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Wind throw is the toppling of a tree due to the force of the wind, this exposes the root plate and adjacent soil beneath the tree and influences slope stability. Wind throw is a factor when considering one tree on a slope; however, it is of lesser importance when considering general slope stability for a body of trees as the wind forces involved represent a smaller percentage of the potential ...
Some plants show contact angles up to 160° and are called ultrahydrophobic, meaning that only 2–3% of the surface of a droplet (of typical size) is in contact. Plants with a double structured surface like the lotus can reach a contact angle of 170°, whereby the droplet's contact area is only 0.6%. All this leads to a self-cleaning effect.
The structure of cells and vessels is also different, resulting in additional strength. The effect of reaction wood is to help maintain the angle of the bent or leaning part by resisting further downward bending or failure. There are two different types of reaction wood, which represent two different approaches to the same problem by woody plants:
Strength depends upon material properties. The strength of a material depends on its capacity to withstand axial stress, shear stress, bending, and torsion.The strength of a material is measured in force per unit area (newtons per square millimetre or N/mm², or the equivalent megapascals or MPa in the SI system and often pounds per square inch psi in the United States Customary Units system).
Where is the ultimate tensile strength, and is the strain at failure. The modulus is the maximum amount of energy per unit volume a material can absorb without fracturing. From the equation for modulus, for large toughness, high strength and high ductility are needed.
Bamboo's strength-to-weight ratio is similar to timber, and its strength is generally similar to a strong softwood or hardwood timber. [20] [21] Some bamboo species have displayed remarkable strength under test conditions. Bambusa tulda of Bangladesh and adjoining India has tested as high as 60,000 psi (400 MPa) in tensile strength. [22]
To photosynthesize, plants must absorb CO 2 from the atmosphere. However, this comes at a price: while stomata are open to allow CO 2 to enter, water can evaporate. [33] Water is lost much faster than CO 2 is absorbed, so plants need to replace it, and have developed systems to transport water from the moist soil to the site of photosynthesis. [33]
According to the classical theories of elastic or plastic structures made from a material with non-random strength (f t), the nominal strength (σ N) of a structure is independent of the structure size (D) when geometrically similar structures are considered. [1] Any deviation from this property is called the size effect.