Growth performance of cork oak plantations recently established on farmlands in Sardinia, Italy

Abstract

Growth performance of cork oak plantations recently established on farmlands in Sardinia, Italy. Recently, significant forestry activities have taken place in Sardinia thanks to EU Regulation 2080/92 funds. Some 80% of the afforestated surface has been planted with holm oak and cork oak. The latter also characterizes 89% of the reforestation area. Given the funding source, plantations have been established on farmlands. Growth performances of these recent cork oak stands have been quantitatively evaluated and compared with the performances of two experimental plots. In Gallura (north-east of Sardinia), that is the traditional cork production area and still is economically the most important cork district of the island, these new cork oak plantations have an average size of 28 ha. They have been established on lands that, before plantation, were either pastures (30%) or arable lands (70%). Plantation failures are limited to 8.8% of the total (in term of mass) and seem independent of environmental factors or plantations species composition (conifers have been frequently used as secondary species). Average growth of the stem, measured above cork at collar height, is in the range 4 to 8mm/year with a mean value of 5.5mm/year. No correlation appears with either environmental conditions or species composition of the plantations. In the first experimental plot, soil management practices (natural vegetation removal vs its cutting and mulching) does not differentiate young plants growth trends. In the control subplots (no removal) stem collar diameter is 20% smaller. Localized manual hoeing around trunk base increased the diameters by 13% but reduced cork thickness by 21%. The second experimental plot allows comparisons among 27 Mediterranean proveniences of cork oak. The trial exhibits reduced genetic influence: diameters and heights growth are significantly different only among extreme groups. In conclusion, reduced growth performances of the plantations established in farmlands is due, to some extent, to the limitations inherent with private land management (constrained to costs minimization) and, on the other hand, to the generally very limited thickness of Gallura soils. Demand for good quality commercial cork is steadily raising. To sustain the request, in the short term, it would be necessary to extend financial support for plantations care, from 5 to 10 years, or even up to the first stripping (virgin cork). IntroduzioneOltre l'80% delle foreste di quercia da sughero italiane si trova in Sardegna, dove è anche presente la gran parte dell'industria di trasformazione in uno specifico distretto industriale che trova nel tappo il prodotto principale e il maggiore valore aggiunto. La fase espansiva globalmente registrata dai vigneti fa prevedere per il 2010 una richiesta di 24 miliardi di tappi di sughero a fronte degli attuali 19 miliardi, anche se la sempre più ampia diffusione di chiusure e contenitori alternativi delinea sul lungo periodo previsioni meno ottimistiche (Repetti 2005). Si può presumere una...

Characterization of Sardinian cork oak (Quercus suber L.) genetic resources for economically important traits

“…In Europe it is mostly present in Portugal and Spain and to lesser extent in Italy and even less in France, while in Northern Africa it is widespread in Algeria and Morocco and also occurs in Tunisia. In Italy, the major cork oak resources are found on the island of Sardinia (Dettori et al 2006), the species is also present in Sicily and in small areas of the mainland Italian regions of Latium, Tuscany, Apulia and Calabria.…”

Land Take and Landslide Hazard: Spatial Assessment and Policy Implications from a Study Concerning Sardinia

“…Managed forests were almost completely made up of cork oak woods (27%), while negligible percentages concerned other types of managed woods, either broad-leaved (for instance, eucalyptus woods) or coniferous (for instance, pine woods, especially in coastal areas). While many cork oak woods are still managed for production purposes, especially in North-Eastern Sardinia [54], eucalypti and pine trees (both non-native species in the island) were planted mainly for swamp reclamation, slope stability, and erosion control in coastal dunes in the XX century; as of today, they are often unmanaged, to the extent that some have undergone a renaturalization process and have evolved into mixed forests, as a result of successional processes [55] and native species' regaining their spaces. Once a vector map of the LEAC groups was retrieved, for each cell in the 300 m square grid shown in Figure 3, the explanatory variables L_TAKE, ARA, PMF, FOR, and GRSH, in model (1) were calculated as the percentage of the cell occupied by LEAC groups listed in Table 2, respectively, as nos.…”