Tree shelters influence growth and survival of carob (Ceratonia siliqua L.) and cork oak (Quercus suber L.) plants on degraded Mediterranean sites

Tree shelters were used in an ecological restoration effort in 1999 and 2000 to test the decrease in transplant shock and increase in growth and survival of two selected Mediterranean species, carob tree (Ceratonia siliqua L.) and cork oak (Quercus suber L.), planted in a dry degraded region. At plantation, two treatments were established, one planted with 60 cm tall TUBEX Minitubes (TM) and the other planted without tree shelters. Results have shown that tree shelters dramatically increased survival of sheltered plants and also stimulated height growth, probably caused by reduced light regimes inside shelters, inducing shade adaptation. Different biomass partition occurred between sheltered and unsheltered plants, although no effect in increased biomass production was observed. This work shows that individual tree shelters successfully increase establishment of newly planted plants in dry, degraded areas of the Mediterranean.