The effect of Broussonetia Papyrifera on the regeneration of selected native timber species in Mabira central forest reserve, Uganda

Abstract

Broussonetia papyrifera has been identified as one of the top invasive species in Mabira Central Forest Reserve with potentially devastating impacts on the forest ecosystem. This study determined the effect of B. papyrifera on the regeneration of selected native timber species in Mabira Central Forest Reserve. The abundance, basal area and population structure of the selected timber species were compared between areas invaded and uninvaded by B. papyrifera in Mabira CFR. Employing a complete randomized block design a total of forty plots, each measuring 30 m x 30 m, and equally distributed between invaded and uninvaded forest areas with similar habitat conditions were surveyed. Counts of seedlings were recorded and diameter of saplings and trees measured. Generalized linear models were used to analyze the abundance, tree basal area and size class distributions of native timber species in areas invaded and uninvaded by B. papyrifera. The study revealed that B. papyrifera has no significant effect on the growth of seedlings of the selected native species. However, the species limits the recruitment of saplings into the mature stage as the number of trees was significantly lower in the invaded compared to the uninvaded forest area. B. papyrifera invasion has no significant effect on tree basal area. This study found that B. papyrifera invasion suppresses regeneration of some but not all native timber species. This therefore calls for interventions to control the spread of B. papyrifera to other parts of Mabira CFR and its multiplication in areas where it is already invasive so as to ensure continuous regeneration and recruitment of native timber species.