Cajanus tube conquers Norway

I returned last Friday from Norway, where I participated my first ever field measurement campaign outside Finland. Svein Solberg from Skog & Landskap contacted us to ask if some Cajanus tube experiments in Norway could be arranged. As Miina was busy with her travels, I volunteered for a substitute. And so after the usual flight and train travels I found myself in a farmhouse guest cabin, sitting nicely above a river valley near Svarstad in Southern Norway. And the river Lågen seemed to swarm with fisherman and salmon, wish I had known to bring my fishing tackle…

River landscape

The plan for next days was to make some Cajanus tube measurements and compare results to terrestrial laser scans obtained from the same plots. So I headed to forest with the TLS team, and had some time to follow their work before Svein and others arrived to discuss how the measurements should be arranged. We decided to do very typical dot count sampling but record also gaps inside the foliage, which is more difficult than usual between-crown gap measurement.

Terrestrial laser

Following days were typical field work with small differences to Finnish conditions, like climbing up to 30 minutes before arriving to the plot, cow dung and sound of the bells in the forest, and a Norwegian Cajanus tube that was considerably sturdier than the Finnish ones. Norway spruce forests were quite similar to Southern Finland, except usually more sloping. Also the rain that hindered our attempts was a very familiar experience… All in all, even though the final plot result remained once again smaller than planned, the campaign was definitely a success: also Norway now belongs to the international Cajanus tube family.

Two Cajanus tubes and an American implementation, GRS densitometer.