Please, be sure you have Max 2017 updated to the latest update.
This problem has been reported in other Max versions, and was caused by a bug which is fixed in recent service packs:https://knowledge.autodesk.com/sites/default/files/file_downloads/3dsMax2017_SP2_Readme.htmMAXX-30316 Slow node creation / modifier application in complex scene
We cannot reproduce the problem here (Max 2017 SP3 + Hotfix 1).
There is a delay of of 5-8 sec. with some events (not 2 min.), because the Forest object must be rebuilt. That's normal because there are 2.7 mill. of scattered items:
Please note that using Interactive Render, Forest is computing the number total of items for render, not for viewport. So the performance hit may be significative.
But the 2 min. delay probably is caused by the bug described above.