# Earth Observation and Biodiversity Big Data for Forest Habitat Types Classification and Mapping
## 2 Materials and Methods
### Study Area  
The study area encompasses Italy (Figure 2), which covers about 300.000 km\({}^{2}\), and it is characterized by a noteworthy geo-morphological and land use heterogeneity (there are two mountain ridges, the Alps in the northern, and the Apennines in the southern), as a result of complex tectonics processes starting from the Upper Cretaceous and centuries-old land management, respectively [59]. The area also shows a marked climatic variability, from the Mediterranean climate along the central and southern coasts, up to the alpine in the mountains [60].  
Figure 1: Flowchart of the approach for forest habitat mapping using a supervised machine learning model. For more details about EUNIS codes (i.e., II and/or III level) see Table 3.  
The land use is characterized by three main classes: croplands (51.46%), natural (43.05%), and urban areas (5.49%) [44, 61]. Within the natural areas, the woodlands and forests cover 85830 km\({}^{2}\), corresponding to the 28.5% of total land surface [62]. The forest habitat (shrublands and tree plantations excluded) was subdivided in nine forest types [63], as shown in Table 1.  
Over centuries, along the Italian peninsula these climatic, morphological, and land use features have defined peculiar geographic regions with similar environmental conditions, which support plant and animal species with comparable life strategies and adaptations (i.e., the biogeographical regions) [64]. Indeed, in 2011 from EU Member States consultation meetings, following Article 17 of the Habitats Directive (92/43/EEC) and Natura 2000 Biogeographical processes, the biogeographical regions were defined for the whole Europe [65]. Italy is included in three Biogeographical regions (see Figure 2): Mediterranean (characterized by hot dry summers and humid, cool winters); Alpine (where extreme temperatures and annual precipitation are strictly related to the physiography and in late fall and winter all precipitation above 1500 m a.s.l. is in the form of snow); and, Continental (with significant annual variation in temperature, hot summers, and cold winters, and precipitation tends to be moderate, being mostly concentrated in the warmer months) [60].  
\begin{table}
\begin{tabular}{c c} \hline
**FOEST TYPE** & **DOMIANT Species** \\ \hline Hemiboreal forest and removaliferous and mixed & _Picus abies_ (Norway spruce), _Pinus pinaster_ (Maritime pine), \\ broadleaved coniferous forest & _Pinus sybies_ (Scots pine) and _Pinus nigra_ (Black pine) \\ Alpine coniferous forest & _P. abies, Larix decidula_ (European larch), _Pinus mug_ (Bog pine), _Pinus cembra_ (Swiss pine) and _Abies alba_ (European silver fir) \\ Coniferous forests of the Mediterranean, Anatolian and & _P. pinaster, Pinus halepensis_ (Aleppo pine), _Pinus pinea_ (Stone \\ Macaronesian regions & _P. pinasp, Pinus haldeeicrii_ (Bosnian pine) \\ Mesophytic deciduous forest & _Carpinus betulus_ (Common hornbeam) \\ Mountainous beech forest & _Fagus sylvatica_ (Europe beech) and _A. alba_ (European silver fir) \\ Thermophilus deciduous forest & Deciduous Oaks, _Tilia_ spp. (little leaf linden), _Ostrya carpinifolia_ (European hop-hornbeam) and _Castanue sativa_ (sweet chestnut) \\ Broadleaved evergreen forest & _Quercus lix_ (everygreen oak) and _Quercus sulber_ (cork oak) \\ Floodplain forest & _Salix_ spp (Willow), _Populus_ spp. (Poplan) and _Almus glutinosa_, \\ Not riverine alder, birch, or aspen forest & _Almus cordata_ (Italian alder) \\ \end{tabular}
\end{table}
Table 1: The forest types present in Italy according to the National Forest Inventory of 2005 1 and the European Atlas of Forest Tree Species 2.