Sycamores: nature's ghosts in the woods

Species name: Platanus occidentalis

Common name: American sycamore, American planetree

Location: Western University campus

The American sycamore (just "sycamore" from here on out since I live in North America) is native to eastern North America and has quite an extensive range throughout the Carolinian forest (from Ontario south to Texas and Georgia and everywhere in between). Depending on the environment, it can be an absolutely enormous tree, reaching heights of 40 or 50 meters (sycamores are some of the easiest trees to spot from the edge of a forest, especially during the winter, because they reach above the rest of the forest canopy) and diameters as large as 4 meters. The largest sycamore ever recorded was in 1770 recorded by the one and only George Washington near the junction of the Kanawha and Ohio rivers; he recorded in his journal the tree was approximately 14 meters in circumference! Go measure out a piece of string 14 meters in length and go wrap it around the biggest tree you can find. I bet your "incredibly large tree" will be tiny in comparison to your string! This tree, for obvious reasons since trees don't live forever, is no longer standing but it's not uncommon for a sycamore to be 6 or 7 meters in circumference if rooted in deep soil.

Sycamores are spectacular trees to see, but especially during the winter. Some people call them the "ghosts of the forest", but not just because of the colour of their bark. The new growth of the tree is almost pure white, and that scaly brown bark develops near the base of the tree as the tree ages. The white bark is actually iridescent; when the moonlight shines on the forest and sycamores sway in the breeze, it almost looks like they're glowing and sparkling in the moonlight. It's pretty cool to see, but also a bit creepy. If you've ever had nightmares about sycamores coming to life and grabbing you off a trail while you're running from ghosts through the forest, this could be why! The brain does some mysterious things... :) The sycamore is an interesting study in the use of common names assigned to species, and how they differ with geography. If you're from North America, this tree, being in the genus Platanus, is a sycamore. If, however, you're in Europe (especially in Britain) trees in the genus Platanus are called planetrees. Seems simple enough. But the plot thickens. If you are calling a tree a "sycamore" in Europe, you're actually referring to a species of maple called Acer pseudoplatanus. And if you're referring to a planetree in North America, you're referring to the hybrid Platanus x acerifolia (to be profiled in the next blog). Ugh! Oh how I wish things were simpler...

So what's so special about sycamores? Well, they're relatively unique trees in that they're riparian or riverbank species, and at the same time they have incredibly weak root systems. How do I know that, without ever having seen a root system of a sycamore? Well...look at the trees. Next time you're walking along a stream or a river with sycamores growing, look at the shape of the trees. Chances are, none of them are straight up and down. This is because when the trees were young and growing along the bank of the river, the freeze-thaw (or extreme floods of the rainy season) cycles caused the damming of ice up against the trunk of the tree. The roots weren't strong enough to support the tree upright, so it started to lean the same direction that the ice was pushing. If you look at a mature sycamore, it still has the lean of the direction of the river or stream. Extreme flooding would do the same thing; it would wash away the soil near the base of the tree causing the trunk to shift, and lean the direction of water flow. If you see a sycamore growing out all by itself in a big farm field and it leans, chances are the farmer has reclaimed the land where the river or stream used to be and put pipes to drain away the water instead. That lone sycamore is the only remnant of the forest that used to be present.

There are two main uses of sycamore trees today. The first is as an ornamental wood for a very specific purpose: in butcher blocks. Many wooden cutting boards are also made out of sycamore wood. It is strong and very durable, with very coarse grain that shows a nice pattern when stained and sealed. The coarse grain makes it very difficult to work with, but is still sometimes used in constructing furniture. The other main use of the tree is as a biofuel crop, since initially it grows very quickly and accumulates a lot of carbon. The wood of the tree can be burned in an oxygen-poor environment to make charcoal, and then burned again for fuel. Not necessarily the cleanest method of energy generation, but certainly better than burning coal (and charcoal could be burned in many of the pre-existing coal plants, providing there was enough charcoal to make it worthwhile!).

Sisal here, sisal there, everywhere a sisal sisal...

Species name: Agave sisilana

Common name: agave, sisal

Location: teaching lab at Western

So once again we have a plant in a pot (the next few blogs will all be plants in pots) from my favourite course ever. This plant is from the same lab exercise as the previous one, flax (which you can read all about HERE). The point of this lab was to introduce students to five major fibres and where the come from, as well as providing them with visual representations of what the plants actually look like since most are pretty foreign concepts to the average undergrad student. The five plants we feature are hemp (not as a plant, but we have a huge display about hemp cultivation and harvesting, as well as products commonly made, and some uncommonly made, from hemp), flax/linen, banana/musa, sisal/agave, and cotton. We also feature products made from each of these plants so the students actually get to touch the fibres to see what they feel like, and why one might be used for one thing over another (for example, it would be extremely unlikely for you to want to wear a pair of jeans made out of sisal, but some made out of hemp would be lovely).

Sisal, also commonly called "agave" after it's Latin name, is native to the Yucatan area in Mexico where it is still commonly cultivated (and found in the wild) today. There are many, many other countries that cultivate this plant for its fibres, not the least of which being my favourite country to visit in the whole wide world: Cuba. The story of how they started farming sisal is actually a funny one! Back in the "good old days" (the 1600s and 1700s, not the 1980s), world exploration was quite the hot topic everywhere in the world. Cuban people, whether it be immigrants to Cuba who have now called it home for decades or native Cubans who have lived there for centuries, were big into exploration after Christopher Columbus piqued their interest (he made landfall in Trinidad in Cuba, where he was attracted by all of the same plants he found in the Dominican Republic). They set sail for the west, hoping to come across something exciting and they did: Mexico. What they observed there was fascinating to them; people turning plants into beverages, and then singing and dancing after consuming those beverages. I don't know about you, but it sounds like a fun time to me! Cubans agreed, and offered to buy some of these plants off of their hands; Mexico refused. So what's a Cuban to do when you want to make the "happy drink" but they won't give you the plant to make it? Why you steal it, that's what you do. Minor detail: the plant in question was the plant called Agave tequilana, or perhaps even Agave americana, not Agave sisilana. Since pretty much all green spiky plants look the same after an over-indulgence of tequila, you can probably understand how they got the two mixed up. Once they brought the plants back to Cuba, grew them, and tried fermenting them into alcohol they were likely sorely disappointed since the resulting beverage would taste nothing like Mexican tequila (it's much more bitter, and would be a much darker brown). They quickly rectified their mistake by becoming one of the world's most important producers of sisal fibres around the world, used to make marine ropes and twine. At least it wasn't all for nothing!

Sisal has recently come back into fashion as an alternative plant to grow in an area, especially in tropical countries, when you're letting a field plot go to rehabilitate the soil as it out-competes weeds and animals avoid eating it because of its physical defenses. It will just happily grow, producing long strands of fibres in the leaves without any kind of human intervention. Even harvesting the plant for fibre is non-destructive; you simply cut the leaves from the stem and leave the stem to grow more leaves. Most commercial sisal varieties are sterile, meaning they will never produce the flower stalk that is so characteristic of other members of the genus Agave (which you can read all about HERE or a closely related plant in a different genus HERE). Should those flowers have been produced, the flower stalk could also be used as a source of fibre. Like with the tequila agave, once the flower stalk is produced and the flowers are pollinated, the entire plant dies so there is incentive for sterile varieties to be grown to prolong the life of the plant.

Aside from rope, there are many uses for sisal and even more are being discovered now that varieties of sisal can be produced in the lab that make longer, softer fibres. Sisal is now commonly used to make paper, dartboards, scouring cloths and sponges, filters, carpets, and even some texturized wall coverings (paints and wallpapers). Sounds like a great plant! The one major downside in using this plant as a fibre source is the amount of waste: only about 4% of the total mass of the plant are useable fibres. The rest is all waste that is composted (rarely) or burned (more likely). The odd time the burning of sisal waste will turn into a dirty fuel, but more often than not it's just set on fire in the field and the ashes are spread around after the pile has been burned off. There are now efforts into looking at how microbial decay by bacteria can be used to turn sisal wastes into biogas, or methane.

While not officially a state "tree" (not actually a tree, despite the ability to produce a stem that looks quite woody, as it is a monocot), it appears on the coat of arms of the state of Yucatan in Mexico, and Barquisimeto in Venezuela.

This clock won't tell time

Species name: Thunbergia grandifolia

Common name: clockvine

Location: Dominican Republic

One day my mom and I went on an excursion that drove all around the countryside and visited a traditional house and farm in the middle of nowhere (and what a beautiful middle of nowhere it was!). We got to walk all around the house and look at the gardens, and they led us through their "agricultural plot" behind the house that had a lot of traditional Dominican food growing. This was one of the plants that was being used as an ornamental species in one of the gardens of the home, and I bet it won't be long before they regret planting it. The clockvine is native to China, India, Nepal and Burma where it grows like a weed. It is capable of living happily in any tropical habitat, loves both very soggy soils and dry, arid soils, can tolerate full sun as well as full shade, and other plants in the garden are the least of its troubles. In some tropical areas of the world, like tropical Australia, it has taken "invasive weed" to a whole new level. It is nearly impossible to eradicate because of its successful growth from either seeds or underground rhizomes, and so it will likely destroy all of the native habitat is has grown into before snuffing itself out.

Since this vine is such a beautiful flowering vine, it's no surprise that it's popular around the world for its ornamental value. In fact, almost every species of the genus is prized for their flowers and very fast growth (as well as the ability to tolerate almost every environmental condition that is thrown at it; including light snow for some species!). Unfortunately, this means that this vine has become invasive on all continents, everywhere it has successfully grown. Something needs to be done to ban the sale of these plants!

There are also studies that are currently looking at what to do with these vines, since they're already in numerous locations around the world in gardens (where they are relatively easy to control as long as you have garden shears and some time on your hands) and have since escaped cultivation. There was the suggestion that these plants would make excellent biofuels since they grow so quickly and are so tolerant of environmental fluctuations, but I'm not sure if anything has been done about this suggestion. They are most definitely "sustainable" in the traditional sense, but at what price? Once we harvested all of the plants that are growing in wild areas, then what? Do we plant more of them and risk them escaping again? Using highly invasive species for biofuels (either fermenting parts of the plant to produce bioethanol or just burning the plants directly to produce energy) is a very fine line to walk between rehabilitating an ecosystem and encouraging its complete destruction.

A cold-tolerant eucalypt

Species name: Eucalyptus gunnii

Common name: cider gum, eucalyptus

Location: Ontario

For anyone from Australia, to see any eucalyptus plant in Canada outdoors would probably be surprising. In fact, it's not just Australians that would be surprised; this Canadian was mighty surprised, too. I was shocked to see that the campus landscapers would have thought this plant was going to survive in our climate, which is inhospitable to tropical trees to say the least. To my surprise, the more I read about this plant the more I wanted to put one in my back yard for novelty sake; it's actually incredibly cold tolerant! This species of eucalyptus will readily survive winters with extended periods below -10 degrees Celsius, and can even survive short periods below -20 degrees Celsius. It's still not a good idea to trust this plant to a harsh Canadian winter, but finding out it could survive snow cover was a surprise to me. This is actually becoming a popular garden plant in Europe since it has the attractive evergreen foliage of a eucalyptus (and the incredible smell) while not having to be taken indoors every winter.

All eucalyptus trees are native to Australia and the surrounding area, but most have been successfully transported outside of this restricted area for ornamental and medicinal use. This particular species, the cider gum tree, is native to a very small area in Tasmania. Like Madagascar periwinkle (which you can read all about HERE), there are few individuals left in the wild in its native range, despite being so incredibly common in other locations in the world due to its ornamental value.

One spectacular morphological characteristic of this plant that is rarely seen to this degree in nature is the morphological variation of the leaves along a single branch. The leaves start off almost circular, with a very short (sometimes absent) petiole at the base of the leaf. The leaves spiral around the branches of the tree, and are a brilliant grey-green. As the branch grows longer, the leaves also elongate until they look very similar to willow leaves, and there is a change in colour so the leaves are a much darker, deeper green. If the tree is pruned into a shrub (as is most common in an ornamental plant setting), the shrub will retain its juvenile leaf form and never progress to having elongate leaves.

While this species of eucalyptus is not often used for anything other than as an ornamental plant, other species in the genus are used for their essential oils, which are very powerful antibacterial chemicals, insecticides, and even industrial solvents. The oils are sometimes also added to food, but only in very minute quantities (the saying "a little goes a long way" is absolutely true in the case of this plant, but also even moderate amounts of the essential oil when consumed is toxic to humans). The tree's leaves are the main food source of the koala, an animal often regarded as the "icon of Australia". Eucalyptus trees are also known as "water-suckers" since they can completely dry up a swampy area in only a few years, turning the soil into arable land. This doesn't last long, however, and the land quickly converts to desert after only a few growing seasons. The wood of eucalyptus trees is very quickly produced, and so it was once considered as a biofuel before being abandoned for other crops that were easier to care for.

Fountain blood grass

Species name: Pennisetum setaceum

Common name: fountain grass

Location: Ontario

This species of grass is native to Africa, where it survives very hot and very dry temperatures on a regular basis. Despite this, fountain grass can also tolerate very wet conditions, making it an ideal plant for areas where there is a prolonged dry season but also a wet season as well. It can tolerate very cold temperatures (but the leaves should be cut back to the ground level or a few inches above the ground in order to tolerate the winter), and so is a popular plant in Canada and much of the United States. The grass in its natural or wild type form is green, but many varieties and cultivars have been created with different amounts of red; the plant commonly known as "blood grass" is another variety of this species. The major downside to this plant, and the reason why I would never recommend it to be planted in Canada and especially the southern United States is that it is an invasive species when left unchecked, and can completely dominate dry grasslands if given the chance. In Canada, the plant doesn't flower well, and when it does flower (as the plants in the pictures above are doing) it doesn't produce many viable seeds. This is a completely different story than in Georgia and Florida, where it thrives and outcompetes native grass species. If you could tolerate the razor-sharp edges of the blades of the leaves, it would make a fantastic lawn grass! Mowing it constantly would ensure that no seeds are produced.

Other than the ornamental value this plant has, it has no economic value. It was once suggested as a possible biomass crop, but it only grows to 3 or 4 feet at most in a season which is significantly less than other suggested biomass crops. Since it also can be invasive (and can increase the risk of forest fires in an area because of the low, dense, dry vegetation), it has been abandoned as an economically viable biomass species in favour of efforts being concentrated with other grasses like Miscanthus (which you can read all about HERE and HERE).

Miscanthus for fuel?

Species name: Miscanthus sinensis

Common name: Chinese silver grass, Eulalia grass, Suzuki grass

Location: Ontario

As you can probably guess, this species of ornamental grass is native to Asia (China, Korea, Japan and Taiwan). It is a very popular ornamental grass species in North America, if not the most popular. There are about 15 different varieties that are widely grown with varying selected characteristics; this variety (along with a couple of others) has purple flower bracts. Another variety that I've previously blogged about is the infamous zebra grass, which you can read all about HERE.

I'm actually surprised at how many people believe that grasses don't have flowers, just because they don't have a structure that you would traditionally believe to be a flower. Any plant that produces a fruit must have a flower (but not every plant that produces a seed; pine trees, for example, produce seeds but no flowers. Instead the seeds are produced in a cone), and the fruit of a grass has a special name called a caryopsis. The caryopsis of any edible grass species is what we eat: the oatmeal you have for breakfast is the oat caryopsis, the grain that is ground to make flour for your morning toast is the wheat caryopsis, and the rice that you cook for your stir-fry is the rice caryopsis. As a general rule, any flower that's not overly flashy is probably pollinated by wind, since they make no effort to attract insects (through scent, colour, mimicry, etc.).

Miscanthus grasses are very successful reproducers in temperate ecosystems. They produce a huge number of seeds, and can spread through the soil via underground rhizomes. Recently, the suggestion has been made that perhaps they would make a good biofuel alternative compared to corn, since we eat corn and we don't eat Miscanthus. Instead, we could use corn for food (both for us and for livestock), and make fuel out of Miscanthus. A good idea in theory, but the problem is that we make bioethanol currently out of actual corn fruit (the corn caryopsis!) which is full of sugar and easily fermentable by yeast. We do not make bioethanol from corn husks or the green parts of the plant. This would involve turning plant cellulose into sugar, then the sugar into ethanol. Completely possible, but incredibly expensive and slow. The same would have to happen with Miscanthus; this makes the process currently economically a moot point. Any benefit we would get from growing Miscanthus instead of corn would be outweighed by the obscene price it would cost to build cellulose reactors. Until we can find an economically viable way to turn cellulose into sugar, producing bioethanol will always be a very expensive process. Expensive because corn is expensive to grow (unlike Miscanthus which grows like a weed with no chemical or labor inputs) but also because we're diverting perfectly edible food out of the food production chain.

Ribbon grass is an invasive native plant

Species name: Phalaris arundinacea

Common name: reed canarygrass, ribbon grass

Location: Ontario

This is one example of a plant where, in hind sight, I wish I had made a species status diagram that included "invasive" as a category with "native". This species of grass, native so Ontario and the surrounding area, is incredibly invasive and downright impossible to eradicate once established (at least, without the use of harsh chemicals). It produces chemicals in the roots that prevent competitors from establishing in the same area, while at the same time being incredibly successful at reproducing both sexually by seed and asexually by thick underground rhizomes. Anyone who has ever tried pulling this plant out of the ground knows about the thick rhizomes! The natural form of this plant is solid green, but horticulturalists have bred this plant to be variegated, which has allowed this plant to become an attractive garden plant, especially for moist garden areas. Despite thriving in boggy areas it is also incredibly drought-tolerant once established, and has also been suggested as a good phytoremediator since it can sequester contaminants from the soil.

The reed canarygrass has also been suggested as a possible candidate for burning as biofuel, since it is so fast-growing. It has recently been used in trials of contaminated soil rehabilitation mimicking the Chernobyl or Fukushima nuclear disasters, to experiment with different plants that can be used to clear contaminants out of the soil. This plant, along with the common sunflower and a few other garden plants, have actually shown great promise. One of the neat things about plants is that they can be genetically manipulated to store radioactive waste in specific parts of its plant body while not in others. This means that, theoretically, you could get a sunflower plant to store radioactivity in its leaves that you could harvest and dispose of safely, while you could also harvest the seeds to be used for food, grain, or for oil production. Since the radioactive waste wouldn't ever make it to the seed, the seed would be perfectly safe for human consumption. I'm not sure how many of us would knowingly eat "Fukushima sunflower seeds" at a baseball game, but it's a neat idea. Still many, many years away from being a viable ecological treatment since so much safety testing must be done. By the time it was approved, I'm sure there would be other ways of remediating the soil that would be favoured instead.

This plant contains incredibly high concentrations of the chemical gramine, which causes brain damage and death in sheep who consume it. This effect isn't always translated to humans, but still probably a good idea to make sure this plant is always out of reach of children and beloved pets. Levels of hordenine have also been reported (a chemical present in high concentrations in germinating barley seeds, but denatured at the high temperatures used in malt production, for those of you who make beer in a home-brew), which act as a central nervous system stimulant by increasing heart rate and blood pressure. This effect is most strongly noted in horses, and the effect appears to subside after 30 minutes (although, it's hard to ask a horse how they're feeling and understand the resulting "speech"). Again, probably a good reason to keep this plant away from small children and pets.

No matter how you pronounce it: the zebra that's a grass

Species name: Miscanthus sinensis

Common name: zebra grass

Location: Ontario

I mentioned in a previous blog post about the tufted hair-grass, Deschampsia cespitosa, that there was essentially only a couple other very easily identifiable grasses without the use of a microscope, and this is one of them! Zebra grass is a grass species native to Asia that has the potential to become incredibly invasive in North America. Thankfully, there are many modern cultivars that do not produce viable seed, so this possibility has been reduced. The plant can still reproduce asexually through the use of rhizomes, but this mostly helps to "fill out" a patch, as opposed to spreading underground to a new location. That being said, I have seen some zebra grass in roadside ditches around southwestern Ontario (with the striped foliage, it's hard to miss!), so some has still very clearly (and very successfully) escaped. With a little background knowledge about this plant before you landscape with it, the chances of zebra grass escaping and becoming an invasive species is slim. This is definitely one plant where gardener responsibility is key: if you remove the plant from your back yard make sure you dispose of it properly, and make sure you plant a hybrid cultivar.

Other than ornamental value, it currently has no other uses. It is, however, being examined as a possible candidate for bioenergy (either through fermentation of the leaves to produce ethanol or burning the plants to produce combustion energy) due to the fact that it is extremely fast-growing during the growing season. It would rival sugarcane as an energy source (sugarcane currently accounts for up to 80% of Brazil's energy production annually in some areas, up to 50% of the energy produced for large cities. The Olympics in 2016 will run exclusively on sugarcane!) for temperate areas where it thrives. It also is not as destructive on an ecosystem like corn (so an attractive alternative for corn-based ethanol) and has much higher levels of genetic variation than typical crops so you don't have to worry as much about pathogens wiping out the entire crop in a growing season.

A word of caution about this grass: while it might not seem that way at first, the edges of the grass have saw-like projections which can seriously harm human skin if grabbed the wrong way. I was weeding in the garden and found this out the hard way. If you've got this grass easily accessible to a small child, make sure you put a fence around it until the child is no longer tempted to grab at the attractive leaves. If not, you might end up being the single reason why Band-Aid is still in business!