flora – Page 14

Fungi at my feet

One of the things about hiking through the forest is you tend to spend a disproportionate amount of time looking at the ground. Walking along a well-groomed trail, through a meadow, or down the road, you’re able to keep your eyes up and take in your surroundings, or watch the birds or butterflies or other organisms that are generally found above the ground. In the forest, though, your eyes are busy scanning the ground for rocks, roots or logs that you’re liable to trip on.

Unsurprisingly, one’s observations tend to have a natural bias to organisms and features close to the ground. Since such a large proportion of them grow from the ground or fallen vegetation, fungus figure prominently in such observations. I saw quite a number of neat fungi while we were out yesterday, or at least what I thought was a large number given the time of year. There are some types of fungi that are found year round, mostly bracket fungi, and those ones I’d expect to encounter, but there were many fleshy ones that surprised me, as well. The guides never mention the time of year these things are found, or how late into the fall they’ll persist, and I’d just sort of figured they’d all have faded by now.

(Of course, after saying that, the photo I put as the header image happens to be an above-ground fungus. I think it’s a bracket fungus called Cerrena unicolor, which I talked a bit about last winter. It’s got a really neat life-history that involves a horntail wasp and an ichneumonid wasp as well.)

I believe this one is a type of jelly fungi called Black Witch’s Butter, Exidia glandulosa. It’s a fairly common species, usually found on the dead twigs and branches of hardwoods. I’m used to seeing fungi mostly on logs or snags, so almost missed this one, growing on the end of a broken branch half-hidden among the leaves. Jelly fungi are a neat group that don’t have the typical fungi shape, instead forming gelatinous masses that shrivel and grow according to the available moisture. We’ve had a stretch of wet weather, so these ones were filled out.

These are a common and widespread species with the delightful name of Lemon Drops, Bisporella citrina. It’s in the superficially similar but unrelated group Sac Fungi. Unlike the jelly fungi, which are basically just blobs, sac fungi do actually have stems, but in the case of this species they’re short and well-hidden. It’s found on dead logs where the outer bark has been shed (which has the fancy name of decorticated, I learned), and often occurs in huge numbers, up to hundreds of individual fruitbodies in a cluster. This group was relatively small by comparison.

This was a cool one. At first I thought it was another jelly fungi, or some other sort of fungi. It took a bit of searching around on the internet, since I didn’t locate it in my mushroom guide, but I eventually found it while searching images of Copper Penny. It turned out not to be a fungus at all, but rather a lichen (I suppose technically a lichen is a symbiotic relationship between a fungus and an algae, so it is still part fungus, but not wholly so). I believe it is Peltigera hymenina. I couldn’t see a common name for it, but a related species, P. canina, is called Dog Lichen, or sometimes Dog-tooth Lichen, for the resemblance of the spore-producing projections to dogs’ teeth. The species belong to a group sometimes called the Felt Lichen, for their flat, soft appearance.

This is another type of lichen, and one that kept catching my eye throughout the hike, once I’d stopped and peered close enough to notice it. It’s a Pixie Cup lichen, a member of the genus Cladonia, although I’m not sure exactly which species. I tend to think of lichens as mostly those flat leafy formations seen underneath the cups in the photo, so I wasn’t sure whether the cups and “clubs” were part of the same lichen, a different species, or even perhaps a fungus. Turns out there’s a whole variety of lichens, not just the leafy sort, in all sorts of shapes, from flat, to cup, to coral-like. This one was just small, perhaps a centimeter tall at most, less than half an inch.

Speaking of looking closely at things, part of the reason I was paying closer attention to surfaces was because of a recent post by Wandering Weeta, and specifically one photo where she shows some fungal growths on the stem of a fallen leaf. It amazed me that she even noticed those, and it made me pause to wonder what I may be missing.

If a tree falls in the forest

Forests are generally known specifically for their living trees. The tall pillars, their stout trunks reaching for the sky, the branching canopies casting shade on the ground below – they are the very definition of forest, and without them the forest would not exist. And yet, the living trees are only a small part of what forms a forest. Just as vital are the dead trees, the ones still standing as snags and, perhaps more importantly, the ones that have fallen as logs.

Logs play a vital role in the forest ecosystem. As they begin to break down and decompose, they return nutrients back to the soil that may have been locked up in that tree for decades, or even hundreds of years. Because they’re essentially nutrient-rich piles of fertilizer, they provide excellent spots for new life to grow. Often in the tropics, where the majority of the nutrients in the ecosystem are contained within the living matter, fallen trees are swarmed by young plantlings looking for a good start in life. It’s not unusual to have trouble seeing the log for all the little trees and plants growing on it. Such is not usually the case in the temperate north here, but they do still foster growth, often moss or fungus, sometimes ferns or grasses, occasionally young trees.

Rolling a log over can reveal many secrets. They are home to many critters, from vertebrates like salamanders or frogs that hide underneath, to insects and invertebrates that tunnel below or inside. These latter groups are an important part of the decomposition process, breaking it down into pieces that are easier for bacteria and little organisms to digest. The longer a log has been down, the further along the decomposition process as all the little critters get to work. A newly-fallen log is still strong enough to support a person’s weight, but do the same with one that’s been on the ground a number of years and your foot will go right through it. The amount of time it takes for a log to break down completely varies according to the size, density and composition of the wood and the local conditions. Dry and cold conditions tend to slow the decomposition process, as the organisms responsible for much of the cycle are less active, and denser wood will take longer to rot (even within the same tree, sometimes, different densities between the sapwood and the heartwood can create hollow logs, or logs where just the centre remains). A giant red cedar, which has a dense, oily wood, may take a century to completely return to the soil.

I wrote about carpenter ants before, but there are many species of invertebrates that also call dead trees and logs home, and which woodpeckers find tasty. Fallen logs are riddled with woodpecker holes just as often as standing snags are, and it’s not unusual to flush a Pileated or other woodpecker up from what seems like the forest floor. Woodpeckers, and Pileateds specifically, probably help in breaking logs down as they chip pieces off during their excavations. Woodpeckers aren’t the only birds to use logs, though. Ruffed Grouse males will sit atop a large log to perform their drumming displays, where they beat their wings rapidly to create a deep staccato beat, using the log to amplify the sound’s acoustics. Many species of ground-nesting birds will build their nests under the overhang of a fallen log.

Forests go through different stages of maturity, and one of the characteristics of a mature forest is the presence of many fallen logs. A truly mature forest, however, not only has fallen logs, but also has fully decomposed logs. Because the latter no longer look like logs, they can be hard to spot. In walking the woods around here I spent some time searching for a fully-decomposed log to take a photo of, but the forest is too young. I suspect much of the land around here was cleared for farming at one time or another, as there is evidence of split-rail fences that apparently run through the middle of the forest. It could be that the forest in this area is only about 60 or 70 years old. Certainly the really thick, tall, craggy trees that characterize a very old forest are few and far between.

I found a couple that might possibly have been an old log or stump but couldn’t say for sure. The above was one (it’s quite difficult to get a photograph that adequately conveys the sense of a bump in the land, it turns out). These old, decomposed logs show up on the forest floor as raised hummocks. Often they’re long and narrow, much like the log they used to resemble. They can be mistaken for burial mounds, as they have the same sort of formation. Oftentimes you can see two or three trees growing in a line along the hummock, evidence of seedlings that got their start on the decomposing log, now long gone. Because of the amount of time necessary to return a grown tree back to the forest floor, these hummocks are often used as a sign of forest maturity.

Logs are good for having fun, too. Children use them as balance beams. Small ones can be used to create forts. Hollow ones can be crawled through as tunnels, or lived in like treehouses. And I know one puppy who had a blast vaulting over them like agility jumps.

Prehistoric cedar ferns

Of course, one of the neat things about moving, once you’ve made the decision to do it and gotten over the shock of everything being different and new is that everything is different and new. It’s a whole fresh start with fresh surroundings. And this doesn’t just apply to the house and the neighbourhood. It also applies to the natural landscape. Unless you only moved two doors down the street, chances are you’ll have moved into a slightly different plant and animal community than you left behind. It may be very slight – perhaps in your new place you notice a catbird nesting in the shrub in your backyard, where you never saw a catbird in your yard at your old place. Or it may be dramatic – you’ve moved from pastoral countryside and rolling hills into rocky Shield country and thick forest cover. In the case of the latter, the whole ecosystem community can change.

The move for Dan and I was fairly dramatic – even if you skip over the urban Toronto stage, much of the surrounding GTA countryside is fairly pastoral, even the areas that are relatively wooded. Where we live now a pasture is uncommon, and the huge expanses of forest, the lakes, and the landscape full of ridges are all features that weren’t found where we grew up. For my parents the move is less of a change. If anything, they’re going to a more agriculturally-dominant area than what they’re leaving, since the Niagara Escarpment is not very suitable for farming so much of it remains forested. The landscape here is a lot flatter than that surrounding their old home. The differences manifest themselves in other ways. For example, there are ravens here, and they’re fairly common, but the species doesn’t make it as far south as Toronto.

And there is this stuff. And it is everywhere. I don’t recall seeing it before, although that doesn’t mean it doesn’t occur in other regions I’ve frequented, simply that if it does then I’ve overlooked it. It certainly caught my eye here, though, because it’s so abundant, and it seems to favour the open areas along the trails, forming the predominant ground cover in some areas.

I had no idea what it was, so I had to look it up upon my return to the house. Naturally most of the books are still packed up and haven’t been moved yet, so I had to rely on vague search terms entered into Google. It was surprisingly easier than I was expecting to find an answer, however, and including that it seemed to favour “moist ground” into the search string helped. It is Diphasiastrum digitatum, variously known by the common names Fan Clubmoss, Trailing Ground-Pine, Southern Ground-Cedar, Running Cedar, Southern Running-Pine, and others.

By clearing the leaves away from the base of the plants you can see the reason for some of the names. What looks like a colony of little plants is actually a single plant putting up vertical branches from a runner. When encountered in the forest they are often growing in lines, a result of growing along a runner (as below).

However, only the name Fan Clubmoss is actually accurate otherwise. The plant is a member of the family Lycopodiaceae, the clubmosses. Clubmosses are not pines, however, nor cedars, nor in fact even closely related to trees at all. If they have a close relative it might be considered ferns, and sometimes they are referred to as “fern-allies”, but even this connection is relatively distant.

Clubmosses are an ancient group of plants, going back 420 million years ago to prehistoric times where some species could grow to the size of palm trees, and in a similar manner (losing the lower “leaves” from the trunk as they grow, leaving a tuft at the top). These days none of the remaining species grow that large. The modern world’s diversity of clubmosses is pretty sparse compared to what existed millions of years ago. The majority of known genera in this family are actually extinct.

The plants are evergreen, like their namesake trees, and do actually resemble cedar a bit in the scaly appearance and waxy texture of their leaves. Unlike most plants, they don’t reproduce through seeds, but rather through spores, like ferns or fungi. They send up clubbed shoots (which give the group their common name), which, when brushed or blown in the wind, release puffs of spores into the air for the wind to carry to a new location.

In centuries past the spores were used for a lot of things. Violin makers used them to fill in pores in the wood of their instruments. Theatres used them for pyrotechnics, because they burn quickly and with little heat, so were considered safe by the standards of the time. They’ve been used as fingerprint powders, as a stabilizer in ice cream, and suspended in air during physics experiments to visualize soundwaves. A species of Asian clubmoss is currently under investigation as a possible treatment for Alzheimer’s.

Pretty neat for a simple ground-growing forest plant.

Thanksgiving colours

This weekend was the Canadian Thanksgiving. I was at my parents’ house for the holiday, gone for two days. I had fully intended to put together a post-dated post that would go up while I was away, but a last-minute change of plans regarding the weekend arrangements meant I had less time than originally planned. It was a nice weekend, I don’t get to see my family very often now that we’re spread out all over the province. Also, with my parents taking possession of their new house at the end of the month, and listing their current place soon, it may be the last family event we’ll have there. It’s a little sad to think about; my parents have been there some 30ish years and it’s been the only real home I’ve known, until this move to what will hopefully be a longer-term residence here in Frontenac. I still catch myself saying “I’m going home for Thanksgiving” even though I haven’t resided at my parents’ in a number of years. To me, that place will always feel like home. Look at me, I’m starting to get a little choked up already.

So it was a nice weekend. The Niagara Escarpment is always gorgeous in the fall. The area has a higher percentage of forest cover compared to the surrounding regions, and the trees, a lot of maple and other species that tend to turn bright colours, form brilliant blankets over the rolling hills. While living in Toronto I would always look forward to return trips to my parents’, to enjoy the fall colour. Thanksgiving weekend always seemed to be right around the peak, which was great timing.

Dan* and I had great hopes for the region surrounding our house when we moved in in the summer. It’s nearly completely deciduous here, except for a few evergreens scattered along the lake’s shoreline, with maples making up a large part of the species composition, so we anticipated a spectacular autumn show. Up to this point this fall we had so far been rather underwhelmed. The maples, it seemed, were turning yellow or brown and then dropping their leaves before they got a chance to form any sort of bright displays. There were a handful of trees that were behaving in a respectable manner, producing flame-orange and red foliage, but they were just scattered individuals, here and there.

*Now that Blackburnian has his own webpage and blog up and operational, he’s requested that I use his real name, Dan, rather than his codename, Blackburnian. I’m just as happy to oblige, since inevitably I start to type the former as I’m writing these posts anyway.

The Frontenac region seems to have reached its peak this weekend, while I was away. Driving back up our road, all the trees seemed to be afire. Perhaps it was simply being away for a little while that skewed my perception on things, or perhaps it was the particular weather patterns recently, cooler weather last week followed by a couple of gorgeously warm days this weekend, that prompted the rapid colour change. Either way, it was a beautiful drive up our road. It’s a beautiful drive anyway, but the eyecatching colours just made it that much more scenic.

The brilliant colours of autumn is a phenomenon unique, for the most part, to deciduous trees of temperate regions. We often tend to think of it being a feature of northeastern North America, but fall colours can be observed through much of North America and northern Eurasia, from Scandinavia to Japan. Many of these regions, including New England and eastern Canada, have developed an autumn tourism industry built around a pasttime sometimes called “leaf peeping”, driving the countryside enjoying the show. The Weather Channel in North America even has a segment in the fall where they report on the state of change for different regions, and they maintain a similar page on their website.

The changing colours is the result of the tree pulling its nutrients back into its trunk and branches prior to dropping its leaves. There are a lot of valuable compounds and nutrients invested into a leaf during the summer that would represent a huge loss to the tree if it had to replace them again in the spring. By removing these important compounds from the leaves before they fall, the tree saves a lot of time and energy. But why does a tree shed its leaves? It is believed that the costs associated with maintaining leaves during the sub-freezing winter months far outweigh any benefits the tree may gain through photosynthesis during that relatively dark period, and so it is more energy-efficient, in the long-term, to drop the leaves for the winter and grow new ones in the spring.

Leaves are green during the summer because they contain a compound called chlorophyll. This is what the tree uses in photosynthesis, which is the process of converting carbon dioxide and water to sugars using the energy in sunlight. During the summer the chlorophyll is constantly being replaced as it wears out in the leaf, maintaining the rich green colour. Come fall, the tree stops replacing the burnt-out chlorophyll, and gradually the tree loses its green. The extremities of the leaves are the first to go, with the veins often remaining green well after the rest of the leaf has changed colour.

The reason it turns various colours, though, instead of just going brown, is because of the presence of other pigments within the leaf that are masked as long as the chlorophyll is present. Once the chlorophyll starts disappearing, those other colours begin to show. The yellows and oranges are the result of carotenoids, the pigment that also gives carrots, egg yolks and Baltimore Orioles their characteristic colours. Many trees, such as aspen, birch, black cherry, sycamore, and others, contain these pigments and will generally turn primarily yellow in the fall.

Some trees, though, turn reds, purples, or fire-orange. These colours are produced by different pigments, called anthocyanins. Cherries, blueberries, red apples, and other similarly-coloured fruits contain these pigments. Unlike the carotenoids, the anthocyanins aren’t present in the leaf during the summer growing season. Rather, they are actively produced by the tree in the fall as the chlorophyll is starting to disappear. Why would the tree invest so much energy into producing pigments when it’s just going to drop the leaf anyway? There are a few hypotheses, the most frequently proposed being that these pigments protect the leaf from scorching and dessication from the sun, extending the lifespan of the leaf and allowing the tree to get the last of the sugars, nitrogen and other nutrients out of it before it falls. It also helps to make this process more efficient. Maple, oak, dogwood, and others, are among the trees that actively produce these pigments.

The cues that trees use to know when to start reabsorbing nutrients aren’t clear, but may have something to do with changing light levels. As the days get shorter and the tree starts receiving less light, it will trigger the tree into beginning its fall process. I recall hearing on CBC Radio One back in late August that the reason some trees were starting to change already is because we’d had such a wet summer, and all that cloud cover had triggered the low-light mechanism in some individuals. That could also explain some of the lack-lustre colour this fall, since the brilliance of the fall display is proportional to the amount of anthocyanin produced, and the amount of anthocyanin produced is proportional to the amount of light received during the reabsorption process. Bright, cool days with chilly (but not freezing) overnight temperatures produce the best colours. Interestingly, recent research suggests that rising carbon dioxide levels delay the onset of fall colours, though I’m not sure exactly how the extra CO2 (the “breath” of trees) helps to extend the life of the chlorophyll and green leaves.

The fall colours are fleeting, and before we know it winter will be upon us, but in the meantime I enjoy the bright displays and that indescribable smell of fallen leaves that indicates autumn has arrived.

Today at Kingsford

I had plans to post about fungi today. Not going to happen, but hopefully tomorrow. My sister was up to visit this weekend, which was really nice, I haven’t seen her in a couple months, since well before we moved out here. She left early afternoon, and I spent the rest of the afternoon watching one of the football games. When the game ended, Blackburnian suggested we boat over to the park to take Raven for a hike, so we bundled everyone up and headed out.

The outing didn’t go quite as planned; I was supposed to take the trail around and meet up with Blackburnian further down along the shore, but I hadn’t paid close attention to the map before we left, and the trail didn’t do what I was expecting it to. Since I didn’t know how far I’d have to go or how long it would take me to finally get over to the trail I was meeting Blackburnian on, and I didn’t want to get lost, I decided best would be to turn around and head back to the shore where we’d been dropped off. Unfortunately, I wasn’t able to communicate this to Blackburnian, so he was waiting for us at the rendezvous point, and when we didn’t show, started hiking up and down the trail there assuming we got lost (hopefully, as that was best-case scenario). Eventually he did return to the boat and found Raven and I sitting out on the rocks, so it all worked out, but it was dark by the time we returned home. As Blackburnian said when he finally found us, that won’t happen again.

In addition to some more interesting fungi I found while we were wandering around trying to figure out how to navigate the trail system, I was also admiring the start of the fall colours. We’re still not quite at peak here, that’ll probably be next weekend, or possibly even the following. But there’s lots that’s starting to show vibrant colour changes. The most striking were the above Virginia Creeper, brilliant red against the aqua lichen and green moss growing on the rock, and the small swamp below, with the yellow ferns and red-orange maple set against the bright green of the pondweed on the water.

I’ve noticed both of these (Virginia Creeper and swamp-dwelling individuals) have been among the first to change colour. I’m not sure why the creeper changes colour first, but I think the water cools the roots of the trees in the swamp sooner than those of upland trees, stimulating the earlier colour change (similarly, trees that are at the edge of the forest, or that poke out through the canopy are exposed to cooling winds and are more likely to change before their sheltered neighbours).