First of all, there's loads of trees in that picture. You'll have to explain which one you want. Second, instantly creating one of these large trees is quite ridiculous. Generating it is not easily possible as far as I know. Your solutions: You could import a map with huge trees that are made on computer for your server. You could download a world edit plugin, and make one tree, then copy paste it over.
but both solution defeat the point, dont they? some people are here because they want to learn (with help of us/or not) again i wont say it is impossible, PC generators have made these so do we could if we really wanted as for how, there not much example existed other than these that existed in PM https://github.com/pmmp/PocketMine-MP/search?utf8=✓&q=tree
Very true. I was being realistic though. I currently am working on adding a large tree generator to my world edit plugin, so I'll have to dive in that.