1. Introduction
In Finland, there are currently over 37,000 archaeological sites (or archaeological remains) protected by the Protection of Antiquities Act. Spatial data concerning the sites are stored in the Register of Ancient Sites [
1]. About 60% of these sites are located in forests [
2]. These sites encompass various types and historical periods, including settlement places, burial sites, defensive structures, work and manufacturing sites, and culturally significant locations spanning from the Stone Age to the present day. The Finnish Heritage Agency maintains an archaeological database and a register of ancient sites, containing essential information about all mainland Finnish sites [
3]. This information includes, at minimum, the site’s name, coordinates, a unique identification code, and basic details regarding its age and type. Despite these protective measures, archaeological sites in Finland suffer annual damage or destruction, most commonly as a consequence of forestry activities, according to a report by the Finnish Heritage Agency [
4]. While archaeological remains do not impede forest utilization, it is crucial that forest management practices do not inflict damage upon these sites.
In Finland, forestry is a central and rapidly evolving sector. Therefore, this research focuses on forestry practices and their implications for archaeological spatial data. Cooperation between both fields could be utilized to address the shortcomings presented earlier in this section. Finland is, proportionately, the most forested country in Europe, with forests covering over 75% of its land area [
5]. Abundant forest resources have historically shaped Finnish society, culture, and lifestyle, emphasizing the importance of forests in Finnish identity. The economic importance of forests has also motivated the development of national forest inventories and more detailed forest attribute information.
The type and intensity of forest operations greatly impact their effect on archaeological sites and, for example, thinning operations generally have a positive effect on the sites [
6]. As the surrounding landscape opens up, the site becomes visible, making its preservation easier. The soil surface and structures related to an archaeological site must not be damaged [
6]. Some sites are particularly susceptible to damage, for which manual harvesting is advisable [
6]. In even-aged forestry, new trees should not be allowed to grow on the archaeological site during the seedling stand phase, because this makes it easier to preserve the sites as treeless later [
6]. However, due to restrictions related to regeneration, it is recommended to use continuous cover forestry methods in and around archaeological sites to avoid mechanical soil preparation [
6]. Prior to harvesting, landowners are required to submit a
notification of forest use. This notification must be presented to the Finnish Forest Centre at least 10 days and no more than 3 years before the commencement of logging or any other relevant operations [
7]. The notification system is used to enforce the laws (Forest Act, Environmental Protection Act, Waters Act, and Protection of Antiquities Act) and restrictions of land use plans affecting forest use. In general, the responsible governmental organization is informed about the intended forestry action if it overlaps spatially with their area of responsibility. In the case of the Protection of Antiquities Act, regional responsibility museums’ archaeologists provide assessments related to these notifications. Notifications automatically reach the museum authorities if the proposed forestry action is within 200 m of a registered ancient monument. However, the substantial volume of forest management notifications places a significant workload on archaeologists affiliated with the responsible museums.
The Finnish Heritage Agency has published guidelines on its website regarding forestry activities and archaeological sites [
6]. Additionally, instructions and quality guidelines for archaeologists conducting field work have been published by the Finnish Heritage Agency [
8]. Archaeological surveys in Finland are primarily conducted by commercial archaeology enterprises, often in conjunction with urban planning and construction projects. During the surveys, archaeologists visit already-known sites as well as new potential areas to find possible new sites. The number of registered archaeological sites has been increasing by approximately a thousand annually in recent years, revealing the richness of Finland’s cultural heritage. Many undiscovered sites likely remain, especially in areas where construction and land use are less active, although these areas often coincide with active forestry practices.
The relevance and significance of this research topic is particularly pronounced in the current context. Finland is undergoing legislative reforms concerning archaeological cultural heritage [
9]. This legislative reform will significantly impact the research and protection of archaeological cultural heritage, and thereby also affect forestry practices in Finland. However, the proposed legal draft does not adequately address the precision of archaeological spatial data. Furthermore, the guidelines for archaeological fieldwork do not provide directives on the level of precision required for spatial data on archaeological sites [
8]. Consequently, it is not possible to directly deduce the accuracy of an archaeological site’s location or the method by which the location was determined from the register’s information. As a result, the accuracy and quality of archaeological spatial data vary significantly. Archaeological sites are not systematically surveyed in the field, and some registry spatial data may rely on surveys conducted decades ago or even observations made in the 1800s. Some practitioners are still employing outdated and imprecise handheld GNSS (Global Navigation Satellite System) devices for on-site measurements of archaeological site coordinates. Under the forest canopy, the mean positioning error of such devices rises to over ten meters [
10]. Nevertheless, these sites enjoy legal protection, regardless of the precision of their spatial data. The Register of Ancient Sites was originally created for use by archaeologists working as authorities, and the descriptions of sites vary widely in both quality and content. Some verbal descriptions may be very brief, consisting of only a few sentences, and may not be easily understood by users unfamiliar with the field of archaeology and its terminology. Concurrently, the Finnish Heritage Agency is initiating a renovation project for the archaeological information infrastructure, although it is still in the phase of seeking funding [
11]. With the legal reform, it will also be necessary to update the register of ancient sites and other archaeological databases administered by the Finnish Heritage Agency.
The proposed new legal amendments include stricter penalties for damaging or destroying archaeological sites, emphasizing the importance of accurate spatial data from a preservation standpoint. Legal provisions alone, however, cannot safeguard archaeological sites if their spatial data lack precision or are inaccurate. During the initiation phase of the registry renovation project, the Finnish Heritage Agency found that almost 42% of ancient sites lack territorial boundaries (polygons) [
12]. The absence of a boundary delineation may also suggest that an archaeological site has not been inspected in the field for a considerable period, since contemporary practices typically aim to define boundaries for sites unless they are clearly very small or point-like phenomena, such as individual find spots. The current registry contains unreliable spatial data in many instances, making precise spatial data beneficial for researchers, authorities, and landowners alike. Inaccurate spatial information may burden landowners unnecessarily or complicate land-use projects, resulting in avoidable additional costs. This research is pertinent due to the demonstrated significance of location accuracy in previous studies [
13,
14]. For instance, from the perspective of spatial data analyses, correct location information is essential for ensuring the reliability of results. While precise location data may not always be inherently crucial or interesting solely from the standpoint of archaeological research, the broader infrastructure requiring and utilizing spatial data must also be considered.
In this study, our primary aim is to (1) investigate the precision of spatial data required for archaeological sites from the perspective of forest management. Concurrently, the forestry sector is moving towards increasingly precise spatial data and adopting precision forestry techniques. At the same time, archaeological spatial data in Finland often lack accuracy and precision. As a secondary research question, we aim to (2) identify archaeological sites that may be endangered by forest management activities. According to a survey by the Finnish Heritage Agency, Stone Age settlement sites in particular could be at risk of destruction due to forest management, based on reports collected between 2010 and 2019 [
4]. However, there is currently no clear understanding of all the types and the number of archaeological sites that are at risk of being destroyed by forest activities in Finland. The third research question (3) addresses the utilization of forest resource data in archaeology and collaboration between the fields. While some collaboration has taken place between the forestry sector and archaeologists, like the project that was conducted in 2011–2013 [
15], comprehensive projects on this topic are reportedly scarce. Archaeologists who are employed in the Finnish Forest Administration have experience collaborating with forest researchers, but this collaboration has not spread more widely.
2. Materials and Methods
This study uses and combines several different research materials and methods, which are presented in the table (
Table 1) as well as in more detail below.
The research methodology chosen for this study involves a literature review and case studies to construct a current comprehensive overview of both archaeology and forestry in Finland. The literature review and case studies aim to address the first and third research questions, facilitating the dissemination of contemporary research findings to experts in both fields and encouraging dialogue between them. Scientific articles on archaeology and forestry, including various reports and studies, particularly those produced by the Finnish Heritage Agency, serve as the primary written sources for our research. Additional literature, including works aimed at the general public, was also reviewed as part of the information-gathering process. In the absence of prior research data in Finland regarding the accuracy of location information for archaeological sites, case examples were sought to address this gap. The registry’s descriptions of archaeological sites have been utilized to find case examples, as the registry does not always allow for the assessment of location accuracy, or the method used for determining locations for all sites. The register in point form includes a column named “annotation”, which describes the basis of the site’s location. However, for the most part, this column is empty, and only a small fraction appears to have an annotation indicating the location method used for each site. Archaeological fieldwork reports also provided information on different fieldwork methodologies and practices related to location. These reports often reveal how the work was conducted, although older reports may lack detailed information. Background information was further obtained from experts at the Finnish Heritage Agency and archaeologists working in regulatory roles, whose expertise was instrumental in identifying case studies for this article.
The study’s funding did not cover archaeological fieldwork; however, it was decided to inspect a few example sites in the field to gather more detailed background information. The fieldwork was conducted collaboratively by the first and second authors, serving as a case study of cooperation between the archaeology and forestry sectors. Field inspections at several archaeological sites were carried out within a single day. Subsequently, a decision was made to apply for a research permit to verify the location of one legally protected archaeological site. Following the grant of the research permit, a small-scale invasive investigation was undertaken at this archaeological site. The objective of the research was to locate a mass grave of individuals who died of the plague in 1711, located in a forest. The method chosen for this purpose was the excavation of a test pit, as it was deemed the only way to confirm the existence and precise location of the archaeological site. No visible structures or phenomena on the surface could aid in locating this particular archaeological site. This approach highlights the challenges and methodologies involved in archaeological research, especially when dealing with sites that lack surface indications of their presence. The collaboration between authors and the integration of fieldwork, even on a limited scale, underscores the importance of direct site verification to enrich historical and archaeological understanding.
The Register of Ancient Sites served as the material for addressing the second research question. By utilizing the existing classifications within it, the study aims to identify those sites or phenomena that are more likely to be at risk of destruction and which should, therefore, receive special attention in the future. This approach has allowed for a targeted analysis of the register’s data, highlighting areas of potential vulnerability and informing strategies for the preservation and protection of archaeological sites. Through this examination, the research aims to contribute to the development of more effective conservation practices by pinpointing specific sites of significance that are in urgent need of safeguarding against the impacts of modern activities, including forestry. Despite numerous problems in the register’s utility for research purposes, it still provides valuable statistical background information.
The spatial data from the register were downloaded on the first of September 2023, and any changes made thereafter were not considered in the statistical information. While minor updates to the register are likely to have occurred during the autumn of 2023 and in the beginning of 2024, there do not appear to have been significant changes in the number of protected sites, meaning that the statistical results are still valid in spring 2024. Furthermore, the research background included information gathered from earlier studies of the Register of Ancient Sites [
14]. Reviewing the previous study’s data (585 archaeological sites from the Eastern Häme region) already highlighted the variability in the accuracy of archaeological spatial data and the different methods by which archaeological spatial information has been collected over the decades [
14]. Thus, a comprehensive understanding of the accuracy of archaeological spatial information had already been formed before the commencement of this study, which, in turn, guided the selection of this research topic.
The spatial data downloaded from the Finnish Heritage Agency’s website [
16] at the beginning of September includes all registered sites in point form (muinaisjaannospiste_t_point) and, as a separate layer, those sites with boundary delineations in polygon form (muinaisjaannosalueet_t_region). Regrettably, the polygon-form spatial data lack all attributes of interest for statistical analysis, such as date, type, and subtype. The point-form table, on the other hand, does not allow for the differentiation of sites without polygon delineations since there is no column in the table to indicate such a status. A solution was selected that employs the simplest possible method of data extraction, ensuring that it could be easily replicated by all stakeholders in the field and does not require extensive expertise in working with spatial data or special programming skills. This approach aims to facilitate the accessibility and usability of the data for a wide range of users, underscoring the necessity for straightforward and effective methods of data analysis in archaeological research.
QGIS geographical information system software was applied in this study due to its open availability and its use in institutions such as the Finnish Heritage Agency and numerous museums. Both attribute tables, representing point- and area-form sites, were exported from QGIS to Excel spreadsheet format. Subsequently, these tables were imported into Microsoft Access to create a unified database. Both tables contain a unique identifier column for the sites, specifically the site’s numerical code, which was used as a primary key to establish a linking relationship between the two tables. This setup enabled the creation of queries in Access to identify all sites listed in the point-form table that were absent from the area-form data table (a query for finding unmatched records). The query generated a new table listing all registry sites lacking boundary/polygon delineation. Further filtering in Access allowed for the direct extraction of interesting statistical information. This table was also exported as a CSV file, from which a vector file (shapefile) was created and then opened in QGIS. This process enabled the visualization and further filtering of information directly on a map, enhancing the spatial analysis capabilities of the study. This methodology underscores the necessity of integrating various software tools when facilitating comprehensive archaeological data analysis, from database management to spatial visualization.
4. Discussion
First, we would like to discuss accuracy in general. How is accuracy or precision defined in archaeology, especially in archaeological surveys? How do we define or conceptualize ‘a site’ in archaeology [
56]? For forest resource information, accuracy is more easily defined and can utilize quite a few clear metrics. However, precisely determining the location of an archaeological site is not always straightforward. Archaeological phenomena or sites, for instance, are not always clearly defined, and they are influenced by several factors such as origin, time, soil, materials, natural conditions, and subsequent human activity. Not all archaeological sites are distinguishable from the land’s topography, and they may be difficult to detect, especially in forests, due to vegetation. Remote sensing, other geospatial technologies and, for example, geophysical methods can assist in locating archaeological sites [
57]. These methods do not work for all types of sites, as Case Example 5 in this research clearly demonstrates. Therefore, more research on the applicability of new geospatial methods to archaeology is needed. Above all, however, there needs to be a discussion on how to define the precision of spatial data in terms of archaeological sites.
In concluding research objective 1, we suggest that efforts should be made to ensure the accuracy of archaeological spatial data, taking into account the specific conditions, the type of site, and the objectives of the research. For some archaeological sites, determining the exact location may be impossible due to conditions or the type of site. However, the aim should be to achieve a level of accuracy comparable to that of forest compartment data. In practice, this could mean favoring precision GNSS devices whenever possible and especially reducing the use of old hand-held GNSS devices as the primary recording method in archaeological fieldwork. However, it is crucial to keep in mind that archaeology and archaeological sites are not ‘exact sciences’. Precise spatial data are often only achieved after excavating the archaeological site and meticulously documenting the structures, finds, or observations. Often, the location information is merely an estimate, and this should be clearly indicated, for example, in the metadata. On the other hand, the forestry sector’s trend towards more precise spatial data, along with general advancements in location accuracy, should be taken into account in archaeological surveys, striving for increasingly accurate spatial information for archaeological sites as well. Given that information on archaeological sites is not systematically updated in the register and inspections are not conducted regularly, it is desirable that the currently produced data are collected as carefully and accurately as possible to avoid the need for re-examining the same archaeological sites after a short time due to insufficient spatial data. Resources in archaeological fieldwork are scarce, and fieldwork and site visits especially are costly and time-consuming. As Laulumaa noted in 2014, inaccuracies in the location data of ancient sites are one of the most significant issues [
17]. Unfortunately, there has not been much progress in ten years, nor has there been a discussion on location accuracy in Finland, although the problem is well recognized in the field. With new legislation, new quality requirements for archaeological fieldwork will also emerge [
9]. In this context, it would be logical to update requirements or guidelines related to the accuracy of spatial data.
There are some solutions for improving the accuracy of archaeological spatial data. At the very least, future data repositories should include information on how or by which method the coordinates were collected, their estimated accuracy, and the rationale for choosing that method (for example, the so-called handheld GNSS device) as the positioning method. In some cases, even inaccurate data can be important and useful, for example when dealing with a potential archaeological site whose status is still under investigation. However, the chosen method should be justified, and information about the method should be available, so that later researchers or entities using the data can assess its suitability for their intended use. Consequently, it is not possible to directly deduce the accuracy of an archaeological site’s location or the method by which the location was determined from the register’s information. This limitation underscores a significant gap in the register’s utility for precise archaeological research, highlighting the need for enhanced documentation and data collection practices to improve the reliability and comprehensiveness of archaeological site records. Moreover, this gap poses a considerable challenge for this study, as the accuracy of the sites could not be statistically analyzed at all. Additionally, the registry should be developed so that archaeological data are available in accordance with the FAIR principles and more easily utilized for research purposes. The current deficiencies and errors in the registry significantly affect the scientific reliability of the analysis results.
The issue with archaeological sites endangered by forest management is important to discuss. There are many archaeological sites endangered by forestry, and the resources available for their study are limited. It is, therefore, important to prioritize those archaeological sites that are at the greatest risk of being damaged as a result of forestry activities. Archaeological sites lacking boundary delineation information can be extracted from the register using the simple steps described in the Methods section. Subsequently, information such as Stone Age settlement sites can be selected in GIS software, and those located on forestry compartments can be identified by utilizing the open data on forest stock figures provided by the Finnish Forest Centre [
58]. Prioritization would be most sensibly conducted by regional responsible museums, as these authorities are most familiar with the specific characteristics of their area and would be able to select the most critical sites for field inspection. The same so-called critical sites could also be emphasized in commercial surveys, if such are being conducted in the area.
Furthermore, entirely new innovative solutions could be explored for updating the information on archaeological sites. Finland has active amateur archaeologists and hobbyist associations [
59]. These enthusiasts participate in excavations, and those using metal detectors, especially, generate a lot of new information. An app has been created for enthusiasts to report finds and new sites [
60]. The information and location accuracy of archaeological sites could potentially be improved in a manner similar to that tried by the National Land Survey for locating boundary markers, for which a dedicated game app was developed [
61,
62]. Crowdsourcing is the art of the collection of geospatial data by a large group of voluntary people. In Hyyppä et al. (2018), the feasibility of smartphone-based Lidar for crowdsourcing forestry information was demonstrated [
63]. Since then, Apple has integrated Lidar to many of their products, and it is possible to create 3D models for documenting valuable sites. Additionally, crowdsourcing and smartphones have been successfully used in documenting landmarks [
63]. The use of crowdsourcing in cultural heritage and conflict archaeology has been discussed, for example by Seitsonen in 2017 [
64].
The literature review clearly demonstrated that the discussions and research on archaeological sites and their impact on forest management are highly one-sided. The subject has been addressed to some extent in archaeological publications, but hardly at all in publications related to forest research. This indicates a gap in interdisciplinary research and highlights the potential for more integrated studies that could benefit both archaeological conservation and forestry management. However, the discussion on forestry in Finland is very active at a general level, with the current focus on issues such as climate change, technological advancements, logging practices, and conservation perspectives. To date, there has been little to no research or discussion on archaeology or cultural heritage within this discourse. There could be several reasons for this one-sided perspective, but from a Central European viewpoint, the topic may not be deemed as crucial since forestry does not hold as significant a role in many areas as it does, for example, in Finland. Dialogue and cooperation would benefit from incorporating perspectives from both fields and enhancing interaction. Archaeological publications often focus on the protection of sites and the negative impacts of forestry on archaeological sites, which are indeed important subjects. While there is likely practical or field-level dialogue between the sectors, there appears to be a lack of interaction in terms of scientific research.
New innovations are also needed to increase collaboration. Approaching the accuracy of archaeological spatial data and related details, such as site descriptions, from the perspective of the forestry sector could be intriguing. Future studies could, for example, aim to determine whether the register’s information is sufficiently understandable for different user groups, such as forestry experts or forest owners. Archaeological sites often interest landowners, and many may have substantial further knowledge about their own land. Case Example 5 in this research was familiar to the owner of the forest, who also wanted to protect that archaeological site. In this instance, the forest owner voluntarily refrained from conducting thinning operations in the area where they believed the archaeological site was located. According to a survey conducted in 2021 on behalf of the Finnish Heritage Agency, the Ministry of Education and Culture, and the Ministry of the Environment in Finland, nine out of ten people consider cultural heritage important, and over a third would like to be more involved in protecting cultural heritage [
65]. On the other hand, the protection of archaeological sites and reporting about them is associated with certain beliefs, and many landowners may fear the consequences of protection for their own activities, such as forestry, farming, or construction [
66]. Cooperation could be increased, for example, from the study phase itself. Both archaeology [
67] and forest sciences [
68] are taught at the University of Helsinki, and joint courses could encourage collaboration between the fields. Shared research projects could also lay the foundation for dialogue and make discussions more open. Clearly, the forestry sector is often viewed in archaeology more as a threat or as endangering archaeological sites. One of the most significant results of this study was achieved through practical cooperation. Case example 5 is a significant archaeological site, as it has now become the first confirmed separate plague cemetery in Finland, thanks to this research. While individuals who died of the plague have indeed been buried in common cemeteries, a separate, secluded plague cemetery where victims were buried within a relatively narrow time frame is a rare type of site. Future research on this site could address many research questions related to, for example, the plague or the rural population of the early 1700s.
Finally, we would like to discuss some general future directions. Possible topics for further research could include a follow-up study a few years after the new law on archaeological heritage has been implemented. Only then will it be possible to see the practical effects of the new legislation, for example, on forestry and the damage to archaeological sites as a consequence of forestry activities. The use of archaeological spatial data and the methods used for collecting spatial data could be further examined, for example, through surveys aimed at industry stakeholders. Surveys targeted at the forestry sector could also generate valuable information and lay the foundation for new types of cooperation. Regarding cooperation, it would be interesting to see if efforts to organize collaboration between the fields are pursued in the future. Additionally, technological advancements and new innovative inventions in both fields are possibilities, and could enable the collection of even more precise spatial data in archaeology as well. The topic is very timely. For example, the Finnish Heritage Agency is initiating a reform project related to the archaeological research infrastructure [
11]. In Sweden, a large project somewhat similar to this, known as Swedigarch, is underway [
69]. There is also a need to update the register of ancient sites in line with new legislation, which uses the term ‘archaeological information repository’ instead of ‘register’ (muinaisjäännösrekisteri) [
9]. Several industry discussion events have been organized on the topic, the most recent being a meeting/workshop for archaeological fieldwork practitioners in March 2024 [
70]. Discussions on archaeological surveys and their practices have also recently been initiated by archaeologist Timo Jussila on an archaeologists’ email list [
71]. New guidelines and practices are currently sought from the perspectives of both fieldworkers and authorities. The forestry perspective has so far been underrepresented, but future collaboration could bring this viewpoint to the fore as well. Field work is also common in forest studies, and some of the field methods for forest inventories could be tested for archaeology as well.