On pokemon platinum i encountred 2 shinys
1. Shiny Ponyta ( at route 206 ) ( Now As a Shiny rapidash )
2. Shiny Wurmple ( At Route 205 ) ( Now As Shiny Beautifly )
The Shiny Ponyta Broke My Geodude Chain
The Shiny Wurmple Was Ramdomly Enoucountered With Honey Tree

How many times did you check your Honey Tree before encountering Wurmple? I've slathered honey on every tree from Sinnoh to Kanto and I've NEVER encountered a shiny before.
How big was your chain before you got Ponyta?
Just curious....

I thought you couldn't use honey on the trees in any region except for Kanto. But I think you can still use the Honey in any region for a Sweet Scent effect.