I want to suggest to a gardener to plant trees for reducing pollution and poisonous gases emitted from a factory. Which species is preferable to plant in the area around the factory?
I was curious about which trees absorb the most CO2 and Googled for this a while back. I found that there are several websites that list trees that are good in absorbing carbon, e.g. this website and this website. Both sites list trees like:
- Pine (Ponderosa, red, white and Hispaniolan pines)
- Oake (Scarlet, Red and Virginia Live Oak)
- Douglas fir
- Bald Cypress
- Common Horse-chestnut
- Black Walnut
- London Plane
- American Sweetgum
However, there is one site1 2 that has an entirely different list:
- Trembesi a.k.a rain tree (Samanea saman)
- Bamboo (Bambuseae)
- Cassia (Cassia sp)
- Cananga/Kenanga (Canangium odoratum)
- Pingku (Dysoxylum excelsum)
- Banyan/Beringin (Ficus benyamina)
- Krey Payung (Fellicium decipiens)
- Matoa (Pometia pinnata)
- Mahogany (Swettiana mahagoni)
- Saga (Adenanthera pavonina)
Note that for good sustainability you will have to consider more things than simply the amount of CO2 a tree can absorb.
First of all not all trees grow in all places. The tree you have in mind should be appropriate for the region and climate. If you have to water it, add fertilizer regularly or package it during cold winters to survive, etc. then it will be less sustainable. If the factory does indeed exhaust poisonous(?) gases as you said, then trees may not grow at all near it.
Second, think about what will you do with the trees once they are mature. If you harvest them and plant new trees then you can capture more CO2. But if let the tree fall down and rot or if you burn wood from harvested trees, then the captured CO2 will be released again.
1 update Jan 2015: sadly the link has died, but I found the same list in this forum post along with some statistics on how much CO2 the trees take up
2 update Aug 2017: the linked article can be viewed in this capture dated 27 Jun 2012 on Internet Archive Wayback Machine.
Basic chemistry here. Plants consume carbon dioxide and water to produce glucose. They then polymerize the glucose to create cellulose. In general, the amount of biomass that a tree produces is dependent on its net carbon uptake. If all you are trying to do is ensure that you take some CO2 out of the air, you want to plant fast-growing trees, ideally which are harder than softer.
Edit: one more thing to keep in mind: particulates.
One of the best things that trees are good at is removing particulates from the air, particularly if you have frequent rain. The particulates stick to the leaves and are washed off by rain. This is actually a function of the leaves since it means that trees get to catch floating sources of nutrients (for example, animals grinding dung into dust that then ends up in the wind). So one of your most effective reasons to plant around factories is to reduce particulate pollution.
Trees absorb carbon dioxide to grow and build biomass. If you want to absorb much CO2 you need a tree that grows fast at your local conditions - consult with your gardener about that.
Note that this will not solve problems with other pollutants, and will only put a rather symbolic dent into wordwide CO2 emissions.
The factory will pollute much more than can be undone by planting trees (up to a reasonable number). Any approach that reduces the pollution of the factory will be more effective than planting trees as counter-measure.
It is true, however, that, say, a forest around the factory would help clean the air and absorb much of the pollution, so that planting trees is always a good idea, of course.
Plant bamboo. Its also an excellent biofuel. Pines and evergreens collect pollutants on their leaves/spines/firs but are unable to drop them and assist in decomposition. this is why the bottom of a pine forest is always devoid of other plants. Bamboo is an excellent "growth" plant in terms of CO2 absorption as well as allowing pollutants to biodegrade within the lower level detritus.
Well, I know the question is more about outdoor plants (Trees) but I found a Wiki page on NASA's study about Indoor plants, which help remove toxic agents like benzene, ammonia etc. from air. NASA Clean Air Study has the details.
Gingko Biloba has high pollution tolerance! (speaking from a biology perspective, it's also my favorite)
Short and sweet answer is Bamboo and plants from that family. You can also reuse them as sustainable fuel.
Avoid the conifer and pines as they kill everything that lives beneath them due to toxified leaf (in their case needle) litter.
I'm a gardener who is always interested in these topics. I discovered Birch trees absorb a lot more pollution than most other trees but tend to prefer cooler climates. They will grow in the south of England but with a shorter life expectancy. If the soil is acidic and the summer is cool enough they should multiply on their own. To absorb street pollution from roads small trees would be more effective as the leaves do all the work. For a factory the planting needs to be diverse and well placed.
some useful suggestions here. i think understanding how it all started is important in finding the right solution to today's emission problem.
if we go back in time when the planet was inhospitable. all the early living organisms that came into existence eventual died and became trapped somewhere underground cos the planet was unstable at that time. in time they become fossil fuel loaded with Carbon and Hydrogen. this was ideal because all the excess CO2 was removed from the atmosphere (early living organisms on the planet were different from what we are today). anyway, this cooled the planet and it became more hospitable for our kind to thrive and flourish.
but in the last couple of centuries, human found an ingenious way to release all that CO2 trapped in the fossil fuel back into the atmosphere. so if we do not reverse this trend, then we will be the next store of fossil fuel for a different kind of life form on the planet. planting trees definitely helps, but its hardly the global solution we need. more research into harvesting hydrogen and using it as a substitute will be the solution i feel. if not we have to find ways to trap CO2 underground somehow. the kyoto protocol was a good global response, but nobody gives a damn.
recently, i was in the maldives. from the air, the horizon is no longer the picture perfect destination that travel brochures sell. for hundreds of miles all around, i could only see haze. its sad. the blue skies we were used to seeing as a child will be just a myth to our children and grandchildren.