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The Sugar Maple

Leaf litter and sugar maple saplings in the sugar maple mono-culture of the Morgan Arboretum.

Acer saccharum, also known as “Sugar Maple”, is a deciduous tree species native to the St-Lawrence Lowlands’ area. It is usually found in the northeast of the United-States and in the southeast of Canada. The sugar maple is very dominant and broadly distributes in the northern hardwood forests of this region (Lovett & Mitchell, 2004). It usually grows to 35m tall with a trunk diameter of around 0.6m in width. Its bark changes from light gray and smooth to dark grey and furrowed as it ages. This species forms clusters of green-yellow flowers in the spring which produce red-brown paired samara fruits of 2-2.5cm in length. The dark green leaves usually grow to 5-11cm in length and width. They have 5 lobes which are shouldered by pointed teeth. This species is sometimes considered as an ornamental tree because it produces a striking fall foliage (Westing, 1966). Its leaf colour change ranges from yellow to red in autumn. The sugar maple’s name comes from the properties of this species sap. The Native Americans discovered that if you boil a sugar maple’s sap, it will form a syrup due to its high concentration in sugar. This knowledge was passed on to the European settlers and has since been a tradition in this area.

Sugar maple Leaves and fruit.

Sugar maples, Acer saccharum, are an eastern maple species inhabiting mixed deciduous forests. They range from the Maritimes, excluding Newfoundland, to Ontario. They are distributed as far north as the most northern part of Quebec and go as far south as Louisiana, USA (USDA). Depending on where it is distributed, the sugar maple can tolerate different elevations (Cornell University).

Sugar maples, based on their geographical range, can tolerate a wide temperature spectrum (Cornell University). The temperature range which is best for optimal growth is known as a temperate climate (Ressources Naturelles Quebec). In the summer, April/May till August/September, the average temperature in a temperate climate will range from 160C to 270C while the maximum summer temperature can go from 320C to 380C (Cornell University). In the winter,  October/November till March/April, the average temperatures are -180C to 100C where the minimum winter temperature can reach up to -400C (Cornell University).  The main concern regarding the health of maple trees, especially for a silviculture, is the effects of frost which can damage young maple buds and hinder their growth (Cornell University). It has been recorded that the first frost occurs between the months of September and November and the last frost phenomena occurs from March to May (Cornell University).

Sugar maple canopy in the mono-culture of the Morgan Arboretum.

The annual precipitation of a temperate climate has an average of 51 cm to 127 cm of rain, whereas the average snow precipitations are 2.5 cm to 381 cm (Cornell University). In more southern regions where the probability of heavy rainfall is much higher than northern regions, the amount of rain precipitation can reach up to 203 cm (Cornell University).

The sugar maple grows on low pH soils that are also low in calcium, magnesium and high in aluminum.   To obtain a good amount of calcium, the sugar maple can extent their roots to collect the element from the lower horizons.  Forests who count a large number of sugar maple tend to have a large quantity of nitrogen in the soil.  The nitrate leaches in the soil from the sugar maple trees.   In addition, the tree plays a large role for the nitrogen cycling in the forest ecosystems.   The tree is also called a “hydraulic lifter”, which means that the roots can raise the water located in the deep soil to bring it to the surface horizon so that the whole soil can maintain its moisture.  Sugar maples also contain micorrhizae, which is a symbiotic association between a fungus and the roots of the tree.  This symbiosis emphasizes the quantity of nutrients to the soil (Lovett, Mitchell. 2004).

Sugar maple mono-culture of the Morgan Arboretum.

There are many reasons and different ways of managing the sugar maple in a forest. The tree can be used for the production of maple sap or logwood. Landowners must first determine if the soil is suitable for the tree. For the sugar maple, the ideal soil would be one that has moderate to good drainage as well as fine texture. If the landowner wants to use the sugar maple for the production of sap, the trees need to be big, have large crowns, and have branches that extend close to the ground. In order to have this, the land needs to be free from competition for sunlight so the tree can grow fast. However, if the landowner’s intention is to produce logwood, the trees need to be tall and straight. Therefore there must be competition for sunlight. The shading will also lead to the shedding of the lower tree limbs, which will result to a clearer and more valuable lumber (Forest Management, 2002).

Sugar maple seedlings have to face a number of different insect and diseases throughout their development.  The health and survival of young trees may be greatly affected depending on the extent of damage that they face.  According to Gardescu (2003), the types of damage that sugar maple seedlings can suffer are ‘’ 1) herbivory of the stem or cotyledons, by caterpillars, slugs, and beetles; 2) damage associated with pear thrips; 3) leaf herbivory by caterpillars and beetles; 4) white flecking on leaves, caused by leafhoppers; 5) phloem-feeding insects (with no visible seedling damage); 6) leaf fungal diseases; and 7) other kinds of damage, such as stem breakage or burial’’ (Gardescu, 2003).  The insects which dominate all other types of insects present on young sugar maples are the pear thrips.  These insects are less than 1.5 mm in length and feed on emerging flowers and leaves.  They also lay their eggs in the same areas (Gardescu, 2003).  Pear thrips also attck other types of maples but cause the most damage on sugar maples.  The insects return every year.  Some signs of pear thrips damage are unusually small leaves and yellow or white spots on leaves (Pear Thrips, 2011).

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References

Lovett G. M. & Mitchell M. J. (2004) Sugar maples and nitrogen cycling in the forest of eastern North America. Frontiers in Ecology and the Environment, 2, 81-88.

Westing A. (1996) Sugar Maple Decline: An Evaluation. Economic Botany, 2, 196-212.

Gardescu, S. (2003). Herbivory, Disease, and Mortality of Sugar Maple Seedlings. Northeastern Naturalist, 10(3), pp. 253-268.

Websites:

The Life of a Sugar Maple Tree. The Research Center Cornell University, N.d. Web. 10 October, 2012.

USDA. Sugar Maple. Natural Resources Conservation Center. USDA. N.d. Web. 10 October, 2012.

Ressources Naturelles Quebec. Giants of the Plant World. Highlights on Forests. Ressources Naturelles Quebec. N.d. Web. 10 October, 2012.

Pear Thrips. (2011, October 27). Retrieved October 21, 2012, from Natural Ressources Canada

“Forest Management.” Maple Info. Departments of Forests Parks & Recreation.2002. Web. 21 Oct. 2012

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About Crystal Ernst

Hakai Institute postdoctoral scholar at Simon Fraser University (B.C.)

10 comments on “The Sugar Maple

  1. Thanks for introducing me to the pear thrips! You say that “for the production of sap, the trees need to be big, have large crowns, and have branches that extend close to the ground.” Why have branches close to the ground? In one érablière I noticed the oldest trees (huge) were shaped like that. All younger trees (though mature) had straight branchless trunks. Does this represent a change in production technique? Any light on that question would be appreciated!

    • The fact that there are branches near the ground is a sign that the tree did not face a lot of competition for sunlight. When the sugar maples face more of this competition, they then to shed their lower limbs, which makes them more valuable as lumber, according to the last website in our references. As for the change in production technique, I am not sure how it would relate to that, but the trees you are talking about seem to be competing for sunlight. Were they more closely packed than the older trees? Hope this helps!

      • I had misread, I thought you meant that for (better?) sap production the tree needed these lower branches… sorry! It may be intersesting to compare the architecture of these old trees with more recent ones. They may indicate that a far less dense forest was favoured for production in older times? Thank you.

  2. The fact that there are branches near the ground is a sign that the tree did not face a lot of competition for sunlight. When the sugar maples face more of this competition, they then to shed their lower limbs, which makes them more valuable as lumber, according to the last website in our references. As for the change in production technique, I am not sure how it would relate to that, but the trees you are talking about seem to be competing for sunlight. Were they more closely packed than the older trees? Hope this helps!

  3. Wow thats really cool i didnt think there was that much to it

  4. Wonderful blog! I found it really interesting how different usage goals for the maple leads to a distinct way to care for the tree as to amplify the efficiency of its use…
    Very nice!

  5. Paul Kennedy, curator of the National Memorial Arboretum in Staffordshire, UK, would add to the description of the trunk the development of shaggy plates, which are a distinct feature as the tree ages. In addition to sugar production are there are other uses for the timber itself and how would you describe the timber?

  6. HI, Do you think sugar maples can survive in eastern Newfoundland? I have a red japanese maple that is thriving, could that be an indication that they can?
    Thank you

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