Looking for some hands-on, creative fun? Head to the Family Tent, 5:30 – 7 pm, to help the creative team behind the signature New Year’s Eve Parade presented by Giant Eagle before it steps off at 8 pm. Teaching artist Alison Babusci and others will show you how to create parade ribbon wands. Afterwards, you can join the parade and march along Penn Avenue through the Cultural District!
Fall is the perfect time to watch the foliage around us explode in color. Deep reds, bright yellows and cozy oranges shimmer in the wind for just a few weeks before the branches are once again bare and the cold weather ensues.
But why do leaves change color in the fall, and while we’re at it, why do they fall off their trees at all?
Why do leaves change color and fall?
What leaves do for a tree
In a nutshell,leaves make food for the plant they are attached to, whether that be a tree, a shrub or a flower. Leaves are connected to its plant through a vascular system that carries these nutrients around the plant, similar to how our human vascular system carries blood around our body. They do this all through a process called photosynthesis, a system you probably remember learning about way back in middle school.
During the warmer months that make up spring and summer, leaves work constantly to convert sunlight into nutrients for the plant. Chlorophyll, the chemical that gives leaves that green color, absorbs light energy and contains it in the leaf, which then interacts with the natural enzymes found in plant cells found in the leaf. That reaction between the light energy and the enzymes helps to break down the chemical components in the water (supplied to the plant from the roots), breaking it down into oxygen and hydrogen.
The hydrogen reacts with the carbon dioxide found in the plant enzymes to create a form of sugar, and that sugar is what’s funneled through the plant’s vascular system to provide the nutrients the tree needs to grow. Any remaining oxygen is released through miniscule pores found on the leaf’s surface.
Interestingly enough, leaves don’t just fall off with a strong breeze or a cold wind; the trees actually shove the leaves off! If anything, this season should be called “Push” rather than “Fall,” if we want to be scientifically accurate. But anyway…
If we think of leaves as solar-powered cooks, then during the summer months these tiny cooks are working all day every day to make the most of that bright sunlight, all the while depositing an abundance of food and nutrients into the plant. It’s a great system, and those leaves make it well-worth the effort of keeping them around full-time.
In the colder months, though, the days are much shorter and the sun is not nearly as direct. The quality and quantity of sunlight decreases with each passing day, and the tree has to decide if it wants to keep its staff of full-time chefs all winter long, or if it wants a break. It takes a lot of nutrients to keep leaves alive, and if the leaves themselves aren’t able to make a lot of nutrients in the first place, then the tree can be quickly sapped of its reserve. Plus, if the water in those leaves gets cold enough to freeze, then the leaves could die completely and damage the tree’s vascular system.
The process by which trees drop their leaves is a fascinating one, and it all starts with the decreasing sunlight.
Hormones inside the leaves can sense when there is less sunlight and lower temperatures, so those hormones will activate a process called abscission that starts to shut down the production process. This means that the chlorophyll stops working, changing the leaf’s color back to its natural state ofyellow, orange or red (yes, leaves are not naturally green!). It also means that tiny cells begin building a wall between the leaf and the twig it’s attached to, slowly cutting off the flow of nutrients and water from the leaf.
These abscission cells eventually grow thick enough that the leaf is shoved completely off the twig with just the slightest of breezes, falling to the ground in that magnificent display that we just love to watch. And, because those cells formed such a thick wall, there is no open wound on the branch where the twig was, and the scab of plant cells keeps the twig protected all through winter as the tree lies dormant.
This process is purely self-preservation, and we see this happening in other adverse conditions, too. When faced with a particularly horrific drought, the tree may cut off nutrients to leaves or branches in order to strengthen the more vital parts of the tree. The tree will reactivate these dormant pieces when there are enough nutrients available, and the process starts all over again!
Food for spring
Wading through a forest full of fallen leaves can feel like trudging through snow, as there are just so manyleaves! Yet when we return in spring, those blankets of leaves are gone! Where do they go?
Webs of fungus called mycelium send tiny strands of hyphae into organic matter around them, where those hyphae secrete enzymes that break down the chemical structure of the fallen leaves. The nutrients extracted from those leaves are transported through the mycelium to the trees and plants all around it, feeding and strengthening the forest through this massive underground web.
Finally, small critters and bacteria eat through the remaining leaves, breaking down the physical structure and secreting even more nutrients into the soil via their waste.
In the end, all the nutrients stored in those bright green leaves returned right back to the ground, where they will feed the tree yet again come spring. Then, the cycle continues once again.
Fall is a magical time for many reasons, but seeing how this brief interval of time can so drastically affect the livelihoods of deciduous trees makes it all the more fascinating.
Enjoy the beauty of the changing color of the leaves. Take a short rode from your home at http://www.starloftspgh.com to the Laurel Highlands this weekend.
After many long months, the streets of the Cultural District will again be bustling, the theaters and galleries will be full, and arts lovers from around the region and beyond will share experiences, live and in person. Lights On! A Three-Day Celebration of Pittsburgh’s Cultural District marks this special occasion with more than 50 free outdoor performances, exhibitions, and more presented by your favorite Cultural District organizations, right next to your home at http://www.starloftspgh.com!
The Liberty Magic team is excited to announce that mystery and wonder will return to Liberty Magic for the 2021-2022 season. They are elated to open our doors and welcome you back to the Cultural District. The unique close-up magic experiences of Liberty Magic are not possible without our valued audience members. Season subscriptions are now on-sale. Consider becoming a subscriber, so you don’t miss a moment of the wit and wonderment.
After many months, the streets of the Cultural District will again be bustling, the theaters and galleries will be full, and arts lovers from around the region and beyond will share experiences, live and in-person. Lights On! A Three-Day Celebration of Pittsburgh’s Cultural District marks this special occasion with free outdoor performances, gallery exhibitions, and more, September 9-11, 2021.
10 ounces Bartolotti beans, drained and cooked with a pinch of bicarhonate 8 oz. cleaned tiny mollusks; baby Octopus, baby squid, curled octopus, mussels and tartufo (warty venus) 3-1/2-5 oz. lobster bisque 1/4 cup white wine 1/4 cup olive oil 2 oz. smoked pancetta bacon Salt and chilli pepper 2 cloves garlic 1/2 onion, thinly sliced 5 0z. tomato pulp Aromatic herbs: parsley, etc.
7 oz. fettuccine-type pasta cut in small, irregular pieces Cook the beans. Sauté in oil the cloves or garlic, onion, chilli pepper and smoked bacon. Remove the garlic when brown. Add the tomato pulp and the mollusks, which have been previously cleaned and prepared. When the cooking is completed, mix beans, mollusks (plus the cooking liquid) and pasta (which may be cooked separately or together with the rest). Add the lobster bisque, which will provide a good base and mix all the ingredients together. Sprinkle with parsley and serve.
In a large bowl or pan, soak the clams in lightly salted water for at least 2 hours; every 30 minutes, use your hands to gently drain them without stirring up any sand that has filtered out; transfer them to a plate, change the water, which will have become cloudy, and add a pinch of salt. Be careful not to break the shells during this process.
Trim the parsley, removing only the leaves; wash and dry with a paper towel and finely chop. Crush and mince 1 garlic clove.
Bring water to a boil in a large pot. Season with salt; add spaghetti and cook, stirring occasionally, until about 2 minutes before al dente. Reserve 1 cup pasta cooking water.
Meanwhile, in a pan large enough to hold the clams and spaghetti, sauté the garlic with 4 Tbsp. oil for 30 seconds, then add the parsley.
After a few seconds, add the drained clams: cook them for 1-2 minutes until they start to open, then add 3 small ladlefuls of pasta cooking water.
Drain the spaghetti and transfer to the pan with the clams. Cook together for 1 minute, adding extra water pasta cooking water if needed. Cook until the pasta is al dente and a dense sauce forms due to the starch being released from the clams. Top with chopped parsley to taste and serve.
The public art exhibition curated by Tereneh Idia features the work of 11 artists of color, found in nine locations throughout the Cultural District.
At 707 Penn Ave., right next to the StarloftPgh, guests can check the time — through rap lyrics. Steven Montinar’s installation, “Flava Flav’s Digital Clock,” uses 142 distinct lyrics in which capitalized letters spell out the time of day.