Yes, interesting indeed. As an educator I am particularly interested in these findings. I would like to think, however, that in schools the situation is improving. The lunatic H&S culture seems to have moderated; teachers were afraid to take children out of the classroom for fear of litigation, in fact my union actually advised us not to take any extra-mural trips. The ongoing issue seems to be the results driven assessments of schools. You cannot measure the benefits of introducing children to the natural world empirically; school league tables are interested in test results. School leaders struggle to justify time and investment in getting children outside.
At my school I am very lucky. We have a programme that starts with 4 year olds going on "Teddy Bears' Picnics" leading to DofE Gold Awards to 18 year olds. We have a 14 acre patch of ancient thicket adjacent to the school owned by the National Trust. Despite this, and my own interests in getting out, we find it very difficult to get the children out as much as we would like. It's not the time required for the trips that we lack, it's planning, risk assessing and training time that we're short of.