THE 6TH MASS EXTINCTION
Four iconic trees threatened by climate change
…just when we needed more trees to absorb CO2
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1. The Norwegian Spruce
Found all over European temperate forests and beyond, this is the iconic Christmas Tree. Have you ever noticed, when going on a skiing holiday or mountain trek, how these trees only start to appear at very high elevations? It is because they need two things: good levels of humidity, and most of all, lower temperatures compared to other trees.
Why is it dying?
As the planet heats up, climate change is pushing the habitation zone of these iconic trees towards higher and higher elevations as well as higher latitudes, where they can still find the low temperature conditions that they need.
But what happens when a mountain is not high enough? Well, the trees run out of altitude. They risk literally being pushed off the mountain, and off the planet in some regions.
While the Norwegian Spruce could in theory gradually migrate towards the poles to escape the heat, climate change is happening too fast for the forrests to migrate. Human-assisted planting of seedlings may be required to save the species, although this has never been tested and the effects of disturbing and tampering with entire ecosystems cannot be predicted.
Needless to say, Norwegian Spruce are huge carbon sinks and losing significant parts of these forests would send millions of tons of CO2 into the atmosphere.
2. The Joshua Tree
The iconic Joshua Tree lives in the namesake Joshua Tree National Park in California. It became famous worldwide in 1986 when it appeared on the cover of the U2 album that was called, well, guess: The Joshua Tree. It remains as one of the best-selling albums of all time, with 25 million copies. Now the real Joshua Tree faces an uncertain future.
Why is it dying?
Being a rare, endemic species confined exclusively to the Mojave desert, and growing in an arid environment, the Joshua tree has never had an easy life. As with all xerophytic plants, drought resistance can only go so far. Unfortunately even the Joshua Tree’s patience for rain has been exhausted under California’s new climate. Able to live up to 300 years, the trees are facing their toughest times yet.
The intensity and duration of California’s droughts has meant that the trees are struggling to propagate themselves. The lack of humidity in the ground means that young plants are unable to establish themselves. Older trees are much more resilient as they are able to store large amounts of water in their trunks.
Will there be a next generation of wild Joshua Trees? Or will we have to visit a climate-controlled greenhouse in the future to remind ourselves what they looked like? According to research in the journal Ecosphere, by 2070 the “livable” habitat of the Joshua tree will have dwindled down to 20% of its current surface area.
The Pine Tree
There is no introduction needed here. There are hundreds of pine tree species around the world, covering a significant proportion of the global forest area.
Why is it dying?
Climate Change has disturbed the pine’s equilibrium with one of its most important predators, the pine beetle. The insect makes its home in the bark of the pine, and a typical infestation can easily destroy huge expanses of forest.
However the infestations have been growing more and more extreme. In by far the worst infestation ever recorded, more than 70 million acres across West America have been killed. It is believed that the warmer weather has extended the pine beetles habitat and yearly cycle, while at the same time potentially weakening the pine, making it more susceptible to the insect.
The Olive Tree
Sorry, but this is not a joke. Italy’s olive oil industry is in crisis mode after the country’s olive oil production fell by 57% in 2019. The country is literally running out of olive oil. Climate change has been implicated in this, with the harvest being affected by “erratic rainfalls, early spring frosts, strong winds and summer droughts”.
Why is it dying?
Unfortunately climate is not the only threat for the olive tree. A mysterious fungus, xylella fastidiosa, has been sweeping through Italy, wasting olive groves that have been around for millennia, destroying trees hundreds of years of age that were passed down from generation to generation. The situation is tragic, with olive growers literally trying to quarantine their crops with fences, walls and other ways. The plague has been sweeping ferociously through the country’s Puglia region and parts of Greece killing the trees, and risking infecting other Mediterranean olive-oil producing countries. It is unthinkable that we might, one day, run out of olive oil.
It is not known whether the fungus is directly related to climate change. However, as with all pathogens, opportunistic infestations can happen when trees have already been weakened by other factors. The olive tree prefers a Mediterranean climate, free from the temperature extremes that have been observed lately.
Stay updated by following me as I continue to investigate and discuss The 6th Mass Extinction
