[boost] Boost.BGL and SoC Boost.tree differences

Hi, How far can we use the Boost.BGL as a generic tree container. * I mean why SoC Boost.Tree when BGL is around? * If BLG has limitations then couldn't that be extended/prettified instead of the Soc Tree container? * Can someone please clarify/rationalize the differences/similarities? Also I noticed that Boost.Interprocess had some sort of tree implementation. * Why the reason for this and if used internally then what is for, otherwise can't it be just made generic for everyone to use instead of the SoC Tree implementation? Thanks Shams