American Beech Tree (Fagus grandifolia)

American Beech Tree (Fagus grandifolia)

General Natural History

The American Beech tree (Fagus grandifolia) is a deciduous hardwood tree, native to eastern North America. Its habitat ranges in Canada from Nova Scotia to southern Ontario, and in the United-States from its western limit of Illinois, south to northern Florida (Forrester, McGee & Mitchel 2003). Although, it may have a wide range, F. grandifolia stands tend to be located where the soil is predominantly well-drained, loamy podzols derived from glacial till (Latty, Charles & Marks 2004). F. grandifolia can grow up to 20 – 35 meters in height and live upwards of 300 years; it is also covered with a distinctive smooth silver-gray bark and produces dark green foliage (Forrester, McGee & Mitchel 2003). The tree also produces hard mast (nuts), which are small and sharply angled contained within a soft-spined husk.

F. gradifolia’s mast and leaf

When considering the long lifespan of the beech, it is no surprise that it will typically not create large quantities of mast until approximately 60 years of age (Faison & Houston 2004).

In-part due to the vast range in which F. grandifolia can be found, and the abundance in which it can be found in that range, it plays an important role in the forest ecosystem. Many vertebrates, large and small, from black bears to squirrels depend on the hard mast produced by the beech for survival; many rely on it as an important autumn food source (Faison & Houston 2004). In the case of the American black bear (Ursus americanus) as well as many others, it is possibly the most important food source. This is especially true for those in the northern range of F. grandifolia’s habitat, which is dominated by spruce-hardwood forests; the hard mast produced by the tree may be the only available to the animals (Faison & Houston 2004).

F. grandifolia’s importance to animals not withstanding, it is also a defining factor in the ecology of the forest’s soil. Due in part to the green foliage created by F. grandifolia it plays an important role in the nitrogen cycle. Its leaves contain the highest concentration of nitrogen (3.0%) of all canopy trees growing in North America’s eastern forests (Latty, Charles & Marks 2004). The thick foliage also restricts a large portion of light from reaching the forest floor and in autumn, when the foliage falls, the thick layer of slowly decomposing leaf litter it produces also inhibits the ability for new species to take hold (Forrester, McGee & Mitchel 2003).

Specific Natural History and Research Done

There is a lot of research out there on the American beech tree concerning the Beech Bark Disease (BBD). This disease has killed many beech trees across North America (Latty, Canham & Marks 2003). It is caused by two organisms, the introduced beech scale Cryptococcus fagisuga, and one of two fungi, either the native Nectria galligena or the invasive Nectria coccinea var. faginata (the latter one is more often associated with the disease) (Latty, Canham & Marks 2003; Faison & Houston 2004).

Nectria coccinea var. faginata (fruiting body)

BBD starts when a forest becomes heavily infested by the beech scale insects (Faison & Houston 2004). They invade the trees and feed on the bark, causing death to the bark cells (Ehrlich 1934). This renders the trees susceptible to infection by the fungi (Ehrlich 1934). This results in the death of many beech trees, sometimes within one or two years (Ehrlich 1934). After this, the forest consists of root sprouts and a few large trees; tree mortality is usually lower in this aftermath stage (Faison & Houston 2004).

There are various factors that determine the extent of beech scale invasion and infection on American beech trees. Some factors include: genetic resistance to scale infection (about 1% of the population); the formation of crustose lichens on the bark, making unfavourable conditions for the insect; the nutritional content of the bark; and presence of predators (Houston 1994; Latty, Canham & Marks 2003). Another important factor is the prevalence of wind, animals and people in the environment, as this is how they are transported (Wainhouse 1980; Houston 1994). Tree diameter is another important consideration; the larger the tree, the more susceptible it is to invasion by the beech scale (Latty, Canham & Marks 2003).

There are also factors that determine extent of fungi infection. The most important one being the extent of infestation by beech scales, as fungus can only invade where the scale has colonized (Ehrlich 1934; Houston 1994). Furthermore, populations of fungus can be affected by parasites, such as Nematogonum ferrugineum, and by the prevalence of wind and rain in the environment, as this is how they spread (Houston 1994).

This disease has huge effects on the ecosystem and humans alike (Barker et al. 1997; Hane 2003). BBD greatly reduces the mast production of beech trees; many animals depend on the nuts as a food source (Latty, Canham & Marks 2003). The disease causes defects in the wood, such as cracking and falling away of the bark, which can affect the quality of the wood for human use (Ehrlich 1934; Barker et al. 1997).

Visible defects of the wood

Seeing as these trees are also an important sink for soil nitrogen, their increased mortality affects nitrogen cycling (Latty, Canham & Marks 2003). Furthermore, the increased mortality of mature trees, and the cutting down of infected trees for disease control, has resulted in higher amounts of beech saplings in the forest, which has an adverse effect on maple tree seedling survival, and results in stands of genetically susceptible American beech trees (Hane 2003; Latty, Canham & Marks 2003).

For more information please consult these links:

American Beech Fact Sheet (Virgina Tech Department of Forest Resources and Environmental Conservation)

American Beech (Forest and Range.org Landowner Fact Sheet)

Beech Bark Disease: Proceedings of the BBD Symposium (USDA Forest Service)


Find out more about American Beech Tree:




Barker, M.J., Pijut, P.M, Ostry, M.E. & Houston, D.R. (1997) Micropropagation of juvenile and mature American beech. Plant Cell Tissue and Organ Culture, 51, 209-213. DOI: 10.1023/A:1005953212568

Erhlich, J. (1934) The beech bark disease: A Nectria disease of Fagus, following Cryptococcus fagi (Baer.). Canadian Journal of Research, 10, 593-692. DOI: 10.1139/cjr34-070

Faison E.K. & Houston D.R. (2004) Black bear foraging in response to beech bark disease in northern Vermont. Northeastern Naturalist, 11, 387-394. DOI: 10.1656/1092-6194(2004)011[0387:BBFIRT]2.0.CO;2

Forrester, J.A., McGee, G.G. & Mitchell, M.J. (2003) Effects of beech bark disease on aboveground biomass and species composition in a mature northern hardwood forest. Journal of the Torrey Botanical Society, 130, 70-78. DOI: 10.2307/3557531

Hane, E.N. (2003) Indirect effects of beech bark disease on sugar maple seedling survival. Canadian Journal of Forest Research, 33, 807-813. DOI: 10.1139/X03-008

Houston, D.R. (1994) Major new tree disease epidemics: Beech bark disease. Annual Review of Phytopathology, 32, 75-87. DOI: 10.1146/annurev.phyto.32.1.75

Latty, E.F., Canham, C.D. & Marks, P.L. (2003) Beech bark disease in northern hardwood forests: The importance of nitrogen dynamics and forest history for disease severity. Canadian Journal of Forest Research, 33, 257-268. DOI: 10.1139/X02-183

Latty E.F. Charles D. Canham C.D. & Marks P.L. (2004) The effects of land-use history on soil properties and nutrient dynamics in northern hardwood forests of the Adirondack Mountains. Ecosystems, 7, 193-207. DOI: 10.1007/s10021-003-0157-5

Wainhouse, D. (1980) Dispersal of first instar larvae of the felted beech scale, Cryptococcus fagisuga. Journal of Applied Ecology, 17, 523-532. DOI: 10.2307/2402634


About Christopher Ernst

Hakai postdoctoral scholar at the University of British Columbia and Simon Fraser University (B.C.)

10 comments on “American Beech Tree (Fagus grandifolia)

  1. Nice post! You guys sure covered a lot of primary literature – wow!

  2. […] The first part of this project involves providing an overview of the natural history of their study species, and this overview is being released in the form of a scientific blog post.  Starting today, and for the next three weeks, the nine blog posts will be released on the following site.  (Today’s release is all about American beech Trees). […]

  3. I love your video guys! Very clear and nicely done. You have a lot of content in your post also, very interesting.

  4. Hi Beech group
    This is a good post especially if you want to learn to identify beech bark disease. We have seen the infestation progress in the last decades with some of the oldest beech stands in Quebec (like the one in the old-growth Muir Forest, now an ecological reserve) being infested. Beech was probably a more important component of the forests of southern Quebec than it is now, but its decline had started even before the disease.

    • Thanks so much for your comment. That’s actually very interesting! Why were the American beech trees declining before the disease? And why are they no longer considered as important a component of the forest as they used to be? We did not cross research that suggested that.

  5. I only had a basic notion of Beech Bark Disease. You have done a good job explaining the whole thing. With pictures and a video? That is top quality! Thanks!

  6. Very good posting regarding the importance of beech and of the impacts of BBD. I especially liked the inclusion of information about how beech trees influence nitrogen cycling and regeneration. Beech is often a “foundation species” in stands in the Great Lakes-St. Lawrence Forest and sudden mortality due to BBD will produce biotic and abiotic cascade effects that have not been studied yet in any depth. I have been studying beech and BBD in Ontario for several years and have come to consider beech as the “banquet table of the forest” not to mention its high-rise apartment building! I can’t think of another tree species that provides more ecological services to other forest inhabitants from microbes to macro-fauna!
    BBD has been spreading across the range of beech in Ontario at least since the early 1980s although its presence was only “officially” recognized in 1999. Its spread into south western Ontario seems to be slower than its spread northward, perhaps due to the more fragmented forest cover in SW Ontario as well as to better growing conditions contributing to greater disease tolerance.
    Here are a few more specific observations related to Ontario. (i) Regarding use of beech mast by black bears, almost every beech tree >30 cm dbh along the northern advancing front (approximately on a line from Parry Sound to just north of Ottawa) is scarred by bear claws, evidence of them being climbed. (ii) The indigenous fungus Nectria galligena (a.k.a. Neonectria ditissima) is an insignificant factor in BBD; Neonectria faginata (new name for N. coccinea var. faginata) is the only species we have detected creating cankers of any size or abundance. (iii) The mycoparasite Nematogonum ferrugineum is observed occasionally but is not having any significant effect in bio-control of the pathogen, nor is the larval stage of the indigenous Twice-Stabbed Lady Beetle which feeds on the scale insect. In both cases the abundance of scale and fruiting bodies of the pathogen is so great that the presence of the bio-control agents is a mere footnote in the story. (iv) Along the northern front infected trees can go from a vigour rating of 1 (healthy) to 5 (dead) in one year! (v) Some trees suffer extensive but superficial damage from BBD; tree defences restrict the area of bark colonized by the pathogen to outer layers beyond the cambium. We refer to this as “disease tolerance” to distinguish it from “disease resistance” which is exhibited by trees that do not even become infested by the scale insect. (vi) We have found evidence that trees that exhibited disease tolerance during one wave of infection subsequently suffered more serious infection (i.e. cambial death) in a later wave. We don’t have an explanation for this change in susceptibility but hypothesize that it is due to a difference in tree vigour at the time of the attacks, perhaps due to absence/presence of other factors impacting tree health such as drought, root disease, insect defoliation. (vii) To what degree root sprouting will occur after tree death is under investigation. It does not seem to be an inevitable consequence, and is likely affected by individual tree genetics, level of stored nutrients in the root system, and several other factors. (viii) BBD is a major concern to forest managers for several reasons including impacts on regeneration, biodiversity targets, wood supply, and meeting basal area targets during partial cut operations.
    Here is a link to an Ontario Ministry of natural resources publication on BBD in Ontario: http://www.mnr.gov.on.ca/en/Business/OFRI/Publication/STDPROD_096010.html

  7. […] comprehensive professional report on the natural history of the American Beech, by the Morgan Arboretum of McGill University in […]

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