## 3 Results
### Forest Cadastral Data  
In the next stage of the study, forest cadastral data were used to monitor forest cover change in the long term. The downloaded forest cadastral data were uploaded into the ArcGIS software package and data analysis and comparison with previously conducted research was performed. The following attribute data were used in this study: forest area and age. The areas of forest plots in the municipalities of Jurbarkas District and in the district itself were determined during the research. Analysis of these data aimed to determine the current officially declared forest area, which does not necessarily coincide with the forest cover areas and the distribution of forest areas according to the age of the trees growing in them. Table 7 presents the area occupied by forest land valuation plots as a percentage of the municipal areas. Table 7 shows that according to the forest cadastral data provided, the area of forest valuation plots in the elderships is 18.8-82.8% of the area of the elderships. The size of the forest areas in Viesvile and Jurbarkas elderships stands out from other elderships--82.8% and 56.2%, respectively. The forest area covers more than 30% in six out of twelve elderships. The average forest area in the municipalities is 35.4%. The forest area reaches 38.9% in Jurbarkas District. Additional research was carried out with the help of historical GIS methods. After dividing the data into groups according to the age of the dominant trees in the plots, an analysis of the dominating forest areas according to age was carried out. Age intervals are every 19 years, ranging from 10 to 225 years. In order to distinguish clear cuttings and newly planted areas, the first ten years are divided into periods of 0-5 and 6-9 years. After \begin{table}
\begin{tabular}{c c} \hline \hline
**Elderships** & **Area of Forest, \%** \\ \hline Erzvilkas & 26.4 \\ Girdziai & 33.2 \\ Juodaiciai & 18.9 \\ Jurbarkai & 56.2 \\ Jurbarkas city & 18.8 \\ Raudone & 25.7 \\ Seredzius & 35.4 \\ Skirsnemune & 20.5 \\ Smalininkai & 40.9 \\ Simkaiciai & 29.1 \\ Veliuona & 36.4 \\ Viesvile & 82.8 \\ Jurbarkas Distr. & 38.9 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Forest areas according to the data from the Forest Cadastre as a percentage of the area of the elderships. determining the polygons falling into the relevant age ranges, the percentage of the total area of the polygon of the forest located in the elderships (Table 8) was calculated. Jurbarkas District elderships and Jurbarkas District are dominated by forest areas comprising trees from 0 to 99 years of age. Forest areas with trees of 100 years of age and older are few and insignificant. Areas (in eleven out of twelve elderships), when examined according to the age of growing trees, decrease significantly after reaching the age of trees of 100 years or more and make up only 0.4-8.8% of the area of elderships. Considerable areas occupied by 100-139-year-old trees have remained only in the urbanized area, i.e., in the City of Jurbarkas. Only three of the twelve municipalities have forest areas with trees older than 160 years. One eldership stands out--Viesvile--where we can see even small areas with trees over 200 years old. The distribution of trees by species in the plots (dominated by trees older than 160 years) is as follows:  
1. From 160 to 179 years old: 50% of pines, 16.7% of spruces, 33.3 of oak trees;
2. From 180 to 199 years old: 71.4 % of pines, 28.6 % of oak trees;
3. 200 years and older: 95.7 % of pines, 4.3 % of spruces trees. The data visualized by the forest cadastre on the maps are presented in Figures 14 and 15.