About buckthorn, Hippophae rhamnoides
It isn't native in Estonia, but is widely cultivated, and has been so long before it was "discovered" for food and health e g in Sweden. For a large group of the modern high-yield cultivars Russian / Siberian species have been used in breeding.
It is a fascinating shrub - fixes its own nitrogen fertiliser, like alder and many Fabaceae (Leguminosae) plants, with bacteria living in nodules on the roots.
Good for - absolutely everything, it seems. To ward off, or to mend. If I were a horse, I would get beautiful, glossy hair too. From the leaves, even. The berries have an extremely high content of Vitamin C and a number of fat-soluble beneficial substances. Dishes made with sea buckthorn berries get a glorious golden-yellow colour, and a rather special taste.
Why only 1 litre picked per hour? The berries sit almost directly on the branches, with only tiny stalks, many and very close together - see for instance HERE
. Imagine a corn (maize) cob, but the corns are filled with juice, and the skins burst if you press just a little too hard when you pry the berries off. I have considered everything: mini sickle, tiny scissors, growing one nail like a claw (as Chinese empresses had) with a cutting edge ...
A common commercial method is simply to cut off branches with berries, freeze them, then shake - berries and leaves break off at the stalks, berries are then separated from leaves and other debris by blowing or vibrating.