Module 5 Test Flashcards
T or F - Compression wood typically has a smaller, thinner cellulose pipes, with more latewood and lignin content
True
T or F - Flexure wood may impact the development of trunk taper and buttress roots
True
T or F - The presence of decay indicates that the tree is likely to fail
False
T or F - Delignified wood retains its compressibility, but loses its tensile strength
False
T or F - Definite indicators of decay include fungal fruiting structures, cavity openings, and carpenter ants.
True
A special type of growth that produced in response to wind loading is called. _______
Flexure wood
A tree’s ability to effectively ______ decay is an important factor in assessing structural stability and likelihood of failure
Compartmentalize
Some _______ Indicators of decay include cavity openings, nesting holes, conks, and mushrooms. Some _____ indicators of decay include oozing, cracks, and sunken areas of bark.
Definite ; Potential
Two of the stresses within a tree include ______, which is squeezing a material, and ______, which is stretching or pulling a material.
Compression ; Tension
The cross-sectional strength formula does not account for ____ on the shell wall, so tall trees and short trees are treated identically.
Load
When assessing load, potential ____ ______ are cankers, cracks, sharp bends, and other factors that can magnify stress.
Stress raisers
A limitations of using cross-sectional strength models for residual strength of solid wood surrounding internal decay in trees is that.
A.) Mature tree trunks tend not to be circular in cross section.
B.) Decay may be off center
C.) decay may be irregularly shaped
D.) all of the above
D.
Cross-sectional strength models have several limitations: 1.) the formulas are based on round stems with centrally located decay, 2.) they do not account for large-diameter trees or trees with stronger than average wood, which might require less solid wood, 3.) they do not account for cavity openings, and 4.) they do not consider the load on the shell wall.
The problem with breaching CODIT wall 4 during decay detection procedures is that
A.) all four walls are necessary to sustain water transport
B.) the reaction zone may be killed.
C.) compartmentalized decay may spread into uninfected wood.
D.) all of the above.
C.
Decay does not spread beyond the wood present at the time of wounding if there is a strong compartmentalization response. Breaching wall 4 could allow pathogens to spread to the uninfected wood.
A type of stress caused by twisting motion is called. A.) Tension B.) Compression C.) Torsion D.) Strain
C.
The four basic stresses within a tree are compression, tension, shear, and torsion. Torsion can create a special type of shear stress caused by twisting force
Wind moves branches in different directions acting to dissipate wind energy and slow the movement of larger branches in a process called. A.) Force reduction B.) Mass Damping C.) Load dissipation D.) Dampening
B.
Mass damping results in reductions in truck loading and oscillation. If a tree lacks interior or lower branches, there is less damping within the crown, so more force is transferred to the trunk and roots.
Flexibility and strength in tension wood comes from A.) Parenchyma B.) Cellulose C.) Lignin D.) Rays
B.
Tension wood has thicker cellulose pipes with less of a lignin matrix between.
Response growth develops as a result of
A.) The repeated deformation of cambium and new wood cells due to loading
B.) Inner xylem sensing shear stress and allocating resources to strengthen heartwood
c.) The fiber orientation of the middle lamella in response to ring development
D.) all of the above
A.
response growth, a form of tree growth adaption, is the production of new wood in response to damage or additional loads to compensate for higher strain (deformation) in outermost fibers; response growth includes reaction wood, flexure wood, and woundwood
Woundwood is produced in response to A.) Cambial Damage B.) Fungal invasion C.) Phloem disruption D.) xylem desiccation
A.
Woundwood is a special type of growth that is produced in response to cambial damage. It is chemically different from, and sometimes denser than, other wood and resists decay better than normal wood
Which of the following is NOT a true statement
A.) Brown rots primarily breakdown cellulose, leaving behind lignin
B.) Brown rots primarily affect conifers, but some occur in hardwoods
C.) Brown rots are often considered serious due to significant strength loss.
D.) Brown rots decrease wood rigidity, but the wood remains flexible
D
Brown rots primarily break down cellulose and hemicellulose, but generally leave the lignin intact. Major loss of bending strength can occur early in the decay process. Brown rots are often considered more serious than white rots due to the greater loss of strength in the decayed wood. The primarily affect conifers, although brown rots can also affect hardwoods.
In CODIT model, the reaction zone consist of
A.) The earlywood cells in each growing ring
B.) Pre-existing wood tissue that changes after injury.
C.) Vessels blocked by tyloses in the walls of the ray cells
D.) new xylem that develops after injury.
B.
The CODIT model consists of the reaction zone and the barrier zone. The reaction zone describes the first three walls, which occur in the preexisting wood tissues. The barrier zone (Wall 4) is developed in the new wood, after wounding.
Decay of outer wood is considered
A.) More important to stem strength loss than internal decay
B.) Insignificant as long as the heartwood in unaffected
C.) very slow in progression because sapwood resists decay
D.) Rare, and happens only after inner wood is already decayed.
A.
Loss of outer wood is considered more important to the stem strength loss then internal decay because outer xylem tissue contributes more to stem than internal fibers.
When assessing loads on trees, you should consider all the following EXCEPT
A.) The load from self-weight, Wind, ice, snow, and other factors.
B.) The area upon which the load will act.
C.) Stress raisers, such as cankers ans sharp bends that can magnify the stress
D.). The distance the tree or tree part will fall, given the increase in load.
D.
Factors that may increase load, such as wind, snow, and ice, should be considered when assessing load. The area where load will act and any stress raisers should also be evaluated. the distance the tree or tree part will fail may be considered during the consequences of failure assessment, but not when assessing load
