Assessing the Role of Quality Thresholds on Early Performance of Tree Seedlings Planted on Degraded Highlands

Abstract

The present study highlights the effect of seedling quality on the resultant early performance of our planted tree seedlings. Four priority species tree seedlings: Cordia africana, Casuarina equisetifolia, Cupressus lusitania and Grevillia robusta were raised in the nursery using recommended substrate mixes of ratio (3% top soil: 2% manure: 1% sand). Seedlings were then sorted in to sturdiness quotient classes: quotient class one (I) comprising height to collar diameter ratio less than 6 and quotient class two (II) height to collar diameter ratio greater than 6 to compare early growth and survival among species and evaluate the significance of correlations between quotient categories and tree growth parameters on the degraded highlands of Yerer, Ethiopia. Two factor RCBD with three replications was used as an experimental design to handle eight factor combinations that resulted from four species types and two quotient classes. ANOVA indicated significant difference among tree species tested in the study area in terms of survival and early growth performances at P=0.05. Casuarina equisetifolia though its height and diameter performance in varying quotient categories was not statistically different it was found a priority species to establish plantation in the study area. The correlations between quotient categories and growth parameters were found statistically non-significant at P=0.05. Cupressus lusitanica and Grevellia robusta followed in the priority list to best adapt the site though the observed differences were not attributed to the anticipated variation in sturdiness quotient. Thus, the study results revealed that sturdiness quotient plays lower predictive role in early growth performances and survival of planted seedlings and it was found out to be a less rigorous quality parameter.