Question
Hello. I recently moved to the country with a large yard underneath 90% Ponderosa Pine and 10% Oaks in Northern California (Twain) and would like to know if the bed of needles should be raked up to foster native grasses and wildflowers? I have heard somewhere that coniferous pine needles inhibite ground growth. Is there anything to this? I also heard not to tamper with the ground needle cover as it removes a protective layer of ground. My soil is mostly sandy (Feather River) riverside soils. Topsoil is minimal. Please render your opinion on this. I am getting two sides to this problem. Thanks. Larry W.  

Answer
Gardening in California is outside of my area of expertise.  Nevertheless, I offer the opinion that you can leave the pine needles alone, but they do increase the acidity of the soil (as do oak leaves), and sandy soil generally is pretty acidic to begin with.  This will limit the number of native species that can grow there.  The decaying leaves and needles will add much needed organic matter to your thin layer of topsoil.

In your situation I would do a bit of research into what native plants like those conditions, and do a soil test as well.