permaculture

["Gene Monaco" <efmonaco@comcast.net>]

Been reading up on biochar lately, and I get this sick feeling in my stomach
as if it is surrounded by darkness, cloaked in an illusion.  But I'm often
wrong.  I get the basic idea of it, but I have some questions I'd like to
ask this distinguished group, for whom I have a lot of respect.
1) The literature seems to be divided as to whether or not it actually makes
plants grow better.  Some do, some don't.  How could we trust it in a
permaculture guild?  Experimentation is the best way, but that takes time
and controls.
2) If the idea is to get biomass into the ground without it having a chance
to break down, wouldn't it be better to re-afforest degraded areas in
northern climates where winter will slow things down, burying layers of
carbon over time, rather than talk of tropical plantations to burn
fast-growing plants into charcoal before burying it?
3) Some biochar literature says that the product needs to be made at temps
>500C, which seems to me to be a lot hotter than what naturally occurs in a
temperate forest fire.  Less than that and it's no good.  So how is the
comparison to charcoal from natural fires or camp fires relevant?
4) How do they heat the biomass to more than 500C to make the biochar?  And
doesn't that produce its own greenhouse gases?  
5) And finally, what about building soils?  Seems like the stalks of wheat
that are a "waste" to big ag, would be better off as organic inputs to an
organic system.
What am I missing?
-Gene