Less impact to camp above or below the tree line?

Question

What has less impact from an ecological point of view — camping below or above the tree line? US and Swiss organisations appear to contradict each other:

From the American lnt.org comes the advise (or rather order) to not camp above tree line:

Travel and Camp on Durable Surfaces: While visiting these areas stick to the trail or bare rock to help protect this beautiful environment. Camping is not permitted above tree line.

However, from the swiss alpine club comes the advice it is better to camp above tree line:

Aus ökologischer Sicht sind Standorte oberhalb der Waldgrenze meist unbedenklich.

Meaning from an ecological point of view, locations above the tree line are usually unproblematic. They advise to particularly avoid the forest near the tree line, as animals seek shelter there, but otherwise their reasoning appears to be: the higher up, the less life, the less humans are disturbing (plus the lowest elevations in the Alps are more often in use by humans).

It would seem that in alpine territory, durable unvegetated surfaces are more common the higher one goes, until reaching the territory of only snow and ice, where all surfaces are durable (ecologically speaking). On the other hand, a lush warm rainforest may recover much more quickly if I do camp on vegetated surfaces. From an ecological point of view, aiming to leave no trace, should I rather camp above or below the tree line?

The other advice from the Swiss organisation (bury human waste, carry out toilet paper, camp on durable surfaces, etc.) agrees with what I have read from American organisations.

Answer 1

Summary: I suspect that this is a question of whether the glass is half full or half empty:

• "you can camp unless [list of factors that prohibit camping]" vs.
• "you cannot camp unless [list of conditions that need to be fulfilled to allow camping]"

The order to not camp above the tree line in the LNT post is a legal regulation for the White Mountains. Thus corresponding to the Swiss "no camping in [pick any of the Swiss protected areas]".

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• The LNT website has the general rule to Camp on Durable Surfaces and besides saying that judgment about the local conditions is required explains:

   The most appropriate campsites in arid lands are on durable surfaces, such as rock and gravel

  Which is a criterion that would be met in alpine regions sufficiently high above the tree line so that there is no vegetation. Note that rock or gravel also means "no soil to disturb".

• Though I find it somewhat ambiguous, my impression of the LNT post is that it applies the LNT rules to a particular region (Franconia Notch, NH).

• High altitude wild camping in the US:

  • The National Forest Service and Bureau of Land Management allow dispersed camping, or camping outside developed campgrounds, on public lands except where specifically prohibited. [...] Alpine soil above the treeline is very fragile; it can take years to repair damage from footsteps or driving in tent stakes. For this reason, alpine terrain is often off limits to campers.

    source (emphasis mine)

  • In the White Mountains National Forest in New Hampshire/USA which surrounds Franconia Notch, camping is prohibited in the alpine zone where trees are < 8 ft (except with > 2 feet snow) (official backcountry camping leaflet with more details)

  • Camping in N.H. State Parks [such as Franconia Notch] is only permitted in organized campgrounds

  I conclude that the order to not camp above tree line is a legal requirement in that specific region.

• There are lots of regions in the Swiss Alps that are above the tree line and are "no camping": The offical map linked in the Alpine Club post shows plenty of the protected areas to be well above the tree line.

• The Swiss are very clear that the ecosystem at the tree line is rather fragile, and one should not camp there.

• One specialty of the Alps is that due to Almwirtschaft at the high pastures, there is often no clear forest line but rather zone with a transition from alpine forest to meadow to no vegetation, or the forest line is artificially low due to pasture use. It may be difficult to judge where the forest line would be without grazing. Pasture land that does not have further factors that make it particularly vulnerable (e.g. mountain bogs) above the factual/current forest line can be well able to cope with a low density of LNT campers. And camping there may be less disturbing to wildlife than camping at the fringe of the forest or the transition zone.

• There are probably further considerations.

  • E.g Switzerland has a general right for everyone to access forests and pastures (including e.g. the right to collect mushrooms or berries for private use; camping needs permission of the owner, though), regardless of whether they are privately owned or not. AFAIK, this is not the case in the US.
    This also means that in Switzerland "hiking land" includes lots of not particularly vulnerable land that would not be "hiking land" in the US and that does not require paricular restrictions on LNT/low impact (single person, single night) camping from an ecological point of view.

  • In general, however, it is up to the Kanton (and the community) to decide camping/bivouac rules. And there seems to be a whole lot of regional variety

  • Not sure about Switzerland, but Geman Länder distinguish bivouak (no tent) from camping (with tent). In Switzerland, Obwalden distinguishes between "camping" and "staying one night" (including in a tent). The list above suggests that some Kantone distinguish single person from groups.
    Also, if you look at the Obwanlden example above, it specifies that you are not allowed to disturb any private or public interests. Thus, you cannot stay where you'd disturb any fragile ecosystem.

Answer 2

I would say less impact to camp below the tree line. One reason alpine camping is discouraged in the US is to protect the cryptogamic/cryptobiotic crust.

"Crusts are easily disturbed and extremely slow to recover. Considering the growing number of backcountry users, it is imperative to improve alpine resource managers understanding of the ecology of these fragile organisms." From UW report to USDA

Also known as biological soil crusts, they are communities of lichens, mosses, algae, and cyanobacteria that cover the surface where vascular plant growth is restricted due to harsh environmental conditions (desert, alpine, arctic etc.). Alpine systems are slow to recover from damage due to the short growing season, harsh climate, and nutrient-poor soils. The living crusts are the basis of the alpine food web and provide important ecological functions of nitrogen fixation, soil insulation, and increased nutrient and moisture retention.(Crisfield et al. 2018)

Answer 3

You are ignoring the context.

The full paragraph is:

Überlege dir vorab gut, wo du übernachten willst und nimm dabei Rücksicht auf die Natur. Suche dazu auf der Landeskarte möglichst unproblematische Lebensräume. Meide Auen- und Feuchtgebiete, da sie oft seltene Pflanzen beheimaten. Aus ökologischer Sicht sind Standorte oberhalb der Waldgrenze meist unbedenklich.

Which translates to:

Think carefully in advance where you want to stay overnight and be considerate of nature. To do this, look for habitats that are as unproblematic as possible on the national map. Avoid floodplain and wetland areas as they are often home to rare plants. From an ecological point of view, locations above the tree line are usually harmless.

The swiss are not recommending that it's better to camp above the treeline, they are noting that you should avoid extremely problematic areas and are listing the areas above a treeline as less problematic.