At first glance, a tree line poem seems to be a haiku. It looks like haiku but its topic is about nature, the main subject of a senryû is about someone. It's quite easy to distinguish haiku from senryû...
Just ask yourself: "Is the subject about anything treating of the natural world or is it in the human realm?" Once you ask yourself this question, you'll be able to see the difference!
Perhaps, if we lived in Japan for years, we'd understand the many hidden meaning in many of the haiku poet's work. In fact, the Japanese have hundreds of words to describe the nuance in seasonal change. We here in the west don't.
We're more straightforward and somehow as much Zen like. Japanese haiku has that quality and I suppose it's just a matter of time. We in the west might learn much from the Japanese haiku poets and develop a unique way of expression.
Most people who write haiku think they are creating haiku when in fact, they are making senryû. What's senryû you ask? It's exactly like haiku except its subject matter has to do with anything besides nature.
Mostly, it has to do with what goes on in the human realm. Another trademark of the senryû poem is that quite often, they are satiric or sarcastic. The senryû is an excellent form for this and has much to offer both poet and reader.
Notice that the subject would be fireflies for examples, no humans in sight or anything to do with a person, that’s what haiku should be. Unfortunately, many people who write haiku poems think they are writing haiku when in fact, they are writing senryû.
Another trademark of the senryû poem is that quite often, they are satiric or sarcastic. The senryû is an excellent form for this and has much to offer both poet and reader. Whichever form you prefer it's good to know the differences between them!
Senryû has been a victim of censorship some decades after its birth, and it never really got back... Why a censorship? Because those poems are satirical and sarcastic! Particularly concerning social life or people in general.
It is striking, derisive or derisory, without respecting people’s life. Its first rule is to be humorous or contemptuous. Without humor or derision, they will not exist any of the senryû!
Edward A. Weiss