Topic 2: Maintenance of Forest Health


Forests are entire ecosystems and, as such, they comprise a wide diversity of species. From the perspective of a manager seeking an economic return from a forest, some of these species are more desirable than others. Trees provide timber, with some being more valuable than others. They may also provide a range of other products, including flowers, fruit and bark. In a few cases, other parts of the tree may be used, such as the traditional use of cedar roots for weaving by Aboriginal people of western North America, or the use of foliage to provide essential oils. Other species in the forest may also provide products, including bamboo, rattan, and a variety of trees, shrubs and herbs. Many fungi, part of the decomposer cycle within the forest, may provide edible fruiting bodies.

Many agents can disrupt the productive functions of a forest, some natural and some anthropogenic. In this module, we will look at these agents, and how they can be managed. At all times, it is important to remember that a healthy, natural forest will always contain dead plant materials. Indeed such materials are an essential part of the ecosystem, and also represent an important carbon store (a topic discussed in the next module). In plantation forests, there is much more of a focus on keeping all productive trees healthy, and diseased trees may be removed fairly quickly in order to maintain the overall health of the stand.

Video Lectures

2.2.1 What is forest health?

2.2.2 Forest disturbances

2.2.3 Bark beetles: A case study

2.2.4 Air pollution and forests

2.2.5 Making a diagnosis

2.2.6 Indicators of ecosystem health and vitality: An Australian example


Textbook Reading:

  • Chapter 5 of the course textbook:
    Innes, J., & Tikina, A. (Eds.). (2014). Sustainable forest management: From principles to practice. London: Earthscan Publications. ISBN: 1844077241

Further Reading:

  • Agee, J.K. (1993). Fire ecology of the Pacific Northwest forests. Washington DC: Island Press. ISBN: 9781559632300; ISBN: 9781610913782
  • Bell, J.N.B., & Treshow, M. (2002). Air pollution and plant life (2nd . Chichester: John Wiley & Sons. ISBN-13: 978-0471490906
  • Butin, H. (1995). Tree diseases and disorders: Causes, biology and control in forest and amenity trees. Oxford: Oxford University Press. ISBN-13: 978-0198549321
  • Brookes, M.H., Campbell, S. J., & Liegel, L. H. (Eds.). (1996) Disturbance and forest health in Oregon and Washington (General Technical Report PNW 381). Portland, OR, USDA Forest Service, Pacific Northwest Research Station, 105 p. Retrieved from
  • Ciesla W.M. (1998). What is a healthy forest? Forestry Chronicle 74(4): 470-474. Retrieved from
  • Edmonds, R.L., Agee, J.K., & Gara, R.I. (2011). Forest health and protection (2nd). Long Grove, IL: Waveland Press. ISBN: 978-1577666523
  • Kimmins J.P. (1996). The health and integrity of forest ecosystems: Are they threatened by forestry? Ecosystem Health 2(1): 5-18.
  • Lindenmayer, D.B., Burton, P.J., & Franklin, J.F. (2008). Salvage logging and its ecological consequences. Washington DC: Island Press. ISBN: 9781597264037; ISBN: 9781610911467
  • MacCracken, J.G. (1997). The forest health problem. Wildlife Society Bulletin 25(4): 760-761.
  • Manion, P.D. (1991). Tree disease concepts (2nd). London: Prentice Hall. ISBN: 978-0139294235
  • Maynard, D.G., Stadt, J.J., Mallett, K.I., & Volney, W.J.A. (1994). Sulfur impacts on forest health in west-central Alberta (Information report NOR-X-334). Edmonton, Alberta: Canadian Forest Service, Northwest Region. 51 p. Retrieved from
  • Nair, K.S.S. (2007). Tropical forest insect pests: Ecology, impact and management. Cambridge: Cambridge University Press. ISBN-13: 978-0521873321. Retrieved from
  • Paine, T.D. (Ed.) (2006). Invasive forest insects, introduced forest trees, and altered ecosystems: Ecological pest management in global forests of a changing world. The Netherlands: Springer Verlag. ISBN: 978-1-4020-5161-6 (Print) 978-1-4020-5162-3 (Online). Retrieved from
  • Perera, A.H., Buse, L.J., & Weber, M.G. (Eds.). (2008). Emulating natural forest landscape disturbances. New York: Columbia University Press. ISBN-10: 0231129173; ISBN-13: 978-0231129176.
  • Rapport, D. J., Gaudet, C. L., Costanza, R., Epstein, P.R., & Levins, R. (Eds.). (1998). Ecosystem health: Principles and practice. Malden: Blackwell Science. ISBN-10: 0632043687; ISBN-13: 978-0632043682
  • Sankaran, K.V., & Suresh, T. A. (2103). Invasive alien plants in the forests of Asia and the Pacific. RAP Publication 2013/06. Bangkok: Food and Agriculture Organizati on of the United Nations (FAO) Regional Office for Asia and the Pacific. Retrieved from
  • Sinclair, W.A., & Lyon, H.H. (2005). Diseases of trees and shrubs (2nd). Ithaca: Cornell University Press. ISBN-10: 0801443717; ISBN-13: 978-0801443718
  • Skelly J.M. (1993). Diagnostics and air pollution damage appraisals: Are we being sufficiently careful in appraising our forest health?. Forstwissenschaftliches Centralblatt 112(1), 12-20. Retrieved from
  • Staebler, R.N. (1994). Forest health: Everyone wants it, but what is it? Journal of Forestry 92(7): 5.
  • Strouts, R.G., & Winter, T.G. (1994). Diagnosis of ill-health in trees. London: HMSO. ISBN: 0117529192 9780117529199
  • Van Driesche, R.G., LaForest, J.H., Bargeron, C.T., Reardon, R.C., & Herlihy, M. (2013). Forest pest insects in North America: A photographic guide. Morgantown: United States Department of Agriculture (USDA) Forest Service. Retrieved from and
  • Wainhouse, D. (2005). Ecological methods in forest pest management. Oxford: Oxford University Press. ISBN-10: 0198505647; ISBN-13: 978-0198505648
  • Watt, A.D., Stork, N.E., & Hunter, M.D. (1997). Forests and insects. London: Chapman & Hall. ISBN 978-0-412-79110-9
  • Wylie, F.R., & Speight, M.R. (2012). Insect pests in tropical forestry (2nd). Wallingford: CABI. Retrieved from


Module II - Topic 2: Self-test

Quiz Description:

The following self-test quiz is designed to check your understanding of important learning concepts for this topic. The quiz contains ten multiple choice questions. There is no time limit for you to take the quiz and you may attempt to take it as many times as you like. After you click the Submit button, you will see your Grade, number of Correct Answers, your answers, and the Answer Key for each question.

Quiz Instructions:

While you are taking the quiz, we advise you not referring to any course materials. After you Submit your answers, you may self-reflect the missing points, review relevant contents as necessary, and retake the quiz again until you get the full points

Answer the following questions to see how well you have learnt in this topic: