When one is interested in growing trees for a living, one of the most important questions to ask is – will it be possible to grow trees even in the future?
There has been a lot of articles and information in the media recently about the global warming. Perhaps little less talked about is how the global warming will influence precipitation. That is for sure one of the most important growth determining factor for trees.
Carbon Brief has published an interesting article explaining this and difficulties in projecting the global precipitation patterns. I find this map fascinating:
The map shows a mix of a number of precipitation models and where they agree on same patterns. The orange color represents decrease in precipitation and the purple color an increase. There is consensus on precipitation increasing in the polar areas, far north and the far south. The same applies for regions close to equator. Northern hemisphere in general might become wetter with the exception from the Mediterranean region, Mexico and south-west US.
The seasonality of precipitation is interesting too.
Winters in the north will be giving much more snow it seems (or rain if the temperature increases a lot). In autumn the equator will have heavy rains, and far north will be very wet. India and north east Africa looks worrying, will we have severe flooding here? Summers will be generally much dryer, and I am getting worried about Southern Africa, Central Europe and Mediterranean – it will be very dry. Having recent bark-beetle outbreaks in Central Europe in fresh memory, it is likely it will get worse unless different silviculture is applied.
It seems, if the projections are correct, that the areas with more even distribution of rainfall, although increased, will be in US north, Canada, Northern Europe, Russia and China. Will winters in these areas mean snow or rain, or both, and how much snow and ice damage on trees will we see? How will this increase in precipitation influence pathogen occurrence in forests? Already today, we see an increase of certain fungi, for example the phytophtora species, which may take hold even more.
If I had to decide today where I would put my money in forestry, I’d say Scandinavia, northern US and Canada. Then I’d curiously look on the maps above and wonder if we should bet on greening the Sahel region and the Horn of Africa.