Zentralstelle der Forstverwaltung - Landesforsten Rheinland-Pfalz

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for deadwood. Corg pools vary between 90 and
528 t/ha with a median of 228 t/ha for the bze
ii plots. the most important carbon reservoir is
the growing stock (Median 114 t C/ha), followed
by mineral soil (78 t/ha), humus layer (17 t/ha),
deadwood (5,7 t/ha) and ground vegetation (0,16
t/ha). ecosystems dominated by spruce have the
highest, ecosystems dominated by oak the least
carbon pool. the Corg storage of the soils does
not distinguish significantly between both investigations
in Rhineland-Palatinate.
a regression analysis showed that C storage in
the humus layer depends mainly on growing
stock (percentage of spruce and pine) and water
regime of the site. C storage in the mineral soil
depends on the total annual precipitation, the
clay content and the water regime of the sites
(sauer et al. 2012).
heavy metal pollution
at the bze i the concentrations of Pb, Cu, Cd
and zn in the humus layer were investigated. in
addition at the bze ii the heavy metals Cr, ni, as
and hg were investigated in the humus layer and
in all mineral soil depth levels, each with a aqua
regia extraction. While the lead contents were
clearly reduced in the humus layer between the
bze i and the bze ii, the contents of Cr, Cd and
zn show no significant changes. at 13 (hg) to 59
% (Cr) of the plots the precautionary values for
the humus layer after PRÜss (1994) and at < 2 %
(hg, Cr) until 55 % (ni) the precautionary values
for humus-poor mineral soils after bundesbodenschutzverordnung
(1999) were exceeded. at < 1
% (hg, zn, Cd) to 30 % (Cu, Cr) of the grid points
harmful effects on soil biota are to be expected
according to guideline values after tyler (1992).
the distribution patterns of relatively high heavy
metal contents indicate an overlap of several
sources. Most of Rhineland-Palatinates parent
rock materials already contain higher geogenic
heavy metal contents. furthermore diffuse heavy
metal inputs into top soils were caused by two
thousand years of mining normally connected
with local smelting of ores. Younger diffuse inputs
e.g. lead from the traffic increased the already
existing load. only for a few plots local industrial
sources were identified.
Regeneration ability of forest soils
for the estimation of the ability for regeneration
of forest soils with historical depleted and
through excessive pollutant input impaired buffer,
filter and storage functions acid-extractable
nutrient storage, mineral compounds of the
substrates, weathering state of clay minerals and
calculations of the nutrient supply by mineral
weathering were used.
the acid-soluble calcium storage was classified
as “low” and “very low” at two thirds of the
grid points. on the other hand, the acid-soluble
magnesium and potassium storage at two thirds
of the plots was assigned to the classes “high” or
“very high”.
the results of the mineral analyses were used
to define mineralogical based substrate classes
following a proposal of butz-braun (2009).
illite-rich substrates are most frequently and
occur at almost half of the plots. also quartzrich
substrates play an important role in the
Rhineland-Palatinates forests and occur at 16
% of the grid points. at 13 % of the plots the
mineralogical analyses referred to destruction of
the clay minerals. substrates with comparatively
high buffer potential like carbonate-, amphibole-
and smectite-containing substrates are quite rare
with a total of 13 % of the plots in Rhineland-
Palatinate.
simulations with PRofile show for many plots a
comparably high delivery by mineral weathering
for potassium in particular on the illite-rich substrates
of the Rhenish Massif, however very often
only a weak delivery for calcium.
Compensation liming
the bze-data prove very clearly the effects of
the compensation liming which had been done
on about two thirds of the woodland area of the
state. the comparative evaluation of limed and
not limed bze-plots shows that the improvement
of the acid-base-state of forest soils basically
appeared only in the limed collective while in the
collective of the not limed plots no significant
changes occurred. the bze-data prove a precise
selection of the limed sites. the limed collective
showed clearly a smaller base saturation before
the liming when compared to the not limed coll-