The Impact of Fencing on Regeneration, Tree Growth and Carbon Stock in Desa Forest, Tigray, Ethiopia

Guo Ruo¹*, Brhane Weldegebrial², Genet Yohannes³ and Gebremedhin Yohannes⁴

Received: November 27, 2018;   Published: December 11, 2018

DOI: 10.26717/BJSTR.2018.12.002183

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Abstract

Dryland forests of Ethiopia are facing a rapid rate of deforestation and degradation. This affects the growth and survival of plant density, diversity, growth and carbon stock. The aim of the study was to investigate the effect of fencing on regeneration, bonsai growth and carbon stock potential of Desa‟a forests. Data were collected on 24 plots of 20m×20m for trees and shrubs, 5m×5m for seedlings and on 40m×40m for bonsai growth on permanent plots established in 2009. Data were analyzed using paired t-test to estimate any change on regeneration and carbon stock within the fenced and unfenced block over time. However, an independent t-test was used to measure any significant difference on regeneration, carbon stock and bonsai growth between fenced and unfenced. Results showed that a total of 27 woody species were found representing 18 families. Olea europaea subspecies cuspidata and Juniperus procera were with the highest Importance Value Index. The overall diameter distribution showed an inverted J-shape indicating active regeneration status. Fencing has a significant effect on the regeneration of seedlings (P=0.007).

Significant change in the regeneration of woody plants were found within the fenced plots overtime (P=0.001). Unfenced has a significant effect on basal area over time (P=0.036). Bonsai height and diameter growth was significantly affected by fencing (P<0.001) showing mean height and diameter growth of 14.4cm and 1.34cm per year in the fenced plots respectively. Total tree carbon stock of the fenced and unfenced plots was increased from 15.88 to 19.43 and 12.05 to 12.95 Mg C ha-1 respectively over time. Fencing had a significant effect on tree carbon stock over time (P=0.005). In general, long term fencing was found to be an effective management option to enhance regeneration and carbon stock of the forest. Particularly, fencing is very important management options to improve the regeneration of Olea europaea and bonsai growth which is reported to have low regeneration record on an open environment. However, the regeneration potential of Juniperus procera is weak on both management options indicating the need of further study and conservation priority in the dry Afromontane forest environment.

Keywords :Regeneration; Bonsai Growth; Fencing; Carbon Stock; Permanent Plot