The Growth of Multipurpose Tree Species in the Almeria Province of Spain and Its Relationship to Native Plant Communities

A series of multipurpose tree species trials were undertaken in the Province of Almeria, south eastern Spain, to determine suitable species for economic and sustainable land use in a degraded, semi-arid Mediterranean region. From an elimination trial comparing the performance of 21 native and exotic species, eight were selected for a growth trial. After 2.5 years, the highest survival rates were recorded for Schinus molle L. (85%), Prosopis alba Stuntz (76%) and Gleditsia triacanthos L. (74%). Acacia salicina Lindl., A. saligna (Labill) H.Wendl, Prosopis alba and Schinus molle had the highest growth rates based on height and diameter suggesting that these five species may be useful for semi-arid land reclamation in this region. The growth trial site had four communities of native vegetation with differing soil pH and water conductivity. Native vegetation can indicate physical and chemical characteristics of soil, topography, local climate and vegetation density of a particular region. Tree species used for desert reclamation trials respond differently to these variables. By assessing the growth rate of multipurpose tree species planted in native vegetation communities, it may be possible to use the native vegetation as indicators to match tree species to specific areas, in order to enhance their growth rate and survival. The eight tree species used in the growth trial were planted in three plant communities that are common to the region. Tree growth differed between each community; Prosopis alba and Gleditsia triacanthos grew equally well in all three communities, whereas Acacia salicina and Acacia saligna grew better in Helianthinum viscarium Boiss. and Rueter/Linum strictum L. and Trachynia distachya (L.) Link/Vulpia muralis (Kunth) Nees communities. A Trachynia distachya/Artemisia barrelieri Bessel. community had the lowest growth of planted trees. The results suggest that the growth of the Acacia species can be enhanced by site specific matching using native indicator vegetation.