Great! My background was originally chemistry, and from there I kind of drifted into soils and geomorphology, but most of what I do is wetland biology and hydrology - there just aren’t any fields as interdisciplinary as natural resources. That’s one of the thing that makes it fun, interesting, and marketable. Chemistry and biology are the cornerstones, but there’s botany, forestry, fisheries, oceanography, limnology, etc., etc., etc. Good luck to your kids!
I think wetland biology is where Tom would like to end up. There’s nothing like hearing about all the microinvertebrates in your water supply ... unless it’s when the kid takes the Public Health Merit Badge and tells you about all the awful things in your food ;-).