LCF5771 - Tree Biomechanics

Credit hours

Instructor
José Nivaldo Garcia

Objective
Develop an in-depth theoretical-practical study of the reaction of tree and forest to internal and external forces and stimuli during individual and joint development.
Producing and analyzing models of wind-tree and wind-forest interaction and also of forest management, focusing on the impacts on survival, productivity, yield of sawnwood and quality of this wood for uses in the timber industry.

Content
The content is subdivided into six modules;

1 Action of the wind in the trees
-Wind obstruction area (canopy and trunk)
-Concentrated and distributed wind force
-Diagram of bending moment and tensions along the shaft
-Weight of the canopy at different levels of temporary water on the surfaces of the leaves and branches -Center of gravity of the crown and tree

2 Impacts of forest management
-Competition factors
-Reorientation of crown and stem
-Density and persistence of the branches
-Natural and artificial factors of suppression of branches
-Diameter distribution of trees and shape of the stem
-Root architecture and soil interaction for the nutrition and anchoring aspect

3 Isopropic curves in the stem
-Specific wood mass
-Compression resistance
-Dending resistance
-Flexural modulus of elasticity
-Wood quality
= Physiological humidity
= Saturation humidity
= Plasmolysis and turgidity

4 Tree stability
-Stresses and peripheral deformations
-Distribution of tensions and deformations along the radius and height of the tree
-Critical break point
-Artistic of the shaft of trees
-Critical displacements
-Factors of maintenance and reversion of the displacements unfavorable to the survival of the tree
-Developments associated with growth stresses

5 Techniques of determination of the peripheral tensions
-original in the standing tree
-residuals in logs
-distribution of stresses during unfolding

6 Deployment Techniques
-for maximum output
-for maximum use-oriented quality

7 Experiments
-Madeira under wind action
-Strength format test of the trunk

Bibliography
ALMÉRAS, T.; COSTES, E.; SALLES, J. C. Identification of biomechanical factors involved in stem shape variability between apricot tree varieties. Annals of Botany, v. 93, n. 4, p. 455–468, 2004.
ALMÉRAS, T.; FOURNIER, M. Biomechanical design and long-term stability of trees: Morphological and wood traits involved in the balance between weight increase and the gravitropic reaction. Journal of Theoretical Biology, v. 256, n. 3, p. 370–381, 2009.
AMERICAN SOCIETY FOR TESTING AND MATERIALS. D198-84. Standard Methods of StaticTest of Timber in Strutural Sizes. West Conshohoken,1997.
AMERICAN SOCIETY FOR TESTING AND MATERIALS. D4688-99 Standard Test Methods for evaluating strutural adhesives for finger jointing lumber. West Conshohoken, 2005. 7p.
ARCHER, R. R.; BYRNESS, F. F. On the Distribution of Tree Growth Stresses -- I ) art I : An Anisotropic Plane Strain Theory. Wood Science and Technology, v. 8, p. 184–196, 1974.
ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS. Norma NBR-7190: projeto de estruturas de madeira. Rio de Janeiro, 1997. 107 p.
FOREST PRODUCTS LABORATORY. Wood handbook - Wood as an engineering material, Madison: U.S. Department of Agriculture, Forest Service, 1999. 463 p.
GARCIA, J. .N. States of stress in trees and strain in lumber pieces. Tese (Doutorado) - Escola Politécnica, Universidade de São Paulo. São Paulo, p 262. 1992. (In Portuguese)
GILLIS, P. P. Theory of growth stresses. Holzforschung, v. 27, n. 6, p. 197–207, 1973.
JAMES, K. E. R. J.; HARITOS, N. I. H.; ADES, P. K. Mechanical stability of trees under dynamic loads. American Journal of Botany, v. 93, n. 10, p. 1–9, 2006.
ONODA, Y.; RICHARDS, A. E.; WESTOBY, M. The relationship between stem biomechanics and wood density is modified by rainfall in 32 australian woody plant species. New Phytologist, 185.2: 493-501. 2009.
TAYLOR-HELL, J. Biomechanics in botanical trees (Master’s thesis). University of Calgary, 2005.