This type of Forest could turn against us
- 20 Dec 06, 02:56 PM
Spruce forest, like this in the rocky mountains, could actually make make global warming worse.
In the last programme of PEuT we run a story by Lara Kueppers of University of California, Merced. She explains in perfect detail the two great physiological processes of plants: Respiration and photosynthesis - And it's the tussle between these two processes, with a forest fire to boot that can make temperate forests contribute to global warming, not combat it.
Gloabl warming is drying the forests in the Rocky Mountains, her research shows. And her work points to the idea that in warming and drying conditions, forests might give up more of their carbon than they absorb. If they do that, they are feeding back positively on global warming..making it worse.
Photosynthesis is the process unique to plants where the (usually) green pigment absorbs sunlight and fuels a process where by the plants make sugars from atmospheric carbon dioxide. Plants also respire just like we do as they go about their bodily functions. Respiration gives off carbon dioxide to the surroundings.
we've all been assuming that if you plant trees the increased forest cover will absorb more carbon. Lara's work shows that with increasing temperatures the fungi and microbes in the forest floor actually speed up their respiration, so the over all effect of the forest is to give up more carbon than they can abosrb.
Drying conditions also make forest fires more serious...burning more than a damp forest - and giving up even more carbon - And fires can be more frequent..releasing the stored carbon.
These are powerful ideas. Forests have been a comfort zone up to now. They also store a lot of carbon - that's a fact. Tropical forests are different to the boreal forests above...they do absorb more than they emit - buit maybe not if they dry out. And they can dry out. The tropical forest fires of Indonesia and Borneo are probably fresh in your minds. We also hear reports of the Amazon dying out. El Nino coupled with global warming can cause havoc with rainfall patterns, so even the tropical forests could cease, in places, to be the damp strore houses of carbon - and if they catch fire, could contribute to the "runaway climate change".
Back to so many of your blogs..the issue is about tackling global warming...And as is discussed in the last programme - let's not rely on trees to bail us out.