How Much of a Tree is Actually Living Tissue?

Why Non-living Tree Cells are Important

Understanding Living Tree Cells

Only 1% of a typical mature tree when dormant is actually is biologically living while the rest is composed of non-living, structural wood cells. Very little of a tree's woody volume is composed of "living, metabolizing" tissue. The major living and growing portions of a tree are leaves, buds, roots and a thin film or skin of cells just under the bark called the cambium.

There are other living cells in root tips, the apical meristem, leaf and flower buds that are totally important for tree growth but are a very small percentage of the total living volume of a tree's cells. These living cells do most of the nursing by feeding, breathing, breeding and growing the tree. However, a tree can not do it without the structural support of viable but "dead" cells.

Interestingly enough, trees start out in life as a germinating seed with every living cell in hyperdrive.  As a tree seed becomes a seedling, and then a sapling, and then a mature tree, it's living contents become less and less as a percentage of total volume. So trees increasingly lose their living cytoplasmic cells and metabolism ceases in that cell. They are no longer alive but now provide protective, transport and physical support.

For a fuller understanding of how a tree continues to thrive:

    Understanding Sound Non-living Tree Cells

    The large, non-living portion of a tree does the heavy lifting and is very important structurally to the tree. Also, a tree's bark cover is essential in protecting thin living cell layers underneath.

    This supporting and protective wood is created by cambial-hardened wood cells produced on the inner and outer cambial layer.

    Sandwiched between the outer cambial layer and the bark is the ongoing process of creating sieve tubes which transport water and nutrient food both from leaves to roots and back.

    The sound, non-living cells of a tree are very important to helping a tree protected from attacking pests like insects and disease. Compromising these bark and structural cells will introduce pathogens and other pests and environmental damage into the vulnerable living tissues that maintain life.

    To be more precise, future dead tree cells have the responsibility of transporting nutrients both to the leaves and sugars made by the photosynthetic leaf and then back to the growth of parts that determine a tree's healthy future.

    Learn more about a tree and it's parts.

    Angel Oak on John's Island, South Carolina - Photo by Steve Nix, Licensed to About.com