GNU GPLv2:
3. You may copy and distribute the Program (or a work based on it, under Section 2) in object code or executable form under the terms of Sections 1 and 2 above provided that you also do one of the following:
a) Accompany it with the complete corresponding machine-readable source code, which must be distributed under the terms of Sections 1 and 2 above on a medium customarily used for software interchange; or,
...
Seems pretty clear to me that, yes, you do. Is the wrapper executable? Is it based on a GNU GPL'd source? You'd have a hard time arguing that section 3 doesn't apply.
At last, someone mentioned the open circuit voltage!
For typical PV cells, open circuit voltage is proportional to the log of incident intensity, but short circuit current is linearly proportional. That's why most PV inverters have a dynamic impedance, to maximize power generation over the range of sunlight during the day.
What a tree-design has going for it is more end-of-day available energy (if you don't have an energy store). It also has cooling benefits (which can easily cost 10-20% in efficiency).
(And if you want to see what the sunlight in San Jose, CA was doing several years ago, check out my PV energy captures.)
Today is a good day for information-gathering. Read someone else's mail file.