Are trees preserved by mummification if they were buried under volcanic ash?

Trees can be preserved by mummification if buried under volcanic ash, as the ash can create an anaerobic environment that inhibits decomposition. This process can lead to the preservation of the tree's structure and some of its organic materials. However, the extent of preservation depends on factors such as the ash's chemical composition and the conditions of burial. In some cases, this can result in fossilized remains rather than true mummification.