Neuere Werke scheinen sorgfaeltiger zwischen "timberline" und "treeline" / "tree line" zu unterscheiden, waehrend die Begriffe in aelterer Literatur oft mehr oder weniger synonym gebraucht werden (z.B. EB). Note: "timberline" is usually written as _one_ word.

Landscape: Pattern, Perception and Process by Simon Bell, pg 174:
There is a terminology to distinguish between different parts of a treeline. The 'timberline' refers to the upper limit of continuous canopy forest. The 'treeline' is the limit for individuals to grow erectly up to two metres tall and be recognizable as trees. The 'tree species line' defines the limit where trees will grow, although by this time they are stunted and deformed. The area between the timberline and the tree species line is called the 'kampfzone' (zone of struggle) where the decrease in height, density, canopy continuity and increase in shrubbiness and presence of dwarf trees occur.

Dances With Trout by John Gierach, pg 17:
This is the area that lies between timberline (above which trees won't grow tall and straight) and treeline (above which trees won't grow at all). It's called krummholz: a German word meaning "crooked wood."


Encyclopedia Britannica:
timberline
upper limit of tree growth in mountainous regions or in high latitudes, as in the Arctic. Its location depends largely on temperature but also on soil, drainage, and other factors. [...]

Tree lines
As one proceeds northward or as the elevation increases, the height of the trees gradually decreases while the spacing between them increases until a point is finally reached where the trees give way to tundra. This is called the tree line.
[...]
The transition to the treeless condition is more commonly gradual. Initially in a closed, tightly spaced forest (forest line), the spacing between trees widens rapidly as tree height decreases (the kampf zone). This zone gives way to a region of low twisted and stunted trees called the krummholz.

Wenn es dieselbe Unterscheidung aber auf Deutsch nicht gibt, ist diese semantische Frage für LEO irrelevant. Wichtiger wäre zu klären, ob timber line AE ist.

In meinem IUFRO (Internation Union of Forestry Research Organizations) World Series, Volume 9, 1998 wird zwischen Baumgrenze und Waldgrenze wie folgt unterschieden:

Baumgrenze = timber line / tree line(in 2 Wörter:-))

Seehöhenmäßige Begrenzungslinie über der das Wachstum von Einzelbäumen klimatisch bedingt nicht mehr möglich ist.

Waldgrenze = forest boundary / forest limit
Klimatologisch/Seehöhenmäßige doer der geographischen Breite entsprechende Begrenzungslinie, außerhalb deren das Wachstum von Beständen (Bestockungsgrad) > 0,3 klimatisch bedingt nicht mehr möglich ist.
Nach Bodennutzungsart: Trennunglinie zwischen Wald und anderen Bodennutzungsarten. Der Begriff wird im allgemeinen für standörtlich bedingte Begrenzung des Waldes benutzt.

1) timber line
n
(Earth Sciences / Physical Geography) the altitudinal or latitudinal limit of normal tree growth
See also tree line

Collins English Dictionary – Complete and Unabridged © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003

2) Noun 1. timber line - line marking the upper limit of tree growth in mountains or northern latitudes
timberline, tree line
line - a spatial location defined by a real or imaginary unidimensional extent

Based on WordNet 3.0, Farlex clipart collection. © 2003-2008 Princeton University, Farlex Inc.


3) Die Waldgrenze ist der Rand des Lebensraums, in dem Bäume geschlossene Bestände bilden.

4) Davon zu unterscheiden ist die Baumgrenze, jenseits derer auch keine einzelnen Bäume oder Baumgruppen mehr vorkommen.

5) The tree line is the edge of the habitat at which trees are capable of growing. Beyond the tree line, they are unable to grow because of inappropriate environmental conditions (usually cold temperatures, insufficient air pressure, or lack of moisture).

S o m e distinguish additionally a deeper timberline, where trees can develop trunks.



http://encyclopedia.thefreedictionary.com/treeline

forest limit = Waldgrenze