We laid cumaro decking 3 years ago and there was no particular scent at all. When sawing them (they are haaaarrrd....), a scent of resin or sap appeared but it disappeared after a minute.
But I have three experiences to share:
- The surface on ours was a bit splintery, I've gotten splinters in both my hands and feet. The splinters are rock-hard, like needles. Can probably be remedied with a floor sander.
- Cumaro requires recurring oiling to age nicely.
- I screwed from underneath. Must be pre-drilled, the screws break before they're even halfway otherwise.
/Joakim