In a field trial, the effects of five different types of treeshelter on the microclimatic conditions, survival, aerial relative growth rate (RGR) and root growth of Quercus coccifera L. seedlings were compared with the results obtained from seedlings of the same species grown without treeshelters. The tested treeshelter characteristics were: ventilation, height and material of which they were made. During the experiment the microclimatic conditions were monitored in order to control the factors affecting the seedlings' development. Results showed that a brown plastic protector of only 30 cm in height appears to be the most beneficial for biomass growth, both above and below ground. The more extensive development of the root system facilitates a faster growth rate as accessibility to soil water is increased. The benefit gained from such a shelter is probably due to the reduction of radiation inside the protector to around the optimum photosynthetic levels for the species, and also due to a small increase in the temperature compared with values detected in taller protectors. The shelter ventilation did not show a significant effect on root and biomass growth compared with unventilated shelters.