Small burrows into grass & lack of trees ?

[kennysou]

Hello,

I was up Glen Taitneach a few weeks back. It was not much fun, mounds of wet snow everywhere impeding progress so I shortened my trek.... anyway... what caught my eye from time to time were numerous holes in mounds of grass, about the diameter of a 50 p piece & 10-15 cm deep, the grass looking like it had been twisted down into the mounds of grass, like the way one would twist in a screw. What animal might have made the holes ?

On another note, why is there a lack of trees on Scottish mountains ? I ask as I see that trees are found at high altitude in the likes of France, the US, Canada and Afghanistan. Is the lack of trees as a result of the acts of men over the years or a combination of Scottish climate & geography ?

Thanks all...

[CharlesT]

I can answer the former straight away - field voles. The latter will require a bit more research, but for starters land clearance occured in the late neolithic through to the iron age as the climate warmed and more of the uplands could be brought into cultivation and population density increased. Later on a cooling climate resulted in the development of blanket bog and though agriculture became unsustainable in this environment it was also not conducive to extensive tree growth. Maybe birch and alder scrub and ericaceous plants, lings and heathers, but not forest trees. Lower altitudes were probably populated eventually by Caledonian pine which were extensively cleared from the middle ages on. There is also the question of the effect of grazing by growing deer populations to be considered. That's without referring to my source publications, may have to correct parts if my memory has failed me.

[Skyelines]

This is an interesting read http://press-files.anu.edu.au/downloads/press/p223441/html/cover.html?referer=146&page=0#

The first chapter covers the natural history.However there are alternative views of the history.

[jmarkb]

Good answer, CharlesT! The natural treeline in Scotland is around 500-600m, depending a bit on aspect. This is largely due to poor soils, strong winds and cool summer temperatures, rather than cold winters or snow cover.

[CharlesT]

This is an interesting read http://press-files.anu.edu.au/downloads/press/p223441/html/cover.html?referer=146&page=0#

The first chapter covers the natural history.However there are alternative views of the history.

Thanks for the link. Interesting as you say, quick skim only as of now. Reminded me of how much I have forgotten and how complicated the whole subject is. I will now have to revisit my little collection of relevant publications.

[Caberfeidh]

Those voles are crazy wee creatures, sometimes the moor seems alive with wee sleekit scurrying beasties. Their populations rise and fall; sometimes a glut of voles helps predators reach large numbers as their young can all be fed well on voles, then the population crashes and the predators which depend on them crash too. They seem to live quite happily under the snow cover, down among the dried grass tussocks. When the snow melts away the little tunnels through the undergrowth are obvious.
The lack of trees in the highlands is mostly due to human interference; cutting down trees and allowing grazing animals to roam freely so no seedling grows unmolested. If an area is fenced off so no deer, hares or sheep can get in, then forestry grows back fairly quickly. In Glen Feshie where the overly-large deer population restricted tree growth, a massive deer cull happened, and for three years nothing seemed to change, then suddenly young pines appeared, and the whole area is now flourishing with a new forest growing form naturally occurring seedlings. I had thought that cold weather and sea gales were mostly responsible for the lack of trees in the Western Isles; Harris in particular seems almost lunar in its lack of trees; but when I visited Norway, Sweden and Finland I noticed that trees grow from the water's edge to high up on the mountains, purely because they do not farm free-range sheep in the way they are farmed in Scotland, and it is very common for people to shoot deer in Norway. In the U.K. shooting deer is a preserve of the wealthy and privileged, most people never even taste venison, whereas in Scandinavia it is common for most families to have someone who shoots game, and game is a large part of the people's diet. So there is not the pressure of grazing on forestry there that we have here. A massive cull of deer and sheep would help, but I don't think people like the idea.

Kristiansund, Norway.

[kennysou]

Hello & thanks to everyone for their detailed & helpful responses; the link provided by Skyelines to the book is a pretty good read.