Great demonstration - and I'm hoping someone can answer a question that has been on my mind for several years regarding pruning tomatoes: since tomatoes rely on their leaves to feed the whole plant, and therefore, I presume, help with fruit development, too, is it counterproductive to prune as severely as the video shows in short-season zones, say USDA Zone 4 or colder. My thinking is that in a warm season you can prune back the plants pretty hard and use the long season to reap the benefits but in a short season is there a risk that too much pruning will reduce fruit production because the frost will arrive too soon and the benefit of pruning will be lost to the cold? In other words, in short seasons is it better to do only limited pruning because the plant needs all the leaves it can get to feed the process of making 'maters in the relatively short time available?