*** GARDENING and/or SOIL EXPERTS ***  I need your help!!!

I have tried to google this but not having luck finding an answer to my exact question ... Here is a picture of a bed that I plan to plant a veggie and flower garden in ... It is in our back yard behind our house ... For many many many years Gary has been putting leaves in here and each year maple tree saplings start growing and Gary just clips them off ... I started preparing this bed recently and my plan was to put black plastic over it all and help everything to die down and out and then put new soil on top of the plastic. As I started doing this Gary suggested I go ahead and clip any saplings that might be sticking up and so I did start this process. The earth that the saplings are coming up in is soooo black and rich and I just hate to cover it all up and not use it ... I've started now beginning to not only clip the saplings but also to start pulling out as many as I can and am finding more and more rich dark black soil (the result we think of all the leaves over like 30 years that Gary has been putting in there) ... so my question is ... once I get most of these roots pulled out (it is impossible to get every last one pulled out ... can I just plant my plants and seeds into this black soil and how can I keep any leftover saplings from coming up too? should I get other types of soil to mix in it and then plant? It just seems so wasteful to not use this amazingly black rich soil and to just cover it up .... but I don't really want maple saplings taking over my garden either ... anyway ... hoping some of you gardening experts that I know are on my page somewhere can help with advice? Thanks so much!!! oh and I may repost this some so I can hopefully ensure someone that knows will see it ... so forgive me if I repost ... thanks!!! LOVE LOVE LOVE (oh and in the pic you see black plastic being laid down but I've taken it all up and started over at that far end to clip and pull out as many roots systems as I can and then covering with black plastic to keep the process going until I decide what to do with the black soil underneath ... there are still a lot of leaves and all the roots so I'm thinking I really need to start a real compost pile somewhere but not sure where in the yard ... assuming it needs to be away from the house? although there is a perfect spot that is not seen from the front of the house but it is right under the kitchen window so would compost smell and thus not a good spot to have under a window of the house?)

okay this shows to the right what i've already one in clearing out the bed ... 

see the dark soil on the right and the leaves and sticks and saplings to the left?

this photo shows how much more i have to do!!!! yikes!!! and yes that is bowing out ...

and this photo shows the beginning of what will be compost ... 

this is what I've gotten up from the top of the bed and also dug out (roots and stuff) from the bed so far ....