Analysing the mechanical performance and growth adaptation of Norway spruce using a non-linear finite-element model and experimental data

• Published in: Journal of experimental botany 2008-06, Vol.59 (9), p.2513-2528
• Main Authors: Lundström, T, Jonas, T, Volkwein, A
• Format: Article
• Language: English
• Subjects: Acclimatization; Agronomy. Soil science and plant productions; Bark; Bending; Biochemistry and biology; Biological and medical sciences; Chemical, physicochemical, biochemical and biological properties; Climate; Computer Simulation; Coordinate systems; critical load; Ecosystem; Frozen soils; Fundamental and applied biological sciences. Psychology; mechanical optimisation; Microbiology; model performance and errors; Nonlinear Dynamics; Physics, chemistry, biochemistry and biology of agricultural and forest soils; Picea - chemistry; Picea - growth & development; Picea - physiology; Plant adaptation; Plant Stems - chemistry; Plant Stems - growth & development; Plant Stems - physiology; Research Papers; Rotation; Shear stress; Snow; Soil science; stem taper; Stress, Mechanical; structural behaviour; thigmomorphogenesis; Tree crowns; Tree growth; Trees; Wind
• ISSN: 0022-0957; 1460-2431
• DOI: 10.1093/jxb/ern116

Thirteen Norway spruce [Picea abies (L.) Karst.] trees of different size, age, and social status, and grown under varying conditions, were investigated to see how they react to complex natural static loading under summer and winter conditions, and how they have adapted their growth to such combinations of load and tree state. For this purpose a non-linear finite-element model and an extensive experimental data set were used, as well as a new formulation describing the degree to which the exploitation of the bending stress capacity is uniform. The three main findings were: material and geometric non-linearities play important roles when analysing tree deflections and critical loads; the strengths of the stem and the anchorage mutually adapt to the local wind acting on the tree crown in the forest canopy; and the radial stem growth follows a mechanically high-performance path because it adapts to prevailing as well as acute seasonal combinations of the tree state (e.g. frozen or unfrozen stem and anchorage) and load (e.g. wind and vertical and lateral snow pressure). Young trees appeared to adapt to such combinations in a more differentiated way than older trees. In conclusion, the mechanical performance of the Norway spruce studied was mostly very high, indicating that their overall growth had been clearly influenced by the external site- and tree-specific mechanical stress.