its 183 celcius and for cellulose it is 230 so at 230 the plant material will burn but at 180 the thc will start to vaporize
to preserve the thc u need to know the enemy of thc and that is ligth and air and high temperatur so the best u can do is keep it dark and airtight and to really presereve for years u can even freeze it
as for trim fresh or dry well in most cases u get more yield with the dry trim but u get more plant material in ur hash since the dry plant is more britel and brake into small pices more easy ,when u use wet trim u get more pure hash but less since the filte can clog up a bit plus the crystal tend to brake more easy and get smeard all over the trim in this case i make butter with it afterwards
K.I.C.C
proud member of JO.int since 1998