It never decomposes. It will tarnish, but not decompose. This is one reason silver objects are found that are thousands of years old and look as good as when they were made.
Do you really need cardboard? What can you use Instead of cardboard? Does it decompse? If so how long does it take to decompse?
hundreds and hundres of years
Yes
Wood chips can take anywhere from 1-3 years to decompose fully, depending on factors like moisture, temperature, and microbial activity. Incorporating them into soil can speed up decomposition as they undergo decomposition with the help of microorganisms and fungi.
a long time
Yes, as long as you take the recommended dose of colloidal silver,
you need soil and worms to decompse fast
200 hours
well fungi can decompse things as can some organisms
lv 50
About two hours.
See the list of silver isotopes and isomers at the link below.