Correlation of carbon isotope ratios in the cellulose and wood extractives of Douglas-fir

Abstract

Cellulose is usually isolated from the other components of plant material for analysis of carbon stable isotope ratios ( δ 13C). However, many studies have shown a strong correlation between whole-wood and cellulose δ 13C values, prompting debate about the necessity of cellulose extraction for tree-ring studies. The δ 13C values were measured in whole wood, extractive-free wood, purified cellulose, acetone/water-soluble extractives and hot water-soluble extractives of Douglas-fir sapwood. Cellulose and acetone/water-soluble extractives from heartwood from the same trees also were compared. Although the various materials showed different absolute δ 13C values, the components of the same samples, including the extractives, were correlated. The correlations of carbon isotope ratios of cellulose, extractive-free wood and extractives, and the relatively low concentration of the extractives in the wood, suggests that extraction of purified cellulose from Douglas-fir wood samples may not be necessary for some tree-ring analyses.