Soil type - pine needles

[onslowsmith]

Does anyone know if soils in forested areas (white pine in particular) contribute more to coil or metal decomposition that other areas? I've seen shallow coins in pine duff almost completely corroded away. Maybe this is because of the aerobic vs. anaerobic environments???

 

[JohnTN]

Pine needles are very acidic this is why they are used in landscape applications as a natural weed barrier/mulch. I imagine they would be very corrosive on coins.

 

[TheMarshall]

Copper coins just melt over the years in pine needle littered soil.

 

[Chris(SoCenWI)]

n/t

 

[JohnnyI]

I was wondering the same thing myself the other day. We all have experiences with coppers buried among old oaks, and how usually they are very corroded. I'd assumed it was the tannic acid that did this, but it may be that oaks, pine, and other acidic trees thrive in acid soils and the trees themselves have little to do with it. I dug a federal period button the other day in an old patch of junipers (also like acid) and it was very corroded also. You got me wondering enough to look up what trees thrive in acid soil and those that thrive in neutral soil. Yews for instance like a neutral soil, and if memory doesn't fail me, some of the nicer "shiny green" colonial coppers that I've found have been in the vicinity of old yews.

 

[onslowsmith]

Thanks for confirming that. I know that organic material decomposition lowers soil pH, but I always wondered if that had any significant effect on coins. I've seen coins from the 70's and 80's pretty eaten away in these conditions.