Silviculture and Cinegetics Review - Societatea Progresul Silvic

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FORESTRY BELTS SILVICULTURE AND CINEGETICS REVIEW XVII/30/2012 Although at the beginning of the 20th century our country, through the shelterbelt programme for Bărăgan, Ialomiţa and Brăila regions, was first worldwide ranked in this domain, after 1962, the political regime of that period decided to cut off most of forest shelterbelts. Only the forest shelterbelts established by the Romanian foresters in the Cadrilater (Southern part of the Dobrogea, ceded to Bulgaria in 1940), in the interwar period, have been maintained and remain functional. The question of forest shelterbelts in Romania was returned after 1989, and the Law no. 289/2002 create the legal frame for their establishment (Ianculescu, 2001; ***, 2002a; ***, 2002b). The paper represents a synthesis of the research outcomes gathered in the field of the forest shelterbelts, of the gained experience also of designing and implementation of the forest shelterbelts, and has prevalently approached the Danube Plain and the Dobrogea Plateau, because in these regions there are signals of degrading processes of environmental conditions, especially the drying aspect (Costăchescu and Dănescu, 2005, 2006; Mihăilă, 2006; Dănescu and Costăchescu, 2009). This paper addresses to the experts in agriculture and silviculture, the institutions responsible for fundament agriculture and forestry policies, and physical and juridical person wishing to establish forest shelterbelts, presenting available solutions to achieve the forest shelterbelts networks at territorialadministrative level, based on current conditions: environmental, land use and land register. 2. Materials and methods To establish the forest shelterbelts network at the level of geographical units discussed (the Danube Plain and Dobrogea), based on the results of the previous research studies that became official by technical norms, only arable lands and pastures were considered (by orthophotomaps vectorization at 1:5000 scale), being excluded from the beginning the orchards, vineyards, built settlements and, of course, the lands covered by forest vegetation. Therefore, it resulted the total infield area considered for establishment of the forest shelterbelts network (2.806.989 ha in the Danube Plain and 679.958 ha in Dobrogea). 2.1. Theoretical location of the forest shelterbelts network in the Danube Plain and Dobrogea In order to adopt the technical solutions to establish the shelterbelts, it was necessary to framing the ecological site conditions of the analyzed territory. During this stage an important phase was the establishment of the dominant soil types in all localities, mentioning that the preliminary classification was made based on the information provided by the pedological map scale 1:200 000, carried out by the RIPA (Research Institute of Pedology and Agrochemistry) (***, 1963-1986), over which were overlapped administrative boundaries of localities. For this purpose it was necessary the preliminary geo-reference of the soil map, using ortorectified aerial images. The afforestation solutions were established by soil types and soil types groups ecologically similar, linking the ecological requirements of species with the ecological soils characteristics. Transfer the afforestation solutions on the plans was, therefore, carried out by their association with the soils already highlighted on the working maps. Over these layers of diverse information (geographical, hydrological, pedological, afforestation solutions, administrative, infrastructure, etc.), was established the theoretical network of forest shelterbelts (Figure 1). The network consists of the main shelterbelts spaced at 600 m and secondary shelterbelts that intersect the main shelterbelts at a distance of 1200 m (this being the most frequent size of agriculture plots). Considering the direction and frequency of the prevailing winds, the main shelterbelts were northsouth oriented. For reasons related to the necessity to compensate the protective effect reduction due to the increasing distances between the shelterbelts (to distance optimal considered –1000 m x 500 m) by increasing the width of the secondary shelterbelts, and the necessity to simplify the design and subsequent establishment of the network shelterbelts, for the shelterbelts a unique width of 10 m was adopted. The theoretical network of shelterbelts was interrupted in the crossing points with the main communication ways (railways, highways, national roads and county roads) and with the waters (rivers, lakes, ponds). The network shelterbelts area of localities, land use categories and afforestation solutions were resulted of overlapping that network over the above-mentioned information layers, on that basis being further determined also the required quantity of afforestation stock. 51
FORESTRY BELTS SILVICULTURE AND CINEGETICS REVIEW XVII/30/2012 To achieve the GIS analysis of the existent information in order to assess the area to be planted with forest shelterbelts for field protection, but, also, to identify the corresponding areas for different afforestation solutions, the following information sources (data) were used: • Geomorphological map included in the atlas of Romania (Institute of Geography), printed in 1976, has been used to delineate the two geographical units (the Danube Plain and Dobrogea), carrying out the layers of polygons that highlights the two regions. • Ortophotoplans were used to accurately identify the arable land and pastures. On the ortophotoplans the outlines of arable lands and pastures were vectorized, to which was assigned the appropriate code (arable land or pasture). Through this operation the areas which are not subject to the establishment of the forest shelterbelts network for field protection, have been eliminated from the very beginning (orchards, vineyards, social-economic objectives, built settlements, forest areas etc.). • Administrative maps at county level scale 1:100.000 were scanned, georeferenced and used to vectorize the joint limits. After their vectorization corresponding attributes (commune name, Siruta code, and the county they belong to) have been introduced. Therefore, resulted the polygon layer with administrative units (communes, counties). • Soil maps 1:200.000 made by the Institute of Geology in 1969 have been scanned, georeferenced, and then vectorized, introducing the corresponding characteristics of each soil type and resulting thus a GIS data base of the studied area soils. At this stage, using the pedological criteria, the floodplains areas with alluvial soils (usually sandy) have been delineated, that have not been taken into consideration, because they are considered as wetlands and the necessity of establishing forest shelterbelts is lower (also questionable) and also such areas show a low productive potential to agriculture (being more suitable for larger-scale afforestation). • GPS data were collected through field visits conducted in the sandy soil areas identified in the above-mentioned data base. Visiting some of such areas it was observed the fact that they have extended and their extending boundaries were marked (by points or continuously) using GPS Trimble equipment class GIS type GeoXT and Geo XM and the Trimble TerraSync software. For an easier identification georeferenced images were used (ortophotoplans with the limits of the sandy areas or the topographic maps) uploaded in the GPS. The GPS data were downloaded and processed at the office stage by the Trimble Pathfinder Office software and finally were integrated in the GIS system. Using the GPS data and the existent pedological data, has been assessed an estimation of the extension of the sandy soils areas and it has been materialized in this extended database. Based on this estimation, the areas with sands and sandy soils were delineated, that also were not taken into consideration, requiring a specific approach, different from the one used for the field forest shelterbelts, due to the low agricultural productivity and to the additional aridity determined by the extended sands. 2.2. Generation of shelterbelts network and GIS analysis • The network of forest shelterbelts with theoretical dimensions of 600 m x 1200 m has been automatically generated for the entire country area, following that after the clipp type GIS analysis only the area which is the objective of this stage. • GIS Analysis. Finally, by using the GIS data layers could be carried out the specific spatial analysis. In pursuance of the spatial analysis have resulted the GIS data necessary to establish the areas corresponding to the afforestation solutions, on geographical units, land use categories and administrative-territorial units. For this purpose the GIS ArcGIS 9.2 software has been used. The main factors that have to be taken into account in the settlement or distribution of the forest shelterbelts on the administrative area of the localities in case of design the shelterbelts network at the localities level are: topography, surface shape, climate, soil and bedrock, hydrologic conditions of the region (represented by groundwater, surface waters courses and the irrigation canals network), spontaneous and cultivated woody vegetation, the work methods and the machinery used in agriculture, as well as the railways, highway and roads of general use network. Depending on these factors the necessary basic elements for shelterbelts establishment are determined, as following: orientation, distance, width and openings between shelterbelts. For knowing of the land shape the localities topographical plans at 1:10000 or 1:5000 scale are used, obtained from the specialised units (National Agency of Cadastre or county land registration offices). 52
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Silviculture and Cinegetics Review - Societatea Progresul Silvic

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