Asked by: Anonymous
Trees that produce thick resin, instead of runny sap, need much wider phloem vessels (vein-like structures) to transport it along the trunk. This leaves less space for the cellulose and lignin that provide the strength of the wood. In Northern Europe, evergreen conifers are softwood and so the term is used for all evergreen conifers, even though lots of tropical ‘softwood’ conifers actually have quite hard wood.
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