Most of these images, despite the flickr references seem to have been copied directly out of Thomas Pakenhams books,
Meetings With Remarkable Trees
http://www.amazon.com/Meetings-Remarkable-Trees-Thomas-Pakenham/dp/0375752684
Remarkable Trees of the World
http://www.amazon.com/Remarkable-Trees-World-Thomas-Pakenham/dp/0393325296/ref=pd_bxgy_b_img_b
Which is cool, as I've got copies of both and they are awesome, but he deserves some attribution. The books have many more incredible pictures and much better accompanying descriptions and histories behind the trees.