Bark: Tree Following, April 2016
|This is my last month following my red maple (Acer rubrum). The tree has begun to flower, which is where I began last May (see Following a Tree); but my focus this month is not on the flowers, but on the bark.
One way to think of bark is as the tree’s outer skin, a layer of protection that provides insulation from cold or heat, deters insects, keeps moisture in and also keeps diseases and infections out. As the diagram below (from Forest Trees of Maine, Maine Forest Service, 2008, p. 21) shows, what we usually think of as the bark is actually the outer bark and is made up of dead cells called “cork.” Beneath the outer bark is a layer of living cells (the inner bark) that are part of the tree’s vascular system. Known as phloem, these cells transport food created through the process of photosynthesis to other parts of the plant.
|Forest Trees of Maine is the textbook for a course on Maine trees that I am currently taking at my local Senior College. One of my goals for the course is to learn how to identify trees by their bark. (This would be especially helpful during our long winter when deciduous trees have no leaves and when I often have trouble telling them apart).
Bark may be smooth or textured, and smooth bark may have prominent breathing pores (lenticels) or not. The variety of bark textures is dizzying. One web page on tree bark from UCLA includes the following descriptors for bark texture: scaly, fissured, peeling, cracked, and furrowed. I’ve also seen descriptions of bark as “shaggy;” and Forest Trees of Maine describes the bark of mature red maple (pictured here) as “ridged and broken into plate-like scales” (p. 73).
The outer bark of a tree may be made up of dead cells, but that does not mean it is devoid of life. On the contrary, bark can provide habitat for other plants.
|At the base of this tree, the bark is providing a home for mosses,|
|…and several different types of lichen are growing on the trunk.
Getting to know this red maple tree over the past year as part of the tree-following meme graciously hosted by Pat English at Squirrel Basket has helped me to appreciate what marvelous plants trees are.
Next month, I will choose a new tree and get to know it by following it for a year.