I have no idea, to tell you the truth. It is not often that new enclosures are created in this animal park. In many ways it is pretty much the same as it was when I was a kid in the 1960s (very good then - very good now!). I have been to it three times during the last 7 or 8 years, but before that I had not visited it since about 1979/1980. And I don´t remember if this enclosure was built then.
Hey Blackduiker, I got the answer today from the park that both this enclosure in the picture and the smaller one (shown in other pictures in the gallery) were built at the same time: 1952.
This surprises me, I thought the bigger one were built later, but apparently this is not the case. So that means that it is 57 years old.
Actually, the park is trying to raise funds to replace both enclosures with bigger and better ones.
(Borås Zoo, also in Sweden, has just started building a new, 3 acre, enclosure for their brown bears.)