Exotic pines from the southern hemisphere grow faster and withstand drought better

One of the most widely accepted ideas in plant ecology is that plants cannot grow rapidly and at the same time tolerate water stress. This concept is called into question by a new study, which indicates that exotic pines from the southern hemisphere are capable of doing so.

The team warns that the results do not mean that reforestation with exotic species is a general solution to the climate crisis, since their introduction can also have repercussions on the biodiversity of native ecosystems.

In fact, some of the conifers studied are invasive species in the southern hemisphere, such as the contorta pine, whose spread beyond plantations poses a conservation problem for the native ecosystems of the Aysén region, in Chile, the IEB recalled in a note.

What the study consisted of

A total of 192 sites distributed across America, Europe, Africa and Oceania were analyzed in native and exotic populations, to determine the width of annual growth rings, which are closely related to climate.

The exotic conifers reached growth rates up to four times higher than those of northern hemisphere populations, and the most striking finding was that this was not accompanied by a lower tolerance to drought, as would be expected.

The southern hemisphere populations showed greater resistance and resilience during drought periods, meaning that their growth was less affected by the lack of water and they had a greater capacity to recover after those episodes.

The team also discovered differences in the functioning of these trees that help explain this behavior. The conifers growing outside their natural range had higher concentrations of carbon reserves.

These reserves, also known as non-structural carbohydrates, play an essential role in plants and have been associated with a greater capacity to cope with periods of water stress.

The carbon isotopic signature in the exotic conifers growing in the southern hemisphere was related to a greater capacity to maintain photosynthesis under water stress conditions.

One possible reason for this advantage of the exotic conifers is related to the absence of natural enemies, so their growth and carbon balance are not altered.

Source:ABC.com