Two Pinus aristata samples submitted by C W Ferguson were separated in different fractions, as was done earlier with Pinus silvestris L from Sweden, to yield different fractions for studies of the pretreatment. One sample in this new series consisted of heartwood and the second of sapwood.
The treatment performed in the radiocarbon laboratory involved an acid treatment by boiling, washings, an hydroxide treatment at 80°C, washings and, finally, another acid treatment before being dried before the combustion. The sodium-hydroxide treatment was repeated to yield at least two soluble and two insoluble fractions.
The treatment performed by the wood chemists involved extractions with ethanol-benzene and water. The remaining wood was dated but was also used for the production of holocellulose. The extractives were partitioned between ethyl ether and water and that from the older wood was used for the isolation of neutrals, acids, and phenols. In all, 19 fractions of these two wood samples were dated.
It is confirmed that a treatment for 30 min in sodium hydroxide at 80°C is not sufficient to remove the extractives from the heartwood or the sapwood. A treatment at 80°C overnight with 1 percent NaOH yielded a sample from the older wood with a 14C content in good agreement with the results predicted from the curve presented by Stuiver (1978). The final statistical uncertainty in the present investigation was ca 4‰. The younger wood yielded results indicating a lower activity than that given by Stuiver.