Introduction

Research objective

Near Krakow, the most famous wooden churches are the wooden churches of southern Małopolska, which were inscribed as UNESCO World Heritage Sites (WHSs) in 2003 (Kurek and Iop, 2018). This includes the six best-preserved and oldest gothic wooden churches in the region (Table 1Footnote 1). These churches were constructed via the horizontal log technique common in Eastern and Northern Europe since the Middle Ages (14th–17th centuries), featuring intricate spatial structures that typically include a tower, nave, chancel, and external galleries. They are renowned for their exquisite woodwork details, unique architectural designs, and engineering solutions (Lubowiecka et al., 2021).

Table 1 Basic information on wooden churches near Krakow, Poland (WHS).
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The vulnerability of wooden churches

Wooden churches are considered endangered monuments because of the perishable nature of their building materials and the incomplete understanding of this particular architectural type (El-Gamal et al., 2016; Mirra et al., 2023). Moreover, as wood is more susceptible to adverse atmospheric conditions and fire than stone/brick, wooden churches are less durable and more prone to destruction and reconstruction, necessitating more frequent restoration (Chang et al., 2021; Poljak and Ponechal, 2023). Additionally, artifacts that form within these buildings have varying reactions to changes in temperature and relative humidity, which may affect their mechanical, biological, and chemical damage (Silva and Henriques, 2015). Historical buildings are often required to meet necessary indoor environmental conditions. Inappropriate microclimates can lead to damage to panels and structural deterioration (Sharif-Askari and Abu-Hijleh, 2018). Maintaining relative humidity at appropriate levels is crucial, as fluctuations can be particularly detrimental to multicolored wood and oil paintings on canvas (Ferdyn-Grygierek and Grygierek, 2019). Wood is a hygroscopic material, and its moisture content depends on surrounding conditions, with the response of wooden objects to fluctuations in relative humidity not always immediately apparent (Grottesi et al., 2023). However, when exposed to specific temperature and humidity levels, wood reaches an equilibrium moisture content (Bratasz et al., 2012). The stability of relative humidity can be influenced by excessive or inadequate ventilation. Therefore, wooden cultural heritage, exemplified by wooden churches, is sensitive to climate and meteorological conditions and requires focused assessment and maintenance.

Impact of climate and meteorological conditions on wooden cultural heritage sites

Changes in humidity affect the growth of microorganisms on wooden heritage materials, with an increase in relative humidity exacerbating the biodegradation of cultural heritage site materials during climate warming (Haugen and Mattsson, 2011). Prolonged humidity increases the relative humidity and moisture content of materials. With increasing temperatures, conditions favorable for various biological activities are created. The accumulation and decay of biomass from fungi, algae, lichens, and insects lead to the deterioration of historical wooden buildings (Richards and Brimblecombe, 2022). Termite activity can cause the collapse of wooden structures, with their range of activity potentially expanding further north in the case of climate warming. Fungal infestation is one of the main causes of wood degradation. Haugen and Mattsson (Haugen and Mattsson, 2011) identified temperature, air humidity, and wood moisture content as the three main variables leading to fungal and insect biodegradation. Wood moisture content is influenced by increases in precipitation, storms, and floods (Orr et al., 2018). With increasing temperature and humidity, wooden structures in northern and eastern Europe, as well as northwest British Isles, face a greater risk of fungal colonization (Zakharov, 2019). The risk of decay in wooden historical buildings in northern Europe is predicted to increase. In contrast, due to expected drought, the risk of fungal growth is lower in southern and western Europe (Giordani and Incerti, 2008).

This study collected geographicl, transportation, hydrological, climate, and meteorological data for the study area, using the six wooden churches near Krakow in southern Małopolska (a World Heritage site) as examples. This study qualitatively and quantitatively explores the impact of climate and meteorological conditions on the cultural heritage sites of Poland. This study aims to comprehensively investigate and explore the following questions: (i) How do meteorological conditions and historical climate conditions directly and indirectly affect Poland’s cultural heritage sites? (ii) What are the characteristics and lessons learned from the construction, materials, and maintenance of Polish wooden churches to address local climate and meteorological conditions?

Methodology

Literature review

Recent international research related to key terms such as “wooden churches,” “wooden cultural heritage sites,” and “climate change” has been summarized. The review encompasses (i) the significance and role of wooden churches in Poland, (ii) the impact of climate change and meteorological conditions on wooden cultural heritage sites, and (iii) practical restoration, preservation, and issues concerning Polish wooden churches.

I have marked the six wooden churches included in the UNESCO World Heritage list near Krakow, Poland, on an administrative map of Poland (Figs. 1A and 2, Table 1). The smallest core area of the six wooden churches occupies 0.14 ha, whereas the largest covers 2.2 ha, with buffer zone areas ranging from 16.5 to 64 ha (Table 1). The six World Heritage churches share a common historical origin (Fortuna-Marek, 2017) and are located in the hilly region in the southwest corner of Poland, with elevations ranging from 280 to 533 m (Fig. 1A, Table 1). Geographically and climatically speaking, the area where wooden churches are situated is characterized by lower terrain, located in the heart of the East European Plain (Frensch et al., 2023), with slopes ranging from 1.1° to 5° (Robinson et al., 2014), and a predominantly cold temperate and arid climate (Metzger et al., 2013). The annual average temperature ranges from 0.1 to 10 °C, with annual rainfall between 501 and 750 mm (Hijmans et al., 2005), making the climate conditions favorable.

Fig. 1: Distribution of wooden churches near Krakow, Poland (WHS).
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A Distribution and elevation. The red dots represent the location of the research area. B Large-scale map of wooden churches. 1. Church of the Archangel Michael, Binarowa; 2. Church of All Saints, Blizne; 3. Church of the Archangel Michael, Dębno; 4. Church of the Assumption of the Blessed Virgin Mary and the Archangel Michael, Haczów; 5. Church of St Leonard, Lipnica Murowana; 6. Church of St Philip and St James the Apostles, Sękowa. Red blocks, church group registration zone; yellow blocks, buffer zone, scale of direct protection of foreground exposure for the registration zone.

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Fig. 2: Representative views of wooden churches near Krakow.
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A Church of the Archangel Michael, Binarowa. B Church of All Saints, Blizne. C Church of the Archangel Michael, Dębno. D Church of the Assumption of the Blessed Virgin Mary and the Archangel Michael, Haczów. E Church of St Leonard, Lipnica Murowana. F Church of St Philip and St James the Apostles, Sękowa. Photo from Fortuna-Marek (2017).

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Geographicl, transportation, hydrological, climate, and meteorological data for the study area were collected to qualitatively and quantitatively investigate the impacts of climate and meteorological conditions on the cultural heritage sites of Poland. Various spatial analysis techniques and data sources were utilized for this study (Table 2). Additional graph data were sourced from papers published in scientific journals (Linke et al., 2019). For example, climate zones (Metzger et al., 2013), temperature (Hijmans et al., 2005), precipitation (Hijmans et al., 2005), climate humidity indices (Hijmans et al., 2005), elevation (Robinson et al., 2014), and terrain slopes (Robinson et al., 2014) have been used.

Table 2 Data used and their sources.
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Furthermore, daily relative humidity (RH, %), daily temperature (T, °C), and monthly/yearly relative humidity (RH%) data were collected from current weather and historical climate data of the six wooden churches located in southern Małopolska. On the basis of the literature review regarding microclimate standards for protecting wooden cultural heritage sites (Table 3), a risk assessment of historical and current climate and meteorological conditions for the protection and maintenance of Polish churches was conducted via monthly/yearly relative humidity (RH, %) data from current and historical weather data. For ease of reference, the six wooden cultural heritage sites are labeled 1–6 in the figures throughout the paper, corresponding to the following: 1. Church of the Archangel Michael, Binarowa; 2. Church of All Saints, Blizne; 3. Church of the Archangel Michael, D ębno; 4. Church of the Assumption of the Blessed Virgin Mary and the Archangel Michael, Haczów; 5. Church of St Leonard, Lipnica Murowana; and 6. Church of St Philip and St James the Apostles, Sękowa.

Table 3 International guidelines on the preservation of wooden cultural heritage sites.
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The fire weather index (FWI) is the fire weather index(FWI) system and is a internationally recognized standard for predicting various aspects of fire activity (Wagner, 1987). First, historical FWI samples were compiled for multiple seasons. Second, the average number of extreme days allowed for each season was determined, and a lower limit was set for extreme classes. Alternatively, the FWI scale can be simply divided to provide a predetermined proportion of days in each class. The average FWI data for Europe from 2000 to 2020 are sourced from ECMWF and Copernicus Atmosphere Monitoring Service, with monitoring stationsFootnote 2, where Danger from weather represents the proportion of days in a year with an FWI exceeding 30. Moreover, I extracted the land-use types of each WHS buffer zone via the site and buffer zone boundary files of the wooden churches. Land use data: CORINE land cover data provide annual information on land cover types for Europe at resolutions of 250 and 100 mFootnote 3.

I used ArcMap 10.5 to visualize the map atlas. I used the packages “sf”, “raster”, “rnaturalearthdata”, and “rnaturalearth” in R 4.0.1 software to read the map data and the packages “ggrepel”, “ggplot2”, and “showtext” in R 4.0.1software for plotting. Finally, worldwide datasets were captured by drawing software such as Adobe Illustrator 2020 along the administrative boundaries of Poland.

Results and discussion

Locations of the wooden churches in the study area

In terms of Poland’s transportation network, the region where the wooden churches are located has relatively sparse transportation infrastructure (Fig. 3A), with a low percentage of artificial surfaces in the buffer zones (ranging from 12% to 34%, Table 4). Therefore, the wooden churches in this study are primarily situated in suburban and rural areas with low levels of urbanization and minimal direct human impact. Looking at the primary land use types in the buffer zones of the six churches (Table 4), fores and tland use predominates, significantly increasing the risk of forest fires in the region, necessitating a focus on forest fire prevention (Sesana et al., 2021; Sarkar et al., 2022). Despite having a developed network of water systems and a dense river network (Fig. 3B), the area is located upstream in the Polish watershed and has few lakes (Sojka et al. 2020). On the one hand, the upstream location reduces the likelihood of flooding, making the historical positioning of wooden churches logical from a modern scientific perspective (Małecki, 2023). On the other hand, the region is characterized by numerous rivers but few lakes, resulting in a weaker capacity to store extreme precipitation. Therefore, it is essential to assess and prevent extreme precipitation events and their consequences in this area (Woolway et al., 2020).

Fig. 3: Traffic and drainage networks of wooden churches near Krakow, Poland.
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A Traffic networks. B Drainage distribution. The red dots represent the location of the research area. 1. Church of the Archangel Michael, Binarowa; 2. Church of All Saints, Blizne; 3. Church of the Archangel Michael, Dębno; 4. Church of the Assumption of the Blessed Virgin Mary and the Archangel Michael, Haczów; 5. Church of St Leonard, Lipnica Murowana; 6. Church of St Philip and St James the Apostles, Sękowa.

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Table 4 The first-level land use types within the Wooden Churches buffer zone and their weather-driven fire risk.
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Compared with Poland’s wooden churches, Sweden’s churches are located predominantly in rural and low mountain areas, such as in Dalarna Province, where the elevation generally ranges from 200 to 500 m. The terrain is relatively flat, and the cold temperate climate conditions are similar to those in Poland. However, Sweden has greater forest cover and a greater risk of forest fires. Consequently, Sweden has invested more resources in forest fire prevention and has implemented stringent forest management strategies to protect its wooden cultural heritage sites from fire threats (Li et al., 2023). In Finland, wooden churches are found further north, such as in Lapland Province, where the elevation is lower, but the winter climate is harsher, with average annual temperatures below those of Poland and lower precipitation levels. Finnish wooden structures require more sophisticated technologies for insulation and moisture protection. Owing to extensive forest coverage, fire prevention is also a critical protective measure (Monkkonen et al., 2022). In contrast, wooden structures in the Italian Alps are situated at higher elevations, typically between 600 and 1800 m. These areas experience more variable climates with higher rainfall, ranging from 800 to 1200 mm, necessitating more frequent maintenance and protection of wooden buildings. Additionally, mountainous regions in Italy are more geologically active, with greater risks of geological disasters such as floods and mudslides, posing greater challenges for the preservation of wooden cultural heritage sites (Bertolini Cestari and Marzi, 2018). These comparisons illustrate that while the wooden churches in Poland, Sweden, and Finland share similarities in climate and geographical conditions, they exhibit significant differences in forest management, fire prevention measures, and climate adaptability. However, Italian wooden cultural heritage sites face challenges such as higher elevations and more frequent geological disasters. By drawing on the successful experiences of these regions, valuable insights can be provided for the protection and management of Poland’s wooden churches.

Potential impact of fire risk on wooden churches

The impact of fire, as an unforeseeable event, on Polish wooden churches cannot be overlooked. On the basis of the primary land use types from the CORINE land cover data (Table 4 and Fig. 4B), I found that forest and grassland land use types dominate the buffer zones of the wooden churches in the study area, each exceeding 35%. The Church of the Assumption of the Blessed Virgin Mary and the Archangel Michael in Łowczówek has the lowest percentage (36%), whereas the Church of St Leonard in Lipnica Murowana has the highest percentage (over 55%). Given the frequent droughts and extremely high temperatures in Europe in recent years (Spinoni et al., 2018; Dupuy et al., 2020), there is an urgent need to comprehensively assess fire risk in the climate conditions of the areas where wooden churches are located. By evaluating the percentage of days in each of the six Polish wooden church areas where the Polish fire weather index exceeds 30, I assessed the fire risk (Fig. 4A). I found that this region has the lowest FWI in Poland, providing a natural advantage for fire prevention in wooden churches. However, our study also identified the buffer zone of the Church of the Archangel Michael in Binarowa as having the highest fire risk (49.2%), followed by the Church of All Saints in Blizne and the Church of the Assumption of the Blessed Virgin Mary and the Archangel Michael in Łowczówek (both exceeding 35%). Therefore, these three wooden churches require focused fire prevention measures. Historically, between the 15th and 20th centuries, Poland had ~3000 wooden religious buildings, including 1700 wooden churches. Six of these churches are listed on the UNESCO World Heritage List. In the past decade, ~50 similar buildings have been destroyed by large fires, e.g., churches in Tarnow (16th century), Witkow (17th century), and Łódzniewice (18th century). In 2005 alone, there were 222 religious building fires in Poland. The most recent incident occurred on September 13, 2006, at the Orthodox church in Kołomątka (built in 1802) (Kurek and Iop, 2018).

Fig. 4: Potential impact of climate-driven fire risk on wooden churches.
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A Levels of climate-driven fire risk in the regions where the wooden churches are located. Percentage of days with danger by weather, FWI (fire weather index) > 30. B The distribution of land-use types in the buffer zones of the wooden churches.

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In comparison, wooden churches in Sweden, such as those in Dalarna Province, face similar fire risks, particularly under the dry climate conditions of summer. Sweden has implemented effective fire prevention strategies, including the use of fire-retardant coatings and regular fire drills. In Norway, wooden churches, such as the well-known stave churches, also present heightened fire risks due to their architectural form and locations, which are often situated in densely forested areas. Norway has effectively reduced threats to its cultural heritage sites through stringent forest management and community-engaged fire prevention measures (Langley, 2000). Additionally, wooden structures in the Italian Alps face more complex risks of fire and geological disasters. Italy has enacted comprehensive risk management strategies in these regions, including meteorological monitoring, community education, and emergency response plans, to protect its wooden cultural heritage sites (Grinzato et al., 2002).

Impact of the current relative humidity and temperature conditions on the protection of wooden churches in Poland

Traditional wooden buildings made of organic hygroscopic materials are highly susceptible to the influence of local microclimates (Verticchio et al., 2021; Camuffo et al., 2022). To protect and preserve these structures, it is essential to assess the impact of microclimates on the deterioration of building materials, following internationally recognized guidelines and protocols (Table 3). Among these factors, the impact of relative humidity and temperature on indoor wooden materials is most significant. UNI 10829 (1999) indicated that for indoor wooden materials such as wooden furniture and sculptures, the allowable indoor relative humidity should be limited to between 50% and 60%, with temperatures of ~19–24 °C (Bienvenido-Huertas et al., 2021). While long-term indoor monitoring data for wooden churches in the study area are lacking, analyses based on historical outdoor climate and current weather data can identify necessary time period for regulating the indoor microclimate of wooden churches, emphasizing the crucial role of human protection (Małecki, 2023).

I focused on daily meteorological data from December 22, 2022, to December 23, 2023, to describe the current weather characteristics of the areas where the wooden churches are located and fit the factor of relative humidity (RH, %) that has the greatest impact on the churches over time (Fig. 5). The annual variation in the current RH is similar among the six wooden churches, with values ranging from <60% in the summer months of July to September, increasing after summer, and reaching the highest values (well above 80%) in the winter and autumn seasons. Additionally, there are significant daily relative humidity fluctuations in spring and summer but minimal fluctuations in autumn and winter (especially in winter), with consistently high humidity throughout these seasons. I marked the ISO 19815 indoor microclimate safety standard (for organic hygroscopic materials: RH = 30–65%) (Camuffo et al., 2022) and the ASHRAE Handbook indoor microclimate safety standard (Chapter 24) (for historical buildings: RH = 30–70%) (Andretta et al., 2017): the current outdoor climate and humidity conditions in the areas where the Krakow wooden churches (WHS) are located significantly exceed the protection standards for the wooden churches and their internal wooden materials, only approaching the upper limit of the ASHRAE Handbook microclimate humidity standard in the summer. Despite Poland’s cool, temperate, and dry continental climate (Metzger et al., 2013), the flat terrain of Poland and the humid maritime breezes from the Baltic Sea result in high relative humidity throughout the year in the region (Tylkowski, 2013). Therefore, significant efforts are required to improve the indoor dryness of wooden church materials and the waterproofing capabilities of external wooden materials (far beyond expectations) to prevent the risk of biodegradation of wooden church materials.

Fig. 5: Seasonal variations of temperature and humidity effects on wooden churches.
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RH time series in Binarowa (A), Blizne (B), Dębno (C), Lipnica Murowana (D), Haczów (E), and Sękowa (F) together with the thresholds defined by the standards: Handbook (Chapter 24) (dark red line) and ISO 19815 (red line). RH, relative humidity (%). The data points of the four seasons are drawn with different colors, and the blue line connects the data points of the time series and plots the trend curve via the “loess” fitting method. The horizontal axis presents only the corresponding year and month.

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Furthermore, on the basis of the UNI 10829 indoor microclimate safety standard (Table 3) (Bienvenido-Huertas et al., 2021), I identified patterns of temperature and RH for the four seasons in the areas where the wooden churches are located (Fig. 6), with the standard ranges for average daily relative humidity and average daily temperature represented by blue and red lines, respectively. I found a similar correlation between average daily relative humidity and average daily temperature under the current climate conditions, with higher temperatures corresponding to lower humidity levels. Therefore, compared with those in summer, more human intervention and energy supplies are needed for indoor heating and moisture prevention in winter. The temperatures in the region during summer generally comply with the UNI 10829 indoor microclimate safety standard (for wood manufacturers: RH = 50–60%; T = 19–24 °C), but the relative humidity remains slightly high. Overall, the current climate conditions in the areas where the Krakow wooden churches are located suggest that protecting the local wooden cultural heritage sites requires sufficient indoor moisture prevention and outdoor waterproofing work throughout the year, especially in winter. Additionally, efforts are needed to maintain indoor temperatures in all seasons, with Polish wooden churches requiring year-round regulation and maintenance of the indoor microclimate (increasing temperature and reducing relative humidity).

Fig. 6: The impact of humidity on wooden churches under historical climate conditions.
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RH vs. T ellipses of data collected in Binarowa (A), Blizne (B), Dębno (C), Lipnica Murowana (D), Haczów (E) and Sękowa (F) together with the thresholds defined by the standard UNI 10829 (red lines in T and blue lines in RH). RH relative humidity (%), T daily temperature (°C). The data points of the four seasons are drawn with different colors, and the blue line represents the trend curve between RH and T via the “loess” fitting method.

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Historical precipitation and relative humidity effects on the protection of wooden church building materials in Poland

This study further investigated the relationships between the conservation of building materials used in Polish wooden churches and historical precipitation and relative humidity (Figs. 7 and 8). Owing to their unique architectural styles and historical value, wooden churches in Poland hold a significant position in cultural heritage site conservation. However, changing climatic conditions pose severe challenges to the preservation of these wooden cultural assets. First, historical changes in relative humidity exhibit clear seasonal patterns, especially during the summer months (June–August), where fluctuations in relative humidity can approach 30%, whereas less pronounced changes, which remain within 10%, occur in winter. These variations directly impact the physical properties of wood. Increased humidity and frequent changes can lead to wood expansion and contraction, causing cracks and other structural damage. According to Kupczak et al. (2019), Fourier transformation of relative humidity data can quantify environmental damage risks to artworks, particularly those impacting wooden panels.

Fig. 7: Historical monthly/annual mean relative humidity variations (from 1980 to 2020).
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The blue line connects the data points along the time series, and the horizontal axis represents only decades. A significant correlation between the mean relative humidity and year is illustrated by solid lines (Spearman correlation, p < 0.05) and is not significant with dashed lines. JAN January; FEB February, MAR March, APR April, MAY May, JUN June, JUL July, AUG August, SEP September, OCT October, NOV November, DEC December, ANN annual.

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Fig. 8: Historical monthly/annual average accumulated precipitation changes (from 1980 to 2020) in Binarowa.
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The blue line connects the data points along the time series, and the horizontal axis represents only decades. A significant correlation between the mean relative humidity and year is illustrated by solid lines (Spearman correlation, p < 0.05) and is not significant with dashed lines. JAN January; FEB February; MAR March, APR April, MAY May, JUN June, JUL July, AUG August, SEP September, OCT October, NOV November, DEC December, ANN annual.

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Second, significant variations in historical monthly and annual cumulative precipitation are evident (R = 0.43, P < 0.01). The notable changes in annual precipitation suggest that short-term climatic variations significantly affect regional precipitation levels. This finding aligns with Varas-Muriel and Fort (2018), who reported that modern heating systems significantly alter microclimate stability inside churches, adversely affecting the preservation of their artistic and architectural heritage. Additionally, Laskowicz and Mrozek (2015) noted that extreme precipitation events could lead to geological disasters, such as landslides, which pose significant threats to wooden cultural heritage in Poland. The study also revealed an increasing trend in relative humidity in November (Spearman rank correlation, R = 0.3, P < 0.05), indicating the need for enhanced moisture control measures in the region’s wooden churches during this month to address the increase in relative humidity. Research by Bertolin et al. (2015) shows that reconstructing historical climates can better assess and improve conservation strategies for cultural heritage sites, which is crucial for developing effective moisture control measures. Overall, this research highlights the necessary protective measures for Polish wooden cultural heritage sites in the face of climate change. Enhancing awareness of the impacts of climate change on cultural heritage sites is vital for formulating scientifically sound conservation strategies (Fatoric and Seekamp, 2017; Sesana et al., 2021).

Problems and recommendations for practical restoration and conservation of wooden churches in Poland

This paper has explored the unique conservation challenges faced by wooden churches in Poland under current climatic conditions, incorporating geographical, land use, hydrological, climatic, and meteorological data to assess their impact on wooden cultural heritage sites and propose specific conservation strategies.

Geographical and hydrological conditions

The source of Polish rivers lies within the study area, where significant flooding is less likely at higher elevations, thus reducing hydraulic impacts on wooden churches. Despite the lower risk of floods, effective rainwater drainage and management remain critical to prevent prolonged moisture exposure to wooden structures, potentially causing erosion (Sesana et al., 2021). Drawing from Abdelmoniem et al. (2020), the application of appropriate microbial inhibitors can control the microbial degradation of wood, thereby preserving the structural integrity of these buildings.

Fire risk

Although the fire risk in the study area of wooden churches is relatively low, significant fire threats still exist, especially within buffer zones composed of forests, grasslands, and farmlands (ElHagrassy, 2024). To mitigate these risks, the protection measures implemented at the Church of Archangel Michael in Narova, such as the use of fire-resistant materials and regular monitoring of the fire index, are commendable. Additionally, managing the surrounding environment to reduce the accumulation of combustibles can decrease the likelihood of fires.

Climate conditions and humidity management

Studies indicate that the relative humidity surrounding the wooden churches in the study area exceeds the range suitable for preserving wooden heritage throughout the year, meeting only the protective standards during the summer months. Historical climate data projecting the next 40 years indicate a significant increase in relative humidity in September and total annual precipitation, suggesting that moisture pressures on wooden churches are expected to rise (Elkhial and El Hadidi, 2022). To address this, several measures can be implemented:

(1) Moisture control: Installing moisture barriers around the foundations and walls of wooden churches to prevent ground moisture penetration. Using breathable materials such as lime mortar can effectively reduce moisture accumulation.

(2) Insulation: Adding insulating materials to roofs and walls to maintain stable indoor temperatures and humidity, minimizing the impact of external climatic changes. This can be complemented by detailed structural analyses via the multi-instrumental survey methods of Elkhial and El Hadidi (2022).

(3) Drainage systems: Establishing effective drainage systems to ensure rapid rainwater discharge and prevent water accumulation around buildings. Drawing on successful experiences in Polish wooden heritage conservation strategies, such as installing drainage ditches and pipes around foundationsFootnote 4.

Protection and restoration recommendations

On the basis of these findings, specific recommendations for the protection and restoration of Polish wooden churches are provided:

(1) Regular inspection and maintenance: Regularly inspect the structure of churches, especially areas prone to dampness and damage, such as foundations, walls, and roofs, and carry out timely repairs and reinforcements.

(2) Microbial control: appropriate microbial inhibitors are applied to control the microbial degradation of wood, maintaining structural stability, following the methods of Omar et al. (2022).

(3) Fire prevention: Fire-resistant materials and equipment should be used, fire monitoring and early warning systems should be strengthened, and the surrounding combustibles should be cleared regularly to reduce fire risk.

(4) Climate monitoring: Establishing a climate monitoring system to track changes in temperature and humidity around churches and adjusting protective measures in a timely manner.

(5) Community involvement: Raising awareness of the importance of cultural heritage protection within local communities, encouraging their participation in conservation efforts, and fostering a community-wide protection mechanism.

Protecting Poland’s wooden churches requires a comprehensive consideration of geographical, hydrological, climatic, and human factors. Through scientific analysis and effective protective measures, the lifespan of these valuable cultural heritage sites can be extended, preserving their historical and cultural value. Future research should further refine these protective measures, integrate modern technological approaches to continuously optimize and improve conservation strategies, and provide insights for the protection of wooden cultural heritage sites in Poland and other regions.

Conclusion

This study qualitatively and quantitatively explores the impacts of climate and meteorological conditions on the six world heritage wooden churches near Krakow. In terms of location, the region where the wooden churches are located is in the hilly area of southeastern Poland and the upstream region of Polish rivers. On the one hand, the density of water systems is low, and the terrain elevation is high; therefore, the region where wooden churches are located is less prone to major floods, and hydraulic impacts have a minimal effect on wooden churches. In terms of fire risk, the buffer zones of the wooden churches in the study have a low percentage of artificial surfaces, with a high proportion of forest, grassland, and farmland land use types. The Church of the Archangel Michael in Binarowa has the highest fire weather index, approaching 50%. In terms of the average daily outdoor temperatures under current climate conditions, only in summer do the temperatures reach the standard for indoor protection of wooden churches; however, in winter, the outdoor humidity significantly exceeds the humidity standard for indoor protection of wooden churches, and the temperatures are much higher than the temperature standard for indoor protection, making winter a critical season for regulating the indoor microclimate of wooden churches. Projecting trends from historical climate conditions, the pressure for indoor moisture protection in the region increases annually in September, and there is a significant upward trend in annual accumulated precipitation. Finally, I propose a series of measures for moisture-proofing, insulation, and drainage to provide recommendations and data support for relevant work.