Winter in Ardmona

There are thousand so of bare fruit trees in Ardmona at the moment, but there is a hive of activity as they are all pruned in readiness for next year's crop. Pruning is one of the most important elements in fruit growing and can only be done successfully by hand.  However it has become much faster now with the use of "cherry pickers" to which are attached hydraulic hoses to power the pruner's secateurs. My Blip today is of a walnut plantation.  Its attraction for me is the bleached appearance of the timber from half way up the trunks. Is it natural, is it a protective spray? Walnuts are relatively new to this area so I know little. The twist of the branches (prior to pruning) is particularly stunning. My extras are of a pruner at work in a nearby pear block and of a 100 year old branch of a William pear tree. You can see the tiny buds already forming of the twigs in readiness for spring. Pears are the longest living trees we have in the orchards here.
I have just been informed by my son that the change in the look of the trees is because they are grafted, ensuring a strong root stock but allowing for the production better varieties of nuts that may not otherwise grow in our conditions.