A New Fertilization Strategy in Declining Forests

Abstract

A~stract.In central Europe and to some degree in North America, the so called "new type" forest d~ages occur over large areas. Various studies indicate the declines are more or less frequently associated with nutritional disturbances that have developed within rather short time periods. The most common disorder is a Mg deficiency that produces specific discoloration symptoms such as tip-yellowing in Norway spruce. But also K deficiencies and other disturbances exist in coniferous as well as in deciduous forests. Good correlations between the site specific substrate chemistry and the actual nutritional status of the trees and stands were found.To explain the sudden and widespread development of the forest declines adverse anthropogenic influences such as increased N and H + deposition, land use and forestry mismanagement as well as natural stresses ere discussed. Soil analyses also revealed a positive change of the chemical soil status when site and stand specific fertilizer applications were utilized in the appropriate amounts. However, under certain site and stand conditions risks and limitations exist that have to he evaluated when fertilization practices are discussed.To overcome or minimize these influences the treatments must be adapted to the site, and stand specific fertilization needs as indicated by soil and feller analysis, humus form, hydrologic parameter and atmospheric deposition rates.

<b>Liming and fertilisation in <i>Pinus taeda</i> plantations with severe nutrient deficiency in savanna soils

“…The symptoms of Mg 2+ deficiency in forest plantations and the study of appropriate rates of Mg fertiliser have been investigated since the 1980s in various regions of Germany (EVERS; HÜTTL, 1990;HÜTTL, 1989;ZÖTTL, 1993;UEBEL;HEINSDORF, 1997). In a review paper on conifer plantations in Germany, Hüttl and Zöttl (1993) concluded that the application of Mg 2+ through liming was effective at increasing the Mg level in the soil and reversing the nutrient deficiency symptoms.…”

Mineral nutrients of beech (Fagus sylvatica) bark in relation to frost sensitivity and soil treatments in southern Sweden

“…Soil conditions have been improved, acidity and the amount of free Al ions have been reduced. Wood ash and nonnitrogenous fertilizers are applied to improve the nutrient status [9]. Trees have nutrient reserves in the trunk which are used during the vegetative period, thus soil treatment is not expected to change their nutrient status within a short period [14].…”

Excess nitrogen affects the frost sensitivity of the inner bark of Norway spruce

“…Leaching of nutrients from needles and increased soil acidification which causes leaching of nutrients from the soil may contribute to nutrient imbalance in trees [13,28]. Increased growth, in response to increases in N availability, may induce deficiencies in other nutrients as a result of dilution effects [1].…”

“…The cause of this reduction in tree nutritional status is not clear but high N deposition and soil acidification in the area are considered to be the major factors [21]. To counteract nutrient deficiencies or imbalances in trees, vitality fertilization with ash and different types of mineral fertilizers can be carried out [13,30].…”