looduskalender.ee

Aspen leaf

Aspens have been offering an amazing array of colours quite some time by now. Aspen forests are the third largest, after birch and alder woods, and as pure aspen forests they grow best in eastern and south-eastern parts of Estonia. With the love for fertile growth-soils, the aspen is our nature`s fastest growing forest tree. It has a strong and wide root system, which provides plenty of root shoots after logging. Old aspen forests are incomparable to other tree stands when it comes to biodiversity.

 

„Shakes like a leaf“ – but still, why does it shake?

 

The movement of aspen leaves with the slightest wind is caused by the shape of the leaf. The leaf blade is round and the stalk is relatively long, almost the same length as the leaf. According to the laws of physics, a leaf shaped like that has to flutter in the slightest winds.

 

However, there is another question - how is this useful for the tree? Let us look at some different assumptions: leaves which are constantly moving are able to catch solar energy more efficiently, or secondly, more water evaporates from the surface of constantly moving leaves and so the root system must provide the aspen tree with a larger amount of water and thus also with nutrients. It is what it is, but it is certainly true that aspens grow faster than other trees and perhaps this is also the reason why its wood is soft.     

 

The aspen has not been appreciated the way it should be as firewood: logs burn without crackling, with a low flame, keeping the glass-doors of fireplaces and stoves clean and there is less soot in the chimneys and flues.

Aspen forest at Pedja river. Altmetsa, Alam-Pedja

Phellinus tremulae

Phellinus tremulaeis a tree mushroom – fruiting bodies grow on the surface of the wood, often located in the axils of „dead branches“. But they cause heartrot in the wood. Damaged aspen trunks become frail and they break easily in storms. It is not easy to find an old tree, which would not have the hoof-shaped fruiting bodies of Phellinus tremulae which sit tight on the trunk.