Changes in Forest Area of Coastal Communes of Baltic Sea as a Result of the Impact of Tourist and Recreational Loads

The seaside area is one of the most forested in the country. At the same time, the forests in the coastal zone are exposed to a strong anthropogenic pressure due to a high concentration of tourism development and tourism. The aim of the study was to analyze the changes in the forest area availability of the coastal tourist municipalities of the Baltic Sea Coast in connection with the changes in the area of tourism development and tourism in this area. The analysis was conducted in dynamic terms, taking into account the years 2000–2016. In this study, all the communes that directly border the Baltic Sea were taken into account as seaside communes. The statistical data of the Local Data Bank of the Central Statistical Office were used as the source material for the implementation of the research problem addressing: the changes in the area of total forests in all coastal communes of the Baltic Sea Coast in 2000–2016, the changes in the area and population of communes, and selected data on the tourist function of the coastal communes including the data on the number of facilities and beds as well as the number of tourists visiting the coastal communes of the Baltic Sea Coast between 2000–2016. In the coastal communes, in the years 2000–2016, the forest cover index increased from 23.3 to 24.1%. Since 2000, the forest area per 1 inhabitant increased from 1741 m2 to 2149 m2. The increase in the forest area and average forest area per capita occurred mainly in the rural communes, large communes with the highest forest cover indicators, in the urban communes while in the communes with a strongly developed tourism function, there was an opposite tendency. The increase in the tourism load on the forest areas and decrease in the availability of forests for tourists in the municipalities and communes with the largest tourist investment (Kołobrzeg, Międzyzdroje, Władysławowo) is observed. The anthropogenic pressure and the availability of forest decreases in communes with lower population and the marginal role of tourism in their socio-economic development (Choczewo, Trzebiatów, Smołdzino, Kamień Pomorski).


INTRODUCTION
The area of forests in Poland amounts to 9,214.9 thousand ha [GUS, 2016], which corresponds to the forest cover (share in the land area of the country) at the level of 29.5% [Sulewski 2018]. The average forest area in the European Union ranges from 32.8% to 37.9%. Compared to the national average and European average, the coastal area in northern Poland is characterized by a high degree of afforestation (Pomorskie Voivodeship -36.3%, Zachodniopomorskie Voivodeship -35.4%). The forests in the immediate shore zone of the Baltic Sea play a crucial role as they stabilize and strengthen the shoreline [Kluczyński and Kreft 2003]. The spatial distribution of the forest sites is very well reflected by the spatial distribution of the dominant species. The dominant species are pine, beech and birch [Piotrowska 2003]. However, due to high seasonal tourist traffic resulting from the high attractiveness of the area, they are exposed to high anthropogenic pressure [Parzych 2001]. The change in forest area is most often associated with the development of both tourist infrastructure as well as the tourist and recreational function of forests. Taking into consideration the subject of this study, the works on the changes in the forest cover in Poland [Nyrek 1997, Ciesielska and Ciesielski 2017, Polna 2017, Falencka-Jabłońska 2017], specific types of landscape [Grzywacz 2002, Polna 2017 or selected regions [Szymura et al. 2010, Kunz 2012, Gorajska 2014] seem particularly important. The issues related to deforestation and afforestation [Fonder 2002, Sulewski 2018 as well as the spatial and organizational aspects of shaping the country's forest cover are also of great significance [Łonkiewicz 1994[Łonkiewicz , Fonder 2002. The issue pertaining to the impact of various anthropogenic factors on the forest ecosystems was addressed, among others, by Pasek and Zalewska [2011], Parzych et al. [2012], Parzych and Jonczak [2013] and Parzych [2014]. To date, however, there has been a lack of studies regarding the subject of the changes in the forest area in connection with tourist traffic and the development of tourist facilities as well as the changes in the tourist and recreational load of the forests in coastal areas. Therefore, research was undertaken to assess the changes in the forest area in relation to population and the number of tourists, the number of accommodation facilities and their capacity as well as the changes in the tourist and recreational load of forests in the communities of the Baltic Coast.

Stand characteristic
The Polish Baltic coast covers 528 km of coastline. The studied area is located within the borders of the Zachodniopomorskie and Pomorskie Voivodships. In physical and geographical terms, the coast is a part of the macro-region of the Southern Baltic Coasts (Szczecinskie, Koszalińskie and Gdańskie) extending from the Bay of Kiel to the Vistula Lagoon). They cover an area of about 19,000 km 2 and were shaped under the influence of the Scandinavian Ice Sheet and subsequent abrasive and accumulative activities of the sea as well as aeolian and fluvioglacial processes. For the purposes of this study, it was assumed that the coastal communes comprise the communes of the Baltic Coast, bordering directly with the Baltic Sea shoreline. In terms of administration, the studied area comprises 36 communes: 15 in Zachodniopomorskie Voivodeship (Świnoujście, Międzyzdroje, Dziwnów (community: urban and rural), Rewal, Trzebiatów, Kołobrzeg (community: urban and rural), Ustronie Morskie, Mielno (community: urban and rural), Będzino, Darłowo (community: urban and rural) and Postomino), and 21 in Pomorskie Voivodeship (Ustka (community: urban and rural), Smołdzino, Łeba, Wicko, Choczewo, Krokowa, Władysławowo (community: urban and rural), Jastarnia (community: urban and rural), Hel, Puck (community: urban and rural), Kosakowo, Gdynia, Sopot, Gdańsk, Stegna, Sztutowo and Krynica Morska). The source material for the implementation of the research problem was statistical data of the Local Data Bank of the Central Statistical Office (GUS) regarding the changes in the forest area, total area and population, the number of accommodation facilities and the number of tourists visiting the coastal communes. The analysis was carried out in dynamic terms, taking into account the years 2000-2016.

Data analysis
On the basis of the collected data, the forest cover indicators, forest area indicators per capita, per 1 accommodation facility, per 1 bed place and per 1 tourist as well as forest tourism and recreation load indices in 2000-2016 were calculated. The results were presented using cartograms. The interrelationships between the changes in the forest area against the background of the population changes, development and tourism intensity were expressed using Spearman's correlation coefficients (p <0.05). Using the Principal Components Analysis (PCA) method, two main factors (F1 -tourist factor, F2 -area factor) explaining in total 75% of the variance, were identified. By using the hierarchical cluster analysis (Ward's method), the diminishing similarity between the changes in forest area in 36 examined communes directly neighbouring the Baltic Sea shoreline and the changes in tourist traffic in 2000-2016 were presented. The STATISTICA 13.1 software package was used for the calculations.
In the years 2000-2016, a decrease in forest cover indices was noticed in 7 communes, the most significant in Międzyzdroje (46.8%) and Kołobrzeg (31.7%). In total, in 2000, there were 93 490 ha of forests in the coastal communes and in 2016 -98877 ha (Table 1). In

The relationship between the density of forest area and the number of tourists in the coastal communes
The relationships between the changes in the forest area, total area of the communes, population and selected measures of tourist function were ex- accommodation services provided and the population (r=0.79 and r=0.61 at p<0.05, relatively). Statistically significant correlations were shown between the number of tourists and the population (r=0.77), the number of accommodation facilities (r=0.57) and the number of bed places (r=0.68). However, no statistically significant correlation was found between the changes in the forest area and other variables describing the area, population and other measures of the tourist function (Table 2). In the Principal Component Analysis, two main factors were identified (Tab. 3). The first factor (F1 -tourist) explained 44% of the variance and indicated the relationship between the number of bed places, the number of tourists and the number of accommodation services provided. These variables were characterized by high, negative factor loading values. The second factor (F2 -area) explained 31% of the variance and was created by high, positive factor loading values: forest area and the total area of communes.
In order to determine the spatial differences in the scope of the interrelationship of the changes in the forest area and the area in total, population and tourist function measures in the coastal communes, a hierarchical cluster analysis using the Ward's method was performed (Fig. 3  In the communes with declines in forest cover, these were most often due to the changes in the area of communes (increase in the total area by the lands of lower afforestation rate). An example would be the communes of Kołobrzeg and Międzyzdroje, where the forest area remained unchanged while the forest cover rates decreased significantly.

Diversity of accommodation facility development density in the forest areas of the coastal communes
In the years 2002-2014 there was an increase in the average forest area per capita, from 1741 m 2 to 2149 m 2 per capita. It mainly concerns the large rural communes, the reverse trend occurred in urban communes (Kołobrzeg, Międzyzdroje, Sopot, Gdańsk) and other intensively developed ones. In the urban communes most intensively used for tourist purposes (Kołobrzeg, Ustka, Łeba, Władysławowo, Gdańsk, Mielno), with intensive development of the accommodation base, there was a significant decrease in the forest area per 1 accommodation facility. This is associated with a drop in the accessibility of forests for tourists and an increase in the tourist anthropogenic pressure in the forest areas. There is a group of communes (Wicko, Smołdzino, Kamień Pomorski, Trzebiatów, Choczewo), where the forest area per 1 facility and per 1 bed place has increased. It is connected with the afforestation of agricultural land or wasteland owned by the Agricultural Property Agency of the State Treasury, originating from liquidated state farms (PGR) [Polna 2017]. The changes in the forest cover indices in some communes are also caused by the changes in the total area and the administrative system [Ciesielski and Ciesielska 2017]. An example is the Władysławowo commune, where the changes result from the separation of the new urban commune of Władysławowo from the area of the previously existing one, with the largest number of accommodation facilities on the coast. The lowest values of the forest area indices per 1 bed place and the highest drops in the values of these indices are characteristic for the communes most intensively used in terms of tourism (Władysławowo Kołobrzeg, Dziwnów, Międzyzdroje and Darłowo). This is due to the dynamic development of the accommodation base. In these communes, the level of potential tourist and recreational anthropogenic pressure on forest areas is much higher. As Pasek and Zalewska

The relationship between the density of forest area and the number of tourists in the coastal communes
The increase in the number of inhabitants and the intensity of tourist traffic in coastal communes is significantly correlated with the spatial development of the residential and tourist buildings as well as elements of tourism and recreation facilities development which determines the decrease in the forest area and the increase in the tourist and recreational pressure on the existing forest areas [Parzych 2001, Stępień 2005, Pasek and Zalewska 2011. This is accompanied by the phenomena of trampling new paths, soil surface erosion caused by riding bicycles on nondesignated routes, excessive noise and pollution associated with walking the dogs [Stępień 2005, Jalinik 2016]. Another problem, also related to the growing scale of tourist traffic in the forest Note: factor loading levels higher than 0.7 are in bold areas, seems to be the entry of new forms of recreation and tourism such as jogging or various types of cycling sports, such as freestyle biking or downhill biking [Cieszewska 2008]. The high level of development of the tourist function is associated with the adoption of new areas for accommodation facilities and other tourist development elements, often at the expense of forest areas [Cieszewska 2008, Jalinik 2016]. This is confirmed by the results of the cluster analysis. The communes in the A1 cluster are grouped by similarity of high development and tourist traffic measures with the moderate and low forest areas, while in the A2 cluster by moderately high values for the facility development and tourist traffic and lower forest cover measures. The B1 cluster included the communes showing similarity due to significantly lower values of development and tourist traffic measures with significant differences in the forest areas, whereas B2 comprised the communes with similar total area, forest cover rates and significant differences in the values of tourist function measures. The C1 cluster consists of the communes with a low number of tourists and bed places, significantly differentiated forest cover rates as well as total areas and population while the C2 cluster comprises the communes similar in terms of total area, forest cover and lower values of tourist function measures (Fig. 3).

CONCLUSION
In the coastal communes of the Baltic Coast, in the period 2000-2016 a significant increase in forest cover rates was observed. The most significant increase occurred in the rural communes, with large areas, sparsely populated and with domination of non-tourist socio-economic development functions. At the same time, the decrease in the forest area per one accommodation facility and 1 bed place as well as per 1 tourist resulting from the intensive development of facilities and tourist traffic in most of the coastal communes was observed. There was also an increase in the tourist load of forests and a decrease in forest area per capita and per 1 tourist in the urban communes and in the communes best developed in terms of tourism (Kołobrzeg, Międzyzdroje, Władysławowo). The lowest impact of anthropogenic pressure and the increase in the forest area per capita and per 1 tourist were demonstrated in the communes with lower population density and low development of tourist and recreational facilities (Choczewo, Trzebiatów, Smołdzino, Kamień Pomorski).