Snowy Owl

Snowy Owl

Saturday, 18 March 2017

Winter photography

The title might conjure up snowy landscapes and such, but this post will be about a different type of winter photography.

I am involved in a project which in part, involves getting photos of twigs of trees and large shrubs, focusing especially on buds, leaf scars and other characteristics that are helpful in their identification. I must admit before this I had never spent a lot of time using such minute characteristics to identify trees. Instead I would consider the type of habitat the tree was growing in and rely on its overall form, as well as the bark characteristics. So this project was a challenge, especially since it relied on a fairly precise form of macro photography. I've explained a little about my macro technique at the end of this post.

I'm not sure exactly how many I have photographed so far, but well over one hundred species. This has involved a lot of time looking through the camera, as well as countless hours processing the images afterwards. But it has been an eye-opener in some ways.

Lots of the buds and leaf scars are extremely small, and at first glance one doesn't look a whole lot different than another. But a closer look just highlights the tremendous diversity there is. This first one is Black Maple, an uncommon tree in Canada limited primarily to southern Ontario. It has fine gray hairs on the cluster of terminal buds.

This next one is Ohio Buckeye. For all intents and purposes it is an endangered species, although not officially so. It occurs naturally at only one location in all of Canada.
A somewhat similar species, at least in the same genus, is Horse Chestnut. It isn't native to Ontario, but is sometimes planted for ornamental purposes. Even though it is the same genus as the previous one, the bud and leaf scar are quite a bit different.
This next one does not have any legal status, although it is extremely rare in Ontario. It is known as Pawpaw, and at least from the historical data, is more common in Chatham-Kent than any other municipality in Ontario, which is a bit surprising given the overall lack of forest cover in C-K.

Next are a few of the hickories found in Ontario. First up is Bitternut Hickory, fairly common in southern Ontario deciduous woods. It is readily identifiable with its bright yellow buds.
 Next is Red or Pignut Hickory. It is quite rare in Canada, being found only in a small part of Essex County and several municipalities from about Long Point east to the GTA.
 Big Shellbark Hickory is scattered across an even smaller part of extreme southern Ontario than the previous species. A telltale feature is that this time of year, many of the leaf stems remain attached to the outer twigs.
 Much more common across southern Ontario and Quebec is Shagbark Hickory.
 These next few are shrubs. First is Flowering Dogwood, an endangered species in Canada. This first image of it shows the non-flowering buds.
 The flowering buds are quite large by comparison, and in late April or early May will open up into an impressive white 'flower', although what appears to be white flower petals are really sepals, another part of a flower, and the petals themselves are very tiny.
A common shrub especially in damp places is Red-osier Dogwood. In the winter its stems are quite bright red, as shown.
 An uncommon shrub is American Hazel, most often found in shrubby prairie, savanna and even drier rocky habitat. These are the male flowers that will open in the spring.
 Not a native species, but occurring in natural areas from time to time, is Winged Euonymus, which has prominent wings along its stem. Not all are as prominent as what shows in this next photo.
 A related, native Euonymus is Burning Bush, which has somewhat square branches.
Ash trees are on the decline in southern Ontario. For more on that topic, check out this previous blog post. This first image shows the terminal buds and twig characteristics of Black Ash, which occurs in quite wet habitat.

In comparison is Red Ash, with its densely hairy stem. It is, or at least was, one of the most common ash species in southern Ontario.
 A real rarity is Blue Ash, found in a few scattered locations in southern Ontario. It has declined due to the Emerald Ash Borer, and is getting harder and harder to find even where it formerly occurred. It is easily identified by its winged stems.

A cross-section of a Blue Ash stem
Another rare and declining tree is Butternut, legally endangered due to a canker that has killed many individuals.
 Closely related is the much more common Black Walnut.
 Next is English Walnut, not native but occasionally planted in landscape settings. The green twig is clearly distinctive.
The unofficial flagship tree species of the Carolinian Life Zone is the Tuliptree, with its distinctive buds.
 Hop Hornbeam, shown next, is identifiable as its partially developed male flowers are present throughout the winter.
Oaks are plentiful across the Ontario landscape. Their buds and twigs aren't always that distinctive, but in these next two examples I show White Oak, with its reddish, hairless twigs.....
 ....and Swamp White Oak, with its somewhat shaggy twig.

An extremely abundant shrub across southern Ontario, is Staghorn Sumac. Its twigs are densely hairy.

Another shrub is Wayfaring Viburnum, native to Europe but commonly planted  for ornamental purposes and as a food source for birds. The leaf buds are very different from almost every other species I have seen so far.
 Prickly Ash is not something one wants to go charging through at any time of year. The thorns are quite stout. The thorns in combination with the leaf scar bundles almost looks like a face, with arms outstretched.

And last, but not least, is this next one: Cherry Birch. It is native, legally endangered, and limited to one site in all of Canada, in the Niagara peninsula.

These are just a few of the many twigs and buds, etc that I have photographed over the last few months. It is a laborious task, but enjoyable, and I have been able to work with some really keen botantists and horticultural specialists in the process. Many of these photos were taken from specimens from the University of Guelph Arboretum, and I have lots more to do!

All of the above photos were taken with a full frame camera, a 100mm macro lens, and up to 68mm of extension tubes. Even at that, some of the photos were cropped. Almost all are at life size or more, although the photos as shown here are actually much greater than life size. The depth of field at this magnification is extremely shallow, in some cases only a couple of millimetres, so I have had to use flash, as well as a flash diffuser. I have also had the camera set-up on a tripod with a ball head, and a focusing rail which enables me to fine tune the focus to fractions of a millimetre.

So next time you are out hiking or birding during the leafless season, take a moment or two to explore and enjoy the interesting examples of nature's design all around you, including twigs. You might have to reverse your binoculars and use them as a magnifying lens to see some of the features.

Sunday, 12 March 2017

Ice is nice

Now that it is unseasonably cold again, at least for a few days, this post may not seem so out of place.

Most people like ice, one way or another. Some like it in their drink of choice. Some like it to skate on. Or fish through. Or go ice-boating or snowmobiling on.

Some photographers find ice to be very photogenic.

Outdoor ice can be fickle if one's desire is to play a bit of pond hockey, especially in a 'winter' like we have just experienced.

Ice, just like its liquid state, is remarkable for a whole lot of reasons. One of the most remarkable aspects of water is that as it gets colder, it gets denser and heavier, and is heaviest at about 4C. I remembered this fact from my high school days, but was reminded in a very practical way one time a few years ago. One of my colleagues and I had chartered a fishing boat late in the season to get to one of the islands in the western basin of Lake Erie to do some field work. The captain wanted to know exactly how much travelling we needed to do, since because the water was much colder, and denser, than it was in the summer, it took more fuel to operate the boat and he didn't want to get stranded!

The colder the water, at least down to when it gets to 4C, the heavier it is, and the lower in the pond or lake it gets. Anyone who goes swimming knows that the water is always colder near the bottom, unless it has been quite wavy, mixing the water. When the water is calm, it settles into layers, with the warmest layer always at the top.

Once water gets to be a temperature lower than 4C, it gets lighter, returning to the surface and may eventually turn to ice. That is why ice cubes float in a glass, and a pond or a lake is covered with ice rather than freezing from the bottom up. If it froze from the bottom up, it could freeze solid, destroying all the life in the pond or lake. But with the ice on the top, sometimes covered by an insulating layer of snow, the ice and snow protect the water and life underneath from long term and perhaps bitter cold. Since the water at the bottom of the pond or lake is a bit warmer than at the surface, that is why ice fishermen sometimes see a Snapping Turtle crawling along on the bottom, or they catch a Mudpuppy (a type of salamander) nibbling away at the worm or minnow on their line. Both turtles and mudpuppies are cold-blooded, but apparently able to function in temperatures just a bit above freezing.

Just something to think about, next time you are enjoying the tinkling of ice cubes in your favourite beverage on a warm summer day!

Tuesday, 7 March 2017

Ancient hieroglyphics, or???

If you are out and happen to see these patterns on a barkless tree trunk, you might wonder just what has created this.

It isn't some form of ancient writing, of course, but the markings of a non-native and highly invasive insect known as the Emerald Ash Borer (EAB).

The EAB is a metallic green beetle that is native to Asia. The consensus is that it arrived in North America via wood packing material, which isn't surprising in many ways due to the huge volume of things that North America purchases from Asian countries. It was first detected in Michigan in the late 1990s, and shortly afterwards, expanded into southern Ontario, being first detected there at Windsor.

The EAB specializes in feasting on ash (Fraxinus spp) trees. In its homeland, it is not considered a major problem since the ash species there apparently have built-in resistance. However North American ash trees do not have that resistance, and so are quite vulnerable. The adult EAB feeds on the leaves and are not all that destructive, but the larvae burrow under the bark, feeding on the woody material immediately under the bark. This is where the critical transfer of sap and nutrients to feed the tree takes place, and the larvae's burrowing and feeding action cuts off the flow. In fairly short order the upper part of the tree dies. The roots may still be alive and there may be some subsequent sucker growth of the tree, but it will likely never grow to a mature specimen.

The EAB has quickly spread in less than two decades to many provinces and states around the Great Lakes and points farther east. The travel of adults to colonize new areas is facilitated by wind, so the prevailing westerly and southwesterly winds cause eastward spread more quickly than westward spread.

Ash trees are a major component of eastern deciduous forests. Or at least they used to be. There are several species of ash occurring in southern Ontario: White Ash, Red Ash (and its varietal form, Green Ash), Black Ash, Blue Ash and the only 'non-colourful' one, Pumpkin Ash. All species are susceptible to the EAB, although it has been surmised that Blue Ash is somewhat more resistant.

Due to the aggressive nature of the EAB most forests in southern Ontario, and especially southwestern Ontario, have been devastated, and dead ash trees are now dominant. But given the brittle nature of standing dead ash trees, many are now snapping off and if they don't get hung up in an adjacent tree, come crashing to the ground. Every moderate to severe wind storm brings more and more down.

The main reason for the preceding discussion is that over the past few weeks I have had quite a few comments and questions directed my way regarding the apparent unsightly mess along the roads and trails of Rondeau Provincial Park. The mess is actually the result of the attention being given to the thousands of dead ash trees.

So many falling trees are a hazard, to people, to vehicles and to the structures in the forest. This next image shows a couple of trees that came down and not only blocked the trail, but also did some major damage to the information sign along the trail.
 This next image shows a repaired boardwalk structure along the Tuliptree Trail, which was heavily damaged when a dead ash tree fell on it.

There is currently a major effort to take down the myriad dead ash trees along the roads and trails, in a controlled manor rather than waiting for the next few wind storms. As a result, the road sides and trails look a bit unsightly, to be sure.

This next image shows one of my favourite views along the Tuliptree Trail, taken in April, 2014.
Now it looks like this next photo, so the nice clean appearance of the above photo will take a few years to get back to.

For anyone planning to visit Rondeau in the next few weeks, scenes like this will be commonplace, but please bear in mind that it is a temporary appearance. The dead ash trees will decompose fairly quickly in the next few years. The freshly cut stumps will gradually weather and blend into the background, and with the growing season beginning in May, the greenery will cover up the messy look to some extent.

Major changes to the forest are a periodic occurrence. In some forest ecosystems, fire occurs periodically, killing trees and shrubs that are not resistant to fire. In other forest ecosystems, major wind storms or ice storms cause significant changes. At Rondeau, I can remember several such events:
-a huge ice storm in March of 1976, where many trees or major limbs came crashing down and virtually every tree in the park was affected;
-major winter blizzards with high winds occurred in late January of 1977 and 1978, causing major damage;
-more recently was the major downdraft of July 1998 that caused considerable damage to many trees (and structures).

Admittedly the outbreak of the EAB is not as natural an event as a storm, but the results are much the same. And just as the forest recovered to varying degrees following those other major events, I expect that the forest will recover after the ash trees cease to become a dominant species. But it will never be quite the same.