Green wood = cresote buildup and dripping in a wood stove. The greener the wood = faster buildup.
There are some cities which do not allow burning wood which has a moisture content greater than (left up to the city). In some locations it is against the law to sell firewood with a moisture content greater than (left up to the city).
I've burned green wood in the past and ended up with a gummy buildup in the flue and underside of the raincap.
Nosmo