North American Fruit Explorers mailing list at ibiblio

[Douglas Woodard <dwoodard@becon.org>]

In my limited experience, there is a lot of difference between part 
shade or an edge, where a plant is exposed to direct diffused radiation 
from the blue sky and maybe a little direct sunlight part of the day, 
and full shade.

The late Robert Nitschke mentioned that the English Morello sour 
cherries which he grew on a north wall "were of a size and quality 
unobtainable in full sun." He didn't say anything about the yield though.

By report Actinidia kolomikta prefers something a little less than full sun.

Here in the Niagara Peninsula of Ontario, I know of a wild or feral red 
raspberrry which produces bristly, pleasant tasting (but not 
outstanding) fruit sparsely in dappled shade.

I have seen a spicebush (Lindera benzoin) fruitng sparsely in dappled 
shade in heavy soggy clay near Fort Erie (beside Buffalo). I have read 
of spicebush fruit being used by a gourmet chef in a relish-type 
concoction for human consumption.

My observation of shaded plants generally is that they fruit sparsely.
I'd say that unless you can harvest from the canopy you should expect 
very light yields. Since harvesting from the canopy is usually practical 
only with small trees, I think that the notion which seems to be current 
among permaculturists, of harvesting plant food from a forest, is not 
practical unless one is a forager harvesting from a lot of land without 
competition. Waiting for drops means accepting competition from wild 
animals which are on the job full time and seem very alert to 
opportunity. One might do not too badly in woodland with incomplete 
canopy coverage, or in a place with a lot of edge, but in northeastern 
North America that means suppressing forest in the long run.

Even harvesting from a canopy seems to need pruning for long term yield 
and quality - although I would be very interested to hear testimony from 
personal experience to the contrary. I see that old untended apple trees 
in full sun can produce a moderate amount of fruit almost every year, 
lots of typically small apples, but not of the best quality, and a 
fraction of the yield one might get from well tended trees.

I notice that "Foundations of Silviculture" by Toumey and Korstian 
(Wiley, 1928, 1947) devotes several pages to the effect of root 
competition under shade and mentions one Fricke as having published the 
first study in 1904, in German.

Doug Woodard
St. Catharines


Alan Haigh wrote:
>      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.