North American Fruit Explorers mailing list at ibiblio

["Alan Haigh" <alandhaigh@gmail.com>]

     In answer to the question "why do early fruiting varieties do better in shady locations", it is because the sun is higher, and stronger so things in the partial shade usually get more hours of direct light in June and July than later.  That sun is also stronger.  My guess is that trees manufacture the majority of sugar for the fruit in the 2 or 3 weeks preceding full ripeness (sure tastes that way).  

     Greater accest to light in June and July is not without exceptions-  I manage a Baldwin that's got branches from a giant hickory hanging directly over it.  The hickory is on the north side so the Baldwin actually gets more light as the sun gets lower in Sept. and Oct..  On some years this actually seems to improve the quality of its fruit as Baldwin quality deteriates on very warm seasons in my area.

     I have Heritage raspberries growing under fruit trees in my nursery that are in a lot of shade and they do better than the ones I have in the full sun, probably because the soil stays moist there and it is extremely rich.  They would have a richer flavor if they got more light however, but they're still very good.  I have also harvested wild blackberries that were larger and just as sweet in 50% shade as ones nearby in full sun.

     On the issue of tree vigor in shade, I have observed very vigorous tree growth in fairly shady locations if roots from established larger trees are severed deeply in a circle around the establishing tree in early spring.