What big open area? The only open area is the former dig site, as chugh43 said. The trees that the link says are being removed are pretty randomly spread around and are likely for non construction reasons related to their health. Trees have been being removed around the park in that way for years. As for the 'construction' fence, it is the same design the park recently put up around part of The Racer, Firehawk's exit, and the path leading to the picnic grove. Therefore, not really a construction fence. The way I see it there is absolutely no construction for 2019 at the moment.