Spruce degradation process

There is no distinct degradation front in spruce. The process starts in individual cells. Most tracheids are broken down within a range of several annual rings (Figure 35). For a very long time the parenchymateous cells of the resin ducts survive unchanged, and so do the ray cells. 

The results of these studies indicate that a definite amount of the lignin fraction of either aspen or spruce may be removed from the original lignin substance anu degraded into smaller units which are chemically stabilized under the reducing conditions of the isolation process. 

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