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Aim: Vegetation types of Mediterranean thermophilous pine forests dominated by Pinus brutia, Pinus halepensis, Pinus pinaster and Pinus pinea were studied in various areas. However, a comprehensive formal vegetation classification of these forests based on a detailed data analysis has never been developed. Our aim is to provide the first broad-scale classification of these pine forests based on a large data set of vegetation plots.

Abstract. An attempt to obtain a consistent spatial model of natural potential vegetation (NPV) for the mainland Portuguese territory is reported. Spatial modeling procedures performed in a Geographic Information System (GIS) environment, aimed to operationalize phytosociological expert-knowledge about the putative distribution of potential zona1 forest communities dominam in the Portuguese continental territories. The paradigm for NPV assumed was that of RIVAS-MARTINEZ (1976) and RIVAS-MARTINEZ et al. (1999), which presupposes, for a given territory, a univocal correspondence between a uniform combination of bioclimatic stage and lithology iven a biogeographical context, and a ' g unique successional sequence leading to a single climax community (i. e. a vegetation series (VS)). Information issued from both literature and a team of phytosociologists possessing detailed knowledge about Portuguese vegetation, namely about forests and its seria1 vegetation, was acknowledged as a starting point for the construction of such a habitat-vegetation correspondence model. First, a bioclimatic map concerning the "Worldwide Bioclimatic Classification System" (WBCS) of RIVAS-MARTINEZ (1981-2004, obtained by multivariate grostatistical interpolation issuing from the work of MESQUITA (2005), was set. Severa1 partia1 matrices, one for each biogeographical Province, combined such habitat statements to VS. Initial incoherence due to vagueness of statements led to an important amount of both superimposition of VS and habitat gaps in the matrices. Further rearrangement of the table according to known field distribution of VS by experts allowed setting an approximate univocal correspondence VS-habitat. Finally, an intersection of bioclimatic, lithology and biogeographic maps yielded over a thousand habitat combinations to be associated each to a single VS through implementation of the matrices as a set of rules. Again, inconsistencies were solved likewise, but this time by direct observation of the map by experts. Keeping of phytosociological consistency and fidelity to information on actual vegetation field distribution was always mandatory during the process.

Persistence of native forests is a global concern. We aimed at unveiling the main factors affecting tree recruitment in Portuguese native forests, modelling sapling data collected during the 5th Portuguese Forest Inventory, for five main Quercus taxa. Zero-inflated count data models allowed us to examine simultaneously (i) the absence of tree recruitment and (ii) the density of tree recruitment. Using Akaike weights, we obtained importance values for 15 relevant explanatory variables. Results showed that seed availability and climatic variables were determinant to understand regional absence of regeneration for all taxa. Seed availability was also an important driver of sapling density, except for Quercus suber. Other variables impacted on regeneration density: grazing hindered Q. suber regeneration; regeneration of Q. rotundifolia and Q. suber was lower in flat areas; recurrent fire hampered the regeneration of Q. robur and Q. pyrenaica; Q. broteroi and Q. pyrenaica showed depressed regeneration in regions where forest plantations abound, while Q. robur and Q. suber seemed selectively protected. We conclude that caution is warranted when analysing pooled data for Quercus spp. regeneration, as different variables affected Quercus taxa differently. Finally, we suggest dedicated management actions to enhance the establishment of new native forests.