BI is probably the only island that gets the benefit of the volcanic gasses.
http://www.botany.hawaii.edu/faculty/bridges/bigisland/sulfurbanks/sulfur_banks.htm
Sulfur Bank
This site is a bit of a paradox. You can smell the sulfur fumes in the air. You'd expect the rainfall in this area to be very acidic; you'll not be disappointed. The few measurements made indicate that from this perspective, it is a harsh environment. The paradox comes when you look at the plants. There is an abundance of species and many appear to be thriving, even some quite close to the sulfur vents.
Admittedly, many of the plants are stunted. That gives a hint that something is limiting the root growth. As a result, there is more to this environment than just the air -- and rainfall -- quality. Soil acidity is a likely candidate. Soil temperature must also be important although only reconnaissance-level measurements have been made (check this
link for more information).
Take time to examine the distribution, abundance and general health of the plants in this area and you'll see how well adapted the plants are to this type of environment. It is clear that we need more environmental measurements if we are to sort out exactly what is happening here.
Environment
Elevation is about 4,000 ft. Rainfall and air temperature will closely match that recorded at HVNP Park Headquarters.
Plant Species Checklist
Click the following links for the type of checklist that you want.
Getting There
The road to Sulfur Banks (spelled "Sulphur Bank") by the National Park Service) is located about 0.2 miles to the south of Park Headquarters along Crater Rim Road.
The sign along the Crater Rim Road (shown below) is near Park Headquarters and points to a short (about 0.1 mile) dead end road.