If planting trees is ineffective to tackle climate change, why do people plant them?

Question

I've read answers that outline how if we afforested large (continental-scale) masses of land, it would do little in the way of tackling climate change. While it would sequester CO2 for about a century after it was planted (while growing) before reaching equilibrium, the planting of large quantities of trees would also sufficiently decrease the albedo of the land in which it was planted, that it would hold in a lot more heat than the land it replaced (likely desert or otherwise barren land). This means that, all things considered, it would make a negligible, if not negative impact, in tackling global warming.

If this is the case, why do we associate "planting trees" as a good thing, on the scale of individuals planting individual trees? Is it because generally, these trees improve ecosystem vitality/diversity, or for some similar reason unrelated to climate?

Answer 1

Planting trees has a short term benefit in carbon sequestration but will not offset the carbon from fossil fuel burning. However, in some places trees provide a benefit of increasing soil carbon which can have a longer lasting effect. Thus, one benefit is to increase the time needed to implement replacements to fossil fuels. Trees can increase cooling through greater evapotranspiration than grassland, in some climate zones. That, however, may have an impact on water resources. Wood and paper products that are not recycled remove carbon from the natural system, although the effect is small.

Burning wood instead of fossil fuels has a positive impact on the carbon budget where the carbon is recycled back into tree plantations.

Answer 2

Timber, shade, nuts, fruits, animal habitat, flowers, landscaping, erosion control, poles for electric power distribution, syrup, spices,coffee, and other things unrelated to global warming.

Answer 3

Planting trees is a good thing provided it is done properly. In Britain we have some valuable habitats such as heathland, peatbog, and wetland where planting trees would do ecological damage. If for example you managed to put a small stand of trees in an area of wetland, that would encourage hawks and corvids to take up residence to the disadvantage of wetland wildlife, and it's the same with heathland and peatbog. I doubt if it is possible to plant enough trees to make a major impact on the CO2 problem, but they will make some difference if only a small one, and in the right place can be a wildlife asset as well.

It would be impossible to grow trees in most true deserts, but in the Namib and Atacama there are places where sea mists roll in from the sea and condense on any object which protrudes from the sand. Maybe it's possible there. The most promising place for tree planting is in restoring the S.American rainforest, where there could be a huge environmental benefit. It could be financed with foreign aid money which wold go direct to impoverished rural communities, thus killing several birds with one stone.

There is a scheme underway in Britain to encourage the spread of sea grass meadows, which are important to the marine environment and apparently are more efficient at sequestering carbon than most things you can grow on land. Again the contribution will be small, but better than nothing. Sea grass is a true grass, but somehow manages to grow completely submerged in shallow salt water. Few people are aware of its existence. Restoring mangroves, which are basically small trees able to grow in tropical estuarine waters, is another area of environmental improvement which would also assist in the battle against CO2.

Answer 4

Take a look to the Carbon Cycle.

In the atmosphere there are around 700 GTn of carbon. Most of it CO2. The living biomass (plants + animals) keep 600 GTn and the dead biomass is 1000 GTn.

So the biomass it is very effective in order to fix CO2 as it is fixing in 2 ways: photosynthesis (absorving CO2 and emiting O2) and, when biomass die, then it is fixed on the ground.

When you deforest, you are removing the biomass that take some direct CO2 and you are exposing or removing the carbon fix on the ground.

Really, they are not the main actors on the picture: Oceans (38400 GTn, lithosphere carbonats 60000000 GTn, lithosphere Querogens 15000000 GTn) but their cycles takes 100 years on the fastest one and hundreds of million years on the slower. But the fastest one is the biomass, and the most effective one is the tree. (Check Kiri tree)

Take a look