Evaluation of unventilated treeshelters in the context of Mediterranean climate: Insights from a study on Quercus faginea seedlings assessed with a 3D architectural plant model

Unventilated treeshelters have been widely used to protect seedlings against animal browsing and prevent seed predation by rodents, when the method used is seeding instead of planting. This last method has been a common practice in reforestation with oak species in Spain, because it prevents acorn predation. Although unventilated treeshelters have been widely used in this country, the performance of such devices under Mediterranean climatic conditions is a matter that deserves further investigations. To find out if treeshelters also provide protection against abiotic stress and improve the potential carbon gain in sheltered seedlings, we carried out a light and thermal characterization of the atmosphere inside the treeshelter. Moreover, we assessed the impact of treeshelters on light capture parameters, transpiration and photosynthesis using a Y-Plant model with Quercus faginea seedlings. Simulations with Y-Plant have shown that the growth in sheltered seedlings was mainly in spring and was limited by the low light levels. On other hand, in summer, the low values of potential carbon gain and water use efficiency in the sheltered seedlings could limit the seedling establishment. The main limiting factor during this season was the high temperatures. Therefore, the choice of the suitable treeshelter in this region must be carefully evaluated. The treeshelter must warranty high light levels and an optimal air renovation. Photoinhibition risks in leaves of sheltered and control seedlings have not been previously shown.