Broad-Leaved Tree Growth Modulated by Industrial Air Pollution in the Northern Romania (Baia Mare Region)

Abstract

Atmospheric pollutants over the last century have led to increased negative impacts on the environment, especially on forest ecosystems. In the Baia Mare region of Romania, the influence of pollution on the neighboring forests of the municipality has been reported since 1970, and its negative effects have been reported mainly in the form of reduced tree growth, which implies significant losses of wood biomass. The objective of this study is to analyze the temporal and spatial effect of industrial pollution on the auxological processes of beech trees in this region. Quantification of auxological changes was performed by analyzing the resilience, recovery and resistance indices. The most intense negative effect of local pollution with heavy metal dusts, sulfur and nitrogen oxides, and sulfuric acid vapors, on the auxological processes of beech trees was found in the period 1960–1990, with a maximum in the period 1970–1980, when the mining activity was at its highest intensity. Beech trees responded to the negative effect of pollution by significantly reducing their growth during the period affected by local pollution, and after 1990 they resumed their auxological activity close to normal. In addition, it was noted that the index that best captures the effect of pollution over time is the resilience index. Tree growth resilience, recovery, and resistance assessment and analysis significantly contributes to our understanding of trees response to environment pollution more broadly creating also the base for strategic planning initiatives with valuable insight into the efforts of making the forests more resilient and resistant.