughout the trees, which is crucial for the plant’s ability to produce carbohydrates—resources that are vital for both vegetative and reproductive growth. This will directly influence both yields and quality positively.



Prolonging Productive Life and Optimizing Yield Quality

Pruning also plays a crucial role in maintaining the balance between the shoot and root systems of the coffee plant. When too much fruit is produced, the plant may divert resources away from root development, weakening the overall structure and reducing its ability to absorb water and nutrients. Regular pruning helps to prevent this by reducing the strain on the plant and ensuring that the root system remains strong and capable of supporting future growth.


Moreover, pruning is essential for rejuvenating older coffee plants. As trees age, their productivity naturally declines, and they produce fewer high-quality cherries. By removing older, unproductive branches, pruning encourages the growth of new wood, which is more productive and capable of producing higher yields. This practice can effectively extend the productive life of a coffee tree, ensuring that it remains a viable part of the plantation for many years.


In terms of yield quality, pruning allows farmers to control the size and number of cherries produced, ensuring that the tree focuses its energy on producing fewer but better-quality fruits. This is of great importance to obtain a high and consistent quality every year.


Additionally, coffee seed quality is typically higher in younger trees and on younger wood, particularly during their peak productive years, because they are healthier, more vigorous, and better equipped to allocate resources to fruit production. Younger trees and wood tend to produce larger, denser, and more flavorful seeds, with fewer defects and more consistent ripening. As trees age, their seed quality tends to decline due to reduced productivity, susceptibility to disease, and less efficient nutrient uptake. However, rejuvenation practices like pruning can help older trees regain some of their seed quality. In general, coffee seeds from pruned trees are therefore expected to be of higher quality compared to those from unpruned trees. Pruning enhances the size, density, flavor, and consistency of the seeds by optimizing resource allocation, having younger more vital wood, and promoting healthier plant growth. Unpruned trees, while potentially yielding more fruit, tend to produce seeds that are smaller, less uniform, and less flavorful, with a higher risk of defects. For farmers aiming to produce high-quality, specialty-grade coffee, regular and careful pruning is a key practice to ensure premium seed quality.



Types of Pruning & The Poma Pruning System®

There are several schools and types of pruning system. First, you need to apply a pruning system that makes sense for your production system. Distance between trees and rows, varieties- and rootstock choice will all have an impact on how you need to shape your trees. Varieties have different growing patterns and rootstocks alter branching dimension and hence the plant architecture. Denser orchards need to be pruned more intensively and vice versa. There is no one-fits-all. Therefore, decisions around pruning should be made based on experience and design of the individual plantation. Some general techniques are widely used and accepted:

• Stumping / Recepa / Low Pruning – Rejuvenating older coffee trees by cutting the main stems 30-50cm from the soil to encourage new vigorous growth. Basically, renewing the full tree but resulting in one year of lost production before new wood has grown. Good for quality as a lot of young wood will be initiated but poor for yields (see Table 1).
  
  

• Rock’N’Roll / High Pruning – cutting the top to stimulate lateral growth in the lower parts of the trees. Good for production since the full tree will be utilized better but poor for opening the canopy and hence quality (see Table 1).
  
  

• Skeletonising – Removing all side branches leaving only the main stem behind to force new lateral growth. Same as for stumping, it results in one year of lost production before new wood has grown. This is a less common practice than the others.

While all of these have each their benefit, and do their work in the intended way, they all have flaws – either skipping a year, or even two, of production with stumping and skeletonizing, or making the trees quite dense via Rock’N’Roll pruning. For this reason, we created a system that encourages constant rejuvenation, an open canopy, and no hiatus in production. The Poma Pruning System®.


The Poma Pruning System® is designed for high-intensity slender plantations, aiming to balance yield and quality. The system manipulates trees by pruning every fruiting branch at a specific length, based on tree density in the plantation. This approach allows full control of the fruit load on each branch while promoting the transport in the tissue of nutrients, sugars, and water. It also stimulates the growth of smaller side shoots, which will flower the following year. Additionally, a set number of branches (excessive-, overbearing- and poor branches) per tree are removed to open up the canopy, enhancing light and airflow. This method ensures uniform trees, making harvesting and spraying more efficient, and it doesn't require skilled labor since every branch is pruned the same way. Over time, as trees adapt to the system, pruning becomes quicker and more cost-effective. In flatter areas, mechanical pruning devices can be used to further streamline the process. For a demonstration of this pruning system, please contact rama@pomacoffee.com.

Table 1. This table shows the relationship between different pruning methods and the response in shoot growth, fruit yield, fruit-, seed- and beverage quality.

When to Prune

The best time to prune is during the dry season, right after the harvest. This allows the pruning wounds to heal properly in dry weather, reducing the risk of infection, while minimizing stress on the trees since fewer reproductive organs are active at that time. It also helps remove excess fruiting before flowering, ensuring that the tree can focus its energy on vegetative growth and strengthening the remaining flowers for optimal development and good quality fruit.



Challenges

Narrow rows and dense trees make pruning difficult primarily due to limited access and maneuverability. In narrow rows, it’s hard for workers or machinery to move around, making it challenging to reach all parts of the tree. Dense trees can create overcrowded branches, which complicates identifying which parts to prune and increases the risk of cutting healthy or necessary growth. Additionally, when trees or plants have been neglected for too long, excessive growth can make pruning much more labor-intensive and less effective.


Lack of skilled labour and expertise in identifying what should be pruned can result in removing the wrong branches, leading to poor productivity or plant health. Applying incorrect or inconsistent methods can lead to uneven growth or damage to the plant, which is why staff training and demonstration is vital for a good result.



Conclusion

In coffee cultivation, pruning is essential for maintaining the balance between vegetative growth and reproduction, which is crucial for long-term productivity and seed quality. Effective pruning stimulates new growth, controls fruit load, and reduces the risk of overbearing, which can harm plant health and lead to biennial bearing. It also enhances airflow and light penetration, helping prevent disease and improve photosynthesis efficiency. By adopting systems like the Poma Pruning System®, farmers can manage tree structure and fruit production more effectively, improving consistency in yield and quality while optimizing the use of labor and resources. Proper timing, correct techniques, and well-designed plantation layouts are key to successful pruning, ensuring the coffee trees remain productive and healthy for years to come.