Category Archives: Joshua Creek

Joshua Creek – The Emerald Ash Borer

Saturday, April 1, 2017

Joshua Valley Park has seen a lot of change over the course of the two centuries since Joshua Leach arrived.  Leach was just 21 when he arrived in the brand new town of York in 1897.  As a carpenter, he found plenty of work building many of the first homes in the town.  By 1822 Joshua had saved up enough money to buy 200 acres of land which he took possession of on the creek that would later bear his name.  Joshua built a home for his family and dammed the creek to power a saw mill and a thrashing mill.  These were located near where Maple Grove Arena stands today.

This hike follows Joshua Creek through three contiguous parks: Joshua Valley Park, Maple Grove Park and Dunvegan Park.  These parks run from Cornwall Road in the north all the way past Ford Drive to where we connected with the trail from last week’s story.  For convenience, we took advantage of the free parking at Maple Grove Arena which is about midway along the journey.  Cut lengths of ash tree logs were stacked in a pile at the side of the parking lot.  This was a hint of what we were about to find in the valley.  The forest is wide open now that all the ash trees have been removed.

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The emerald ash borer is a beetle that is native to Asia.  It was first seen in Ontario in June of 2002 near Windsor.  The beetle most likely entered Ontario from Detroit where it arrived in wood packaging from Asia.  The emerald ash borer is invasive as it meets both accepted criteria.  It is outside of its native habitat and threatens the environment, economy or society where it is invading.  The City of Oakville estimates that it has 45,000 ash trees and that most, if not all, will be destroyed by the beetle.  In Toronto, the situation is even worse with an estimated 860,000 ash trees in the city.  Every one of which will be destroyed if not treated with appropriate pesticides.  The picture below of an emerald ash borer was taken from Wikipedia.

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All ash trees in Ontario are susceptible to the attack of the emerald ash borer.  Our ash trees are named after colours and we have black, white, red, green and blue as the primary ones.  The female beetle will lay 60 to 90 eggs, individually, in the crevices in the bark.  The larva tunnel under the bark, eating curved galleries.  These galleries girdle the tree and prevent the flow of food and water from reaching the tree.  The larvae overwinter under the bark and pupate in the spring.  The adults spend their lives on the outside and must eat the leaves in order to reach reproductive maturity.  Looking at the ash trees that have been piled up you can easily find examples that are 50 years old.  The one pictured below appears to have 47 rings.

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After a tree has been assessed and found to be clean or in the early stages of infestation it can be treated in one of three ways.  Each of the pesticides is intended to target either the larva, adult or both.  The soil around a tree can be drenched with the insecticide which is carried throughout the tree by the vascular system.  This method won’t work if the tree has too much damage already and it is unable to spread water and nutrients throughout.  Another method of distributing the pesticide is to inject it into the tree.  Lastly, when the adults are newly hatched and are feeding on the leaves they can be sprayed directly, killing them before they can lay eggs. The cost of treating a tree can be estimated at about $10 per inch of diameter.  The picture below was taken last week near the mouth of Joshua Creek and shows a tree that is being treated for emerald ash borer.

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Other invasive species, like the honeysuckle, will prosper now that the canopy has been opened up and they won’t have the competition.  They are already present in the understory and can be seen because they are the first shrubs that get their leaves in the spring.

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A thin trail runs along the back of the houses on Duncan Road.  Old sets of stars can be found leading off of this trail and directly into a solid fence.  The row of trees that has been planted along here seems to be older than the trail which was constructed in 1983. Straight rows of trees often indicate old laneways or roads.

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This section of Joshua Creek has been protected from erosion by the use of gabion baskets filled with stones.  The creek is prone to flooding and when it does it runs brown with soil being carried downstream.  In several places, the creek has overrun the gabion baskets and they are no longer serving a purpose.

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At Cornwall Road we turned back, leaving the northern reaches for another time.  A small bridge crosses the creek just south of Maple Grove Arena and beyond here the ash tree removal is in full swing.  Heavy equipment stands among the trees and there are fresh piles of logs along the sides of the trail.  In many forests, these are being left behind as future habitat but they are being removed from this park system.

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Crews have preceded the cutting teams and have assessed each tree and coded them. Yellow slashes or dots mark trees that are to be removed.  Orange or red dots indicate that a tree is to be pruned.

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We found an area where there were a lot of clam or mussel shells.  The ones below are placed beside a golf ball to give the perspective of their size.

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The wheat market fell after the Crimean War and at the same time, England removed tariffs that protected Canadain suppliers.  The area around Oakville was hit hard and many farmers turned to fruit production. Orchards of apple, plum and cherry trees took over where fields of grain once grew.  In the 1940’s the creek was dammed to create a pond for irrigation of a large orchard that stretched from Royal Windsor Road, all the way to Lakeshore.  The earth and concrete wall still forms a bridge from Devon Road to Deer Run Avenue.  There are two open spillways and a round culvert.  The culvert had a sluice gate on the front end to allow for control of the water level.  The cover photo shows the culvert from the upstream side.  Two spillways and the culvert can be seen in the picture below.  The spillways are about eight feet tall while the culvert is about ten.

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The forest was alive with birds and one particular area was full of woodpeckers.  Both Hairy and the smaller look-a-like Downey woodpeckers were moving through the trees. This female Hairy woodpecker stopped on the side of the tree to do a little preening of its feathers.

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The Joshua’s Creek Trail runs for 6 kilometres and is part of the Oakville Heritage Trails. The northern reaches of the creek still require exploration.

Last week we explored the mouth of Joshua Creek and that post can be found here.

Google Maps Link: Maple Grove Arena

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Joshua Creek

Saturday, March 25, 2017

Joshua Creek is the largest of Halton’s urban creeks.  These 14 watercourses run through Oakville and Burlington but have their headwaters and the entire stream confined within the city.  Joshua Creek has it’s headwaters near the 407 and runs close to the border between Mississauga and Oakville.  The creek passes through fully engineered sections with armour stone or gabion baskets while other parts flow through naturally forested areas.  The sections on the northern reaches still flow through open farmland and the creek boasts one of the best water qualities in the county.  The hike roughly covers the section of Joshua Creek highlighted in blue on the 1877 County Atlas below.  Note the rows of apple trees shown on the map between the creek and the lake.  Some of these orchards remain and can be seen as you walk along the creek.

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A set of stairs descends from a trail linked to Breton Close where there is free parking.  These stairs come with a “V” channel on one side to make it a lot less bumpy if you wish to bring a bicycle onto the Joshua Creek Trail.  The section of Joshua Creek near the stairs has been plated with armour stone but much of the creek from this point to Lake Ontario has been left in a more natural channel.

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American Beech is one of a half a dozen species, mostly oak, that can hold their leaves over the winter.  These beech trees can live for 300 years and tend to grow slowly, taking 20 years to reach 13 feet in height.  In Ontario they are late succession trees that form a part of the Beech – Maple climax forest.  Cleared land will progress from low bushes like sumac and hawthorn to ash and birch trees.  Maple, Beech and Oak trees are signs of a mature forest.  Beech trees can reach 100 feet tall and the canopy can spread to 70 feet wide.  Small beech trees grow in several stands along the creek.  Emerald Ash Borer is a significant problem in Joshua Creek and many of the trees have had to be removed.  This opens up the canopy and will allow the beech trees to have their moment in the sun.

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Footprints leading up to this fallen tree indicate that humans and the local wildlife both use it as a bridge.  It is certainly wide enough but being wet and slippery precluded crossing on this wet morning.

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The lower trail was muddy in places, unlike the main trail up on the top of the ravine which has been treated to chipped up pieces of Christmas trees.

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Snowdrops are native to Europe and the Middle East.  They were brought to North America as an ornamental plant for use in gardens.  Non-native plants can be divided into two categories, those that need human intervention to survive in their new environment and those that don’t. The ones that can survive on their own can further be divided into naturalized and invasive. Naturalized plants can survive on their own and in time become part of the local flora.  Those that are invasive will crowd out native plants and often release toxins into the soils to prevent the growth of competing plants.  Snowdrops are considered to be naturalized rather than invasive because they don’t spread rampantly and they fit in with the local habitat.

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Beavers once filled the rivers and streams of Ontario.  Trapping for the fur trade had virtually eliminated the beaver from Southern Ontario by the 19th century.  Beaver moving back into urban centres has become more common over the past few decades as water qualities have been improved.  New York City, for instance, saw its first beaver in over 200 years in 2007 and High Park in Toronto now has a lone beaver living in Lower Duck Pond.  Beaver can be very destructive and the trees along Joshua Creek show significant damage from the local beaver. At one point we saw a place where it appears that the beaver have built a lodge under the roots of a tree along the embankment.  Further downstream we found the place where the beaver have built their dam.  The dam has been breached by recent high water but they won’t take long to repair it.

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Several foundations line the creek from the days before the estate lands were divided for smaller homes.  The cover photo shows a set of stone stairs that lead down to the edge of the ravine above the creek.  The steps suddenly end with a long drop into the water.  Whatever once stood at the end of that stairway is long gone as is the building that once stood on the foundation below.

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Charles Powell Bell and his wife Kathleen Harding moved into their estate home near the mouth of the creek in 1938.  The house and garage originally stood on 60 acres and had the early name “Fusion” although it was usually known as Harding House.  It is said that the spirit of a woman can be seen regularly at the house and spirits of a boy and an angry spirit of a man have also been uncovered by paranormal investigators.  The house has been given a heritage designation in 1989 and currently is used as an event facility.  The house has been known as Holcim Waterfront Estate but t is being renamed Harding Waterfront Estate.

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The mouth of Joshua Creek has had a few pieces of armour stone dropped in to create a small break wall to provide some protection.

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Looking to the east from the mouth of the creek you can see the Petro Canada refinery dock that extends 700 metres out into the lake.  Equipment towers stand on the end of the dock to transfer oil from tankers.  To the west, there is a brief shingle beach revealing the natural shoreline along this part of the lake. The point in the distance marks the beginning of the armour stone that has been applied to the shore in an attempt to slow down erosion.  The lake was crashing into the chunks of limestone and sending spray high above them.

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Taking the upper trail on the return trip leads past the Oakville South East Waste Water Treatment Plant.

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The creek runs north from Breton Close as well, and hopefully, we’ll return next week and see what lies in that direction.

Google Maps Link: Joshua Creek

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