Four people died Saturday when a small plane crashed shortly after taking off from a private runway in a heavily forested area near Eugene, Ore.

The Lane County Sheriff's Office said the airplane started dropping soon after liftoff, then hit a tall tree, which tore a wing off the plane and made it plummet. The aircraft came to a crash landing, ending up upside down on the ground around 3:10 p.m., the Lane County Sheriff's Office and Fire Department said, according to MSNBC.

All four people on board the plane -- a single-engine Cessna -- were found dead inside its wreckage just west of the city of Eugene, fire personnel told MSNBC.

It's going to take heavy tools to get them out of there, Lane County District No. 1 Fire Chief Terry Ney said, according the Eugene Register-Guard.

The small plane for whatever reason didn't clear the woods, Ney said.

The victims' names and other information are being withheld by authorities until their families can be notified of their deaths, MSNBC reported. The National Transportation Safety Board is investigating what caused the crash near the private airstrip, which is most likely one nearby owned by Conrad Magnuson and known as Crow-Mag Airport, according to the Register-Guard.

The Lane County Fair takes place each July on a slice of land near the airport, so there is some speculation that the victims may have links to the fair.