Relations between Scots pine needle element concentrations and decreased needle longevity along pollution gradients

Area of Science:

• Environmental Science
• Forest Ecology
• Plant Physiology

Background:

• Industrial and urban pollution pose significant threats to forest ecosystems.
• Scots pine (Pinus sylvestris L.) is a key species in many European forests, sensitive to environmental stressors.
• Nutrient dynamics and needle longevity are critical indicators of tree health under pollution stress.

Purpose of the Study:

• To investigate the impact of urban pollution and smelter emissions on Scots pine needle nutrient concentrations and longevity.
• To determine the relationship between heavy metal accumulation, nutrient levels, and needle age.
• To explore the role of manganese leaching in nutrient depletion in polluted environments.

Main Methods:

• Scots pine shoots were collected along transects extending from an urban pollution source and two smelters.
• Needle samples were analyzed for concentrations of magnesium (Mg), phosphorus (P), potassium (K), and manganese (Mn).
• Needle age classes were correlated with nutrient concentrations, needle survival, and proximity to pollution sources.

Main Results:

• Needle Mg, P, and K concentrations decreased with needle age along the urban pollution gradient, though over 80% remained in older needles.
• Reduced needle longevity was strongly correlated with elevated heavy metal concentrations near smelters.
• Decreased Mn accumulation with needle age was observed near all pollution sources, suggesting leaching as a potential cause.

Conclusions:

• Urban and smelter pollution significantly impact Scots pine nutrient status and needle longevity.
• Heavy metals from smelters are closely linked to decreased needle lifespan.
• Manganese leaching from needles and soil is a likely contributor to reduced Mn concentrations in polluted areas.