Towards improved nitrogen use efficiency in aspen trees

Nitrogen is the main growth limiting nutrient in boreal forests.

Fertilization with nitrogen is however problematic since it tends to have a negative impact on the surrounding environment.

It is therefore crucial to investigate the precise nitrogen requirements but also to optimize the nitrogen use efficiency of trees.

Furthermore, it is important to study the effect of nitrogen on not only the biomass production but also properties, such as wood chemistry, structure and mechanical properties, that are important when designing growth strategies of trees suitable for novel products such as green chemicals and lignin derivatives.

In this project, nitrogen utilization and its effect on wood formation is investigated in the hardwood species aspen and hybrid aspen.

Experiments are devised in both greenhouse and in the field to study the nitrogen requirements of aspen and hybrid aspen, and how different forms and concentrations of nitrogen influence wood quantitative, qualitative and bioprocessing properties.

Nitrogen use efficiency (NUE) is investigated in a natural population of aspen, the SweAsp collection, aiming towards identification of aspen clones with high NUE and some of the underlying molecular mechanisms.

RNA sequencing is performed both after very short and longer nitrogen treatments to identify the primary responses in the cambial zone.

The project is expected to provide information to promote short-rotation cultivation of hybrid aspen in agricultural practices.