January 3 2016

Will global warming kill off our pine trees?

The modelling crap below claims it will but is most implausible. Pine trees are very widely distributed -- from the near-Arctic to the tropics. As I look down at the floor of the room where I am writing this, I see polished floorboards made of slash-pine, once super-abundant but now mostly cut out, in sub-tropical Queensland where I live. That such a versatile and hardly genus could be disturbed by a few degrees of climate change is absurd. The distribution of species might alter a little but that's it.

They have been around for at least 300 million years so they have survived huge climate changes in the past -- so it is unlikely that any piddly Warmist scenario will bother them. And note that some species -- such as the Bristlecone pine -- are amazingly hardy and survive in very unpromising situations to this day.

I like this humble sentence below however: "Our ability to accurately simulate drought-induced forest impacts remains highly uncertain"


UPDATE:  Here's some info from the FAO on how pines fail to thrive  in warm climates:

Tropical pine species play an especially important role in modern plantation forestry. Several species, mostly originating from the American or Asian tropics and subtropics are now widely cultivated.  Pines enjoy such great popularity because:

the large number of species allow choice for widely varying environmental conditions;

many thrive on a wide range of sites;

many flourish in dry, nutrient-poor soils or degraded sites;

the volume production of some species can be high to very high, even under unfavourable site conditions;

being robust pioneer species, pines are well suited for reforestation and for simple silviculture (monocultures and clear-felling);

wood qualities that are otherwise in limited supplies in the tropics - of uniform coniferous wood valued for production of lumber, chemical pulp, paper, particleboard, etc

Tragic, isn't it? [/sarcasm]

Multi-scale predictions of massive conifer mortality due to chronic temperature rise

N. G. McDowell net al

Abstract

Global temperature rise and extremes accompanying drought threaten forests1, 2 and their associated climatic feedbacks3, 4. Our ability to accurately simulate drought-induced forest impacts remains highly uncertain5, 6 in part owing to our failure to integrate physiological measurements, regional-scale models, and dynamic global vegetation models (DGVMs). Here we show consistent predictions of widespread mortality of needleleaf evergreen trees (NET) within Southwest USA by 2100 using state-of-the-art models evaluated against empirical data sets. Experimentally, dominant Southwest USA NET species died when they fell below predawn water potential (?pd) thresholds (April–August mean) beyond which photosynthesis, hydraulic and stomatal conductance, and carbohydrate availability approached zero. The evaluated regional models accurately predicted NET ?pd, and 91% of predictions (10 out of 11) exceeded mortality thresholds within the twenty-first century due to temperature rise. The independent DGVMs predicted ?50% loss of Northern Hemisphere NET by 2100, consistent with the NET findings for Southwest USA. Notably, the global models underestimated future mortality within Southwest USA, highlighting that predictions of future mortality within global models may be underestimates. Taken together, the validated regional predictions and the global simulations predict widespread conifer loss in coming decades under projected global warming.

Nature Climate Change (2015) doi:10.1038/nclimate2873







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