Heterogeneity of linear forest formations: differing potential for biodiversity conservation. A case study in Italy

Trees outside forests (TOF) are important elements of the landscape and they supply goods and environmental services such as commercial production of timber and fibre, domestic production of food and firewood, carbon sequestration, conservation of habitats and species (plants and animals), erosion control and soil and water quality improvement. TOF include different types of landscape elements: small woodlands, trees along linear features such as property boundaries, roads, railways, rivers and canals, hedgerows or linear forest formations, groups of trees and isolated scattered trees, which have also different ecological functions. The article focuses on the importance and role of linear forest formations (LFF) in the rural context, with special reference to the biodiversity conservation function. It presents the results of research done in the Veneto region, north-eastern Italy. The authors have designed a sampling scheme for LFF based on the Italian National Forest Inventory and tested an indicator system in order to evaluate the quality and biodiversity of the LFF. The indicators used are: LFF type and tree species composition, vertical structure and canopy cover, naturalness, introduced species and deadwood (standing and lying). The main advantages and limitations of the applied method are discussed.