The tree is thought to be several hundred years old and has provided shade for generations of visitors to the picturesque lake about 20 km inland of Hokitika.
Tim Shaw, DOC's Acting Hokitika District Operations Manager says: "It is very sad to have to remove this much-loved landmark, however its poor condition and position central to one of our most visited locations means it is simply too high a risk to the public."
"Although the canopy of the tree appears healthy there is a large central hollow and large areas of rot visible at its base," Tim says.
"We have completed our assessment of the tree and it has been classed as hazardous - basically not enough healthy holding wood in the trunk to give us sufficient confidence in its stability. Given the high public use of the area, the consequence of the tree failing could be catastrophic.
In the summer months the Hans Bay picnic area hosts hundreds of visitors each day. These numbers swell during powerboat, wakeboarding, water-skiing and triathlon events held at the lake. On hot summer days the tree draws people to its shade. Hans Bay Road is within the fall zone of the tree.
The tree will be felled within the next few weeks by DOC staff to take advantage of the quiet time of the year and when birds are not nesting.
The operation itself will be done over the course of two to three days. Traffic control will be in place for the felling, and the part of the picnic area affected will be cordoned off for the duration of the clean up.
DOC will work with the local community on ideas for planting replacement trees in the picnic area.
