TREEN means literally “made of tree” i.e. wooden. This usage survives in the word ‘treenail’, a hardwood pin used to fasten other timbers together - most usually now in shipbuilding but also in some building joinery. Treen nowadays tends to mean anything made of wood which cannot be easily classified as furniture, or joinery, etc.
What for example is in the dish? Not cabinet making. Not carpentry. Just a load of balls! Treen in fact.
Much of my turning used GREEN or un-seasoned, wet timber. Some was so wet that the resulting bowls, when first turned, were still heavier than water. Bowls turned green change shape and distort as they dry. Having started round they end up more or less oval when dry. For more details on the whole sorry saga and a step by step guide on ‘How To Turn A Bowl From Green Wood’ see ‘What Became of Kilvert's Pips’. And if you think it is a load of rubbish you are not alone! However, all my inscribed sycamore dishes are made from dry timber.