Stanley Kohl said it's a mystery he can't solve. Why would thieves steal his tree farm signs?

"It just can't figure out a reason why anyone would be doing it. I don't know why," said Kohl, owner of Kohl's Stony Hill Tree Farm.

Police said about 20 advertising and directional signs belonging to Kohl's Stony Hill Tree Farm, near Milton were stolen on Monday. Two others were also damaged.

The signs were taken from the Milton, Pottsgrove and Danville areas. Kohl said this isn't the first time this has happened. In 2007 and 2008 Kohl said about 80 of his signs were taken as well. The signs cost about $20 each.

"The volume it adds up. It's just frustrating to put my sign up go through all that work and have it gone in a couple hour periods," added Kohl.

Now Kohl is offering a $2,000 reward to help catch the thieves who target his signs.

"I hoping we get the whole valley looking for whoever is doing it and I hope it stops," said Kohl.