As leaves change colour and plants prepare for winter, Canadian goldenrod, asters and milkweed are just some of the many highlights of the seasonal changes in the Humber Arboretum, where visitors can explore and learn about the natural environment.
Outdoor education instructor at the Humber Arboretum, Olivia Ypelaar, who gave visitors a guided tour in late October, said that her favourite element of fall is the crunching leaves, that are broken down by footsteps,helping to create nutrient soil.
Ypelaar had many other interesting stories to share the tells of fall to the visits.
She explained the word arboretum, often described as a tree zoo, showcases all plants from around the world.
The oldest maple tree in the arboretum is the 200-year-old grandmother maple that has started to drop her leaves with the changing season.
“Grandmother because we think that she is the matriarch of the sugar maples in this area, she’s very special,” Ypelaar said.
Arboretum staff used to get sap from the grandmother maple to make syrup because sugar maples as well as black maples have the highest sugar level content and produce the best sap for syrup making, she explained.
Within the arboretum is a lone gate that used to be connected to a fence to protect the flowers in the upper region of the garden.
Ypelaar explained that deer used to be able to jump over the fence because it was too short for them and they were getting trapped in the garden so the decision was made to take the fence down. But the gate remains.
The horticulture team at Humber Arboretum decides what plants are placed on the grounds to create a biodiverse space and sometimes that can include invasive species, which concerns the educational team.
Ypelaar said that from an ecological standpoint it is not ideal to have invasive species.
Japanese cultivar is an invasive plant that is in the arboretum.
Ypelaar said that while the plant looks nice in the summer, it is not a good enough reason to have it there.
Stewardship is part of what the arboretum staff should be doing, Ypelaar explained
She said it’s supposed to be a pre-colonial land and removing invasive plants and taking care of the land should be prioritized.
As Ontario’s landscape changed with vibrant fall colours, Ypelaar talked about the mythological history behind the name autumn and seasonal changes that show it
She noted that there is no true term for autumn but said that the Etruscans, a type of Italian tribe before the Romans, had a god called Vertumnus, the god of changing seasons who might be where the name’s origin came from.
As the leaves turned shades of red, orange and yellow Ypelaar said that inside the leaves are tannins.
Rafael Lepra, a retired chemical engineer who joined the arboretum walk with his wife Anabel Baklayan, a retired executive assistant, explained that tannins are a polyphenol compound.
Ypelaar said that tannins are what make natural water a dark colour, they leach out of leaves and are also found in nuts that are in trees.
“Tannins will produce nutrients for the ground and for the soil,” she said.
Ypelaar said this process helps new plants to grow.
Leaving leaves on the ground rather than raking them is good for the environment, she said.
“Leaves are great when it rains or when it’s misty in the morning, they help capture moisture so that plant life can remain healthy, leaves are a great way for the natural ecosystems to reproduce and protect itself over the winter period,” Ypelaar said.
Differences in the colour of leaves have to do with the sugar levels in the trees as well as different pigments, she said.
“Chlorophyll is the pigment that would create all leaves to be green, some leaves have a higher chlorophyll content versus other pigments,” Ypelaar said.
“Once the chlorophyll dies off, or the tree stops producing chlorophyll for the season, those other pigments are allowed to come forward and that’s why we see them,” she said.
Ypelaar said access to light plays a strong role in the green colour of trees, and as days get shorter causing less access to light there is no chlorophyll being produced.
Squirrels were the prominent animal on the walk, she said.
“This time of year is peak squirrel time because they’re rushing around to get all their nuts,” Ypelaar said.
Squirrels hide their nuts in random spots and use their saliva to help them track where they have hidden them, she said.
“Sometimes they don’t remember where they’ve hidden their nuts and they can help plant a tree,” Ypelaar said.
Ypelaar mentioned that Humber Arboretum provides guided nature walks for children participating in their school field trips and staff come up with activities related to topics the schools choose.
“It’s cool to see how the forest changes every day, it’s pretty fast,” she said.
Ypelaar said that in the wintertime, turtles, frogs, fish and other species living in the arboretum’s pond will go under and bury themselves under water which is the warmer part as the surface freezes over.
“They’ll slow their heart rate, doing something called brumation, where they’re kind of asleep, and they make their lungs efficient so they don’t have to take many breaths,” she said.
Ypelaar mentioned that many changes happen in all types of ecosystems, not only in forests with leaves changing but also in ponds.
Fall marks the beginning of the end of the natural cycle, she said.
The arboretum will host a seed saving workshop Thursday, Nov. 12. More information and other events can be found on instagram.com/humberarb/
.png;w=80;h=120;mode=crop)