Eastern Slavs certainly harvest birch sap in forests. There many videos on youtube. Use “березовый сок” as a search query.There is a short article on the front page of Slavorum on the birch sap from Russia. There is a brief discussion in Slavic cuisine topic.
Belarusian forestry workers harvest around 20,000 tonnes of birch sap annually. I am going to translate a short article on commrecial collection of birch sap known as ‘biarozavik” in Belarus around Brest area, south-western Belarus.
04 March 2008
The harvesting of birch sap began in Brest region today. Generally, the white trunk beauties ‘begin to cry’ 2-3 weeks later. Typically , the period of harvesting lasts for a couple of weeks. However, today is a real buzz in the forest. From five o’clock in the morning Brest forestry workers are in the birch grooves. Unusually warm weather brought us a surprise. The white trunk beauties began to produce birch sap 3 weeks earlier. The period of harvesting lasts for around 10 days in a year. A single birch tree can produce 30-40 litres of birch sap. Forestry workers follow certain rules in tapping birch trees. Birch trees marked for cutting down or those which are older 70 years of age are the only ones that can be harvested. To make harvesting process easier forestry workers make a certain type of cut in the tree. And it’s real piece of master work. Not following certain procedures can lead to the death of tree.
Anyone can come to a birch groove right now. But come without an axe. The birch sap is sold in birch grooves at a symbolic price. Unauthorised producers of birch sap will be fined for a large sum of money.
Birch sap is delivered to processing plants from a place of harvesting. Later, it’s distributed around retail shops. More than 10% of birch sap produced in Belarus is exported to other countries. http://www.ctv.by/node/12172
Video of birch taping in a forest near Brest : http://realbrest.by/video/belarus/2014-03-24-berezovyi-sok.html
There is a traditional drink ‘kvass’ made of birch sap in Belarusian cuisine.