Exploring native tree seed germination and seedling production to address agroforestry needs in Bugesera district, Eastern Province, Rwanda

Abstract

Native tree species (NTS) offer a wide range of ecosystem services that are very crucial to human life and society development. In the past decades, deforestation rates have been high in Rwanda and many native tree species have gradually disappeared due to overharvesting and forest degradation. Bugesera District in eastern Rwanda for example, has been subjected to massive native tree species cutting to satisfy local people’s basic needs. Hence, there is a high need to be integrated in agroforestry system and afforestation initiatives. This study aimed to explore the current situation of NTS in community farmland, analyze native tree seed germination, and identify how to produce good quality seedlings for domestication. By conducting household survey to understand local perceptions on NTS and by identifying the most preferred NTS through FGD using a pairwise comparison technique, collected data about four NTS that were selected by farmers as the most preferred were tested namely Markhamia lutea, Garcinia buchananii, Acacia sieberiana, and Kigelia africana. Four seeds species were tested in vitro experiment with various pre-germination treatments. In addition, two species were grown in controlled condition in a nursery to assess their growth performance. A statistical analysis about germination rate and key growth parameters were performed such as Germination Percentage (GP), Mean germination Time (MGT), height, collar dimeter and number of leaves. Results of this study revealed that farmers are willing to grow NTS; however, there is a problem of good quality seed availability and insufficient knowledge and skills on propagation management. According to the experiment results, there were statistically significant differences in germination rate among pre-germination treatments tested. Comparing the germination of tested NTS, the highest germination percentage (66%) over seven days for seeds soaked in cold water was recorded for M. lutea and G. buchananii (81.3%) but took long time to germinate (30days). The lowest was observed in K. africana (3.3%) under control treatment. Moreover, the growth performance of M. lutea was much better than G. buchananii. M. lutea recorded the highest average mean height of 20.2cm with (SD=5.15) and average mean diameter of 6.65mm with (SD=2.25) after six months. In contrast, G. Buchananii had a slow growth; average mean height was 9.2cm with (SD=1.88) and average mean diameter of 1.2mm with (SD=0.17). M. lutea performed well in terms of growth performance and germination success. Additionally, G. buchananii could be recommended to farmers because it was likely preferred for its edible fruits, even though it takes a relatively longer time to grow in the nursery. According to local farmers ‘testimonies, there is visible removal of some NTS in the landscape; there is a need to increase the presence of NTS in restoration projects by adopting scientifically proven germination treatments in conducive growth conditions. To address this challenge, during this study, NTS seedling were availed and planted in Bugesera landscape. Thus, it is recommended that the possible propagation of NTS requires supportive programs and policies that focus on the integration of NTS in forest programs and the creation of private nurseries to provide a sufficient supply of NTS seedlings.