From the latest Evergreen newsletter, via DNR, it looks like some timber work will be closing some trails on the weekdays, but weekends will be unaffected:
The Tiger Summit Trailhead (upper lot to most folks), Iverson RR Trail, Connector Trail (between NW Timber and the Trailhead, and #1000 (West Side) Rd. will be closed weekdays due to a timber sale. Closures have started and are anticipated through mid-September
They also offer an alternate route if you do ride during the weekdays:
During the week, go what is for most the normal route and climb the #4000 (Main Tiger Rd.) to access Preston, E Tiger Summit, and NW Timber trails.