Arne Næss considered nature the best source of knowledge and regarded the economists as morally responsible for the ecological crisis. Therefore, this research focused on students of economic fields at the university level. The experimental group (n = 236) led by a teacher-as-researcher completed a Business Economic course by forest workshops for one semester because the sustainability principles can be very well explained and observed on examples of forest fauna and flora and then applied in managerial practice. Many similarities were found between forest and business principles (optimal growth rate, teamwork, cooperation models, parasitism). This paper aimed to identify if students’ proficiency in applying sustainable mindset from a forest ecosystem to practice increased. The achievement test compared outcomes of the experimental and control group (n = 190) of students. Based on statistical testing, it can be stated that the experimental intervention led to better results compared to the control group. For issues in which no suitable parallel with the forest ecosystem was found and were therefore explained according to the textbook, group (E) did not perform better than group (C). The methodology is based on qualitative and quantitative research, a mixed-methods approach.