Hey great work here ! Is there any known connection between morels and different soil types that may be more suited for the soil moisture range you said they prefer? If so I would suggest looking into soil classification maps and overlay that tree data to refine a search.

Also if you look into multi-spectral data you could see if they have a specific reflectance value on a index such as NDVI (normalized difference vegetation index) where you could use open source software like QGIS or R/ RStudio to create classifications of pixels that would be considered a sample of morel!

Again, really cool work!