What is the tone of the passage provided and please identify the words that contribute to that:

After earning a few dollars working on my brother-in law's farm near Portage [Wisconsin], I set off on the first of my long lonely excursions, botanising in glorious freedom around the Great Lakes and wandering through innumerable tamarac and arbor-vitae swamps, and forests of maple, basswood, ash, elm, balsam, fir, pine, spruce, hemlock …