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We all know about droughts and how harmful they can be – not just for the trees and other plants, but for all (plant and animal) life in general. Droughts put a lot of stress on trees and their ecosystems. One way that droughts do this is by decreasing the water levels in the soil to dangerously low values. This, in turn, weakens both the soil and the tree – leaving it more vulnerable to infestation, infection and eventual death.

And, that is droughts in a nutshell – a full-blown natural (sometimes man-made) disaster.

But, sometimes, you don’t need a full-blown natural disaster to kill trees. Sometimes, just hot weather is enough. Yes, you read that right. High temperatures alone can be very harmful to trees. This is especially true today when global temperatures are at an all-time high and rising at historically unprecedented rates. So, it becomes ever so important for us to understand how these rising temperatures affect our trees.

Energy balance in trees – photosynthesis and respiration

Now, high temperatures lower the rate of photosynthesis and respiration in trees. However, they affect photosynthesis more i.e., photosynthesis rates are lowered much more than respiration rates. What this means is that the tree is now using more energy than it is producing. This creates a very negative balance in the tree’s biology.

Evaporation, water loss, and cell structures

Faster rates of evaporation (because of all the heat in the atmosphere) lead to more water loss through the leaves of a tree. This, in turn, puts the root system of the tree in stress – likely because high temperatures usually mean low rainfall and low rainfall means low soil moisture levels. So, now, the roots cannot take up any water from the soil to cool the tree either. As you can guess by now – these problems compound fast… to the point where event the plant’s cell membranes start to break down at an atomic level.

Natural plant response and also – what you can do to help

So, how do the trees deal with these high temperatures? Well, there are many ways. Life has evolved to adapt well and one of the ways in which trees deal with high temperatures is through heat-shock proteins. Heat shock proteins stabilize the rest of the proteins in a tree. This ensures normal cell functioning, even in high temperatures. Similarly, calcium also helps stabilizes many enzymes and membranes in the tree. Other ways in which trees deal with high temperatures is through growing more leaf hair and wax, changing the anatomy and the arrangement of its leaves, etc.

And, we as humans can help trees in giving them the best fighting chance against heat by taking care to plant them in only the highest quality soil that is both fertile and well irrigated. Always consult an arborist on staff with a tree service company.