Possible criteria for selection of Quercus suber plus trees

The field work for selecting superior trees of cork oak is described. Requirements for selection are different from those employed for timber tree breeding, because the product to be improved is not wood, but bark. The field work is being developed in a natural forest of 16 000 ha, 8 000 of which are pure cork oak. As the trees are debarked once every 9 years, each year an area of 800-900 ha is selected. The characters assessed were tree size and form, resistance to pests and diseases, bulk production of cork, and cork quality. At the time of debarking, every 9 years, 64 superior trees are selected for progeny testing.