A Little Bit More
It’s important to understand that much of a tree’s bulk is made up of non-living tissue. The cambium layer (greenish layer just beneath the bark) is the portion of a tree that is alive and growing. Over time as a tree grows, the cambium layer on the trunk migrates farther and farther from the center of the tree leaving behind wood. The woody interior of the tree is the portion that the fungi are using for food and in the process, cause decay. Conks don’t kill a tree, but can undermine its structure over time.
Fungal conk spores that find their way into wounds on a tree, germinate and begin growth there. As the fungus grows, it’s able to cause decay within the tree. Once the fungus is mature enough and conditions are right, the fungus produces fruiting bodies at the exterior of the trunk and these are what you see as conks. Conks produce enormous numbers of spores (some apparently produce billions of tiny spores) that are carried on the wind to other potential sources of growth and development.
If you want to impress your friends and relatives, a little knowledge about conks can do just that! Conks grow from the bark of a tree in a very particular way. The portion of the structure that releases the spores always points toward the ground. As you can see on the poster, the flat, underside of the conk (this is where the spores exit) is pointing downward. Tree trunks on the ground can acquire conks AFTER they fall. When they do, these conks are oriented downward as well but are not aligned to the trunk as those conks that formed while the tree was still standing. In other words, if the conks are oriented downward to where the original roots were, they were there BEFORE the tree fell. If they’re oriented on the side of the trunk, they began growth AFTER the trunk fell.
Activities
Science – Conk Hunt
Objectives: Get a good look at some actual conks
Materials: Careful look at trees in the area
This might be a good opportunity to have your students look around where they live to see if they can find any conks. If any are found, their removal won’t hurt the trees nor the fungus itself so no damage should occur.
Students can bring in what they’ve found to share with the class. If the tree/trunk they’ve found conks growing on is a dead one, they may be able to bring in a slab of the bark with the conk attached. If not, they can simply gently pull or cut the conk away from the tree.
Be sure to look at the underside of the conk and you’ll see the pores from which the spores are released. In most cases, the conk will already have released its spores but if not, you may get some puffs of “smoke” when the conk is tapped. This will demonstrate just how small the spores are and make it a bit easier for students to understand how spores can be transported on air currents to distant areas.
Key Concepts
Food Webs /Food Pyramids, Growth and Development, Identification, Life Cycles, Structures and Functions
Questions
Do you have a question for a naturalist? Go ahead and ask!
It's easy -- just fill out this form, submit your question and you'll receive an answer shortly.