Trees Please Hamilton

Green Solutions to Air Pollution

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Our winter favourites: Pines

Snow is still falling and our pines are carrying a heavy burden of white on their strong limbs. Wildlife finds a great shelter from the storm and a tasty treat.

Eastern White Pine (Pinus strobus)

Ontario’s provincial tree was highly valuable as a tall, straight growing tree, frequently used for masts in ship construction during European settlement in Canada. Unfortunately the giants of those days are now harvested and gone, but when given the chance, White Pine will continue to grow over 40 metres tall, and is the tallest growing tree in our region. Mature trees usually live to around 250 years old, but some individuals have been aged to over 400 years.

The delightfully soft needles grow in bunches of five. The seeds are eaten by different birds and small mammals, the soft branches provide good shelter, and deer like to forage on the soft leaves. Indigenous communities valued the White Pine for its medicinal uses and as a source of emergency food, and the resin provides a waterproofing seal. White Pines are often planted in restoration projects, but they can be sensitive to road salt and urban soil pollution.

Red Pine (Pinus resinosa)

The firm needles grow in pairs and snap crisply when bent – a handy identifier to help distinguish Red Pine from Austrian or Scots Pines. As the name suggests, the thick, plated bark has an orangey-red colour. Pinus resinosa is also known as Norway Pine, despite being native here.

It is a strong wood and can tolerate heavy winds because of its deep root system, which also makes it a useful tree for erosion and stormwater control. The wood is often used for telephone poles. Various wildlife also enjoy the seeds and cover Red Pine provides.

In Hamilton, we most often see mature Scots and Austrian Pines, which were once valued for their urban hardiness and road salt tolerance. We definitely prefer to see native trees being planted, especially when non-natives like Scots Pine are invasive!


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Our Winter Favourites: Cedars

This cold winter, let us spend a moment admiring the native trees in Hamilton that stay green throughout the year, reminding us that spring is not far off! We begin with our two common cedars, neither of which is a true cedar!

Eastern Redcedar (Juniperus virginiana)


Also known as Eastern Juniper, this tree is a relative of the shrubs whose fragrant berry is well-known for flavouring gin. The Redcedar berry is edible and a favourite for many birds. Deer also like to browse this tree, and it is overall a good source of winter food and shelter for different wildlife.

The tree is allelopathic, meaning it prevents other vegetation from growing around it. With strong and fibrous roots, Redcedar is particularly good at preventing soil erosion and holding water.

Eastern white-cedar (Thuja occidentalis)


This fascinating tree is one of the oldest we know of in Ontario, growing gnarled and hidden on the cliffs of the Niagara Escarpment. The oldest one to date is over 1600 years old!

It is believed to have been the source of Vitamin C that staved off scurvy for Jacques Cartier’s crew, and is honoured in Indigenous cultures as a Tree of Life, for its medicinal uses.

With leaf-covered twigs year round, it is a favourite of browsing deer. We use the decay resistant and lightweight wood for fences and posts, and for things that will be standing in water.


Both cedars are great hedge trees and useful windbreaks, with the dense foliage being particularly good at trapping blowing snow. We also like to use these fragrant evergreen varieties for winter decor.

Next week we’ll reflect on our local pine trees, include the provincial tree of Ontario!




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New Year, New Gear

Snow all around, but we are already getting ready for the 2018 Trees Please season in the office! Our brand new set of inventory equipment has arrived, and will help us reach our goals in Sherman and the North End this summer with the help of amazing volunteers.

We are loving the new edition of Trees In Canada by John Laird Farrar – look at those lichen-covered trees!


Join us in 2018: all equipment is provided, no prior experience needed – come expand your tree ID skills with Citizen Science!

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2017: Trees Please Highlights


Trees Please had a great year inventorying in McQuesten and Crown Point! It was fun to get to know these two communities in detail as we looked for trees and roamed with air quality monitors. Thanks to a total of 21 amazing volunteers, we surveyed 2305 trees of over 100 species. Of these trees, 361 were Honeylocust, a hardy street-tree favourite, and 313 were Norway Maples, a once-favourite no longer planted due to its invasiveness. Distant followers were Austrian Pine (98) and Freeman Maple (95), which is a cultivar cross between Silver and Red Maple, and a newer favourite for city planting, especially in The Centre on Barton. We loved seeing some Carolinian native species being planted, such has Hackberry (33), Kentucky Coffeetree (23), Tulip Tree (17), Sassafras (5), and Ohio Buckeye (2).

CPtrees  MQtrees

These trees are providing over $100,000 worth of essential annual ecosystem benefits, from energy conserved, to air quality improved. Our street trees are working hard to capture 50% of particulate matter from the air. Check out the numbers from trees inventories in 2017:


We also had a blast giving away 171 trees thanks to the Hamilton Community Foundation for Canada 150. These native trees are now planted across the city with a focus on our Trees Please neighbourhoods. From fruiting Smooth Serviceberries to Bur Oaks that can support hundreds of species, these trees were thoughtfully selected to withstand an urban habitat and provide multiple environmental benefits. Thanks to everyone who became a steward and will look after these new trees as they grow Hamilton’s forest!


The Trees Please team even got to visit 11 school and summer camp groups this year and teach kids all about our new favourite being: lichen. Many students had never heard of this unique compound organism, made of a symbiotic relationship between an alga or cyanobacteria and a fungus. We’d explore the schoolyard looking for different varieties and discuss how the pollution-sensitive lichen can give us an idea of local air quality, and how we need more trees to clean the air!


Join us in 2018 as we inventory trees in the Sherman Hub and North End neighbourhood. We’d love to hear from you if you know of areas that could use some extra trees. Also be sure to keep an eye out in the new year for exciting workshops and events – lots in the works!


Trees Please is a project of Environment Hamilton and the Hamilton Naturalists’ Club, generously supported by the Ontario Trillium Foundation.

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Decorating with evergreens

owlThere are so many traditions around the globe, the origins of which become foggier as time goes by. The Gore Park tree was lit up earlier this month with a big crowd, and we’re seeing trees in front windows of homes and stores. As we inventoried a variety of conifers with Trees Please this year, we wondered, who ever thought to bring this inside during the winter?

Evergreens have been used for ages to bring some greenery inside and remind us that spring will arrive once more. This was even noted with Egyptians in a warmer climate. Romans celebrated Saturnalia with evergreens to look forward to next year’s plentiful crops, and for Northern Europeans they represented everlasting life.

The first Christmas Tree proper, however, is known to have originated in Germany. Trees outdoors were decorated with fruits, and the birds drawn in added additional beauty. Trees were later brought inside, and often hung upside-down from the rafters to save floor space! Martin Luther is often credited with adding lit candles after seeing how beautifully the stars glittered through a tree in the winter’s evening.

Another possible origin could be the merging of two existing traditions. The Paradise Tree – a fir decorated with apples, representing the Garden of Eden, combined with the Christmas Light – a pyramid of glass and a candle to represent the light of God.

The tradition of decorating a tree indoors wasn’t accepted in the Americas until the mid-1800s, although it had been brought over much earlier by Germans immigrants, especially in Pennsylvania. It was long seen as a heathen tradition until an illustration was published of the Royal family around their Christmas Tree (a tradition likely introduced by Queen Victoria’s German husband, Prince Albert). It then quickly became widely practiced and evolved into the traditions we see today.

We also recently learned that the oldest Tree Lighting Ceremony in Canada is in our own Dundas, which began in 1914! So whether you celebrate Christmas or decorate with greenery, enjoy those evergreens outside or in, reminding us that spring is just around the corner!

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TREE TUESDAY – Do Trees Talk?

We would like to thank Marion Robertson for this article.  For more of her articles, visit Crieff Hills website.  Click here

Do Trees Talk? 

By Marion Robertson 

Before I get started with the article I would just like to mention a person who truly inspired me recently. Lois had been kind enough to allow us a tour of her property and of all the wonderful plants and trees planted over the course of a lifetime. She is truly an ambassador for Carolinian Canada.

Seems like everyone is fascinated with the latest books explaining tree communication. Even though it seems like breaking news, these findings have been known for 30 years. I thought we would delve into this topic. So let’s take a look at the world of trees.

Trees and plants communicate to each other, and their community, above and below the ground. Above soil level, when trees are being attacked (stressed) they release volatile organic chemicals (VOC). These VOC are picked up by neighboring plants and forewarn them to defend themselves. These same chemicals can also attract help in the form of predators to feed on the attacking pests. Each chemical is a ‘word’ and these words are combined to make a specific sentence – this allows plants to chatter. A well known VOC is the aroma generated by freshly cut grass.

Speaking of chatter, do you know that plants do generate sounds? These sounds are generated at frequencies outside of the human range of hearing. This is still a vastly under studied area but plants do use sound since this is faster and can cover greater distances than chemical communication.

Below the ground, when trees are attacked they increase their defense against the invaders by revving up their defensive genes and increase their production of defense enzymes. They send these chemical signals down their roots to the mycorrhiza network, where neighboring trees detect these signals and trigger their own defense mechanisms. This can happen in as little as 6 hours.

It is at the mycorrhiza level, that we are truly beginning to understand forest communication. Myco is Latin for fungus and Rrhiza is Latin for root. Therefore, mycorrhiza is the combination of fungus and root to create a ‘fungus root’. This is a beautiful union that has slowly occurred over 1 billion years. A small thread comes out of the plant root and the fungus infects the root and eventually colonizes all the roots from the plant. Where the fungal cells interact with the root there is a trade off of Carbon for nutrients.

Turns out, trees can’t live without their mycorrhiza. Under a simple footstep there are 300 miles of fungal highway. This connectivity is not just between same species but between all species and works like our internet. This forest connectivity is vast and is world wide. But why have this co operative between tree and fungus? It is quite simple; the fungus can’t photosynthesize but can pick up nutrients, especially Nitrogen and Phosphorus, and exchange these nutrients with the plants for their photosynthetic product of sugar.

The biggest users of the fungal network are the Hub trees. These are the mother trees which are nurturing the young in the understory. The hub trees send extra Carbon to the shaded understory young trees. In this way, the survival rate of the saplings increases 4X. It has been discovered that hub trees have kin identification capability where they can distinguish the difference between strange and kin trees. Mother trees have bigger mycorrhiza nodes and networks with related trees vs. strange trees. When a mother tree is injured or dying it will pour out excess Carbon into the fungal network but also defense signals.

So how does our present day logging practices affect this intricate forest co operative? I was shocked to learn that in 2014, Canada in this past decade had the highest rate of deforestation in the world. NOT BRAZIL OR THE RAIN FOREST. This equates to 4X the rate of sustainability. Not only is our lumbering unsustainable but our reforestation techniques are out dated and non viable. Present forestry only concentrate on replanting few species of trees and actually spraying to kill colonizing aspen and birches. Forests that are almost monoculture are extremely susceptible to infection, disease and pests.

How can we reinforce our forests and help them deal with climate change? Experts are urging the technique of patch cutting and the retention of hub trees. There must be planting of different species with different genes and genotypes. What they are investigating is the pattern of the hub trees. Should the mother trees be retained as singles, in groups or in a shelter wood?

What is clearly indicated is that we need to move away from destructive clear cutting and monoculture plantings and change our ideas and practices. Our deforestation around the world causes more greenhouse gas than all the planes, trains and cars combined. We truly need to embrace ‘sustainable forestry’ at all levels. As a consumer, you can help buy only buying lumber from sustainable sources. And, of course, support tree planting at whatever level you can.



Yours in conservation

Marion Robertson

Marion Robertson is co owner of B Sweet Honey Nature Company and Puslinch Naturally Native Trees.


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TREE TUESDAY – Emerald Ash Borer


Adult Emerald Ash Borer

Have you heard of the Emerald ash borer? It’s story is rather dramatic, definitely not a bore. The beetle was first spotted in Windsor, Ontario in 2002 – suspected to have stowed away on wood packaging from Asia. Since then it has spread, killing millions of trees in Southern Ontario, Quebec and the Northern U.S. The ash borer does not move very far on its own – it typically flies 5km in search of another host tree – but humans have assisted its spread through moving around beetle-infected firewood. 

The borers lay their eggs under the ash’s outer bark, then the larvae eat their way through the inner bark – damaging the channels through which the tree transports water and nutrients. This eventually kills the tree within one to four years of infestation. Emerald ash trees in North America are vulnerable compared to trees in Asia that have co-evolved and built up defences to these beetles. 

This infestation has an extensive impact on urban areas like Hamilton that have planted many ash trees along streets and in parks. According to the City, by 2020 all of Hamilton’s ash trees could be killed. To prevent further beetle spread, the City passed a motion in 2012 to remove or treat 10% of Hamilton’s ash trees every year for ten years. Each ash removed would be replaced with a different species to diversify our urban canopy and make it more resilient to future pest attacks. Significant ash trees are being treated with an injectable pesticide, but it is not financially possible to treat all ash trees in the City. 

While inventorying in McQuesten, we found three ash trees. This is not a common find for us, but don’t get too excited because they were all mostly dead. 

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Information from our inventory in McQuesten