My grandfather made a living from forestry when he was young.
Forestry is still a major industry in this region.
work done in the mountains
Broader than forestry; can include any labor performed in mountainous areas, such as trail maintenance, charcoal making, or gathering wild plants.
During the summer, the villagers get busy with mountain work.
Compound of 山 (mountain) and 仕事 (work). The specific sense of forestry developed naturally from the historical importance of mountain forests as a source of timber and livelihood.