Broussonetia papyrifera invasion reduces the abundance and basal area of selected native timber species in a tropical moist forest in Uganda

Broussonetia papyrifera has been identified as one of the top invasive species in African tropical forests, with potentially devastating impacts on conservation and timber production of forests. This study aimed at understanding the influence of B. papyrifera invasion on selected native timber producing species in afrotropical forests. Employing a complete randomized block design, a total of 40 plots (30 x 30 m each) which were equally distributed between invaded and uninvaded sites with similar habitat conditions, were surveyed for seedlings, saplings and trees of selected native timber species in Mabira Forest Reserve, Uganda. The abundance, basal area and population structure of these timber species were compared between sites invaded and uninvaded by B. papyrifera. The study revealed that the effects of B. papyrifera invasion vary depending on the growth stage and species studied. Overall, B. papyrifera invasion significantly reduced the abundance and basal area of selected native timber species. B. papyrifera invasion suppressed tree regeneration in some of the selected native timber species as shown by individuals missing in large size classes. Our results demonstrate that if the spread of B. papyrifera is not abated, it would lower the timber production potential of tropical forests. Therefore, we call for interventions to prevent the spread of B. papyrifera to uninvaded parts of the forests and halt its multiplication in invaded sites so as to enhance the regeneration and growth of timber species.

Automated summary

This study aimed to understand the impact of B. papyrifera invasion on native timber producing species in afrotropical forests. The results showed that the invasion significantly reduced the abundance and basal area of selected native timber species, and suppressed tree regeneration.