assessment of changes in the phosphorus status of forest ...

P %
0.1 0.2 0.3 0.4 0.5
Eiche
4 4,5 5 5,5 6 6,5 7 7,5 8
Vandenburg-Klasse
adequate
low
very low
Fig 5: Relationship between nutrient classes of van den Burg (van den Burg
1985, 1990) for oak and the critical needle P concentrations used in the
nationwide forest soil survey.
2.5 BZE 1 sites – Re-evaluation of data on foliage P and soil P parameters
Data from the BZE 1 study on P concentrations in the foliage samples covered a range
of forest types. Most sites were occupied by conifer, spruce and pine forests.
Deciduous forests, beech and oak are fewer in number. Foliage data from BZE 1 were
compiled into P levels describing the P status of trees (Table 1) and were grouped
according to the soils based on parent materials. The representation of the tree species
in these groups describes the domination of spruce sites, followed by pine and beech
and oak. Using the criteria of P levels in the foliage samples it can be observed that a
33