Would you beable to rent a lot and sell the trees directly? Still offer the online service because maybe you can order a tree online after they see you in lot, or they can still have it delivered. But renting a lot isnt very expensive and it would give people the option to both buy the tree onsite and off site, if marketed correctly I actually know a person who made about 15,000 dollars profit last year doing this. He said he would have made more but gave away some of his trees to the less fortunate because the christmas spirit cursed him. Online can also use as a marketing tool for your onsite location which can help advertise...think thats the only viable way.