Here's why:
* Traditional focus: Haiku originated in Japan, where nature holds a profound spiritual and cultural significance.
* Concise beauty: Nature's fleeting moments, like a blooming flower or falling snow, lend themselves well to haiku's brevity and emphasis on observation.
* Universal appeal: Nature is something everyone can relate to, regardless of culture or background.
However, this doesn't mean haiku is limited to nature. Modern haiku can explore emotions, relationships, everyday life, and more. The key is to capture a fleeting moment of observation and reflection, with a focus on imagery and sensory detail.