Height isn’t everything: Quality tree seedlings for Cameroon
Tree nurseries that have collaborated with the World Agroforestry Centre produce better quality seedlings than other tree nurseries in Cameroon. This is according to a study by Bertin Takoutsing et al, published in Small-scale Forestry.
For decades tree products have been gathered from various land-use systems including forests. However, population pressure is now increasing the demand for those products–leading to forest degradation. In Cameroon, for example, about 200,000 ha of forest resources are lost each year.
Through the integration of high-value species in various ecosystems, agroforestry has contributed to reducing deforestation and the pressure exerted by smallholders on tree products. In developing countries seedlings are often produced in small-scale nurseries and, provided they are of high quality, can form the basis for successful forest plantation initiatives. These two factors form the cornerstone of the Participatory Tree Domestication (PTD) program implemented by the World Agroforestry Centre (the Centre) and its partners in West and Central Africa. The program supports the establishment of small-scale tree nurseries that facilitate access to improved tree planting materials. Government and nongovernmental organisations also support the creation of small-scale nurseries to produce seedlings. The successes of these two categories of nurseries, in producing high quality seedlings, have not been fully investigated and little information is available about the performances of the seedlings after leaving the nurseries.The quality of a seedling is expressed through two main aspects: genetic quality and physical quality. While improving genetic quality requires a long-term strategy of germplasm selection, improving physical quality can be accomplished in nurseries. Clients of nurseries are unaware of seedling quality indicators and generally use height as the main indicator of quality. In reality, height alone is not an adequate indicator of seedling quality, which actually involves a combination of height, collar diameter, root size, shoot weight and dry weight. Together, these characteristics determine how well the seedling will establish itself once planted in the field. Inability to recognize seedling quality has led to the failure of many tree planting projects. Strategies for assessing quality of planting stock need, therefore, to move away from the traditional approach of considering only the height of seedlings.
This study compared the growth quality indicators of seedlings of three priority tree species namely avocado, kola nut and safou, produced in two categories of nurseries, one collaborating with the Centre through the PTD Program (Category 1) and the other collaborating with government and non-governmental supported projects (Category 2).
Seedlings produced in Category 1 nurseries were found to be uniform in terms of growth characteristics and quality indicators. In the second category, there were relatively higher seedling proportions having measured parameters out of threshold standards for root to shoot ratio and for sturdiness quotient. These seedlings are unlikely to withstand the adverse conditions in most planting sites due to inadequate root systems. Overall, nurseries in Category 1 exhibited ‘better’ results, probably resulting from more intensive nursery management, training and technical backstopping received by the nursery operators.
Nursery operators in both categories have the basic knowledge required to produce seedlings. Most of the operators in category two have gained long-term experiences through trial and errors, while majority of operators in category 1 have gained skills through formal training sessions and technical backstopping from ICRAF. Nevertheless, skill levels of operators in both categories are insufficient and both need training on quality seedling production techniques.
The Centre has improved the quality of seedlings produced in small-scale nurseries by providing training packages and manuals, technical notes, and technical backstopping. Boosting the productivity and sustainability of forestry and agroforestry, and improving policies and institutions that affect these are a key focus of the CGIAR’s Collaborative Research Project 6 on Trees, Forests and Agroforestry—of which the World Agroforestry Centre is a key partner.
The study proves that nurseries exposed to basic techniques can produce high quality seedlings than those that rely on personal know-how. High quality seedlings form the basis for any successful tree planting project whether initiated by government, non-governmental organisations or research institutions. Taking into consideration the investments behind such initiatives, only high quality planting materials should be used.
Policy recommendations from this study are straightforward:
- Regulations to ensure that seedlings can only be procured from registered and accredited nurseries.
- Awareness campaigns to sensitize and educate the general public on the importance of using high quality seedlings and improving nursery seedling production.
- Material, technical and financial support to improve nursery facilities and management.
- Clonal orchards and seed banks to provide nursery operators access to quality germplasm.
Assessing the Quality of Seedlings in Small-scale Nurseries in the Highlands of Cameroon: The Use of Growth Characteristics and Quality Thresholds as Indicators. Bertin Takoutsing, Zacharie Tchoundjeu, Ann Degrande, Ebenezar Asaah, Amos Gyau, Frederick Nkeumoe & Alain Tsobeng.
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