# Forest Dynamic in the Italian Apennines
## 2 Materials and Methods
### Data Analysis  
The Land Cover maps obtained through photointerpretation showed 20 classes (Table 2, Figure A1) coded according to Corine Land Cover (CLC) up to the third level.CLC nomenclature does not distinguish the texture and the crown cover density of the forests and includes, for example, in the class 311 generically \"deciduous and evergreen broad-leaved tree species with >75% cover\". Nevertheless, a different degree of canopy closure is important to understand and to describe the transition dynamics occurring; since, through photointerpretation of the available images, it was possible to discriminate the different crown cover density, in some cases a fourth digit (level) was introduced to describe the texture of forest trees coverage. A simplified LULC map has been obtained by merging the original CLC categories into six larger groups, or macroclasses, which are representative of the main transformations observable in the detailed transition matrix: Artificial surfaces (AS), Arable lands (AL), Grassland (GR), Forest (FO), Shrubs and herbaceous plants (SH) and Bare rock (BR) (Figure 4). Figure 3: Coverage of the photos after orthorectification and georeferencing. The cross-tabulation matrix (transition matrix) was computed using overlay functions in ArcGIS software to analyze Land Cover transitions. Analysis of gains, losses, persistence and net change were carried out for the period: 1954-2016. The computed transition matrix consists of rows that display categories at time 1 and columns that display categories at time 1 and columns that display categories at time 2 and columns that display categories at time 3 and column 4. \begin{table}
\begin{tabular}{c c} \hline
**CLC Code** & **Land Cover Class** \\ \hline
1 & Artificial surface \\ \hline
21 & Arable lands \\ \hline
311-a & Structured deciduous forests \\ \hline
311-b & Compact deciduous forests with fine texture \\ \hline
311-c & Open deciduous forests with rare or none undergrowth \\ \hline
312-a & Coniferous tree planting \\ \hline
312-b & Closed coniferous forests \\ \hline
312-c & Open coniferous forests \\ \hline
321-a & Meadows of the sinkholes on red earth and nardus grasslands \\ \hline
321-b & Mesophilic and xerophilic grasslands \\ \hline
321-c & Grasslands with prostrate shrubs and scattered trees \\ \hline
321-d & Grasslands with tall shrubs and scattered trees \\ \hline
322-a & Prostrate shrubs \\ \hline
322-b & Tall shrubs, arboreal-shrub colonization formations \\ \hline
324-a & Sparse deciduous forests \\ \hline
324-b & Very sparse broad-leaved forests with mainly herbaceous formations \\ \hline
324-c & Very sparse broad-leaved forests with mainly shrub formations \\ \hline
324-dc & Sparse coniferous forests \\ \hline
332 & Bare rock \\ \hline
333 & Sparsely vegetated areas \\ \hline \end{tabular}
\end{table} 
Table 2: Land cover classes for the study area in 2016. Figure 4: Grouped Land Use/Land Cover Maps for (**a**) 1954 and (**b**) 2016.  
at time 2. The diagonal elements indicate the proportion of the landscape that shows persistence of the category, while elements off the diagonal indicate a transition from a category to a different one. The land-cover changes (LULCC) for the 1954-2016 period have been assessed both for the detailed LULC maps (Figure 5) and for the simplified LULC maps (Table 3). The gains were calculated as the differences between the column totals and persistence, while losses were calculated as the differences between the raw totals and persistence. The total change has been calculated as the sum of gains and losses and represents the total surface showing a variation in both directions; on the contrary, the net change, calculated as the difference between gains and losses, represents the real variation of each class. The net change does not consider the simultaneous increase and decrease occurring for a land cover class; this phenomenon, defined as \"swap\" by some authors, can be calculated as the difference between total change and net change.