Cleaned up the background to highlight the tree; simplified the foreground (no tiling) to show better the blood vessel cells. I’ll add more branches and some leaves, but I may skip the shadows. I want the cell photography to star.
Qutub Lab (http://www.qutublab.rice.edu/) has given permission to use their beautiful cell images in this artwork. I do so with gratitude for their generosity and in awe of their research efforts.
cellartworkbyncq 
Wow! I particularly love the tiny branches, roots & dirt.
Thank you, Amina. The cells show well in those areas.