Irrigation regime as a key factor to improve growth performance of Quercus suber L.

Abstract

Cork oak (Quercus suber L.) is a Mediterranean evergreen tree species which plays a key economic role due to its precious bark. Cork oak stands start to become productive 30–40 years after planting, i.e. when commercial cork can be removed every 10 years after the first bark stripping, according to the laws in force. Forcing plant growth with appropriate irrigation, fertilization, top-dressing and stand density minimizes the time between cork oak planting and first bark stripping and makes commercial cork available earlier. In this study, the objective was to determine the influence of different irrigation regimes on cork oak growth. An experimental field was established near Tarquinia (Tuscia District, North Latium, Italy), within the natural cork oak range, to test the effects of irrigation regime on growth performance of cork oak. Three treatments were applied that differed in the amount and timing of water supplied. Treatments were replicated three times. Dendrometric and biomass parameters were measured at three different times for 2 years after planting and statistical descriptive analysis, as well as anova, were used to evaluate the benefits of irrigation. Irrigation with 4 l m−2 three times per week for 2 years improved diameter growth by 33% and shortened the time to first bark stripping by 6–10 years, thus producing substantial economic benefits.