Context: The Earth contains about 434 billion cubic meters of growing stock forest, 47% of which is commercial. As an abundant, carbon-neutral renewable resource, woody materials have been of intense interest as a source of renewable energy. In 1991, approximately 3.5 cubic kilometers of wood were harvested. Dominant uses were for furniture and building construction.

Question: How many cubic meters of growing stock forest are there on the planet?
Answer: 434 billion

Question: What percentage of the Earth's stock forest is commercial?
Answer: 47%

Question: In addition to buildings, what is wood often used to make?
Answer: furniture

Question: About how many cubic kilometers of the vast stock forest's wood were harvested in 1991?
Answer: 3.5

Question: In addition to being carbon neutral, what other adjective describes wood that makes it compelling as a renewable energy source?
Answer: abundant