When discussing the use of plants on a distant space colony, most people will instantly think of edible plants. Two of my previous posts have discussed edible plants for both traveling to a distant planet or moon, and edibles for growing on a massive scale in a colony. Obviously food is a huge concern for the space colonists, but they would almost definitely grow other plants (non-edible) plants in their habitat.
In particular, plants are used by humans to create renewable building materials, fuel, textiles, plants to purify the air, as well as medicine. This latter use of medicine will be discussed in May’s blog, but I want to discuss these other uses in this April post.
Humans have been using plants as a cheap renewable material for many millennia, and even with our ability to manufacture synthetic materials in the modern age; we still find that plants can be cheaper and flexible enough for our everyday needs. The ability to generate large amounts of plant biomass, from carbon dioxide, with the addition of a little water (i.e. photosynthesis), makes plants the ultimate renewable resource for space colonists.
With building, I’m sure colonists will have efficient ways for recycling man-made materials from their voyage, but plants can still serve as a main structural material. In this case, it is possible that the colonists could use fast-growing trees or shrubs, such as poplars, acacia, and eucalyptus. Unfortunately, most quick growing plants tend to be colonizing species themselves, and don’t commit large amounts of structural material to their trunks and branches. In other words, their wood tends to be softer, which isn’t useful for building large structures, but may have other benefits. A large detriment to trees growing on a Titan colony would be the limited sunlight, and these trees would probably need supplemental light sources. This would seem to be a waste of resources given the return.
A different approach could be to use fast-growing monocot plants that grow to tree-size, such as bamboo, palms, or rattan palm vines. These plants do not use wood as a strengthening element, but instead use strengthening fibers internally, and are supported by growing in stands, or cling onto other structures. The amount of biomass produced by these plants has already been realized by Asia cultures, and more recently the green building movement. These plants could produce a fair amount of light but incredibly strong building material that would constantly regenerate. In fact, bamboo is still one of the stronger natural materials per weight and would serve the colonists in manner ways.
These same plants could serve a secondary and tertiary role for the colonists. In particular, stands of palms could work efficiently at removing carbon dioxide and pollutants from the air. NASA has already begun to examine plants that are able to remove pollutants from a space station, and many palms and other monocots perform this duty efficiently. Most importantly, these non-edible plants could remove toxic substances from the air, and sequester them in inedible plant biomass and/or building material.
Lastly, plants such as bamboo could be used to extract fibers for clothing. Traditionally we think of cotton for producing clothing, but this plant would not serve the colonists well. Cotton is a high-demand plant, needing large amounts of light, water, and minerals. The amount of resources needed to create a single shirt would be greater than the colony could provide. Colonists would either rely on recycling synthetic materials that they brought on their voyage, or growing high-fiber, efficient plants, such as flax, jute, or hemp. I think there's a fair amount of knowledge of growing this latter plant in enclosed growing systems.
Next month we discuss which plants the colonists would bring for medicinal and entertainment purposes, for man cannot live by bread (and bamboo) alone!