The color of the leaves of conifers changes in autumn

Of deciduous trees you can tell when the leaves turn yellow and fall off, but from most conifers you can’t see from the surface whether they are ready for frost or not. Their leafy greens don’t decay, they just stop working.

It has only been detected laboriously by measuring the action of the needle.

Now the researchers showed that the resting state of the needles can be seen from the color – however, not from the hue distinguished by the human eye, but from a wider spectrum that can be measured with devices.

In use was a hyperspectral camera, which has previously been used to elucidate, among other things, the chemical composition of plants.

The device revealed whether conifers were in a cold-tolerant state, say Russian researchers In Horticulturae. It was most clearly seen in the change of yellowish carotenoids.

The group investigated imported species grown in a southern Russian garden: the East Asian cypress and the North American Canadian and giant cypress.

In addition to ornamental trees, the method could be applied to monitor conifers’ readiness for frost more generally, the researchers suggest. The need increases when climate change makes cold seasons more unpredictable.

Published in Science in Nature 7/2024