Assessing the potential of trees for afforestation of degraded landscapes in the Aral Sea Basin of Uzbekistan

Land degradation is a serious hindrance to agricultural development in Uzbekistan, a country striving to rebuild its agricultural sector for self-sustained production. The potential of multipurpose trees for upgrading degraded land is enormous. However, knowledge is lacking about the establishment and growth characteristics of different species, the energy content of firewood and the nutritive value of fodder. This study presents such data for 10 selected local multipurpose species grown on gleyic solonchak soil. Elaeagnus angustifolia L. and Tamarix androssowii showed superior biomass growth, respectively producing up to 11.0 and 10.4 t ha^-1 of utilizable aboveground dry matter (DM). E. angustifolia showed high potential for rapid establishment evidenced by root elongation of over 100 m tree^-1 at the age of 3 years. T. androssowii, Prunus armeniaca L. and Populus nigra var. pyramidalis Spach exhibited the greatest fuelwood characteristics, showing calorific values in the range of 14.4 - 16.2 MJ DM kg^-1. E. angustifolia and Morus alba L. demonstrated superior fodder potential given by the crude protein content of 216 and 117 g DM kg^-1. Recommendations on species selection are proposed based on various species characteristics. In assessing the potential of trees for afforestation of degraded land a reliable economic analysis of these aspects must be taken into account. When considering all characteristics concurrently, a mixture of species instead of monocrop cultivation seems to provide the best solution for improving degraded land.