First of all we cannot know what are the implications of doing such a thing. It is also very expensive and technically difficult to do it.
No, too cold. You're probably focused on the carbon dioxide atmospere, but that is far too difused to support something as big as a tree. Tiny anaerobic bacteria is the best you could hope for.
Bacteria and any form of pathogenic microbe for that matter matures dramatically in the vacuum of a space medium. Due to the absence of environmental factors such as light, temperature, humidity, pH variations, and the amount of expose to radiation or light, bacteria may have very little opposition to their survival and cohabitation. Since there is some what of a confinement in space it can be demonstrated in this instance, bacteria in a space shuttle has more of a probability of surviving if does not have and human interference within the shuttle; the only limiting factors are the harmless bacteria that may consume the harmful bacteria, but if the harmful bacteria is more dominant than the bacteria will develop into a foreign strain known to Earth. -- Morgan C. Bruce
Phisoloth
Bacteria!!
bacteria
Anaerobic bacteria or facultative anaerobic bacteria.
anaerobic
aerobic bacteria use oxygen based respiration, anaerobic bacteria use either nonoxygen based respiration (e.g. nitrogen, sulfur) or fermentation.
anaerobic.
used for growth anaerobic bacteria
Salmonella bacteria are anaerobic.
what are the cause is anaerobic respiration in bacteria and fungi
Aerobic bacteria uses oxygen for cellular respiration and anaerobic bacteria doesn't require oxygen to survive. ˇ_ˇ 
Some methanogenic bacteria (which are anaerobic) do have flagella. You can read more in the related link
Anaerobic means without oxygen. Those are anaerobic bacteria.
Firstly, pathogenic is not the opposite of anaerobic. The vast majority of bacteria are non-pathogenic, but this doesn't mean they are anaerobic.
Anaerobic bacteria are bacteria that do not live or grow in the presence of oxygen. In humans, these bacteria are most commonly found in the gastrointestinal tract.