My back yard in Illinois is quite shady.
On the farm I have spots that are sun from sunrise to sunset.
My JBP did not grow dense or look healthy when they got sun less than 5 hours of sun per day. When moved to the farm to the full sun, nice dense fox tails of new growth. Definitely need a lot of sun for pines. Mugo, Scotts pines and Pinus nigra seem to deal with 5 - 6 hours of sun better than JBP. Though all 3 seem to have better growth when they get more than 6 hours of sun, best with 8 or more.
I can't tell for sure but I think my Pitch pines prefer more sun to less sun. In 6 hours of sun they seem, okay, but a bit on the thin and wispy side, I haven't stashed any at the farm yet to see how dense or tight they can grow.
Ponderosa seem to need at least 6 hours of direct sun, seem somewhat happier with sunrise to sunset full sun.
Jack pines and American red pine (P resinosa) both real clearly need at least 8 or more hours of unobstructed full sun. If you look at where they grow in the wild, they are only found in areas that were open fields, open burn areas, or otherwise full sun location. Both need more sun than Ponderosa.
My Thuja, (White Cedars) seem to grow a little loose but pretty decent with 4 or 5 hours of sun, on the farm same trees grow with somewhat tighter foliage. But growth shade or sun is not too bad. Sun is better.
Eastern hemlock - seems fine in full sun, seems just as fine with 5 hours sun, grows a little loose but otherwise not bad in pretty much full shade.
Junipers, in Illinois in my shady yard, my shimpaku had loose wispy foliage. No density. Moved them to the farm. In one season foliage tightened up, now the second year they look like the juniper pictures in books. Dense pads of foliage. Junipers definitely need 6 or more hours of direct sun to keep tight foliage. Junipers look great with sunrise to sunset direct sun.
Most of my deciduous trees seem fine with 4 or 6 hours of sun.
These are my observations.
