We too have what we call 'gulches' or ravines - one right behind our house goes down about 100 ft and there is a stream and waterfall you can access, but not easily.
You can read about my trek here - granted, not as beautiful as your hike, but at my age, anything like this is amazing - LOL
Indeed, this looks pretty much like home to me! Reunion and Hawaii sure share a lot; volcanic islands with tropical weather and plants, friendly folks and good surfing! Now, why do you go down gullies with weed-killer?