Numerous layers of cracked and dead bark accumulate on large branches and stems of aged trees. And both are of no use at all. It actually could inadvertently do some harm, causing substantial damage.
All these crevices, clefts and detached loose scales of bark are the best place for stockpiling of various infections, predominantly, fungal diseases. Also, all these places are an appropriate shelter for winter seasons for things like eggs, pupae, larvae or adult bugs of many kinds.

Bark peeling

How much cleaner and more productive your garden could be the next year If you managed to get rid of unwanted pests. In this regard at the end of October or in early November, after some rains have fallen, when the bark gets soaked enough, you should wait for a spell of good weather and take advantage to terminate them. On such conditions you wouldn’t have to hunt one particular insect or one specific swarm of bugs. It would be much easier to terminate them all together whilst they hide in roughness and clefts of the bark. Place some sheet of fabric, canvas cloth or roofing felt at the base of the trunk within a radius of about 1-1,5 m in all directions. You’ll need a wire brush and a special scraper for the bark peeling.
It is important to scrape off and remove all rotten bark onto canvas at the base of the tree so that pieces of infected with fungi bark don’t fall onto soil, potentially spreading the infections.

It is also very important to not damage live and new bark under layers of rotten. Otherwise, the whole exercise will be counterproductive, as you will be removing potential pests and simultaneously become a real one yourself. Burn all the produced waste comprising of rotten bark and insects.
Peeling the old rotten bark off is highly important operation, but it is not the only way of getting rid of the winter time invaders and diseases. This is also very important as it helps to improve gaseous interchange, respiration of the bark, and thereby increasing, at least a little, viability of the plant.

However, never try to peel off the bark from young trees. It usually is in its best condition and when interfered with you do nothing but harm to it.

Whitewashing the boles

Educational material
Whitewashed trees in garden

After You have peeled off all the old rotten bark from the plants you should whitewash them. Most allotment gardeners whitewash trees with timing to coincide with the beginning of spring or with the first access to the garden with a purpose to make the garden look beautiful and festive. It is certainly nice and praiseworthy. Along with that the main function of whitewashing is a method of disinfection; it protects the plant from bronzing and frost-cracks. Such troubles most often occur in periods from late January to late March, when the temperature on the sunny and shady sides of a trunk sometimes differ a dozen or two degrees. Therefore, we strongly recommend you to whitewash trunks and bases of large stems in autumn. Never do whitewashing of trees in winter, when gardens are usually snow-blanketed and you need to dig up tree for whitewashing and after the work is done have to put snow back to protect your tree. For whitewashing you should use a commercially available proprietary mix. However, you can prepare the whitewash yourself. For that you should take 10 liters of water 2,5 kilograms of lime, 0.5 kilograms of copper sulfate for disinfection and 0.1 kilograms of carpenters’ glue for the whitewash to adhere to the tree.
You should whitewash not only the trees that have bark peeling off, but also young ones. And what is more, the young trunks should be whitewashed on a first-priority basis. They are susceptible to sunburns and frost-cracks.

You can find some more useful information on this topic here

Best wishes and good luck with your gardening.