Performance of Austrarian, Central American and Kenyan tree species in arid sites of Embu, Meru and Isiolo districts

Abstract

This report covers an evaluation of forestry trials that were established by EMI project between 1984 and 1990. The trials' objective was to select appropriate tree species and provenances for planting in the Arid and Semi-Arid Lands. This was based on felt needs caused by the ever increasing demand of forestry products at a time when clearing of natural vegetation for crop production was rampant. Therefore, anticipated products of tested species included poles and a variety of other farm forestry products. Growth and survival were the assessment parameters included in the initial designs. The present evaluation has restricted itself to these parameters. Results of the current assessment revealed that height was the best factor of differentiating species and provenances on growth. Survival was distorted by tree cutting. However, survival ranged from 100% to 0% for the species tested in the trials that were evaluated, suggestin, varied adaptability of species and provenances, Eucalyptus camaldulensis, E. melanophloia and E. microtheca are some of the species that were identified as appropriate for production of poles. Acacia salicina, Melia volkensii and Senna atomaria were the other species with good agroforestry potential. It is recommended that survival of 40 % be adopted as borderline for adaptability. From this criterion, species with a survival of less than 40% should be cleared. This will avail more growing space to more adaptive species. The adaptive species should be thinned to a minimum spacing of 3m to reduce competition, while multi stemmed species should be thinned to a single stem.