Here's a good pdf regarding the potential acidity/basicity of pine needles, looks like the guy did his homework. I hope it's ok to post a link.
2008 F-350 Super Duty Dually gas guzzler
2006 Ram 3500 Dually Cummins Diesel
14x7 landscaping trailer
12x6 P&T hydro dump trailer w/leaf box
We run Gravely ZTRs and Prostance, Honda 21"s, Redmax Backpacks and Trimmers, Stihl Trimmers, LittleWonder loader, Kawi trimmers at the end of their lives and a bunch of stuff you probably have too