Chemistry and functionality of stone cells in loblolly pine outer bark periderms

For the southern pines, interlocking stone cells (sclereids) are a fascinating periderm feature comprising only a small fraction of the outer bark (rhytidome), yet contributing greatly to its density/hardness. This study addresses the long-overdue need to carry out wet chemical analyses on periderm and obliterated phloem layers, the former herein limited to the stone cells. Extractives distributions by polarity were similar between loblolly pine ( Pinus taeda L.) periderm and wood samples; the total extractives content of the obliterated phloem was threefold higher. The claim that stone cells are highly lignified held true, with lignin contents that were 20 % higher than those for the wood.