Research perspectives on historical legacy of the Scots pine (Pinus sylvestris L.): Genes as the silent actor in the transformation of the Central European forests in the last 200 years

The emergence of conifer monocultures in the 18th and 19th centuries led to a comprehensive reorganization of forests in Europe and worldwide. From that point on, natural succession was increasingly replaced by the artificial sowing of seedlings raised from a limited seed pool, whose life cycle typically ended at around 120–140 years. Today, at the beginning of the 21st century, many forests stands still reflect the Enlightenment model of management based on the planting–growing–cutting model (Bonan, 2019) and are struggling with the ongoing climate crisis. The reliance of classical forest management on monocultures of coniferous trees stemmed from their rapid growth and suitability as “Normalbaum”—a tree that grows consistently well under various conditions, facilitating territory-based planning (Alberto et al., 2013). It is important to note that while we consider human life spans to be approximately 60–100 years, the lifespan of Scots pine (Pinus sylvestris L.) (and most tree species) can extend to 300–400 or even 500 years. This disparity implies that in most forests, the stands—and, in a broader sense, the forest ecosystems—do not reach old age. Consequently, the processes associated with old forests may not have enough time to occur.

An important turning point occurred in the 18th and 19th centuries when, during the Enlightenment period, thinkers of the time made a significant distinction between managed forests and natural forests (Samojlik et al., 2022). They contrasted these two concepts and created two narratives—one based on harmony and order (the forest) and the other based on wildness and disorder (the wilderness). The Enlightenment period was marked by the international exchange of scientific ideas; however, regional adaptations of these ideas often revealed unique perspectives and practices. One such adaptation took place in Poland, where the local context influenced the application of Enlightenment principles to forest management. One realm was of human origin and associated with human domination, while the other represented wildness and savagery. Jan Krzysztof Kluk, a leading naturalist in the late 18th century in Polish lands, even stated that forests needed order and management. The most important tree species in these cultivated forests was the Scots pine, which, as a pioneer species, possesses a wide range of ecological possibilities (Szubert, 1827). It can thrive on mineral soils in sandy dunes as well as in more fertile or water-rich habitats. Another advantage of the Scots pine is its rapid growth, a point emphasized by Kluk (1778), who noted that specimens up to 20 years old are excellent as fuel, while those aged 20–30 years are a source of valuable resin. Later, they become suitable as building material (Kluk, 1778). The tree gained new functions as it matured, allowing it to continue being used commercially over time. During this era, the Scots pine also became a species that formed large-scale monocultures, with the main objective of harvesting as much firewood or timber as possible within a planned economic timeframe (Bonan, 2019; Słowiński et al., 2024). This involved a planned long-term conversion of tree stands, significantly reducing the proportion of deciduous trees (Wulf et al., 2017). The introduction of forestry management was also linked to an energy transformation, particularly prominent at the turn of the 18th and 19th centuries. The expanding energy needs of the dynamically developing Enlightenment monarchies led to an increased demand for the most calorific fuel available at the time: charcoal. This charcoal was produced on a massive scale, in part from cultivated Scots pine monocultures (Słowiński et al., 2022).

In this article, we focus on the Polish lands, which, during the period in question, were on the periphery of the Western world. However, the term “peripherality” in this context refers not only to spatial location but also to the significant delay in implementing political and economic transformations in this part of Europe compared to Western Europe. The practice of sustainable forestry, established in the West since the publication of Hans Carl von Carlowitz’s book in 1713 and subsequently documented by Georg Grünberg’s scientific treatises (Grünberger, 1788), was gradually introduced to the Polish territories. Beginning with the partitions of Poland in 1772, 1793, and 1795 by Prussia, Austria, and Russia, respectively, parts of the Polish lands were incorporated into the administrative and economic systems of the partitioning powers (Rutkowski, 2019). In general, it can be asserted that the modern foundations of forest management were finally established in this part of Europe during the 1820s and 1830s.

The Prussian system of forest management was characterized by a high level of professionalism and efficiency, leading to the development of intensive monocultures, particularly of pine, aimed at maximizing timber production. However, this approach resulted in the simplification of forest structure and a decrease in biodiversity, effects that are still visible today in the forests of western and northern Poland (Jaworski and Pach, 2013). In contrast, the Russian partition was less organized and often lacked a unified approach to forest management. In the Kingdom of Poland, which had some autonomy, attempts were made to adapt the Prussian model, but with varying results. This often led to less effective management and a higher degree of genetic inbreeding in the forests of central Poland (Brzeziecki, 2005). Unlike the Prussian system, the Austrian approach placed greater emphasis on sustainable development, resulting in more diverse and stable forest ecosystems and higher biological diversity in southern Poland, which stemmed more from a practical focus on forest stability than from a deliberate concern for biodiversity (Jaworski and Pach, 2013), as the latter was not yet formally recognized as a management goal at the time. The most significant trends in the promotion of forestry were driven by Prussia. The other two partitioning states were influenced to varying degrees by the development of independent directions (Austria) or by the unreflective copying of the German model (Russia until the second half of the 19th century) (Fedotova and Loskutova, 2015). A completely different position on the intellectual map was occupied by the territory of the Russian partition of Polish lands, namely the autonomous Congress Kingdom (i.e., a state under Russian rule formed after the Congress of Vienna in 1815), where a separate model of forest management was established from the outset, based on the Prussian model but adapted to local conditions. This means that a large portion of the stands older than 200 years in present-day western and northern Poland are of German (Prussian) origin, while the stands in central Poland may exhibit a high degree of inbreeding, and the stands in the south are associated with the system that functioned in the Austro-Hungarian monarchy (cf. Figure 1). This historically determined state of forest management, which is also typical of other regions worldwide (Sunseri, 2012), may have significant potential consequences for the management of commercial forest stands during times of climate change and for predictions about the future of economically important species in Europe over the next 50 or 100 years (Dyderski, 2017).

In the broader context, it is important to highlight that the history of forests and their disturbance, whether directly or indirectly related to human activity, does not end with the last 50 or 200 years (Fuller et al., 2017). There is evidence of the influence and shaping of ecosystems for as long as 12,000 years (Lauterbach et al., 2024). However, the pressure that humans have placed on various ecosystems (e.g., wetlands and forests) has never been recorded in recent centuries, particularly in the forests of Europe. Seidl et al. (2017) emphasize that the condition of forest ecosystems is currently exacerbated by external factors resulting from the interactions between various disturbances. Paradoxically, now in the Late Holocene, human-induced changes (increases in air temperature and N and P availability in ecosystems) are causing a continuous increase in biomass (Patacca et al., 2023; Socha et al., 2023). This sheds a different light on the processes that should be taking place today. By considering the glacial–interglacial cycle in a long-term ecosystem context, we can conclude that we should be entering a phase of decreasing biomass (Birks and Birks, 2004).

Therefore, the primary aim of this article is to explore potential research opportunities related to the long-term environmental impacts of forest management practices established approximately 200 years ago (Guz and Kulakowski, 2021). These practices have been the subject of ongoing debate, with both supporters and opponents since the very beginning. However, our current focus is to review the state of knowledge regarding the genetic issues of Scots pine, which is the most economically important tree in the temperate forests of Central Europe. We believe these genetic issues are not sufficiently addressed in current research discussions.

The current genetic resources of Scots pine in Polish forests are a direct result of historical forest management practices that vary depending on the region’s partitioning. These differences in forestry management have left a lasting impact on the genetic structure of forest ecosystems in Poland. For example, the intensive management of pine monocultures in some regions has led to a reduction in genetic diversity, while in other areas, less intensive approaches have allowed for the preservation of greater genetic variability (Wójkiewicz et al., 2016). Genetic diversity is a key factor that enables forests to adapt to dynamically changing environmental conditions. Contemporary studies highlight that preserving this diversity is not only a heritage that must be protected but also the foundation of forests’ ability to adapt to new challenges, such as climate change and increasing environmental pressures (Monastersky, 2014). High genetic variability within and between tree species ensures that forests can develop and adapt to environmental stresses. Trees differ in growth rate, form, and tolerance to pests, drought, and other stress factors. The adaptive capacity of trees is highly dependent on their level of genetic variability, which allows them to survive and adapt to unpredictable environmental changes (Wójkiewicz et al., 2016). Scots pine, as one of the key forest species, exemplifies a tree whose adaptive mechanisms have been thoroughly studied. The genetic diversity of pine enables it to adapt to various climatic and geographical conditions, which is essential in the context of anticipated climate changes. Research has shown that this adaptation includes traits such as growth rhythm and frost resistance (Wójkiewicz et al., 2016; Hallingbäck et al., 2021). Although estimating the value of forest genetic resources (FGR) is challenging, their protection is crucial for the long-term adaptation and stability of forest ecosystems. The conservation of FGR is justified for economic, ecological, evolutionary, and moral reasons (Namkoong, 1992; Kelleher et al., 2015; Potter et al., 2017). Maintaining and utilizing genetic diversity is essential for forests to meet future challenges and continue to fulfill human needs.

The planned management of forests at the turn of the 18th and 19th centuries was driven by energy needs and was particularly important for Central and Eastern Europe, implemented in various forms by different partitioners. The dynamically modernizing states in this region used wood as a significant energy source, both as firewood and charcoal (Warde, 2006), for two crucial reasons: it was relatively low-cost and widely available (Kander et al., 2014). In the early days of forestry, little attention was given to the origin of the seeds from which commercial stands were established. Studies from Norway have shown that Scots pine seeds used in Scandinavian countries during the 19th century came from France, Germany, Poland, or Russia, depending on the period (Myking et al., 2016). In scientific discourse, the origin of seeds gained increasing importance by the end of the 19th century, with two contradictory positions prevailing—one asserting that trees originating from foreign seeds quickly adapt to local conditions, and the other arguing that foreign origin negatively affects tree growth. In the 19th century, Poland, divided among three partitions, was subject to three different seed systems. However, it should be noted that in the 1840s, central Polish lands (the Congress Kingdom) were influenced by a law stipulating that the seed base for forest areas should come from the stands of the respective forest region. It is unclear whether this law resulted from research and experimentation at the time or from a lack of infrastructure to transport seeds between different areas. Perhaps both factors played a role. However, the State Forests (Pol. Lasy Rządowe) issued orders for the indigenous cultivation of key tree species such as pine, larch, beech, oak, and yew (Barański, 1974). Seeds harvested and hulled in forest districts were distributed throughout the Congress Kingdom (Figure 1). In this system, the importation of foreign seeds did not play a significant role. This leads to an important assumption that, in the Polish territories under the Russian partition during the 19th century, the genetic pool of the oldest stands, whose germination began in the mid-century, may reflect the genetic remnants of natural stands from before the introduction of scientific forestry.

The recognition of Polish stands as a seed base began in 1960 (Fonder et al., 2007). At that time, it was assumed that stands over 100 years old were indigenous, due to the intensive seed trade between 1860 and 1910. Older stands were considered evidence of local origin and superior quality compared to younger forests.

Over time, it has been recognized that protecting the native genetic pool is crucial not only for forest quality but also for their adaptive capacity. Scots pine, one of the most economically important species in Europe, has become a primary focus of genetic research. Genetic diversity within pine populations is essential for identifying and protecting local ecotypes that are better adapted to specific environmental conditions (Wójkiewicz et al., 2016).

Genetics enables the selective breeding of trees to produce offspring with enhanced traits. Modern techniques, such as molecular markers and DNA sequencing, allow for precise genome mapping (Przybylski, 2022). These advancements are crucial for implementing sustainable forestry and reclamation practices.

As genetic technologies continue to evolve, their role in enhancing forest resilience to climate change becomes increasingly important. Integrated management of genetic resources (FGR) in forestry is essential for the future of forests, enabling them to adapt to upcoming environmental challenges.

Modern methods of molecular biology help determine the origin of forest stands, making it possible to determine the probability of their origins. Demographic history analyses have been conducted for many forest tree species (Litkowiec et al., 2016; Wójkiewicz et al., 2016). Notable works in Poland include those by Lewandowski et al. (2012), who describe the origins of spruce at the northeastern limit of its range. Lewandowski et al. (2012) demonstrated a significant proportion of alpine genotypes in the stands of northeastern Poland, suggesting that they are not native. For the most important forest-forming species, Scots pine, only a few analyses of its demographic history have been conducted to date. The first comprehensive analysis of the genetic diversity of Scots pine in Poland was carried out by Nowakowska (2010), followed by publications by Wójkiewicz et al. (2016). All these studies showed the presence of numerous alien genotypes of alpine origin in old stands. Analyses by Żukowska et al. (2023) confirm that the low genetic structure between Central Europe and Fennoscandia, along with their high genetic admixture, may result, at least in part, from past human activities related to the transfer of germplasm in the 19th and early 20th centuries. Furthermore, Żukowska et al. (2023) state that genetic research should be intensified in native populations of Scots pine.

The studies mentioned above, along with an analysis of the logical consequences of the uncontrolled trade in forest tree seeds from 1860 to 1910, demonstrate the significant influence of 19th-century forest management on the formation of the genetic pool of Polish forest tree populations. It is important to note that legislation regarding seed origin was not established earlier and only came into effect in later periods (State Document 1924), meaning the early trade was largely unregulated. These regulations were established in response to the observed negative effects of uncontrolled seed trade and aimed to improve the genetic quality of forest stands. Therefore, early forest management practices lacked the regulatory framework that benefited later periods, highlighting the evolution of forestry practices over time.

Seed dispersal under foreign climatic conditions can be viewed as an artificial and human-assisted migration of genotypes, influencing the adaptation process both negatively and positively. If adaptation to climate change is understood as “the adjustment of natural or artificial ecological systems in response to expected climate impacts […], thereby reducing losses or realizing benefits” (Chmura et al., 2010), then artificial migration can be seen as a positive phenomenon. Historically, climate change has prompted the natural migration of genotypes. Unfortunately, the dynamics of current climate change indicate that the rate of natural migration may be insufficient for many forest tree species and their populations (Aitken et al., 2008). Furthermore, natural migration processes are disrupted in forests altered by human activities. Despite substantial research demonstrating the superior breeding quality of local genotypes (Skroppa and Magnussen, 1993; St. Clair et al., 2005), facilitating the best possible adaptation of local ecotypes through the migration of their gene pool (via seed) is essential for the survival of forest tree populations and species (Aitken et al., 2008).

On the other hand, it should be noted that between 1860 and 1910, knowledge of genetics was rather limited. Therefore, the uncontrolled transport of seeds in the 19th century cannot be considered assisted migration of genotypes in today’s sense, and the consequences of this phenomenon were largely negative. According to Noss (2001), the main cause of the weakened health of selected populations is the use of seeds of unknown origin and their adaptation to local growing conditions. The damage caused by the importation of foreign and untested sources of forest reproductive material was first recognized in Sweden. In 1787, Urbański (1999) published the first evidence of negative observations on plants grown from seeds originating from distant regions. Initially, pines of foreign origin grew faster, but over time, they began to be outperformed by native pines and were characterized by crooked, bent, and heavily branched trunks after only a dozen years. Additionally, these trees often did not adapt well to local conditions, leading to higher mortality rates. The negative effects of introducing seeds from other regions were also pointed out by German scientists in the early 20th century. Schott (1903), for instance, wrote about the mismatch resulting from importing into Central Europe plains seeds of trees that grow in Western Europe in coastal climates or come from high mountains. The high demand for seeds, due to the regeneration of forests through full seeding, along with the simultaneous development of steam engines and railroad transportation, led to the industrial-scale procurement of seeds. In large factories (seed kilns), seed ware was obtained from massive quantities of cones collected from across the country and abroad. In northeastern Germany, a marked deterioration in the quality characteristics of the progeny was subsequently observed, especially from the southwestern regions. This deterioration included not only economic traits such as trunk straightness but also poor adaptation and increased mortality. For this reason, a resolution to restrict seed imports was passed at a meeting of German foresters in 1906 (Urbański, 1999).

The question arises as to whether the results of the artificial migration of genotypes from the 19th century, which directly resulted in alleles (i.e., variants of a gene) alien to the local gene pool, persist over generations. Studies conducted in the Tuchola Pine Forest National Park show significantly higher values for genetic variability parameters in a stock of proven foreign origin (Przybylski, 2022). The foreign-origin stand in question was established from seeds imported to Poland from France. It is currently over 150 years old on average, and the trees that comprise it are in good condition as measured by the defoliation index. As previously mentioned, a characteristic feature of a stand of foreign origin is a significantly higher value of genetic variation coefficients, such as the number of alleles and the effective number of alleles, which are important for adaptability. Indeed, studies of stands over 150 years old in Kampinos National Park demonstrated a statistically significant relationship between the number of alleles and the degree of stand degradation (based on defoliation) (Przybylski et al., 2021).

A stand of foreign origin from the Tuchola Pine Forest National Park also showed a significantly higher value of private alleles, which could indirectly confirm its foreign origin (Przybylski, 2022). Private alleles enrich local genetic pools, but their evolutionary significance will only become apparent in subsequent generations. On the other hand, foreign alleles are important for increasing genetic diversity, the decline of which has been described during the Anthropocene (Exposito-Alonso et al., 2022). From a global perspective, this increase in genetic diversity can be seen as an unexpected and potentially positive outcome of the uncontrolled seed trade in the 19th century. Higher genetic variability often leads to better adaptation and greater survivability of populations in changing environmental conditions. However, it is unclear whether foreign alleles will persist in the population over generations. Some evidence is provided by a preliminary study (Przybylski, 2022), which detected a significantly lower number of cones in a population formed from foreign seeds. This should consequently lead to a lack of reproductive success and the elimination of foreign alleles from local gene pools. The phenomenon of assisted (human-assisted) migration can therefore be viewed as a particular disruption of natural genetic variability resulting from evolutionary processes. New genetic information, if it does not contribute to traits that offer a reproductive advantage, is eliminated over generations.

To understand the impact of current seed base management on genetic diversity, it is essential to compare it with historical practices and their long-term consequences. Pine forests in Poland, apart from areas excluded from forest management, such as national parks and reserves, are mostly artificially restored using seed obtained from seed stands and seed orchards. The genetic variation of the selected maternal generation is passed on to the next generation. Gene flow between the pine stands determines high genetic variability but also contributes to the low genetic diversity of the population, which is estimated by Nowakowska (2010) to be about 3%. Seed orchards can also be characterized by a distinct genetic structure due to the fact that they are artificial breeding populations. Studies conducted to date by El-Kassaby (2000) show a higher effective number of alleles in Douglas fir seed orchards compared to natural populations. Similar results were obtained for Scots pine when comparing the genetic variability of seed orchards with that of natural populations (Kosinska et al., 2007). The study by Trojankiewicz (2006) confirmed the intergenerational transfer of genetic variation and the transfer of alleles from the seed orchard to the progeny generation. However, no significant genetic difference between the generations was detected.

With regard to the research results cited, we deduce that there is a similarity between the genetic consequences of uncontrolled seed marketing in the 19th century and those of current seed base management. In the examples of forest seed management described above, humans artificially increase genetic variation, thereby reducing the biological differences between stands. This comparison highlights the need to consider the long-term genetic impacts of our current practices, just as we have observed with historical seed trade.

The experiences of Polish forestry, drawing from both historical and modern practices, can be invaluable in shaping policies related to the conservation and management of genetic resources in Europe and globally. Historically, pine seed management in Poland was influenced by contemporary political ideologies that, in some areas, favored Prussian or Austrian origins over local varieties, aiming to maximize economic benefits from forest stands. This process was stopped in the first half of the 20th century due to Poland’s regained independence and scientific observations confirming the inferior breeding quality of stands established from imported seeds. However, as previously mentioned, there is evidence suggesting that a significant portion of the trees had local origins, as illustrated on the attached map (Figure 1).

Thus, the effects of 19th-century forestry management are still visible in today’s genetic pool. Inadequately selected genetic compositions that are not suited to local growth conditions result in reduced plasticity of the forest stand, limiting its ability to respond to external growth factors. It is also important to emphasize that artificial enhancement of genetic variability occurred through the introduction of additional genes from imported seeds. Mismatched gene variants undergo natural elimination, but this process is prolonged from a human lifespan perspective, spanning several generations of naturally regenerating forest stands.

Genetic variability that accumulates within populations opposes diversity between populations. In the context of Scots pine, commercial populations show little genetic variation among themselves, resulting from both forest management practices and the biological characteristics of pine, whose variability is continuous across its range. Few stands with autochthonous gene variants have been identified in fragments of the oldest forests or isolated refuges (Przybylski, 2022).

According to current knowledge, local genotypes are not always optimal; therefore, assisted migration of seeds is sometimes necessary to achieve positive breeding outcomes. It is important to note that in forestry, “positive” outcomes often refer to the production of “quality” timber, which is defined based on economic value and specific industry standards. Effective management of Scots pine genetic resources requires an understanding of and focus on addressing historical errors while preserving and supporting genotypes best suited to specific environmental conditions. Recognizing these embedded value judgments ensures a more transparent approach to forestry practices.

Therefore, describing, protecting, and promoting unique genotypes in breeding represent some of the challenges of the Anthropocene. In the future, it will be necessary to implement integrated strategies for managing genetic forest resources, which will include both traditional breeding methods and modern biotechnological techniques. International cooperation in the exchange of information, seeds, and best management practices will also be crucial. Only through joint actions and consideration of local specificities can genetic resources be effectively protected and managed, ensuring the sustainability and resilience of forest ecosystems in the face of climate change. Moreover, the significance of ancient natural forest stands, such as the Kampinos pine, known for its drought resistance due to its growth on dunes, should be a focal point for future research. These stands have developed unique adaptation strategies over time, and exploring their potential can offer valuable insights into enhancing the resilience of contemporary forests. This potential reminiscence of ancient natural forests in central Poland may represent a pivotal next step in research, emphasizing the urgent need to leverage historical knowledge in our modern fight against climate change.

No new datasets were created during the writing of this essay.

We would like to express our sincere gratitude to the two reviewers whose comments significantly improved our essay. We also offer special thanks to Charles Watkins (Nottingham) and Péter Szabó (Brno), who took the time to read and comment on our article before its final submission to the journal.

This research was conducted as part of the project entitled “Anthropogenic Transformations of the Environment in the Context of Modernization Processes in Congress Poland,” number 2022/47/D/HS3/02947, funded by the National Science Centre (Poland). This text is also a result of a research internship by TZ completed at the Forest Research Institute from June to September 2024.

The authors declare no competing interests.

Contributed to conception and design: PP and TZ.

Wrote the paper, prepared figures, authored or reviewed drafts of the paper, and approved the final draft: PP, TZ, JK, and MS.

How to cite this article: Przybylski, P, Związek, T, Kowalczyk, J, Słowiński, M. 2025. Research perspectives on historical legacy of the Scots pine (Pinus sylvestris L.): Genes as the silent actor in the transformation of the Central European forests in the last 200 years. Elementa: Science of the Anthropocene 13(1). DOI: https://doi.org/10.1525/elementa.2024.00041

Domain Editor-in-Chief: Steven Allison, University of California Irvine, Irvine, CA, USA

Associate Editor: Anna Harper, University of Georgia, Athens, GA, USA

Knowledge Domain: Ecology and Earth Systems