Rounded | Tree Rings

The bark that once protected this tree from animals and insect pests no longer clings as a secure barrier. The center rings, the heartwood, that hardened to keep this tree growing tall and strong have failed. New layers of wood, the sapwood, cease to grow and nourish this tree. Rounded rings no longer accumulate to tell the the age of the tree.

Downed on the ground, a log cut is decorated with rounded species of mushrooms. Fungus breaks down trees after they die. The species of fungi change as they decompose the wood. Pioneer fungus may go after the easy sugar in the log, while later species unlock the energy in the tougher tissues, like lignin and cellulose. Which particular pioneer starts to feed on a log first can make it inviting to certain species but not to others.

Scientists in Sweden have discovered that the fascinating process of tree decay is not limited to the surface of the log. Samples of wood fiber were rounded up by drilling into decaying spruce logs. They were examined in the lab. In one log, the DNA of up to 398 species of fungi were found. Although not all the logs studied contained this vast number of fungi species, the research helped scientists observe patterns of fungal communities among and within decaying logs.


  1. What Lurks in Logs- link checked 02-18-2021, no longer valid

Weekly Photo Challenge: October 25, 2017 | “Rounded

4 thoughts on “Rounded | Tree Rings

  1. I’m beginning to pay more attention to fungi. My daughter lives along the Oregon Coast and has become quite a successful mushroom hunter. I’m learning a lot from her. 😉

  2. I like to look at fungi and photograph… but, I’m definately not one who will eat mushrooms!!

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