A Survey of the Knowledge of Tru ffl es among Polish Foresters and Implications for Environmental Education

While the use of truffles in Poland has a long tradition, for historical reasons this knowledge was almost lost. Currently, truffles and truffle orchards are again receiving public attention. For example, the Polish State Forests supported the establishment of truffle orchards by the Forestry Research Institute. In recent years, knowledge concerning these unique hypogeous fungi has been disseminated systematically through scientific and popular publications, films, and electronic media. This study investigates the awareness of economically and culinary valued truffle fungi (Tuber spp.) among more than 1400 Polish foresters. The results show that 70% of interviewees were familiar with historical and contemporary information about growing and using truffles in Poland. Based on respondents’ age, education, type of work, and gender we attempted to identify whether these elements were associated with the state of knowledge about truffles. The results indicated that younger foresters were better informed about the presence of truffles in Poland and also about their use in the past in Polish cuisine. Environmental education was an important source of knowledge about truffle harvesting and the soils that are conducive to truffle development. Foresters who have provided forest ecology education and who are 36–65 years of age generally possessed better knowledge about truffles than other age cohorts. More than 30% of respondents expressed interest in educational courses to improve their knowledge of truffles. The results point to the need for forestry education concerning truffles and indicate the need for fostering sustainable agroforestry-centered initiatives disseminating this knowledge to the public.


Introduction
Poland has one of the largest forest areas (ca.9.4 million ha) in Europe [1].The majority of forests (about 80.8%) are administered by the State Forests National Forest Holding (the State Forests headed by the General Director).The General Directorate is in charge of 17 Regional Directorates, with altogether 431 forest districts divided into forest ranges [2].Timber is the main product derived from Polish forests, and Poland's forests remain one of the best stocked in Europe.Non-wood forest products, such as forest fruits (mainly berries), mushrooms, and game animals have been gaining in importance.The Polish Central Statistical Office provides no statistics on the amount of fruits and mushrooms harvested from forests.Due to free public access to Poland's forests, everyone has a right to collect forest fruits and mushrooms without limit, with harvesting restricted only for protected species [3].
Social functions of forests are difficult to define and measure, which include recreation, tourism, education, and various traditional uses [4].The State Forests place substantial efforts into raising public awareness of recreational and educational infrastructure available in forests, including: parks and arboreta (of which there are 17 in Poland), centres for ecological education (over 20), educational rooms (50), scenic viewpoints (318) and nature paths (over 150).The so-called green schools and Promotional Forest Complexes and Forest Education Centres, which are located in Forest Districts, run educational courses for primary school pupils (reaching over 815,000 people in 2015) and middle and high school students (about 450,000 people in 2015) [5].At the national level, more than 9000 foresters in Poland provide public education about forests.A noticeable disadvantage of the current system is the fact that forest education for the majority of foresters is an additional responsibility on top of their other duties [6].
It is estimated that there are over 1000 species of edible mushrooms in Polish forests [7].Their collection has a centuries-long tradition and an established place in Polish culture.Knowledge about mushrooms has traditionally been passed down from generation to generation.However, with the modernization of the country and an increase in the standard of living, knowledge and skill concerning the collection of edible mushroom species has been waning in recent years [8][9][10].
Knowledge among foresters about subterranean fungi such as truffles (Tuber spp.) was lost after the Second World War for some changes of social and cultural character as well as changes of forest management.Primary factors determining truffle forgetfulness were: (i) Changes in forest cover.After the Second World War, forests comprised only 20.8% of Polish territory.Unfavorable conditions for fruiting truffles included changes in species composition, age structure of stands, and changes of forest management.For example, undergrowth shading the forest floor was more common due to the cessation of grazing in forests.(ii) Changes in the structure of forest ownership and use.The disappearance of traditional types of forest use, such as cattle grazing and collection of brushwood.(iii) Changes at the societal level due to war and the great loss of Polish citizens, especially the loss of Polish aristocracy and intelligentsia, including foresters, or social groups with the most knowledge and practice regarding collection, use, and cultivation of truffles; emigration and migration of population from rural to urban areas.(iv) The communist regime promoted "pork chop and carp" as the food for the 'working class' rather than the traditional delicacies of Polish cuisine.Truffles as a luxury product for the nobility were not welcomed by new authorities [11,12].
As a type of mycorrhizal fungi, truffles need a host plant to develop, grow best in calcareous, mainly rendzic soils, and, because they grow up to 30 cm deep in the soil, they need to be found with the help of trained dogs or pigs.
Truffles currently are gaining attention in Poland, mainly due to research projects sponsored by the State Forests National Forest Holding.The projects have been conducted since 2007 by researchers of the Forest Research Institute.Due to this research, six truffle orchards were established (altogether covering almost 5 ha) (Table 1).At the oldest truffle orchard, fruiting bodies of the summer truffle (Tuber aestivum Vittad.) were found, eight years after orchard establishment [11,12].Although establishing of truffle orchards is still in pioneer phase, such an activity is perceived as a new source of benefits in agroforestry.The possibility to grow and collect truffles is important for increasing rural economy and thereby the incentives for planting oak and hazel (main host-plant species).Truffle cultivation can contribute to a stable bioeconomy, both supporting the high biodiversity associated with Quercus spp.[13] and contributing to local economy of rural areas.Since truffle orchards may become a new core of sustainable, high-diversity biotops worth protecting, the topic should be propagated, especially by foresters dealing with education who can based on results of the work cited below.The results of our truffle research are disseminated through publications [11,12,14], monographs [15], and in the film "Truffles in Poland," produced by M. Ogrodowczyk (https: //www.youtube.com/watch?v=sGVQEkaWRjs).Given that environmental education is provided by foresters, we are of the opinion the subject of truffles should be part of the forestry education curriculum.To evaluate the state of knowledge about truffles among foresters, a survey was conducted with the aims of: (i) investigating the level of knowledge about truffles among foresters and (ii) indicating which aspects of knowledge about truffles need better communication.

Materials and Methods
The survey was carried out among foresters from 43 Forest Districts (10% of all districts in Poland).Each of 17 Regional Directorates was represented by one to six forest districts.The names of both the forest district and regional directorates are given in Table A1, Appendix A. In total, 2002 questionnaires were sent, canvassing 7.8% of all foresters employed in Poland, with from 20 to 74 individuals canvassed in each district depending on the number of forest district workers.The questionnaires were sent to the chosen Forest Districts via mail.The data was collected for two months and 1404 questionnaires were received back.
The questionnaire titled "What do you know about truffles?"included four questions to characterize the respondent (independent variables) and ten questions on aspects of truffle ecology, use, history in Poland, etc. (dependent variables) (Tables 2 and 3).The dependent variables were designed to investigate the foresters' knowledge, experience, and preferences regarding truffles.Characterization of independent data based on survey responses is showed in Table 4.The estimated time to complete the survey was 15 min.

Statistical Analysis
Statistical analyses were done using R 3.0.2software, (www.r-project.org).The majority of the data were selected with inner hierarchy.This means that the answers for particular questions were not independent from other questions.We chose one of the most appropriate modern statistical methods for selection of the hierarchy in thresholds and used a conditional inference tree method [16].This method belongs to the family of recursive partitioning, which is based on maximally selected rank statistics.It was supported by using the package for R [17].For our analyses, we used first order of discrimination in the case of significant response.

Results
Out of 2002 questionnaires, 1404 were obtained back.The response rates fell into two distinct groups.Questions to do with fungus identification were responded to by 660 foresters.Questions dealing with more general aspects of truffle occurrence, ecology, and use, received between 1170 and 1174 responses.Unless otherwise stated, there was no significant effect of respondent age, gender, education, or job position on the response received.
The survey revealed that the majority of respondents (70.7%) know that truffle fungi grow in Polish forests.However, only a small number of respondents (15.4%) were aware that truffles can be grown in orchards.Only a small number of respondents indicated that they found truffles abroad or in Poland (0.6% and 2.8%, respectively).Answering the 4th question (Table 5), only 471 respondents indicated a source of information about truffles.The main source of information was TV and only 11 respondents indicated scientific publication (Figure 1).
A large portion of respondents (about 62%) were aware of the historical use of truffles.However, most respondents were of the opinion that truffles were not commonly eaten in the past (only 4.3% of respondents thought they were once a common food item), an opinion especially common among those younger than 36 years old.More than one third of foresters knew the type of soils conducive to truffle growth.Only about 5% indicated that truffles were present on non-calcareous soil.A great number of respondents (1217) knew that searching for truffles is provided with help of dog or swine (Table 5, Figure 2).More than 200 respondents were familiar with other methods of truffle hunting (Figure 2).Out of the four species of fungi (Tables 3 and 5), G. esculenta (Pers.)Fr. was the one most respondents were able to identify.Men more often indicated that truffles grew in their forest district.About 28 per cent of respondents were familiar with truffle products, especially people younger than 46 years of age.

Scleroderma citrinum
The first species was selected correctly in 39.1% of cases.
Men were more often correct at this task than women (Stat.= 6.27; p = 0.048).
The second species was correctly identified only by 9.2% respondents.
The third species was correctly chosen by 5.9% of respondents.
The forth species was correctly identified by 34.1% of respondents.

Discussion
The high cultural importance of fungi is very characteristic of northern Slavic societies.In Poland, mushrooms are widely collected and consumed by the general public.Mushrooms are also widely known, recognized, talked about, and even frequently depicted in children's illustrations [18].The scene of mushroom collection is presented in the Polish national epic entitled "Pan Tadeusz" as a noble occupation, having a strong social and culture-creating value [19].
Truffles, as fungi of special value and taste, were known and eaten in Poland at least since 1661 [11,12].However, after the Second World War, interest in truffles decreased due to changes in social

Discussion
The high cultural importance of fungi is very characteristic of northern Slavic societies.In Poland, mushrooms are widely collected and consumed by the general public.Mushrooms are also widely known, recognized, talked about, and even frequently depicted in children's illustrations [18].The scene of mushroom collection is presented in the Polish national epic entitled "Pan Tadeusz" as a noble occupation, having a strong social and culture-creating value [19].
Truffles, as fungi of special value and taste, were known and eaten in Poland at least since 1661 [11,12].However, after the Second World War, interest in truffles decreased due to changes in social

Discussion
The high cultural importance of fungi is very characteristic of northern Slavic societies.In Poland, mushrooms are widely collected and consumed by the general public.Mushrooms are also widely known, recognized, talked about, and even frequently depicted in children's illustrations [18].The scene of mushroom collection is presented in the Polish national epic entitled "Pan Tadeusz" as a noble occupation, having a strong social and culture-creating value [19].
Truffles, as fungi of special value and taste, were known and eaten in Poland at least since 1661 [11,12].However, after the Second World War, interest in truffles decreased due to changes in social and cultural character as well as changes made in forest management.In the late 1940s, despite the rich body of historical records on truffles, even their presence in Poland was questioned [20].In 2007, research on truffles conducted in the Nida Basin revealed the presence in Poland of T. aestivum and other truffle species [21].Since then, efforts have been made to disseminate knowledge about truffles (Tuber spp.) by publications, a movie, and book [11,12,14,15,[21][22][23][24][25][26], and popular programs.The first Polish truffle orchards were established using seedlings inoculated from native inoculum.In the oldest orchard, which was established in 2008, fruiting bodies of T. aestivum were first observed in 2016 [12].The research and popularization of truffles was strongly supported by the forestry sector, which help to drive research and to promote the subject within forestry education [23][24][25][26].
The survey reported here, carried out among foresters in Poland, revealed that people older than 56 years of age more often did not know about the presence of truffles in Poland.Such a result is surprising given that respondents indicated their main source of information about truffles were TV and Internet (Figure 1).On the other hand, this group of respondents might be less engaged with the Internet, the second leading source of information on truffles.Kalle and Sõukand [27] found that people, even in societies where social media has become prevalent, prefer that knowledge be given personally rather than in books.This is particularly true for mushrooms due to the toxicity of some species.However, field guides are still influential, in that they tend to cause unification of mushroom names throughout the country [10].
The survey showed that women were less likely to have found truffles than men.It might indicate sociological aspects of forest use: although knowledge about mushrooms is held by both sexes, men are slightly more involved in the practice of gathering.This is in contrast to plant gathering, which in Poland has been performed mainly by women and children [10].Mushroom collection is more similar to hunting, usually a male domain, than collecting berries or herbs, as the appearance of fungal fruiting bodies is temporal [10].A strong element of chance is thus introduced, making mushroom gathering more exciting and due to the fact that it has a highly competitive character, male mushroom pickers do not want to confirm their "failure".
Men more often indicated that truffles grew in their forest district.Some of the correct species identification may have resulted from people recognizing the truffle name and correctly guessing which picture it matched.We hypothesize that male foresters may have a higher truffle identification rate than females because of the springtime occurrence of these fungi when field work (planting, thinning etc.) is being carried out mainly by male foresters.
More than one third of foresters knew the type of soils conducive to truffle growth.Foresters responsible for environmental education were more likely to give the correct answer.However, about 5% of foresters indicated that truffles were present on non-calcareous soil.This result may indicate that, among foresters who knew that truffles grow in Polish forests, a minority possessed knowledge of the ecological requirements for truffle growth as for the type of soils conducive to truffle growth.
Popularity of truffle products, especially among people younger than 46 years of age seems to confirm the idea that young people are more prone to follow the news and have a more consumer-oriented attitude and contemporary lifestyle that could include greater knowledge and use of gourmet food [28].
Based on the results of our survey we think a forest education program aimed at raising awareness of truffles should be divided into stages addressed to various groups of recipients (taking into account age, education, and gender).Firstly, it should include foresters working in areas where truffles grow naturally since in the future they would be dealing with nature conservation in the terrain of truffle ecotourism.Secondly, educators and employees of forest education centres should be knowledgeable on the subject of truffles.For this purpose, appropriate guides containing the most important data on truffles growing in Poland, both in the natural environment and in truffle orchards are necessary.

Conclusions
The results revealed that the level of knowledge among foresters still is far from satisfactory.To achieve greater awareness on this topic we think more emphasis should be given to popular science articles in the Polish language dealing with, for example, how to grow truffles in orchards, hunt for truffles in forests, and how to use them in cuisine (e.g., how to preserve and cook truffles).Truffles could also be promoted as an eco-attraction, and to help increase knowledge of the important roles of fungi in forest ecosystems.Considering that TV and the Internet were the main sources of knowledge about truffles, it might be reasonable to develop educational activities in these media, for example by creating a special website <truflapolska.pl> or Facebook page, to make material more accessible on this subject.Acknowledgments: All reviewers are acknowledged for their valuable comments and suggestions, which greatly improved the paper.

Conflicts of Interest:
The authors declare no conflict of interest.12.

Appendix A
Opinion: "The respondent does not know if truffles occur in Poland".0-negative; 1-positive (the respondent is not sure about truffles' occurrence). 13.
Opinion: "Truffles in Poland occur in the forest and in truffle orchards, both of them" 0-any, 1-both selected 14.
Opinion: "The respondent does not know if he/she found a truffle in Poland".0-negative; 1-positive (the respondent is unsure about his/her finding).

17.
Opinion: "The respondent did not find a truffle in Poland".0-negative; 1-positive (respondent did not find).

19.
In Poland, in the past truffles were eaten at by nobles 0-negative, 1-positive.

21.
In Poland, in the past truffles were used as animal feed.

25.
Occurrence of species presented on pictures 0-Any picture picked, 1-At least one picture picked.

30.
Products with truffles available in Poland 0-respondent did not know of any product, 1-respondent heard about product with truffles in Poland.

Figure 1 .
Figure 1.Sources of information about truffles in Poland.

Figure 2 .
Figure 2. Methods of truffles collection known to respondents.

Figure 1 .
Figure 1.Sources of information about truffles in Poland.

Forests 2019 , 13 Figure 1 .
Figure 1.Sources of information about truffles in Poland.

Figure 2 .
Figure 2. Methods of truffles collection known to respondents.

Figure 2 .
Figure 2. Methods of truffles collection known to respondents.

Author
Contributions: D.H., A.R.-G., B.K. and M.S. generated the data.All authors analyzed and discussed the data.Statistical analysis: J.H.The general conception: D.H. and A.R.-G.The manuscript was written by D.H. and B.K. Funding: The research was performed within the project financed by the State Forests National Forest Holding [grant No. OR-271.3.5.2017].

Table 1 .
Truffle orchards under care of the Forest Research Institute.

Table 2 .
List of independent variables.

Table 3 .
List of dependent variables.The symbol "*" in questions 4, 7, 9 indicates that a "yes" answer allowed the respondent to provide an example and for question 7 that it was possible to give a different answer than the choices provided.

Table 4 .
Characterization of independent data based on survey responses, N/A-no answer.

Table 5 .
Respondents' answers with comments based on statistical analysis.The symbol "*"indicates that the respondent were asked to provide an example.

Table A1 .
Data codification for statistical analysis.