Recent secondary woodlands in a regional sample of Southern-Alpine abandoned landscapes: implications for restoration ecology and silviculture

Secondary woodlands are expanding throughout Europe as a result of the abandonment of farmland and the natural or artificial regeneration of forest cover. If properly managed, secondary woodlands can generate significant environmental and livelihood benefits. They can play a key role in biodiversity conservation or loss. In addition, secondary woodlands can represent a land reserve for agriculture and livestock production. Their uncontrolled expansion can lead to the loss of human heritage elements. With this paper we aimed at giving a brief reference of the current status and some management options for recent secondary woodlands based on a regional sample located in the South-Eastern Alps. The study was conducted in the Italian Province of Trento (6207 km2). In order to estimate the secondary woodland area, we adopted a two-stages sampling design. In the first stage, 100 cells were randomly selected with replacement in a 4 km regularly spaced grid according to a probability depending on an auxiliary variable; in the second stage, 100 sample points were drawn randomly within each selected cell and used to estimate the total area of the secondary woodlands by comparing the forest – no forest classification on two orthophotos taken in the years 1973 and 1999. Among the 334 points classified as no forest in 1973 and as forest in 1999, 291 (having canopy cover ≥ 20%, mean height ≥ 2 m, surface ≥ 1000 m2 and width ≥ 10 m) were surveyed further on the ground, recording ecological, biometrical, management and landscape attributes; to 261 of them we assigned a secondary forest stand category.