There are no sandworms on Eco yet. But who knows, it's modable... As for deforestation, each plant has various parameters attached to where it can grow. Change these parameters by ruining the world around you you could create circumstances were it's possible. A much easier way to prevent/limit self-reforestation is to only use the logs and leave the site full of pulp and a stump. At the moment desert is a biome like in MC.