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The Plant Health Instructor

Volume:  |
Year: 2018
Article Type: Lesson Plans
​​CALEDON: Making a Game of Forest Pathology to Increase Awareness of Tree Diseases, Pests, and Production

Alex Batsona and Max Colemanb

aWashington State University, Pullman, WA
bRoyal Botanic Garden Edinburgh, Edinburgh, Scotland

Date Accepted: 01 Jan 2008
 Date Published: 01 Jan 2008


Keywords: CALEDON, forest pathology

For many elementary, high school, and undergraduate students, plant pathology is an unknown field of study. This is most likely a result of the lack of representation of plant pathology in classrooms as well as infrequent publicity in the mainstream media across the United States. In fact, an article in the June 2017 issue of Phytopathology News by David Gadoury titled ‘Changing Landscapes’ reports that the current median age for plant pathologists in the United States is 54, and only 7% of self-described plant pathologists are under the age of 35. Although the number of plant pathology graduate students has increased by 20% over the past decade, there remains a need to recruit more students to train as plant pathologists to fill positions that are vacated as the baby boomers approach retirement age. To achieve this necessitates engaging elementary and high school students and teachers, as well as undergraduate students in activities and learning experiences that expose them to plant science and, specifically, plant diseases. Presenting plant pathology and the sciences to students using an interactive computer-based medium will facilitate and better match the learning styles of a wide array of students. 


CALEDON is a freely available, interactive forest management computer game, developed for Windows and iOS platforms, and available to play online through a range of browsers. It was created by scientists from a diverse group of United Kingdom-based institutions involved in the PROTREE project including the Royal Botanic Garden Edinburgh, The James Hutton Institute, Forest Research, Scotland’s Rural College, University of Aberdeen, The University of Edinburgh, and the Centre for Ecology and Hydrology; in association with game designers at Hyperluminal Games

The objective of CALEDON is to increase awareness especially among young adults, of the importance of forestry and tree health. Players are immersed in the world of CALEDON, where they manage a diverse landscape with the aim of maintaining a forest while balancing budgets, production, pests and diseases. The player must make decisions about where to buy their seeds, which tree species to plant and in how big an area, how to deal with diseases and pests, and when to harvest the timber in order to gain financial reward. The player is first guided through a brief tutorial and introduced to an encyclopedia that contains pertinent information for managing each tree species and specific pests (Figure 1). After the tutorial, the game can be played at three levels of increasing difficulty, followed by a free-play level in which the player manages their own forest. CALEDON forests grow and change in increments of 5 years, but players set their own pace, and each game level can be completed in 20 to 45 minutes. Besides successfully managing a forest, ancillary objectives specific to the level of play are available, from simply keeping the trees alive for 50 years to increasing biodiversity, to filling a percentage of the map with forest, and challenging the player to develop a strategy.

Figure 1. View of the introductory encyclopedia in the forestry
computer game CALEDON. The top panel shows the supply
type of trees, the lower panel shows an information panel
for the ash tree, Fraxinus excelsior.

The lessons learned from CALEDON are directly translatable to the classroom setting. For example, there are three supply types for the tree-seed stock, which can be selected by the player: ‘cash crop’, ‘off the shelf’, and ‘slow but steady’. The genetic diversity, cost, yield, adaptation to the local environment, and susceptibility of the trees to diseases and pests from the three supply types are different. Cash crop trees have the lowest amount of genetic diversity compared to trees grown from the other two seed-stocks, as cash crop seed stocks were developed for rapid growth and high yielding trees to maximize income quickly. However, due to the lower genetic diversity of forests grown from cash crop seed they are more prone to disease and pest outbreaks. The slow but steady seed supply type is the most expensive option for the player, but this stock of seed is locally sourced and adapted to the forest of CALEDON, and trees grown from this slow but steady supply type experience less disease pressure. Understanding the importance of genetic diversity for species survival is a key feature of biology education courses and may be a difficult concept for younger students, therefore some additional, teacher-led instruction may be required in the classroom.

Another factor in the game is that the player needs to effectively balance the importance of raising and harvesting a forest sustainably while also turning a profit. The integration of financial reward and profit into the game requires players to evaluate pest and disease risks to forests. The importance of financial solvency in CALEDON drives players to explore the strategy options and they will learn, with the aid of in-game strategy tips, the importance of diversity in forestry and agriculture. For example, experience will show that a single species of tree planted in high concentration with little diversity creates ideal conditions for disease, lowers lumber yields and increases the costs of managing the forest. The concepts that are introduced to players by CALEDON can be reinforced by having students discuss the strategies that resulted in successful forestry programs and the strategies that met with increased pest and disease pressures. Some questions that could spark discussions with and among students include:

  • Under what conditions was disease the most widespread? Why do you think the spread of specific diseases or pests was so expansive?
  • What disease and pest issues were most common? Why were they common?
  • How did you manage specific diseases and pests effectively?   
  • Which management strategies maximized earnings? Why did those strategies work well?
  • What factors or environmental conditions favor the spread of pests and diseases in a forest? (Examples include animals, wind, rain/water, movement of diseased plants, insect vectors of plant pathogens, etc.)

Integration of CALEDON into educational curricula

CALEDON is unique in that the game subtly introduces students to foundational topics in plant pathology, specifically forest pathology, as well as general plant biology - such as the importance of diversity in agriculture and forestry, selection for pest and disease resistant trees, implementing pest and disease management practices, and cultural planting practices. Faculty from the Royal Botanic Garden Edinburgh stated that CALEDON satisfies several achievement criteria in the Scottish schooling system among students at levels 3 and 4 (grades 6-9 equivalent in the United States public school system), including the sciences, technologies, social studies, and math. The game is used currently as a supplement to the standard curriculum in the United Kingdom, but has also been used to introduce concepts to forestry professionals around the world. For example, CALEDON has been implemented as a training tool for tropical forestry employees in Malaysia (Coles 2017). Although CALEDON is an educational game that is fun to play, it shares some of the qualities of computer simulations used by researchers. The game could therefore be used by educators to test ideas with their students. Consequently, the greatest educational potential of the game is likely to be realized in a classroom environment.

Introducing CALEDON into classrooms in the United States has the potential to reinforce and solidify foundational topics in biology, as well as raise student awareness and increase their interest in careers in forestry and plant pathology. Furthermore, CALEDON’s demonstrated use with a wide range of ages implicates the game as a useful learning supplement for elementary education through, potentially, undergraduate education.

CALEDON can be played free-of-charge.


CALEDON was developed by the PROTREE project with funding from the Tree Health and Plant Biosecurity initiative (THAPBI). The authors would like to acknowledge Joanne Taylor, Steven Cavers, Jill Thompson, and Lindsey du Toit for their input and critique of this manuscript.

Literature Cited

Coleman, M. 2017. Online game changer for tree health. Scottish Forestry 71:40-41.

Coles, W. 2017. Computer game teaches tree health lessons. Centre for Ecology and Hydrology. Retrieved 3 August 2017.

Gadoury, D. 2017. Changing landscapes. Phytopathology News 51:80-81.