The majority of Arabica coffee farms in Uganda are well over 50 years old and are producing coffee below their potential. Poor agricultural practices can lead to the deterioration of coffee trees to the point where they require total stumping to enable the rehabilitated tree to rejuvenate itself.
It is important that rehabilitation be accompanied by good agricultural practices to prevent the same decline from happening on the selected shoots again. Old coffee trees, if totally ignored, would continue to produce less and less coffee up to a point when they can no longer be rehabilitated to produce profitable yields.
At this point, they can only be replanted through a plantation renovation programme. In such a case, young high-yielding seedlings are planted to replace the old unproductive coffee trees.
Rehabilitation, therefore, refers to pruning or stumping of coffee trees to rejuvenate and improve their productivity by bringing them back to their youthful, productive cycle.
This involves cutting down very old and unproductive stems to enable new shoots to grow in order to renew their production cycle. It is, therefore, an extremely important activity for maintaining a good income stream from coffee.
On the other hand, renovation refers to the complete uprooting of old unproductive trees and replanting the field afresh with new and high-yielding coffee seedlings. Therefore, renovation implies the replacement of old coffee trees with new, young, high-yielding and/or disease-tolerant varieties.
Renovation with new disease-resistant and climate-tolerant varieties can help farms adapt to the changing climate. Apart from when poor agricultural practices are used, rehabilitation and renovation of coffee trees can be mitigating approaches in cases of sporadic attacks by pests and diseases. Renovation may be done in situations where:
i. Pests or diseases have irreversibly affected coffee trees and renovation is the only option.
ii. Superior coffee varieties are availed, and yields and resultant incomes associated with such new varieties warrant the renovation investment and compensate for the associated implementation risk.
iii. Climate forecast models suggest that there will be significant change to the suitability of already existing varieties, even when good agricultural practices are applied.
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Productivity Decline in Arabica Coffee and Need for Rehabilitation
Trees produce fewer and smaller coffee berries due to old age, and in such cases, it is not economical to rehabilitate them, making fresh replanting of the coffee field a better option.
Rationale for Rehabilitating Old Arabica Coffee Trees
Coffee rehabilitation could benefit many smallholder Arabica coffee farms in Uganda, as most of them have trees that have already surpassed the 40–50-year age bracket and are grossly unproductive.
The underlying need for rehabilitation should start with understanding some agronomic fundamentals, including soil analysis, root and stem analysis, and the variety that is already planted and how well it is intrinsically suited to future needs (e.g. climate change).
It is also important to note that the need for rehabilitation may be pre-determined by several other factors, which may include:
1. Age of trees: Trees which are younger (less than 40 years) typically do not need to be replanted but rehabilitated through stumping.
2. Disease: Where the stems of coffee trees are badly damaged or affected by diseases or pests.
3. Poor agricultural practices: Such as abandoning coffee under weedy conditions or poor fertility management, leading to poor quality trees that must be rejuvenated by stumping.
4. Climate change: With increasing levels of extreme droughts which require reduction in the number of stems per coffee bush to save the trees from complete drying, or replanting the entire field with drought-tolerant coffee varieties.
Once the underlying needs are analysed, the next step is to decide which option delivers the best results. There may be scenarios where a mix of renovation and rehabilitation is the best way forward, especially where some parts of the garden may be completely damaged and require renovation, while another part requires rehabilitation.
Coffee Stumping Practices for Rejuvenation
Stumping coffee is a practice of selecting and cutting down elderly and unproductive stems existing on a coffee bush. It is done to rejuvenate the stem cycle by enabling the entire tree stump to develop young, vigorous shoots which make the coffee tree produce more cherries once again.
When the coffee tree has reached 10 years old from initial planting, its bearing heads are less than one metre, produce less than 2kg of fresh cherries per tree, and its stems become too tall for coffee pickers, the coffee bush is due for stumping or “change of cycle.” After initial stumping, the subsequent production cycles should be renewed (converted) every 7 years.
Current Arabica coffee varieties can sustain good yields up to 40–50 years, during which productivity is maintained by renewing cropping cycles through stumping.
Stumping involves pruning off or cutting back all the unproductive stems from the coffee bush, leaving only one vigorous stem (the breather) to assist the stumped tree to remain alive and feed the developing suckers until they are mature enough to be on their own, as seen in Figure 26.
A. Purpose of Coffee Stumping
1. Remove unproductive coffee stems and branches: to redirect energy and nutrients.
2. Guide nutrient flow: towards flowers and fruit-bearing branches for better productivity.
3. Stop non-fruit bearing branch development: that wastes water, energy, nutrients, and inputs.
4. Remove pest- and disease-infected branches: to limit disease spread.
5. Lower flowering heads: for easier harvesting and better productivity.
6. Improve nutrient transport: to ensure efficiency and reduce the need for extra fertilizer.
7. Open canopy for sunlight: to enhance photosynthesis and increase yields.
8. Improve aeration: to control pests and diseases effectively.
9. Facilitate coffee harvesting: by reducing plant height and opening canopy.
10. Enhance other farm management activities: through better access and organisation.
11. Improve drought survival: by renewing the tree structure for resilience.
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Procedure for Coffee Stumping and Cycle Conversion
It is advisable to stump the entire garden if it is due. However, the garden may be divided into parts and stumped at different periods to enable continuous income from the coffee farm.
The stems should be cut at a height of 6 inches (0.5 ft) from the ground, at a 45° slanting slope to allow water to run off and prevent stump rotting (Figure 27). The cut should be smooth to prevent mould and disease attack.
Cut down other stems and retain one single stem breather. The retained stem continues feeding the stump until dormant buds open into grown shoots (suckers).
The selected breather should preferably be the most outward-bending stem, ideally facing the sunset, and not located in the centre of the stump to facilitate easy removal later without damaging the new suckers.
Always disinfect pruning tools using 90% ethanol, 25% diluted Jik, or genuine methylated spirit before starting the stumping process, after each tree, and at the end of the day’s pruning to prevent the spread of disease pathogens.
Used tools may also be passed over hot burning charcoal for disinfection. Tools like pruning saws and secateurs should be oiled regularly to prevent rusting due to sap and disinfectants.
Select and leave well-positioned suckers that will facilitate healthy regrowth and maintain good tree structure. When suckers are about 20 cm (8 inches) tall, select the 3 or 4 healthiest stems and groom them for the next cropping cycle. Suckers growing at the top of the stump should be removed, as they are weakly supported and prone to breaking under heavy crop loads.
Cycle Conversion Timelines in Arabica Coffee Fields
In a well-managed Arabica coffee production system, stumping (also known as “change of cycle” or “cycle conversion”) should initially be carried out at 9 or 10 years after planting. Thereafter, it should occur every 6–7 years to bring the coffee bush back to a fresh productive stage. The vigour and appearance of the trees at these intervals is also influenced by soil fertility and intensity of farm management practices.
Approaches and Types of Coffee Stumping
A. Stumping Approaches
1. Phased Stumping: The farm is divided into parts, and stumping is done over 2–4 years. This approach spreads labour costs and maintains some level of production and income.
2. Non-Phased Stumping: The entire garden is stumped at once. This provides a uniform stand and results in a stronger cash flow when suckers mature, but the field will be out of production for a year. Intercropping with legumes can provide interim income.
3. Staggered Stumping: Only a few bushes are stumped each season. This spreads costs and income, but over-shading from unstumped trees affects sucker quality and complicates fertilization planning.
B. Types of Coffee Stumping
Multiple Breather Stumping: Only one of several stems is cut each year. This leads to stems of different ages on the same tree, which results in poor sucker growth due to shading, thin stems that break easily, and difficulties in planning fertilizer use.
Here is the updated article with every hyphen (“-“) used in list explanations replaced with a colon (“:”). The rest of the structure and grammar remain unchanged:
Full/Complete Stumping
This is where all the stems on each coffee tree are cut back without leaving a breather.
With this type of stumping, the entire stems are removed in one instance or at once. Again the stem should be cut at an angle of 45°: for the reasons mentioned in the previous section. The cut should be made around 15cm/0.5ft above the ground level.
The advantage of this system over others is that the developing suckers are fully exposed to sunlight and vegetative growth is intact on the stems: resulting in highly productive future stems.
The disadvantage is that the field will be out of production for one year: hence no revenue from the coffee farm.
There is also a high risk of stumps drying due to a period of incomplete physiological activity (due to lack of breather) before the shoots re-develop on the stumps.
Stumping in which all the stems are cut without leaving a breather is not recommended: because it may result in death of the entire coffee tree stumps.
Management of Coffee After Stumping
After stumping, a light tillage (preferably using forked hoes) of the soil (not deeper than 10 cm) is recommended: to re-instate the balance between roots and above-ground matter.
Furthermore, it stimulates the formation of new hair roots and loosens the soil that has been compacted over the years: allowing for a leguminous intercrop to flourish.
The majority of these suckers should be cleanly removed with secateurs before they grow big and hard. Three or a maximum of four vigorous suckers should be selected and left on the stump.
The suckers selected for future-bearing stems should be well spaced from one another at the base of the stump: to enable appropriate vegetative expansion as they grow and also minimize competition for space and light between them.
The breather stem should be cut off early enough: so as not to shade the underneath suckers, to avoid etiolation and poor quality suckers, as seen in
Recommendations for 6–7 Year Coffee Pruning Cycle
This is the period when stems are reduced down from three or four to one single stem.
Have the coffee farm properly weeded before cutting down the mature stems: this will allow some time for the suckers to grow before any disturbances related to weed control.
The one stem left is known as a breather: it keeps the stump alive and also allows the farmer to continue harvesting some coffee.
Ensure proper disinfection of tools used for stumping: to avoid the transfer of live disease pathogens from one tree to another.
As more suckers develop, carry out a frequent and vigorous sucker selection operation for the next six months to 1 year
After 1 year, three vigorous suckers should be selected: they must be of the same height, good health, and well positioned around the stump to act as future bearing stems, as illustrated in
During this period the production is mainly from the breather stem and cover crops (if planted). Great attention should be paid: to ensure that the breather stem does not shade the suckers and inhibit their growth, which may result in etiolated/poor quality suckers.
The “breather” stem is also pruned off/cut back after harvesting the crop at the end of year 1 from the time of stumping
Suckers will thereafter stand alone, reaching a height of more than 1.5m and start bearing the crop.
At the end of year three, the lower-most twigs have exhausted more than 90% of their production area moving from the main stems: they should be cut off.
The lower primaries continuously become weaker and unproductive and should be progressively pruned off (cut) from the stems as they become unproductive.
These primaries have already given a crop and have no future bearing potential: most of them are drying up and only struggling to bear at the tips.
The energy that would be wasted in sustaining the struggling lower primary branches should be diverted to more productive branches: for optimum utilization and improved yields.
At the end of 4 years, the stems have reached full maturity: it is recommended to maintain them in that state for about 3 more years after which change of cycle is re-started.
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