October 28, 2012

Big Trees and Small Parasites

Johnson Woods is a state nature preserve in northeast Ohio that features over 200 acres of old growth forest. On a recent visit we walked among its giant trees on a 1-mile boardwalk, marveling at the huge oaks, hickories, maples and other trees. Many of Johnson Woods' trees are over 400 years old and some reach 120 feet in height.

Here is a Black Gum (Nyssa sylvatica) that added a bit of spicy October color to the green canopy.

Gradually the dominant oaks and hickories are giving way to maples and beech. The American Beech (Fagus grandifolia) is a magnificent tree and I've never seen so many huge ones. It is one of my favorites partly because it is so easy to identify, thanks to its smooth bark:

Most beech trees next to a trail have been decorated in various ways:

Since trees grow in height from the top, Aaron and Marie have only become wider in the past 11 years (they are not alone), and will remain at eye level for the life of the tree.

Beech leaves are simple, slightly toothed, and alternate along the twig. The characteristic sharply pointed buds make winter identification very easy.

Fall color can be quite striking:

I really like the way young beeches retain their leaves into the winter, giving a delicate accent to a view through a forest:

The beech’s seeds are contained in these prickly husks. Each husk has seeds which fit neatly together until the husk dries, opens, and releases the edible seeds or beechnuts. 

Apparently beechnuts have little to do with Beech-Nut gum or baby food. The company was named for the beech trees that grew near the town in New York where it was founded, but the "nut" part comes from the nutty-flavored hams that were its first product.

One of the coolest things about beech trees are the Beechdrops (Epifagus virginiana) that often grow beneath them. These small plants produce no chlorophyll, gaining all their nutrition from the roots of American Beech, thus qualifying as parasites. Without the trees they could not survive.

The Johnson Woods beeches supported the greatest Beechdrop density and largest individual plants that I have ever seen. 

Parasitic plants have modified roots that penetrate the host's vascular tissue, but how does the seed of a parasitic plant know that it is near its host, and how do the developing roots find the host plant? Apparently the host plant exudes chemical signals that are recognized by the seed and that stimulate germination. The developing plant's roots then follow a chemical concentration gradient toward the host. Pretty amazing. 

I have a feeling that I'll be repeating that phrase often in this blog. It is fascinating to consider that despite the fact that plants are immobile, they are able to successfully reproduce, protect themselves, get nutrition, and grow. There is a whole lot going on in the plant world, and we probably don't have a clue about much of it.

Something else to ponder: what are the chances that T.S. still loves L.M.?

1 comment:

  1. I was only at Johnson Wood once, before the leaves had come out. It was nice seeing photos of it when its leafy. The photo of the Black Gum tree was way cool.

    I've got a video of one beech tree covered with little bugs that looked like tiny cotton balls. Someone told me in an email what it was, but I can't remember just now. It's probably something like "Beech Tree Bug." LOL