Sasso Fratino Nature Reserve (National Park of Casentino Forests, northern Apennines) is a quite rare example of natural Apennine forest. The Reserve was established in 1959, aiming to protect a forest, although not a virgin one, low-intensively disturbed in the past by comparison with other neighbouring stands. Causes of such a low disturbance are the very limited accessibility of the area due to the very steep slopes characterising the site morphology, as well as historical features. The forest is a pure beech stand from 1250 m a.s.l. upwards, below this altitude is a mixed beech and silver fir forest. The study focuses on the understanding of the processes driving the evolution of the forest in the absence of human activities. To achieve this goal, 9 permanent, long-term research plots were established at different altitudes, in order to investigate on forest dynamics and regeneration processes. Simplified (single-layer) stand structures are more frequent where canopy gaps are absent. Two-layered structures are the result of the occurrence of canopy gaps, which allow the settlement, and subsequently the establishment, of a lower regeneration layer. Where the gap dimensions allow canopy closure, this kind of structure persists. When the gaps are quite large, the regeneration layer reaches the top layer and the structure stand tends, once more, toward a single-layer. Multilayered structures are extremely rare at plot level and become evident only at a wider scale. Our surveys indicate also a high variability of tree diameter distribution patterns in the forest stands. Such variability could be strictly related to the heterogeneity of site characteristics as well as to the effects of disturbance factors (both natural and anthropic). Concerning altitude, we observed an increase both of site index (dominant height) and species diversity in the regeneration layer, moving from higher (1500 m) to lower (900 m) altitudes. As a whole, our observations show that the dynamics of forest vegetation in the reserve is mostly affected by the interruption of tree canopy continuity. This implies substantial local variations of PAR in space and in time, which determine favourable ecological conditions for: (a) survival and growth of beech seedlings, or release of advanced beech regeneration; and (b) release of advanced silver fir regeneration (fir, more shade tolerant than beech, regenerates mainly in locations and conditions where the broadleaf saplings cannot survive for lack of light). The knowledge of the mechanisms of vegetation dynamics in the Reserve can be used to form the basis of close-to-nature silvicultural choices in similar stands in order to increase functionality and stability. Periodical monitoring of RNI will allow the investigation of the evolutionary trends of the forest stands

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An old-growth beech forest stand with silver fir within the strict forest reserve of Sasso Fratino has been examined with the following aims: to characterize forest stand on the basis of classic forest parameters and to assess forest stand structure by means of spatial functions; to provide genetic dating of the beech population. Total census of size and position of living trees and deadwood was performed on a 9200 m 2 permanent plot. Vertical distribution of crowns in the stand was assessed using the TSTRAT function, horizontal stand structure using spatial point pattern analysis. Genetic dating was performed on a sample of beech trees. DNA was isolated and each individual was genotyped at four chloroplast microsatellite loci. Microsatellite profiles were compared with the profiles of control DNA of known haplotypes. Results show a multi-strata vertical structure, a horizontal structure characterized by small gaps (5160 m 2 ) where silver fir regeneration sets in. Deadwood is present with all the decay classes and with relatively high volumes. Genetic dating ascribes the Sasso Fratino beech stand to the ancestral haplotype 2: this population can therefore be considered a hot spot of haplotype diversity of the glacial refugia present in central Italy.

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Advection fog is the sole source of water for many near-the-sea areas worldwide. • We present the results of a long-term reforestation project in the Atacama Desert. • Trees were irrigated with artificially fogcollected water for three years. • After 15 years from planting, about 65% of trees were still alive and growing. • Reforestation induced fast and substantial carbon sequestration.