THE LIVING WOOD FIBRES OF TAMARIX APHYLLA AND THE CHANGES OCCURRING IN THEM IN TRANSITION FROM SAPWOOD TO HEARTWOOD

S ummary The viability of the fibres of Tamarix aphylla has been examined by various methods. It has been concluded that the wood fibres retain their living protoplasts for the same period as the wood parenchyma and ray cells, i.e. 16–21 years. The first structures to disappear from the fibres, parenchyma and ray cells were the starch grains (seventh to thirteenth growth ring, as counted from the cambium). The fourteenth to eighteenth growth rings were the last to show positive tetrazolium tests. In the last step before final heartwood production (sixteenth to twenty‐first growth ring), the disintegration of the nuclei occurred.