I am not sure if I got the question right but if you want to know the pruned shoot volume it would be possible this way: Put the pruned shoots inside a big graduated container and put a weight (preferably with known volume) on them then fill water until a known level then remove the shoots and see how much the water level changes, this would be shoots volume.
Thanks. I want to measure the volume of standing grape trunk+intact cane after pruning and if possible the volume of roots also. Interested to know about Bitterlich relascope, Could you have any other idea about instrument and technology? that would be great for me.
I checked in Internet and found that there are android apps that accomplish the function of Bitterlich relascope fully or even better. These Apps measure the Basal Area or the cross-sectional area of a tree "that is normally described as the tree stem area per hectare (m2 ha-1)".
I think that these apps would be a good alternative to Bitterlich relascope and possibly easier to use.
I have not done similar measurements before but If I was in your place, I would measure some typical tree basal areas (trees which could be considered as representative of the average grape tree that you are working on, 3 is enough) and then you can cut these trees and measure the actual volume. In next stage you can do a regression to find the formula that gives you the volume from basal area. If the regression was significant it means that you can use the basal area to assess the tree volume in the given tree type by use of that formula.