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ŠUMARSKI LIST 3-4/1968 str. 17     <-- 17 -->        PDF

AN EXPERIMENT WITH EASTERN WHITE PINE (Pinus strobus L.) IN A
BOTTOMLAND PSEUDOGLEY AND IN A MINERAL-ORGANOGENEOUS
SWAMPY SOIL NEAR KARLOVAC


Summary


In the area of the lowland forests of Pedunculate Oak (Querco-Genistetum
elatae Horv.) in mineral-organogenous swampy soils (district of »Sušje«, plots 1 and
2), and in a bottomland pseudogley (district of »Karabno«, plot 3) were carried out
pedological and plant nutritional investigations, and a study of the grow.h and
increment of 10—13-year-old cultures of Eastern White Pine. For the sake of comparison
identical data were dealt with for a 10-year-old Eastern White Pine culture
in the heather (Genisto-Callunetum croaticum Horv.) on acid brown soil over
lying a relict terra rossa. For assessing the state of the mineral nutrition of Eastern
White Pine cultures, concentrations were taken of the nutrient substances in the
needles of those Pinus strobus cultures which according to previous investigations
exhibited the best growth-rate in Croatia (i.e. on illimerized soils lying on Pleistocen
clayey-loamy sediments and colonized by the forest association Querco-Carpinetum
croaticum Horv.).


Data on the experimental areas


The sample plots Karabno and Sušje, Nos. 1 and 2, are situated 3 and 14 km.
north of Karlovac respectively, and the culture of »Točak« at 13 km. — distance
south of Karlovac. According to data from the nearest weathetr station of Karlovac
(1948—1960 observational period) for the investigated area the following mean
seasonal temperatures and rainfall are valid: spring: 11.0" C and 248 mm., summer:
20.4" C and 284 mm., autumn: 11.3° C and 311 mm., and winter: 1.5» C and 278 mm.
The mentioned cultures were established in the 1956—1962 period by planting
2500—3500 two- to four-year plants per hectare. The hydromorphic soil in cultures
of »Sušje«" (plots 1 and 2) is characteristic of temporary waterlogging of the soil by
surface and underground waters, while for the »Karabno« culture a recent pseudogleyification
of the soil is specific. Data on several physical and chemical properties
of the soil are in Tab. 1.


Results


The development so far of the cultures studied has been evaluated by the
authors as very promising. The most successful culture (»Sušje«, 2) on a mineralorganogenous
swampy soil at the age of 13 years exhibits a mean height of 7.3 m.,
mean diameter b.h. of 10.6 cm., and a total standing volume (stemwood) of ca. 93
cu.m./ha. It was established that on mineral-organogenous swampy soils and on
bottomland pseudogleys Eastern White Pine is a shalow-rooting species. The state
of the mineral nourishment on the basis of concentration of mineral nutritive
substances in the needles at the end of two growing periods was evaluated as being
favourable. The obtained data are consistent with the nutrient content found in the
soil and the growth of cultures. On the ground of these and some previous investigations
the authors consider the state of nourishment of Eastern White Pine
cultures with nitrogen and phosphorus in Croatia very favourable if their concentration
in one-year needles is 1.67—1.8611/» N and 0.41—0.45´Vo PsOs. A positive effect
of Eastern White Pine on the biological accumulation of substances in the soil was
also established.


Tables and Figures


Tab. 1. Some physical properties of the soil in Eastern White Pine cultures.


Tab. 2. The state of some factors of fertility of the soil under an Eastern White Pine
culture, and on the same site under natural conditions (investigated in
October, 1966).


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