Wednesdays are my CSA pickup date. Since we moved further away from the pickup location, this now means an hour’s drive each way to the farm to get our veggies. I don’t mind, though – in addition to knowing I’m supporting a great guy and his family, and getting homegrown, organic produce, it’s a really nice drive down there. Most of the drive down takes me through Shield country, and since moving off the Shield the Wednesday drive is really the only time I get to see it unless I make a special trip somewhere.
The Shield has beautiful scenery, lots of water and forest, and all of it is nearing the peak of fall colours right now. On the drive down yesterday I spent the entire time admiring the reds and oranges and bright golds. It was overcast, rainy in spots, but the dull sky only seemed to strengthen the colour of the trees. I had taken my camera with me primarily to get a photo of the Tay River when I crossed it (above; it was raining so the colours are more muted), but on the way back I stopped several times at the side of the road and dashed out with my camera to snap a photo.
Fortunately, the road for the northern half of the trip is one that’s not very busy, so I could “slam on the brakes” whenever I spotted a patch of great colour. Many of them happened to be associated with water, partially because you get the best vistas with the open space, and partially because for whatever reason trees at the water’s edge often turn brighter colours than those away from it.
The little boathouse in the top photo is one that I look for every time I go by. I just love the scene it forms, with the river winding through the trees and this little tumbledown shack set at its edge. The small footbridge in the above photo is another scene I admire as I drive by each trip.
Although the transition to autumn colours isn’t unique to northeastern North America, this is the part of the world most renowned for it. The activity of driving around to admire the fall foliage has been called “leaf peeping”, and has become a major contributor to the local economies in much of New England. For example, some four million people might visit the region during leaf-peeping season, contributing as much as $8 billion to the area’s economy – in some states, even out-earning skiing. There are many businesses, such as bed-and-breakfasts, that count on the influx of fall tourists to give their revenue a boost.
When I was searching online for some figures on visitor numbers, most of the hits returned back to me were news articles dating to 2002. That year New England suffered a bad drought during the summer. The lack of water stressed out the trees and caused them to start shutting down for the winter early, about two weeks ahead of their usual schedule. Additionally, the bright colours just weren’t present – instead of reds and golds, there were dull yellows and browns.
I wrote about the process that causes leaves to change colour in a post last year. You can learn more of the details by going there, but the short of it is that the trees stop renewing the chlorophyll that gives the leaves their green colour, and as the chlorophyll disappears what remains are various yellow pigments that were hidden by the green chlorophyll, or red pigments that the tree has manufactured after the chlorophyll is gone. These serve to protect the leaf for a little while longer as the tree removes the last of the sugars and nutrients from the leaf prior to dropping it.
The reabsorption process is triggered through shorter day lengths and cooling temperatures. The production of additional pigments is proportional to the amount of light the leaves are receiving during this time. In last year’s post, I wrote, “Bright, cool days with chilly (but not freezing) overnight temperatures produce the best colours.” We have certainly had an abundance of those these last few weeks. Well, the cool days with chilly overnights, anyway. The last week or two we’ve had rain most days, though we had a really good stretch a little earlier in the fall where it was nothing but blue, sunny skies. Perhaps the amount of pigment production was determined at the start of the fall at the beginning of the whole process, when we were having all that sunny weather. Whatever the reason, the colours this year are fabulous.
I’m not sure why a drought year results in duller colours, except perhaps that the trees start pulling out their sugars from the leaves earlier than usual and decide not to bother with the protective additional pigments. Since the ones that are manufactured are the red pigments, this would explain why there is a general absence of red or orange trees in drought years. Yellow pigments that are left behind once the chlorophyll disappears would still display as yellow, though if the tree normally supplements these with some red pigments, giving it a fire-glow tinge to the yellow, and it doesn’t do that in the drought year, the yellows would be dull. Presumably trees that normally go red by manufacturing pigments would simply go brown if they didn’t make any.
Around here, I typically think of our colour peak as about the Canadian Thanksgiving weekend, which is this weekend. That’s when it seemed to peak last year, and it seems to have timed about the same this year. If you live south of the border, you can find out the particular peak for a given area by checking out this Wikipedia map (the colours stop at the border, it seems). The Weather Network also maintains a Fall Colour Report, which services Canadians here. These reports are often provided by a volunteer army of “Official Leaf Peepers”.
If you aren’t able to make it to New England yourself, there are quite a number of websites that have set up webcams for the purpose of allowing people to appreciate the autumn glory from afar. You can find a list of several such webcams here. Additional “leaf peeping resources” can be found at this site.
Although I’ve done a lot of traveling around the continent, and love just about everywhere I visit for its own natural beauty and unique landscapes, I don’t think I could ever leave the northeast – the gorgeous fall foliage is one of the reasons why.
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.
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).