Humber Arboretum

Saturday, October 15, 2016

The Humber Arboretum was started in 1977 by the horticulture students of Humber College.  Today it covers 250 acres behind Humber College’s North Campus.  It covers an area of the West Humber River Valley between highway 27 and the 427 and features botanical gardens, meadows, and natural areas.  It also features a large variety of trees that have been dedicated to the memory of various individuals.  It is a little tricky to find but look for the first left east of highway 27 off of Humber College Boulevard (see the map link at the end).  This is Arboretum Boulevard and is on college property.  There is free parking in lot 1 and a large sign announcing the arboretum.  There are over 6 kilometers of trails in the park which will allow you to walk among the various ponds and gardens where you can watch for a wide variety of wildlife.

The trees start to prepare for winter by withdrawing useful chlorophyll from the leaves and storing it in the woody parts of the tree for use next year.  This removes the green colour from the leaves and causes them to turn various colours.  Without the chlorophyll to protect the colours of the leaves they are soon broken down by UV light leaving just the brown tannin in the decaying leaf.  This Red Oak is starting to change at the end of this one branch.


The arboretum claims to have over 1,700 species of plants and animals and serves as a living classroom for students at the North Campus.  The common snapping turtle featured below and in the cover photo is about the size of a toonie.  This is just a little baby of a species that can grow to be 75 lbs and live for 100 years in the wild.  The snapping turtle has distinctive ridges on the carapace as well as a serrated shell, especially along the tail end.  This turtle species has the latin name Chelydra Serpentina because of its snake-like neck that can reach to bite near the rear legs.  This little one may be from this spring’s hatching.  It was making its slow way across the path that was shared with bicycles and joggers.


We moved the snapping turtle to the grass near the edge of one of the three little ponds that have been created on the arboretum grounds.  These ponds have been planted to provide habitat for wetland species that are being conserved and presented here.  Students conduct experiments and gain hands-on work experience.


One of the projects is an attempt to help save the endangered butternut tree that was native to this region.  A severe fungal canker threatens the trees but students have teamed up with the Ministry of Natural Resources to plant 5 new samplings in an enclosure in the arboretum.  Plans include planting up to 20 additional trees. Currently, the only method of propagating new trees is to graft a healthy plant onto another plants root stock.  Students are looking for new ways to grow healthy trees.  The enclosure pictured below has some new cedar trees planted by the students.



Golden Weeping Willow is a hybrid tree that was first mentioned in 1888.  The latin name Salix Alba records that it is a  hybrid because all hybrids have the letter x in the name.  Primary Willow branches grow upward but all secondary branches grow down giving it the “weeping” aspect which it inherited from the Babylon Willow.  These trees are distinctive and are among the first signs of spring as their branches take on a golden hue before the leaves start to come out on most of the other trees in Toronto’s urban forest.


Dekay’s Brown Snakes hibernate communally through the winter and breed upon emerging in the spring.  The female carries the fertilized eggs internally until between 3 and 31 babies emerge in late summer.  They are small, just 8-11 centimeters, and will grow to about 50 centimeters at a maximum.  When they feel threatened they can give off a strong musky odour but this one seemed calm enough.


The Centre For Urban Ecology was completed in the fall of 2007 at the arboretum.  It is used by both students and adults to study and promote ecological stewardship.  The building is LEED Gold Certified and incorporates sustainable design elements.  The roof has vegetation growing on it to help with storm water management.  Rainwater is collected and used for irrigation for the landscaping and sewage and gray water is filtered on-site before being released.  The Humber Arboretum and Centre For Urban Ecology are a joint venture between Humber College, The City of Toronto and Toronto Region Conservation Authority.


Alder Trees belong to the same family as Birch Trees.  Alders are unique among deciduous trees in that they have cones.  The picture below shows male catkins but the tree will also have female ones that resemble small pine cones.  The inner bark of the alder tree contains salicin which is an important part of aspirin.


Green Mountain Sugar Maple can grow up to 60 feet tall and 50 feet wide.  They can grow up to one foot per year in good growing conditions.  This tree is a staple in the manufacture of maple syrup, a major industry in Ontario.  It is estimated that in 2011 members of the Ontario Maple Syrup Producers Association grossed $53 Million from 4 million litres of syrup.


We were probably about a week too early for the best colours, but the Humber Arboretum is a place that can be enjoyed all year.

A map of the trails at the arboretum can be found here.

Google Maps Link: Humber Arboretum

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