Influence of anthropogenic activities on the initial establishment and growth rate of introduced Senna siamea in Zomba-Malosa Forest Reserve, Malawi

Gift Gladson Moyo,Marlene Chikuni

doi:10.23954/osj.v1i4.673

Abstract

The study was conducted along the Nkanya-Lusewa rivers catchment as hot spot in Zomba-Malosa Forest Reserve in Domasi area in Malawi to determine the influence of anthropogenic activities on the growth of Senna siamea planted by the community using integrated indigenous-technocrat model. The study focused on 28 gardens along the rivers whose owners encroached the forest reserve and willed to participate in the study. In total we planted 101 S. siamea seedlings within a distance of 10 m on either side of the study rivers and we determined tree total height, canopy height, canopy base diameter and canopy base area in February, May, August, and November in 2014 using a ruler. We found that the average tree total height and canopy height slightly decreased from February to November from initial 34.7 cm to 31.1 cm and 16.8 cm to 12.1 cm respectively due to impact of transplanting shock and bushfires which led to loss of tree tops and some branches but those of canopy base diameter and canopy base area increased slightly following sprouting of burnt seedling stems. We further found that tree growth rates varied among the gardens due to transplanting shock, post-planting care differences, soil moisture variation, and incidence of bushfires.

Highlights

Survival and growth rates of trees in a forestry ecosystem are influenced by a number of factors such as moisture content, mineral levels, pH, temperature, and exposure risks to herbivores and cutting by human beings
Trees planted along Nkanya and Lusewa rivers through Southern Region Water Board (SRWB) and Water Users Association (WUA) in Domasi area have been failing to survive since 2005 but those planted by the community through integrated indigenous-technocrat approach have shown great survivorship within the first 10 months
We found that in the 10 months study period, from February to November, S. seamea planted in the study site had the mean tree total height of 31.1 cm, canopy height of 14.7 cm, canopy base diameter of 30.0 cm, and the mean base area of 704.9 cm2

Summary

Introduction

Survival and growth rates of trees in a forestry ecosystem are influenced by a number of factors such as moisture content, mineral levels, pH, temperature, and exposure risks to herbivores and cutting by human beings. The people in Domasi area, in Zomba district in Malawi, cultivate in marginal land and have invaded Zomba-Malosa forest reserves for cultivation and charcoal production due to the scarcity of land which emanates from high human population growth and poverty level such that survivorship of indigenous trees is very low [1]. During all forest restoration interventions, the growth rates of these trees have not been determined in the study area.

Methods

Results

Conclusion