Boats and Timber-framed houses probably.
Could sell or use the volcanic ash for Roman Concrete or Geopolymer Concrete?
Topsoil takes forever to create. What is the relation between glaciation and topsoil?
FWIU planting a monoculture of trees in the Gobi desert to reverse desertification has not been as successful as planting complete grassland and then forest ecosystems and trees.
https://news.ycombinator.com/item?id=37590409#37623093
Water bunds look like they work to prevent water from flashing off, but probably initially disturb the mycorrhizae in the topsoil: https://en.wikipedia.org/wiki/Semicircular_bund
"Inoculating soil with mycorrhizal fungi can increase plant yield: study" (2024) https://news.ycombinator.com/item?id=38526579#38527264
https://westurner.github.io/hnlog/#story-36158663 Ctrl-F "soil" [depletion], myco