Our second floor has these nifty portholes (shaped just like a ship's portholes) that we can open to create a crossdraft. Of course, said crossdraft works a lot better when the leaves are in and the air is cooler. I have kind of a conflict going on about that. On the one hand you really don't want trees too close to the house (especially if you have a wood stove), because their roots can damage foundations, branches can damage the roof, and bugs use them as handy bridges into the house. Not to mention the fact that a spark from the wood stove could set dry leaves on fire in winter. The same goes for nice, cooling vines that would look so nice on the walls - can't have them, since they're conduits for termites and carpenter ants. On the other hand, there is no better climate control than a nice big tree or a big vine on a trellis. Mer.