Stored energy in plants

My neighbor and I had three large pines cut last December.  I dragged the limbs into my yard and burned them a few at the time.  My neighbor had cut a few of the limbs in two for me to make them smaller for handling.  He noted how heavy the limbs were with moisture.  Some of the limbs I stockpiled in order to let the dried needles fall into an area which I mulch with pine straw.  As late as March I noticed that some of the branches that were covered and damp still had green needles, while most of the exposed limbs had dried brown needles.  I used one of the larger limbs (maybe about 5" in diameter) to border a natural area.  I noticed that the pine needles on that branch were still green.  These needles were on little twigs that came directly out of the branch.  I believe that is called adventitious bud foliage.  I kept watching that foliage.  Gradually it was dawning on me as to how remarkably long the foliage was staying green on that cut branch.  Then I noticed new growth was actually appearing on the tips.  Just today, over five and a half months after being cut, the foliage is still green.  Remarkable.
Here are some pics I took today.
Some of the pine needles are dry and brown as you would expect.

 

 

But this limb has green foliage and new growth.

 

 

 

 

It's amazing to me how much energy was stored in that branch.