Trembling Aspen

Trembling Aspen grove Richard St. Barbe Baker Afforestation Area Saskatoon, Saskatchewan, CA
Trembling Aspen grove [in 2016] Richard St. Barbe Baker Afforestation Area Saskatoon, Saskatchewan, CA

It was the summer of 2017, did you see it?

The Populus tremuloides (Trembling Aspen or Quaking Aspen) groves were struggling, and suffering tremendously. The defoliation caused by the Tent Caterpillar Malacosoma disstria was so severe, that combined with the severe drought, the vigour and vitality of the Aspen Trees was greatly reduced.  2017 saw the fourth year of the Tent Caterpillar infestation in Saskatoon. When healthy trees that are completely stripped of their leaves are able to refoliate their leaves after the caterpillars have feasted, however the second growth is smaller and, indeed, may be inadequate to compensate for the damage caused. The attack of the caterpillars may even kill the top of the tree, side branches and even the whole tree may expire with multi-years of excessive defoliation.



James J. Worrall et al, explains that drought, tent caterpillars and other factors contribute to the decline of Trembling Aspens. Severe drought precipitates the most drastic decline, followed by foliage stripped by tent caterpillars  year after year. Aspen stands cannot recover from such shocks to the system on a multiyear basis, without relief.



“It’s almost as if nature has forgotten how to rain in parts of Saskatchewan,[9]” said David Phillips, senior Climatologist with Environment Canada, who goes on to explain that, “It really does show you the kind of climate you have: a desert — dry, semi-arid, almost like Pheonix, Ariz. — where the days can be very hot, and in this case bone dry and not a cloud in the sky. All that heat from the day radiates into space … It left the nights relatively cool.[2]” Saskatoon received only 243.6 millimetres [9.6 inches] of precipitation, bringing 2017 into the top five driest years for the city.

Not only was 2017 setting records for the driest years in history books, the problem for the Trembling Aspen was compounded as being the worst for the Tent Caterpillar plague. “We’re in a boom period for the tent caterpillar,” [10] ” said Tyler Wist, Field crop entomologist for Agriculture and AgriFood Canada. The tent caterpillar has a natural predator in birds, as well as the eggs of the sarcophagid fly.

 Effects on overall health of aspen.  Repeated defoliation by forest tent caterpillar may not allow trees to recover to a normal state of health, which can lead to decline.  ~ Natural Resources Canada

Trembling Aspen grove Richard St. Barbe Baker Afforestation Area Saskatoon, Saskatchewan, CA
Trembling Aspen grove [in 2016]  Richard St. Barbe Baker Afforestation Area Saskatoon, Saskatchewan, CA

Following two or more years of severe feeding there is a general decline in tree health, including twig and branch dieback. After three or four consecutive years of being stripped of their leaves trees can be weakened and may be more susceptible to insects, such as wood borers, and stem disease. Following forest tent caterpillar infestations the incidence of hypoxylon canker, a fungal stem disease, may increase and cause extensive damage in aspen forests.  “~ Forestry Branch

Late spring frosts kill buds leading to early, mass larval stravation. Alberta Government.

“When populations are low, the egg masses on small plants can be removed by hand and destroyed between July and the following spring. Hand picking can inflict significant larval mortality.
Destruction of occupied tents by hand or with a brush leads to colony collapse. Pruning to remove egg masses, tents, or groups of larvae must be done sparingly to avoid injuring the plant. Using fire to accomplish this is not recommended as it damages the plant more than the defoliation.”~Forest Health Protection
 The trembling aspen is known to grow as a clonal colony in which the stems [trunks] arise from one huge conjoined root system.  Whereas the tree stems of the Trembling Aspen may be determined by its tree rings, the roots may be much older than that of the tree trunks.  In the semi-arid regions of the west, Trembling Aspen are more likely to establish new trees via suckering from an established root system rather than from seed.  It is intriguing to learn that the Aspen Tree is really only a small fraction of a much larger organism.  Malcolm F. Squires reports that clones of Aspens may have sprouted following the Pleistocene era after the retreat of the great ice age, creating the oldest organisms in the world.  One can tell one Aspen clone growth from another, as leaves will emerge in the spring and turn to yellow in the fall in the same clone, and a neighbouring clone will exhibit a different time scale.
If a clone of Aspen trees from the same root is even aged, and has thrived in near to full sunlight, is severely attacked and stripped of its leaves by tent caterpillars causing some of the Aspen trees to die back.  The Aspen roots, in some cases, if the soil is healthy, be able to regenerate from suckers.  Young saplings will rise from the roots in the openings, or these young trees may take advantage of thin crowns.  The Aspen stand will show this uneven age structure, until the remaining tree trunks die off, and all the tree stems become even aged.
“Jack Schultz, a Pennsylvania State University entomologist… discovered that aspens react chemically to insect attack.  Soon after the caterpillar start chewing, the trees’ remaining leaves produce bitter-tasting phenol compounds to discourage further eating” [5]
 In 2017, it was seen that the Trembling Aspen stands lost their leaves, and a second smaller growth was seen coming late in the summer season.  Watch if and how the Aspen stand recovers in 2018.  It will be also interesting to note if 2018 again succumbs to a double whammy of drought and tent caterpillar.  Saskatchewan is a province of cyclical weather alternating between drought and years with a high water table [perhaps even flooding].   The tent caterpillars well, their cycle lasts between three to seven years, and they normally re-occur in 15-20 year intervals.
The round leaves turning golden in the autumn months, quivering, and catching the light as the breeze tosses the golden discs this way and that, give the Trembling Aspen the appearance of being a “Money Tree” as its branches dance in gold.
Silviculture is the practice of controlling the establishment, growth, composition, health, and quality of forests to meet diverse needs and values. The name comes from the Latin silvi- (forest) + culture (as in growing).  Richard St. Barbe Baker attended Cambridge University, graduating as a silviculturist.
Enroll your body, soul and spirit and engage your time to do what you know best. Dedicate yourself to the work at hand and you will be rewarded by the fruits you will bear!”― Israelmore Ayivor, The Great Hand Book of Quotes


1. Allen Bonnie.
‘The damage is done’: Home electricity boxes igniting in Sask. drought
Regina’s driest July in 130 years also threatening livestock, crops and farmers’ livelihoods”
CBC News Aug 04, 2017

2 Climenhaga, Christy. Regina experiences driest July in 130 years. July topped the charts for hot and dry weather in southern Saskatchewan CBC News Aug 01, 2017

3. Climenhaga, Christy. 2017 driest year on record for some Sask. communities
Driest year ever for Assiniboia, Moose Jaw; Regina saw 2nd-driest year, with only 40% of normal precipitation
CBC News. January 6, 2018.

4. Climenhaga, Christy. Regina and Swift Current could see their driest July on record
Southern Saskatchewan still waiting for rain after bone-dry July
CBC News July 27, 2017.

5. Fergus, Charles.  Trees of Pennsylvania and the Northeast. Edition illustrated Publisher Stackpole Books, 2002 ISBN 0811720926, 9780811720922

5. Giles, David. Forest tent caterpillars invade Saskatoon Global News. May 24, 2017

6. Graham, Jennifer. Dry weather withering crops, stressing farmers in southern Saskatchewan The Canadian Press August 6, 2017

7. Graham, Jennifer. This Saskatchewan farm’s ground is so dry a wrench ‘would disappear’ in its cracks Environment Canada figures show Regina had only 1.8 millimetres of rain last month — the driest July in 130 years. The Canadian Press. August 6, 2017

8. Its more than rare.” Environment Canada says southern Saskatchewan’s dry July will break records 620 CKRM Juy 27, 2017.

9. Knox, Shawn. Dundurn, Sask. woman tired of tent caterpillar infestation Global News. June 1, 2017.

10. Lizee, Tiffany. Southern Saskatchewan in drought for almost a year Global News. October 14, 2017

11. Martell, Creeden. ‘They just keep coming’: Tent caterpillar invasion coats Sask. home in insects — and feces  Saskatchewan in a boom period for tent caterpillars CBC News May 31, 2017

12. Petrow, Erin.  Caterpillars thrive for the fourth consecutive year Saskatoon Star Phoenix. May 24, 2017.

13. Prestwich, Emma Caterpillars Cover Saskatchewan Woman’s Property And It’s Super Disgusting Huffpost Canada.

14. Squires, Malcolm F.  Dynamic Forest: Man Versus Nature in the Boreal Forest
Volume 7 of Point of View Contributor John Kennedy Naysmith
Edition illustrated Publisher Dundurn, 2017 ISBN 1459739345, 9781459739345

15. Tent caterpillars: Tips to help control the outbreak Specialist says outbreaks happen every 10 to 15 years and last up to six years CBC News May 31, 2016

16. Tu, Chau Earth’s biggest living thing might be a tree with thousands of clones Science Friday.  May 5, 2015

17. Worrall, James J., Gerald E. Rehfeldt, Andreas Hamann, Edward H. Hogg, Suzanne B. Marchetti, Michael Michealian, and Laura K. Gray. Recent declines of Populus tremuloides in North America linked to climate Volume 299, Issue , July 2013, Pages 35-51


For directions as to how to drive to “George Genereux” Urban Regional Park

For directions on how to drive to Richard St. Barbe Baker Afforestation Area

For more information:

Blairmore Sector Plan Report; planning for the Richard St. Barbe Baker Afforestation Area,  George Genereux Urban Regional Park and West Swale and areas around them inside of Saskatoon city limits

P4G Saskatoon North Partnership for Growth The P4G consists of the Cities of Saskatoon, Warman, and Martensville, the Town of Osler and the Rural Municipality of Corman Park; planning for areas around the afforestation area and West Swale outside of Saskatoon city limits

Richard St. Barbe Baker Afforestation Area is located in Saskatoon, Saskatchewan, Canada north of Cedar Villa Road, within city limits, in the furthest south west area of the city. 52° 06′ 106° 45′
Part SE 23-36-6 – Afforestation Area – 241 Township Road 362-A
Part SE 23-36-6 – SW Off-Leash Recreation Area (Richard St. Barbe Baker Afforestation Area ) – 355 Township Road 362-A
S ½ 22-36-6 Richard St. Barbe Baker Afforestation Area (West of SW OLRA) – 467 Township Road 362-A
NE 21-36-6 “George Genereux” Afforestation Area – 133 Range Road 3063
Wikimapia Map: type in Richard St. Barbe Baker Afforestation Area
Google Maps South West Off Leash area location pin at parking lot
Web page:
Where is the Richard St. Barbe Baker Afforestation Area? with map
Where is the George Genereux Urban Regional Park (Afforestation Area)? with map

Pinterest richardstbarbeb

Facebook Group Page: Users of the George Genereux Urban Regional Park

Facebook: StBarbeBaker

Facebook group page : Users of the St Barbe Baker Afforestation Area

Facebook: South West OLRA

Twitter: StBarbeBaker

1./ Learn.

2./ Experience

3./ Do Something: ***

Please help protect / enhance your afforestation areas, please contact the Friends of the Saskatoon Afforestation Areas Inc. (e-mail / e-transfers )

Support the afforestation areas with your donation or membership ($20.00/year).  Please donate by paypal using the e-mail friendsafforestation AT, or by using e-transfers  Please and thank you!  Your donation and membership is greatly appreciated.  Members e-mail your contact information to be kept up to date!

Canada Helps


“St. Barbe’s unique capacity to pass on his enthusiasm to others. . . Many foresters all over the world found their vocations as a result of hearing ‘The Man of the Trees’ speak. I certainly did, but his impact has been much wider than that. Through his global lecture tours, St. Barbe has made millions of people aware of the importance of trees and forests to our planet.” Allan Grainger


“From the forest and wilderness come the tonics and bark which brace mankind…A town is saved, not more by the righteous men in it than by the woods and swamps that surround it…”
-Henry David Thoreau


“This generation may either be the last to exist in any semblance of a civilised world or that it will be the first to have the vision, the bearing and the greatness to say, ‘I will have nothing to do with this destruction of life, I will play no part in this devastation of the land, I am determined to live and work for peaceful construction for I am morally responsible for the world of today and the generations of tomorrow.'”
Richard St. Barbe Baker


Author: stbarbebaker

This website is about the Richard St. Barbe Baker Afforestation Area - an urban regional park of Saskatoon, Saskatchewan, Canada. The hosts are the stewards of the afforestation area. The afforestation area received its name in honour of the great humanitarian, Richard St. Barbe Baker. Richard St. Barbe Baker (9 October 1889 – 9 June 1982) was an English forester, environmental activist and author, who contributed greatly to worldwide reforestation efforts. As a leader, he founded an organization, Men of the Trees, still active today, whose many chapters carry out reforestation internationally. {Wikipedia} Email is StBarbeBaker AT to reach the Stewards of the Richard St. Barbe Baker Afforestation Area

6 thoughts on “Trembling Aspen”

    1. They are pioneers, and though their canopy was stripped bare, and the trees rallied to come around, the leaf growth was thin and sparse before winter snows came. I wish them luck in the spring of 2018, perhaps, as the roots are large, they may have got enough nourishment to the entire tree colony to survive. They were struggling last year so much. Thanks for your comment.


  1. I have aspens in the tree-hedge in the neighbor’s yard, but aspens are colonists. I really think “my” mountains have changed since I was a kid. Drought, fire, bark beetles, the mountains are not the same. We have less snow than we did when I was a kid, too. I will never understand people who do not understand that without the various ecosystems on this planet, we’re dead. It’s truly the only problem of any seriousness in the world today, yet people dispute its importance — or ignore it.


    1. It has changed ever ever so much. Reading about our pioneers, snowfall was so thick, trains were covered in snow, cows were found in the spring in the tree tops of trees where they got stuck in winter blizzards, kids could indeed tunnel through the snow to make snow forts, and awkwardly adults, had at times needed to tunnel from their homes. But now, barely the snow to cover the ground, and it melts away revealing patches of grass mid winter, that never used to happen. Saskatchewan has always cycled drought and high water table, but the cycles are very extreme, and random. I agree, the ecosystems are truly important, without them I agree we are dead. Yet, I read today of changes occurring in this field around the world, I will write it up over the next while, it offers hope, for the environment, indeed.


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