Chemical Class: MonoTerpenes/Monoterpenoids

Monoterpenes are hydrocarbons with 10 carbon atoms. [Sequiterpenes have 15, di-terpenes 20, tri-terpenes 30 and tetra-terpenes (the carotenes) 40]. Monoterpenoids are monoterpenes with additional atoms beside carbon and hydrogen. In this page they are all mixed up amidst each other. These compounds are very volatile and often smell strongly, the smell being almost always pleasantly. Think turpentine, petrol, peppermint, spearmint, aniseed, camphor, lemon, orange peel, eucalymptos, tree resin, etc; all highly distinctive, but different to each other.

The greatest proportion of monoterpenes (but by no means all) are synthesized within trees, mostly the coniferous variety. It is now known that Formic Acid is a constituent of Acid Rain (besides carbonic-, sulfurous-, sulfuric- and nitric acids), and about 10 times as much natural formic acid is produced annually as was once thought, about 100 million tonnes annually. It has only recently been discovered that the source of this excess formic acid is trees in tropical and northern boreal forests. The trees give off terpene vapours, which are oxidised in the presence of sunlight to formic acid.

However, it seems un-likely that the forests are contributing to their own demise from the formic acid in the acid rain. It is mainly the mineral acid component of acid rain that is leaching aluminium, copper and zinc (toxic metals) from forest soils and poisoning the trees. Of these three toxic metals, copper is the most toxic, browning poplar tree roots at just 50µM concentration, followed by zinc at 500µM and then aluminium at 1000µM.




















































Chemical Class: MonoTerpenes/Monoterpenoids

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