资源环境科技发展态势分析平台

Semi-open oak woods and solitary oaks commonly dominate the wooded fabric (i.e. the 'oakscape') of European traditional rural agricultural landscapes based on animal husbandry. However, modem land use systems fail to perpetuate oakscapes, posing a serious threat to biodiversity conservation and the associated diversity of ecosystem services. Reconstructing the dynamics of oakscape remnants can provide valuable insights concerning the maintenance of oakscapes. We used the socioeconomic transitions at the European Union's eastern border as a natural experiment to explore the drivers for successful oak recruitment in 27 selected units representing 4 oakscape categories. Analyses of tree-ring data, historical maps, and orthophotos were used to reconstruct the oakscapes' establishment trajectories in relation to land use changes in the period 1790-2010. The oaks in cultural semi-open woods and wood-pastures differed substantially from those in closed canopy forests by more stocky shape and faster early age DBH annual increase. We found two distinct recruitment patterns: (1) FAST - recruitment usually completed within 2-3 decades, attributed to an unconstrained succession of abandoned agricultural land, and (2) SLOW - recruitment extending over several or more decades. In Ukraine, frequent illegal grass burning in marginal woods was the most successful mechanism perpetuating oak recruitment. Top-down policy encouraging specialized intensive farming, sustained yield forestry, and conservation efforts concentrated on the preservation of closed canopy forests compromise the future of traditional agro-silvo-pastoral systems. Maintenance of traditional integrated agro-silvo-pastoral management sustaining oakscapes needs to combine local traditional knowledge and landscape stewardship.