As Feynman said, the wood ISN'T stored solar energy, the wood comes out of the air ... the sun allows the tree to grow by knocking Oxygen out of Carbon Dioxide leaving Carbon (and water) to make more tree.
When you burn the wood, the energy that comes out is stored solar energy.
The details are IMPORTANT and you're deliberately getting it wrong.
Why? Heck you posted the links yourself!
In the words of a former US president, it depends what you mean by "is"...
My own feeling is that it isn't helpful to talk about "stored solar energy" anyway, since "stored" suggests some kind of foresight. Perhaps potatoes and carrots "store" energy, and maybe the high energy content of seeds might be "stored" for later use, but I don't think trees do. To first order, trees just grow and make more trees.
The global ecosystem (Brian Cox's current BBC series explains this quite well, in my opinion) maintains and propagates itself by converting high-free-energy solar power into less useful forms of energy.