Variation in the Lignin laid down by Eucalyptus regnans at Different Stages of Growth

Abstract

THE spectrum of softwood lignin shows an absorption maximum at about 280 mµ¹; this is at the same position for various lignin preparations and for calcium lignosulphonates². Hardwood lignin shows an absorption peak at 275 mµ¹, which is the same as that shown by lignin extracted from the wood of a ten-year old specimen of Eucalyptus regnans with methanol at 150° C.³. We have recently observed that the absorption maximum for lignin prepared by the same method from extractive-free wood from the outer growth rings of heartwood of trees 30–100 years old was at an even shorter wavelength, usually below 270 mµ. The spectra of lignins from tension wood from immature trees of E. regnans and E. goniocalyx also showed maxima in the range 267–272 mµ.