Comparative study among experimental plantings and phenotypes of cork oak (Quercus suber L.), Northern Greece: 18 years later

Comparative studies on growth, wood and cork production, survival and germination between two treatments and among three phenotypes of Quercus suber were studied, in experimental plots. In 1992, two-year old saplings of cork oak were planted in northern Greece. Significant differences between the two treatments and among the three phenotypes in quantitative growth parameters (diameter, height, wood and cork production) were identified. Three regression models (linear, logarithmic and quadratic) were used to correlate precipitation and growth of cork oak over the last decade. The quadratic model shows the highest correlation, providing a reasonable prediction of annual tree growth, given the mean annual precipitation for the tested three phenotypes. Marginal climatic parameters (in particular drought and frost) negatively affected the survival and growth of oak saplings.