Bark with Bite

Article by Michael Rosen
Images copyright Arlene Neilson
Image of P. cistena copyright M. Rosen

Extra-terrestrials viewing Canadian gardeners with time-lapse photography must be having a hoot! Earthlings slavishly preparing planting beds, transporting soil, dividing and transplanting plants, pruning, weeding, clipping, watering, flicking, spraying, weeding, weeding and more weeding, all within an intense, five-month period.

The rest of the year, from October to April, we probably would seem to be doing two things: raking leaves and quickly scurrying from vehicle to front door to escape winter’s fury. For many of us, our interest in our gardens stops with the frost. As the hostas turn brown, the shasta daisies lose their petals, and the coneflowers fall over, our interest in the garden reverts to "cleaning up" and hoping for a quick return to spring.

What we fail (or refuse!) to recognize is that our gardens are in a leafless, "winter" condition for at least seven months of the year! Failure to plan and plant for this can make for a dull, dull garden.

Fortunately, there is a cure. It lies in your choice and use of trees to brighten up the winter landscap — not for their leaves of course, but for their bark, twigs, and (sometimes) fruit texture and colour.

Deciding on the type of tree is another matter. Almost any tree’s bark can be considered interesting but some are definitely more interesting than others. Inevitably, tree choice depends on a number of key factors: soil type, amount of growing space, light conditions (shade vs. full sun), and last but not least, your desired look. This last criteria, being the most subjective, is subject to a number of factors:

• Conifers in general have interesting bark. Those that are evergreen (pine, spruce, fir, etc.) will look essentially the same in winter as they do in summer — green! The essential difference is that they will stand out much more in the winter.
• Contrast with your house colour should be a consideration, although not a dominant one. If your house is white, consider a red- or black-barked tree; if your house is red, you may want to consider something lighter in colour.
  All trees, especially the dark-barked ones, will stand out well against the white snows of winter.
• Different trees have different shapes (conical, rounded, flat-topped, etc.).
• As in all perennial choices, knowledge of plant hardiness zones is important (although there always are some trees that can survive outside of their zones). Plant hardiness is the ability of a species to survive in a particular climatic area.
• Canada has a great range of hardiness zones. Ontario alone has a diversity unparalleled in most countries. From Zone 6a in Windsor to Zone 0a in Fort Severn, or, as some put it, from Prickly Pear (Cactus) to Polar Bear! A version of the plant hardiness map exists on the Agriculture Canada Web site.

People should also start asking questions at their nurseries about seed zones. That is, whether the trees they are buying originate from seed collected from the area into which they will be planted. This can have tremendous importance for growth, survival, and genetic conservation. A map of Ontario's tree seed zones can be found on the Ontario Forests section of the Ontario Ministry of Natural Resources Web site.

The following is a look at some good, deciduous tree types for winter interest, the conditions they need to grow, and some appropriate comments:

Hackberry (Celtis occidentalis). A characteristically chestnut brown, curly bark that resembles cork. It is the latest rage in urban tree planting because it tolerates pollution, salt, and compacted soils and (loosely) resembles the once-great American elm. Tolerates all light conditions except for deep shade. Grows large, although one cultivar — "Delta", taken from near Lake Manitoba — is much more oval in crown form. Good to Zone 4.

Birches — White birch (Betula papyrifera) has a characteristic papery bark — always of great interest to people. It can grow on a wide variety of soils, cannot tolerate shade, and is good to Zone 2. Cultivars include "Chickadee" and, as a non-native substitute, European (or weeping) birch (Betula pendula), which is excellent for space-restricted lots. However, as popular as it is, the white birch is tremendously prone to insects, including birch leaf miner and bronze birch borer. Yellow birch (Betula lutea) on the other hand has an interesting, deep yellow, curled bark that makes it an excellent winter choice. It grows slowly, but to a large size in all but deep shade. However, it needs rich, moist bottomland soil, high in organic matter to allow for good growth. Good to Zone 3.

Cherries — Most species of cherry have an interesting, reddish bark with conspicuous horizontal lines (lenticels), attractive spring flowers, and summer fruit. These include the shrub pin cherry (Prunus pensylvanica) and the large, attractive tree, black cherry (Prunus serotina or "b.c.” — burnt cornflakes, which its bark resembles). Other non-native trees of interest include cherry plum (Prunus cerasifera), of which a cross called purpleleaf sand cherry (Prunus x cistena) has proven to be quite popular with gardeners because of its reddish-purple foliage. All cherries, however, are prone to a number of diseases, including black knot canker and dieback. They grow best in full sun. Good to Zone 3.

Beeches — The bark of the beech (sometimes called the “elephant tree”) is well known (unfortunately by graffiti writers) for its smooth appearance. This, its form, and pointy buds frequently give it its reputation as the classic tree of character. Both types — the native, American beech (Fagus grandifolia) and non-native European beech (Fagus sylvatica) — are slow-growing and known for their ability to grow in intense shade. The European beech has a large number of cultivars, including "Purpurea" ( the purpleleaf beech), "Aurea Pendula" (the weeping beech), and "Fastigiata" ( an upright beech of limited spread). American beech is good to Zone 4, European to Zone 5.

Dogwood — A shrub or small tree with very distinctive bright red twigs, dogwoods are a preferred landscaping species due to their hardy growth, attractive white flowers, and berry-like fruits. The most commonly planted species are alternate-leaved dogwood (Cornus alternifolia), which is hardy to Zone 3, and eastern flowering dogwood (Cornus florida), an understory tree (meaning tolerant of shade), which is only really hardy to Zone 6.

Ironwood (Ostrya virginiana) — The flaky, grayish-brown bark of this slow-growing, but attractive, medium-sized tree is not very well known to gardeners or landscapers. It can grow in intense shade on well-drained soils. The fruit clusters are retained and fall throughout the winter. Good to Zone 4.

Kentucky Coffee-tree (Gymnocladus dioicus) — A very underutilized yet interesting tree, due to its rough, scaly-ridged, unique, dark brown bark and long (up to 22 cm) pod, which forms in July, ripens in October, and hangs on the tree throughout the winter. The Kentucky Coffee-tree is also considered "threatened" in Ontario so planting it will help its recovery. It prefers bottomland (rich and moist) soils, does not tolerate shade, grows relatively fast, and forms attractive whitish flowers and attractive, doubly-compound leaves. Good only to Zone 5.

Editor’s Note:

In western Canada you should also consider the following trees:

Arbutus (Arbutus menziesii) — a distinctive tree with reddish-brown bark that peels off in papery curls; native to southeastern Vancouver Island and the Gulf Islands, and scattered along the southern mainland BC coast
Garry oak (Quercus garryana) — a tree of character with grey-brown bark full of ridges and furrows; native to the southern southern tip of Vancouver Island and north along the eastern coast to the Comox area
Western flowering dogwood (Cornus nuttallii) — a beautiful small tree similar to the eastern flowering dogwood; native to Vancouver Island and mainland BC coastal areas into the Fraser Canyon
Bitter cherry (Prunus emarginata) — another cherry for consideration that is found across southern BC to subalpine areas.

Banding Birds in the Yukon

Bird species across North America are showing drastic population declines. Many of these species are migratory—spending summer months in Canada and winter months in the southern United States and Central and South America. Continent-wide monitoring initiatives, such as the Breeding Bird Survey (BBS), collect valuable data to monitor North American bird species; however, there are numerous species that have not been sufficiently monitored.

This used to be the case in the Yukon, which is why the Albert Creek and Teslin Lake Bird observatories were created in the first place. Created in 2001 (Albert Creek) and 2005 (Teslin Lake), these observatories have monitored the bird species of the northwestern portion of Canada’s boreal forest. The Canadian Wildlife Foundation is contributing $16,500 to the important research at Albert Creek and Teslin Lake observatories to support their continued efforts.

Both observatories use standardized mist netting and banding techniques to count the birds as they make their migratory journey. A series of mist nets are opened daily and operated for six hours beginning at sunrise. All birds captured are extracted and banded by qualified individuals in adherence to the North American Bird Banding Code of Ethics.

Then they gather data including the age, sex, wing length, fat score and body mass of each bird, plus plumage characteristics like molt sequence. In addition to being sites scientific data collection, the observatories serve as educational centres where the public can learn about boreal bird migration and the collection of scientific data. Over the long term, the studies currently underway can be analyzed to determine population trends for species migrating through the southern Yukon.

Baffling Bats

Photo: Don Conway

The Canadian Wildlife Foundation recently donated $5,000 to Ph.D. candidate Lynne Burns, of Dalhousie University and Chair of Biology Hugh Broders of St. Mary’s University. The team is researching the fall migration patterns and health of Atlantic Canada bat populations.

Blowin’ in the Wind

En route to breeding and hibernating sites during fall migration, bats are increasingly vulnerable to wind turbine related fatalities. A 2006 research project conducted by Robert Barclay, a biology professor at the University of Calgary, studied bat carcasses found below turbines near Pincher Creek. Barclay found that 90 per cent of the bats had died from internal hemorrhaging while only 50 per cent had shown evidence of actually colliding with the wind turbine blades. This suggests that most bats had experienced barotrauma — from a sudden drop in air pressure — when they flew close to the turbine blades.

Photo: Tom Lusk

Powder Your Nose

White-nose syndrome has spread across bat hibernacula in the northeastern U.S. killing tens of thousands of bats. Bats affected by the syndrome are found with their noses, wings, ears and tails covered in this white fungus, leading to a dramatic loss of their fat reserves, which they use to survive the winter. They can also be found flying outside during the day and hibernating at the entrance of their hibernaculums — a rare sight for bats that usually hibernate deep within their hibernaculums. To date, the eastern pipistrelle, little brown, northern long-eared, small-footed and Indiana bats have been affected by the syndrome in New York, Vermont, Massachusetts and Connecticut. Canadian researchers are concerned the disease will hit home territory because the disease spreads so quickly. In two years, it’s spread in a 250 kilometre radius to various hibernaculums, wiping out between 70 to 95 per cent of the bats that reside there.

Photo: Michael Durham

On the Move

When it comes to finding a companion, bats really go the distance. In early August, male bats peruse caves and mines searching out spots to spend the winter and mate with females. On their search, bats span tens and potentially hundreds of kilometres between overwintering spots. But what happens after the love fest is a bit of a mystery to researchers. We’ve assumed they settle in for hibernation, however, bat banding recoveries show that bats still migrate well into the fall — up to 60 kilometres a night — suggesting bats may hob nob at multiple hibernation sites when the temperature dips before choosing their final resting spot for winter.

Where Broders’ and Burns’ Research Fits

With researchers stumbling upon bat carcasses strewn about the entrance of overwintering sites and under wind turbines, red flags are being raised about the health of these winged wonders. Burns’ and Broders’ team will cover 32,000 kilometres of caves and abandoned mines in N.B. and N.S. where they’ll report on the bats’ general health including their body condition, reproductive condition and will collect small hair and wing membrane tissue for genetic testing. They’ll also study the movements and activities of bats that might relate to the spread of the disease. By installing passively integrated transponder (PIT) antennae at the entrances of key hibernacula sites and capturing and tagging bats with PIT tags, the team will be able to track individual bats and record which individuals visit each site. These records will allow the team to determine the hibernacula bats actually overwinter in. They’ll also help to determine if bats really do move around from hibernaculum to hibernaculum before settling down to overwinter and how their mating activities work to shape bat populations. The results will help conservationists track down key mating and hibernation sites that need protection.

Backing the Leatherback

Weighing in at a hefty 500 kilograms, the leatherback sea turtle (Dermochelys coriacea) may seem indestructible; however, it is listed as endangered in Canada by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) and listed as critically endangered across the globe by the International Union for the Conservation of Nature (IUCN).

The Canadian Wildlife Federation’s Endangered Species Program recently gave $16,000 to the Canadian Sea Turtle Network to determine the risk that commercial fishing gear poses to leatherback sea turtles in Nova Scotia waters.

Feeling Nesty

Western Atlantic Ocean leatherback sea turtles lay 5,600 eggs in a 20-year span, while their eastern Pacific Ocean comrades produce 2,200. However, females have had a rough time scouting out good nesting locations due to beach development. Once she finds her nesting spot, a female turtle and her eggs are at risk of human poaching. Moreover, after the turtles hatch and make their way from the beach to the ocean, many become distracted by city lights and don’t make it.

Chow down

Every year, leatherback sea turtles migrate thousands of kilometres, from their nesting grounds to northern waters, on the hunt for their primary prey – jellyfish. The Canadian Sea Turtle Network reports that leatherbacks make their journey to feed in Atlantic Canada waters from the USA, Costa Rica, Panama, Colombia, Puerto Rico, Anguilla, Venezuela, Grenada, Trinidad, Guyana, Suriname and French Guiana.

But their journey en route to their feeding grounds and back is a dangerous one. Approximately 6.4 tons of marine debris is dumped into our oceans every year, and between 60 and 80 per cent of it is made up of plastics. Moreover, 60 per cent of the trash strewn on the beach and 90 per cent of debris floating in oceans is plastic. To leatherback sea turtles, many of these bits look like jellyfish, and they get gobbled down. While the turtles may be able to digest smaller plastic pieces, the larger pieces can plug up the digestive passage and cause internal injury and infection. In the last 40 years, over a third of the leatherback sea turtles examined had ingested plastic. Where does all the plastic come from? You might be surprised to hear that approximately 80 per cent is from land – landfills, industrial facilities, sewage and storm runoff. The remaining 20 per cent is due to merchant and passenger ships, offshore oil and gas platforms, recreational, commercial and military craft and fish farming operations.

The Net Result

The primary threat to leatherbacks is fishing gear. The species get caught in plastic straps, ropes, lines and nets and either drown or break free with a high risk of injury. When fishing nets are lost or thrown away, they are called ghost nets. These nets, which can reach epic proportions of 15 metres in depth and 90 kilometres in length, can continue to travel up to 600 years, catching sea turtles and other marine wildlife.

How the Canadian Sea Turtle Network’s Research Fits In

The Canadian Sea Turtle Network’s team is studying the risk that fishing gear poses to leatherback sea turtles in waters off Nova Scotia. To date, the Network has the largest collection of leatherback sea turtle data in Canada. This research will be fundamental to conserving the turtles that travel from 12 different countries to feed in northern Atlantic waters.  

Avian Acrobats

The barn swallow is one of the world’s most common and widespread species, inhabiting every part of the globe except Antarctica.  In Canada, it graces every province and territory, arriving in late April and departing in early November. During this time, they tend to inhabit areas very close to humans.

Feeling Nesty
Barn swallows build their nests on a variety of man-made structures, including barns, of course, using mud pellets and fibrous materials. Within those nests, both monogamous parents will raise and care for up to two clutches per summer. If by any chance both parents are busy, other juveniles give them a hand feeding the hatchlings in their absence, acting a bit like babysitters.

Backyard Heroes
If you ever notice a barn swallow nest on your property, rejoice! Having barn swallows nesting nearby is a great thing: these birds feed mostly on flying insects, making them one of the natural agents for controlling fly and mosquito populations. When fall comes, barn swallows gather in large groups (sometimes, even with other species of swallows!) to feed intensively. That’s because they will need a lot of energy in the weeks to come, as they will migrate all the way to Central or South America, only to come back the following spring.

A Solemn Story for Swallows
As many other species of aerial insectivores, populations of barn swallows are on the decline. Although the reason behind this is poorly understood by researchers, it is thought that the loss of their nesting habitat (many of the older buildings where swallows opt to nest have been destroyed), the use of pesticides to eradicate their main preys and climate change are to blame.

You to the Rescue
You can still lend a hand to help the barn swallow remain a part of our natural heritage. For example, if you see a barn swallow nest, do not destroy it (these birds and their nests are protected by law), and instead, get information on how to cohabit with the species. If you have a suitable outbuilding in which you wouldn’t mind welcoming barn swallows, leave a door or window open to encourage them to build a nest inside.

Providing a source of mud nearby will also help with nest building, as they can make over 1,000 trips to build a single nest! Barn swallows may also use artificial nest cups attached to an appropriate surface, if you feel like offering a house warming gift. Whatever you do, please ditch your pesticides in the garden. They can have terrible affects on swallows. And, last but not least, embrace curiosity and learn all about barn swallows and share your knowledge with your community. The more people know about these beautiful birds, the more chance we have at saving them.

A Rocky Future for the Northern Pacific Rattlesnake

Photo: Emily Lomas

The northern pacific rattlesnake (Crotalus oreganus oreganus), also referred to as the western rattlesnake, is the only species of rattlesnake in British Columbia. It’s also the only venomous species in the province. But it looks like we’re doing more damage to the snake than the snake is likely to ever do to us – it’s listed as Threatened due to habitat loss. The Canadian Wildlife Federation is giving researchers Karl Larsen and Emily Lomas of Thompson Rivers University $17,900 through its Endangered Species Fund to discover how human disturbance has affected the snake’s behaviour and population and what we can do to save the species.

This species is At Risk due to urban development and the alteration of their critical habitat from human activity. Since, aside from the few months it hibernates, the snake is constantly on the move to and from its summer foraging grounds, a change in their route can devastate the species. And boy do they move.

As the female northern pacific rattlesnake moves around her habitat, she leaves a trail of odour the male simply can’t resist. The odour’s origins? Her fat. Once pregnant, it’s that fat the female relies on for survival – females don’t eat a morsel while pregnant. And since she births her young from September to October, birthing between two and eight snakes, she might simply emerge from hibernation, birth and head back to her den without eating anything. That means females can go over a year without eating. Now that’s extreme dieting. But females need to spend  time to recuperate from the ordeal. They usually only reproduce every two to three years so they can take that time to regain the weight they lost during the pregnancy.

In the spring, the snakes emerge from their den. Most of them mosey on to their summer hunting grounds, and it’s only pregnant females that opt to stick around close to the den (which the snakes call their winter abode year after year making these dens crucial to their survival) where they’ll bask on cliffs and slopes – perfect to provide some heat and shelter for their young.

Conservationists are scrambling to find ways to reduce the risk of human activity impacting the northern pacific rattlesnake. Thus far they’ve tried relocating, fencing them out (or in), and creating safe pathways for the snakes. But all these options come with their own share of problems including altering the snake’s movement patterns, basking regimes and the time they spend foraging.

How Larsen and Lomas’s Research Fits In

In the town of Osoyoos, B.C., researchers Karl Larsen and Emily Lomas of Thompson Rivers University are studying how development in the town is affecting the species. In particular, the researchers are studying a new condominium project that is currently being constructed in identified habitat for the snake. The snake uses this area as a migratory corridor and it’s not far from its dens and shedding sites. Larsen and Lomas are interested in how the fencing impacts the movements of the northern pacific rattlesnake and what they can do to minimize any negative impacts on the snake. A permanent wall was erected to stop rattlesnakes from entering territory where they might come across humans and human altered habitat. 

A Shift Towards Environmentalism

Pick up any newspaper and you’re likely to come across an environmental story that’s making headlines – usually in a negative way. The recent oil spill in the Gulf coast is an example of an environmental tragedy of such epic proportions that trying to wrap your mind around just what happened is almost too much to bear. For many people the easy answer is to tune it all out, especially when it seems impossible to make a difference. But you can. Isn’t that a relief? And oh, what a difference you will make!

What Difference Does It Make?
Like anything in life getting results takes hard work and perseverance; the same could be said for taking care of the planet. With everyone putting in their two cents on the different ways you can green the planet, you’ve probably thought to yourself at one time or another ‘What difference am I truly making by purchasing energy efficient appliances?’ or ‘ Why am I bothering to turn off my lights when that business down the road leaves its lights on all night’?  Well, the good news is that these small differences are a part of a larger picture –change. Questioning these green-savvy ideas is only natural, but here’s the thing; that energy efficient appliance will  definitely save your bill payment on top of the energy savings.  And that business down the road with the lights on?  Well they use solar energy to run their lights off the grid. Everybody’s going green. And it’s this collective spirit that’s going to change our world.

The Bigger Picture
Being a part of cleaner technology isn’t a fad; it’s taking steps to ensure the future of our world, the one we’re leaving to our children, is a good one, a healthy one. But waiting for the masses to agree that all this ‘green hoopla’ is in fact worth it shouldn’t be what we’re holding out for.  Thanks to support from the OntarioTrillium Foundation, CWF recently installed 10 more solar panels to our roof-top grid, bringing our total to 30.  Together, the panels produce 24 kilowatt hours of energy a day and reduce carbon emissions by close to three tonnes each year.  The solar panels provide enough energy to supplement office equipment and lighting. 

And we want to encourage you to be the voice in your community that asks which business are operating off the grid or utilizing environmentally friendly technologies. Not so polished on your knowledge of green technologies? We’ve broken down the basics of the kind of energy your community might be utilizing or could think about investing in.

Solar Energy
Solar energy comes from the sun and travels to Earth in the form of electromagnetic radiation. The total amount of solar energy that is available to Earth is continually altered by variables such as cloud cover and Earth’s distance from the sun. Once the energy enters our atmosphere, it is measured in watts per metre (meaning how much energy is entering and at what capacity). After the cost of the solar panels is absorbed, it is an extremely easy way to collect your own energy. Solar energy is popularly collected for heating, cooling and electricity.

Earth Energy (Two types: Earth and Geothermal)
When the temperatures found beneath the Earth’s surface are used to naturally generate heating or cooling processes, that is called using Earth energy. Geothermal energy is slightly different in that it is harnessed through use of steam or hot water in the Earth’s crust. The main focus for both of these energies is that they utilize the Earth as the source, which saves processed power from local grids.

Earth energies can be used to provide heating, cooling and power generation by use of bodies of water like oceans and lakes, or steam and hot water in the Earth’s crust. However, geothermal energy isn’t for every region because there needs to be natural features such as cracks or holes in the Earth’s surface for the facilities to run efficiently.

Hydroelectric Power
Hydroelectric energy is power generated by the flow of water. At hydroelectric facilities, dams harness water power and water flow is controlled and put through turbines that generate electric power due to the force of the water from gravity. There needs to be a sufficient source and flow of water to accommodate hydroelectric facilities. However, Canada is rich with water and a variety of topography to house hydroelectric power. Whether it’s through waterfalls, rapids, canyons or rivers, this alternate energy source is plentiful throughout the nation.

Wind Power
Wind energy is created by harnessing the power of wind through turbines and transforming it into electricity and mechanical energy.  The amount of potential energy in any current of wind can vary depending on air density, pressure, temperature and altitude. As long as there are wind currents, this form of energy is sustainable and pollution free. Wind turbine generators are popping up all over the world. They can also be connected to existing power grids and provide energy for small homes, farms and even industry. This benefits the majority of the population who rely on the power grid.

Banding Birds in the Yukon

Bird species across North America are showing drastic population declines. Many of these species are migratory—spending summer months in Canada and winter months in the southern United States and Central and South America. Continent-wide monitoring initiatives, such as the Breeding Bird Survey (BBS), collect valuable data to monitor North American bird species; however, there are numerous species that have not been sufficiently monitored.

This used to be the case in the Yukon, which is why the Albert Creek and Teslin Lake Bird observatories were created in the first place. Created in 2001 (Albert Creek) and 2005 (Teslin Lake), these observatories have monitored the bird species of the northwestern portion of Canada’s boreal forest. The Canadian Wildlife Foundation is contributing $16,500 to the important research at Albert Creek and Teslin Lake observatories to support their continued efforts.

Both observatories use standardized mist netting and banding techniques to count the birds as they make their migratory journey. A series of mist nets are opened daily and operated for six hours beginning at sunrise. All birds captured are extracted and banded by qualified individuals in adherence to the North American Bird Banding Code of Ethics.

Then they gather data including the age, sex, wing length, fat score and body mass of each bird, plus plumage characteristics like molt sequence. In addition to being sites scientific data collection, the observatories serve as educational centres where the public can learn about boreal bird migration and the collection of scientific data. Over the long term, the studies currently underway can be analyzed to determine population trends for species migrating through the southern Yukon.