I read in Talmud Moed Katan that Yidden used to be buried without coffins. The Artscroll notes there mentioned that nowadays the Minhag has changed and Yidden are now buried in coffins.
The Artscroll mentions a sefer that explains why this minhag has changed. Could somebody in the CR please find this sefer and explain to me why it has changed?
I believe we want the niftar to be resting on the actual ground which is how it is done in E”Y.
In the US, since the law is a coffin must be used, the wood that is used is one that disintegrates quicky so the niftar will be on the ground as soon as possible. I’ve heard that some remove the bottom board but I have not seen it myself.