I wonder what the lifespan is on those large tree trunk poles; however, they will certainly give the aviary an impressive height. Opole appears to be a very good zoo, with many natural-looking exhibits.
The same kind of poles being on the gibbon islands about 15 years and I don’t think these were exchanged. Maybe they are something preserved.
Until 1997 it was average local zoo and in this year there was a great flood. Zoo was destroyed, many animals died (like yesterday in Tbilisi). After this zoo has been completely rebuilt and today it is most natural and the most pleasant zoo in Poland.