Any Unknown or Unlisted Aircraft Manufacturer
Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine; Flight Crew Instrument
Flight Crew Last 90 Days 100; Flight Crew Total 28000; Flight Crew Type 60
Situational Awareness
Aircraft Equipment Problem Less Severe; Inflight Event / Encounter CFTT / CFIT
General None Reported / Taken
Airport
We were cleared for visual approach Runway 21 at FWB.  Our FMS was programmed and engaged on the RNAV(GPS) RWY 21. On the LPV VNAV glide slope; at 2;000 feet MSL; our GPWS [alerted] 'too low terrain; pull up'. We were still VMC with no terrain concerns; and we continued for a normal landing.  I am concerned that the top of the trees may be interfering with the approach clearance area.  Also; taking off from Runway 21; resulted in a momentary GPWS warning when below 500 feet during climb.
Pilot expressed concern that the top of the trees may be interfering with the approach clearance area while flying a visual approach to Runway 21 into FWB; triggering a GPWS terrain warning.