Changes in carbon allocation patterns in spruce and pine trees following irrigation and fertilization

Area of Science:

• Forestry science
• Ecology
• Plant physiology

Background:

• Long-term forest management studies are crucial for understanding sustainable yield.
• Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) are key commercial tree species in Northern Europe.
• Nutrient availability and water are primary limiting factors for forest growth.

Purpose of the Study:

• To evaluate the long-term impacts of fertilization and irrigation on forest stands.
• To determine the effects of nutrient and water management on stemwood production and biomass allocation.
• To assess the interaction between irrigation and fertilization on ground vegetation response.

Main Methods:

• Conducting long-term field experiments involving Scots pine and Norway spruce.
• Applying different fertilization regimes, including balanced macro- and micronutrients.
• Implementing irrigation treatments and monitoring their effects.
• Measuring stemwood production, biomass allocation (leaf, fine roots, coarse roots), and ground vegetation response.

Main Results:

• Balanced fertilization significantly increased stemwood production in both species over 12 years.
• Irrigation alone showed minimal impact on stemwood production but enhanced ground vegetation response to fertilization.
• Fertilization decreased the ratio of fine roots to total biomass.
• Drought conditions reduced the ratio of coarse roots to fine roots, indicating shifts in root architecture.

Conclusions:

• Optimized fertilization, particularly with balanced nutrients, is key to enhancing forest productivity.
• Water availability significantly influences the effectiveness of fertilization strategies.
• Forest biomass allocation is sensitive to nutrient and water availability, impacting root development.