All in all just another tree in the wall?

Establishing tree cover in drought stricken areas is a challenge facing many countries facing problems with desertification. A new planting technique to improve drought resistance in which planting holes are lined with biodegradable plastic to reduce drainage and evaporation was tested in an arid, erosion-prone, hilly area of the Chinese Loess Plateau between 1997 and 2006, during a period of lower-than-normal precipitation. 15 types of tree were grown with and without the bag. The new tree-planting technique promoted root growth in the topsoil by keeping the soil moisture than the surrounding soil evident during the first 4 months after planting.

Tree survival rates, branch growth increment per year, tenth-year canopy area, and tenth-year canopy density in trees planted using the new method increased by an average of 41.4%, 29.0%, 16.9%, and 65.3%, respectively, compared with the values for the conventional planting technique. This suggests that the new planting technique is more suitable than the conventional method for arid areas such as the Loess plateau and may prove useful elsewhere in the globe. The results of this study offer much hope for the survival of China’s ‘Green Wall’ and long term prospects concerning the countries prevention of desertification.

Cao, S., Chen, L., Liu, Z. and Wang, G. (2007). A new tree-planting technique to improve tree survival and growth on steep and arid land in the Loess Plateau of China. Journal of Arid Environments, In Press.