Tree Mystery

Gary sent in this one – www.independent.co.uk/news/science/tree-structure-mystery-china-scientis… … scientists baffled by prehistoric tree over 300 million years old. They have a more complex structure than trees in the modern world. See also https://phys.org/print427986102.html … a well preserved fossil tree trunk dating back 374 million years ago, found in Xingjiang in NW China, has a surprising structure we are told. Inmodern trees straw like woody strands known as xylem which take water from the roots to the leaves. New xylem produces growth rings in trunks and branches. In the early tree xylem was confined to the outer 5cm of the trunk and the middle was hollow. The strands were interconnected like a finely tuned network of water pipes and each xylem strand generated its own growth ring – each strand behaving like an individual tree. As the strands expanded connections between them broke apart and the diameter of the trunk widened. Why are the oldest trees the most complicatedf? Nature has learnt to be more efficient I suppose. See also www.pnas.org/cgi/doi/10.1073/pnas.1708241114 (provided by Cardiff University).