I can't tell for sure, but that appears to be a 1-bulb fixture. If so, the price seems pretty steep to me...and, depending on your trees and their sizes, I kind of doubt the light from a single bulb would be sufficient, especially if it's the sole light source. Also, skimming through the reviews, it seems different people were receiving different products when they ordered this light stand. I would advise finding a local hydroponic shop, if there is one, and see what they have available. I checked my local shop and the price seemed comparable, and it's always good to see exactly what you're getting.
The other thought...I haven't used T5 lighting, but it may be possible to find a fixture that you could hang from the ceiling...doing away with the stand, which quite a few reviews described as "wobbly". The money might be better spent on a 2 bulb hanging fixture.
Chris