Autumn colors

Jouni Laaksonen 10.9.2018

There is a saying ‘Autumn colors are at their best in Lapland 10 o-clock on 10th September.’ Naturally this phenomenon of colorful leaves is not as exact as the saying implies, but there is a truth behind the lore.

Now, why do the leaves of many plants get so vibrant in autumn, just before they drop down?

Leaves of birch, rowan (mountain ash), aspen and different willows are green in summer. The same applies to bilberry, alpine bearberry and other shrubs. This is because of chlorophyll, the dominant pigment that transforms sunshine to energy. In autumn the chlorophyll supply grows thinner and thinner and the other pigments in the leaves become visible. The leaves are shut off the tree’s system and after having blazed colourfully for some days or weeks, they fall off.

How do the plants recognize when it is time to start to prepare for winter? Cooling temperatures are one factor, and often the first below zero night of the autumn is the start of autumn colours. Also the shortening of daylight time is a big factor, and this is why autumn colours are quite well predictable. Daylight time diminishes every year by same schedule.

And indeed, often ruska, autumn colors, is at its best just around tenth of September. This is, in northernmost Lapland. The height of ruska is the later the more south in Finland you go. In Southern Finland leaves are usually colorful in the beginning of October.

 

Different colors

Let’s get acquainted with the most important players in Lapland’s ruska:

Downy birch, as well as silver birch, too, always changes green dress to a yellow one. Alpine bearberry, on the other hand, every time picks fiery red.

Dwarf birch may don orange. Aspen and rowan (mountain ash) are always very colorful, either red or orange.

Blueberry (bilberry) gets often red…

…as well as bog bilberry, too. When the autumn colors are still blazing and there’s first frost or even first snow, the views get even better.

All these together, especially if combined with some relief, produce great views.

 

Autumn colors in fell terrain, Käsivarsi Wilderness Area.

Autumn colors in forested terrain. Southern part of Urho Kekkonen NP.

Note, however, that autumn colors are not always spectacular. On a very rainy autumn green fades more inconspicuously to brown and grey.

One way to get an idea when the autumn colors start to blaze is to see road condition cameras (choose In English, and then on the right panel click other boxes off and Road condition cameras on). These cameras concentrate more on the road, but you can often see the nearest trees also: are the birches green or yellow? Note that there’s variation on the quality of different road condition cameras. If the first ones show poor resolution, click some other places, and you may find a better quality. For instance Kilpisjärvi camera seems to produce much better quality than Leppäjärvi camera, both in Enontekiö municipality.

This summer and autumn have been very dry, so I would presume autumn colors are going to be good! I’m going to go and explore the situation. We’ll start our week long hike at the end of this week, so there won’t be a post next week. Happy hikes!

 

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