Would it surprise you to learn that only about one percent of a dormant mature tree is biologically living? It did me! What I discovered was that the other 99 percent of the tree is actually composed of non-living, structural wood cells. That means that very little of the tree's woody volume is composed of 'living, metabolizing tissue.' The roots, leaves, buds, and a thin film (or skin) of cells called cambium found just under the bark, is really all that's 'alive" in any tree.
There are, however, other living cells which are are important to tree growth and are found in other parts of the tree; root tips (apical meristem) and leaf or flower buds. But these make up a very small percentage of the tree's volume of cells. Non-living or dead cells comprise the largest volume of the tree. These dead cells provide structural support for the living cells.
Trees start out their early life as a germinating seed with every living cell going into hyperdrive! As the seed becomes a seedling, then a sapling, then a mature tree, its living contents shrink as the main percentage of the total volume of the tree. "Trees increasingly lose their living cytoplasmic cells as metabolism ceases in each cell, and although they are no longer alive, these non-living cells now provide protection, transportation, and physical support for the living ones."
But the dead cells in the tree still provide a vital role. Without the support and structure provided by the non-living cells, trees would likely die and certainly wouldn't grow as large as they do. Those dead cells are vitally important for the tree in the whole process of how it grows. This includes the "heavy lifting" of holding up all the trees branches and the bark which protects the thin layer of living cells underneath. The bark of a tree is an ongoing process of creating sieve tubes to transport water and nutrients from the leaves to the roots and back.
New cells are formed and living cells cease metabolization as they transform into "transport vessels and protective skin," thus creating a cycle of creation, rapid growth, slowing metabolism, and death as the tree reaches upward and grows into a healthy, full plant.
Wood is only considered dead when it is separated from the tree itself because it still serves a vital role in the plant's life as long as it is attached to living cells within the tree. So even though wood is largely made up of non-living cells, it isn't considered dead until the branch falls off or it cut down by a human.
Trees are wonderful. As the largest plants on earth, they provide us with shade and cooling winds. They provide oxygen, store carbon, stabilize the soil, and provide a home to many forms of wildlife. They also provide humans with tools and shelter. While I may not be a tree frog, I can still appreciate the beauty and majesty of trees. Not only are trees essential for life, but as the longest living species on earth, they give us a link between the past, present, and future. Even if they do, on occasion, eat a kite.
Until tomorrow, I wish you