1. If betel nut is not disturbed by natural disasters, the average net profit of one acre of betel nut is about 20,000 yuan. Therefore, the net profit of 100 mu areca nut is about 200,000 yuan. This estimate is based on the fact that one acre of betel nut can plant at most 12 betel nut trees, and the minimum income of one betel nut tree is 300 yuan. Excluding the cost of about 100 yuan, the net profit of one betel nut tree is about 200 yuan.

2. However, please note that the actual income may be affected by many factors, including but not limited to climate, soil, planting techniques, market demand, price fluctuations, etc. Therefore, the above figures are only approximate estimates and cannot be guaranteed to be completely accurate. When making planting decisions, it is recommended to consult agricultural experts or conduct detailed market research.