Functional Biodiversity Aspects on the Nutrient Sustainability in Forests-Importance of Root Distribution

Nutrient availability is of major importance for plant productivity. When estimating long-term sustainability from a nutrient perspective it is therefore interesting to focus on long-term changes in the soil nutrient pools when comparing different forest types. Here, we have highlighted some factors of importance for long term nutrient sustainability (e.g., several forest rotations) and pointed out some important features that differ between forest tree species and also between monocultures and mixed species stands. Using computer models like PROFILE reveals tree rooting depth to be a crucial factor when assessing long-term nutrient sustainability. Literature studies show that soil type and other soil conditions have a strong effect on root distribution. However, Norway spruce is generally a very shallow rooted species, with approximately 80% of it fine roots in the top 20–25 cm, whereas for pendiculate oak, generally 80% of the roots are found down to 60 cm soil depth. Rooting depth of Scots pine and beech seem to be intermediate with 80% of the roots down to approximately 25–30 cm and 30–35 cm, respectively. Importance of mycorrhiza for nutrient uptake in a sustainability perspective is discussed in the paper.