Comparison among different schemes and plant densities in oak plantations (Quercus petraea [Matt.] Liebel.): a case study in Umbria, Central ItalyThe results of tree farming plantation, aged 20 years, characterized by three different planting designs are reported. The plantation designs differ in planting densities and by the presence/absence of N-fixing nurse trees and shrubs. The plantations intercropped with N-fixing trees and shrubs (B 33% and C 66%) showed superior increment in dbh and height. The plantation C characterized by valuable tree planted at definitive distances (8 m), lower tree density and higher percentage of N-fixing trees and shrubs (C) showed the best growth performance and no thinning need, but showed the worst stems quality. In plantation (C) the vigorous development of shrubs and brambles hindered the management, making the plantation not suitable for tourist and recreational activities, though more attractive for local wildlife. The plantation with high tree density characterized mainly by sessile oak (A) was more sensitive to insect attacks and needed to be early thinned, thus it is more suitable for tourist and recreational activities. The plantation B with high tree density and intercropped with N-fixing nurse shrubs showed higher growth, needed to be tinned and can be used for tourist and recreational activities too.