Degradation of Eucalyptus transmission poles varies across regions in Zambia

IRG/WP 18-30727

P Ng’andwe, D Chungu, E Ncube

Evidence from literature shows that Eucalyptus poles treated with creosote last over 30 years before replacement. However, in Zambia, the life span of such poles has reduced to 5-10 years. The aim of this study was to investigate factors associated with degradation of treated Eucalyptus poles and how these varied across regions in the country. A total of 1200 poles were assessed in three different climatic regions. The annual rainfall (mm) differed significantly between regions (i.e. region I < 800, region II 800-1200 and region III >1200). Degradation also differed significantly between regions (F2, 28 = 12.5, p < 0.001) with high proportion of degradation observed in region III (61.0 ± 2.6) and low proportion in region I (39.5 ± 3.8). The Pearson correlation between degradation and rainfall was significantly positive (r = 0.579, p <0.01) while the correlation with temperature was negative (r = -0.20, p>0.01). These results suggest that high rainfall areas experienced high degradation of creosote treated transmission poles in the country. This is not surprising because creosote is known to leach in high rainfall areas thereby exposing poles to agents of degradation. Our results reveal that degradation of Eucalyptus transmission poles in Zambia is a function of rainfall. Therefore, in order to increase service life of poles, preservative treatment systems should be adjusted and tailored to end use, depending on the characteristics of the region where the poles will be used. The detection, identification, fungal richness and density of termites across climatic zones are recommended for further investigations.


Keywords: assessment, basidiomycete, creosote, climatic, poles, termites, Zambia

Conference: 18-04-29/05-03 Johannesburg, South Africa


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