Module 5

Question 1

CODIT

Answer 1

Wall 1-vertical vascular system, plugs tracheids and xylem vessels
Wall 2-resists decay round the center of tree, latewood cell
Wall 3-resists from the point of injury around the trunk. Toxic to decay microorganisms.
Wall 4-prevents from moving outward

Question 2

Vessel

Answer 2

Tube water conducting cells xylem In angiosperms.

Question 3

Tracheids

Answer 3

In gymnosperms, elongated tapering xylem cell transports water

Question 4

Parenchyma

Answer 4

Thin walled living cell essential in photosynthesis, radial transport, storage, protective compounds

Question 5

Cellulose

Answer 5

Strings, whitish in color, provide flexibility and strength under tension.

Question 6

Lignin

Answer 6

Darker brown, blocks surrounding strings, provides stiffness and load Bering capability when under compression.

Question 7

Rays

Answer 7

Specialized parenchyma cells that develop radially across the xylem and phloem

Question 8

Response growth

Answer 8

New wood produced in response to loads and damage; includes reaction, flexure and woundwood. Response includes swelling, ridges, bulges. Compression and tension.

Question 9

Reaction wood

Answer 9

Wood formed in leaning or crooked stems, upper or lower branches, counteracting gravity. Compression and tension wood.

Question 10

Compression wood

Answer 10

Common in gymnosperms is response to increased static load, due to gravity. Formed downslope or under branch. Expand longitudinally.

Question 11

Tension wood

Answer 11

Formed in angiosperms. Form on upper side of a branch or uphill side of the trunk. Pulling trunk vertically. Conifers do not produce tension wood.

Question 12

Flexure wood

Answer 12

Formed in response to wind loading. Example is trunk taper and buttress roots.

Question 13

Woundwood

Answer 13

Responds to cambial damage. Produces callus. Can produce rams horn, curl inward.

Question 14

Saprophytes

Answer 14

Decay that attacks non living cells

Question 15

White rot

Answer 15

Break down mostly lignin and some cellulose, leaves wet spongy wood. Fibrous appearance. Mostly in hardwood

Question 16

Brown rot

Answer 16

Primarily breaks down cellulose. Brittle and crumbly, wood shrinks and cracks into blocks. Loss of strength. More serious.

Question 17

Soft rot

Answer 17

Decay of plant tissues characterized by the breakdown of tissues within cell walls. Breaks down cellulose first. Creates localized pockets of decayed wood softer than surrounding areas.

Question 18

Decay progression relates to:

Answer 18

Tree and fungus characteristics
Codit
Age and vigor at time of injury
Type of pathogen
Interaction btw fungus and tree species
Recent Additional wounds 
Site moisture and temp

Question 19

Suberin

Answer 19

Waxy substance that protects the cambium from drying.

Question 20

If CODIT fails

Answer 20

A column of decay and eventually a cavity

Question 21

Rhizomorphs

Answer 21

A root like aggregation of fungus

Question 22

Potential indicators of decay

Answer 22

Presence of old wounds or branches, allow decay
Response growth patterns, swelling, bulges
Cracks or seams
Oozing from bark
Dead or loose bark, discolored
Sunken area in bark
Termite trails

Question 23

Definite indicators of decay

Answer 23

Cavity opening, nests holes, bee hives,
Fruiting bodies attached to tree
Carpenter ants
Termites

Question 24

Load

Answer 24

Result of various forces acting on a structure, usually wind and gravity.

Question 25

Lever arm

Answer 25

Distance between applied force and the point where the object will bend or rotate

Question 26

M=F x L

Answer 26

Bending moment= Force (wind) x lever arm strength (distance from the ground to center of pressure).

Question 27

Moment

Answer 27

Force multiples by the length of a lever arm to rotate or bend an object

Question 28

Drag

Answer 28

Wind related lateral force on a tree

Question 29

Stress=force/area

Answer 29

Force extended over an area

Question 30

4 basic stresses

Answer 30

Compression, tension, torsion, shear

Question 31

Shear

Answer 31

When components of a material attempt to slide relative to one another at interface btw tension and compression

Question 32

Neutral plane

Answer 32

An imaginary plane where there is neither tension nor compression

Question 33

Shell wall

Answer 33

Remaining solid wood around a cavity or internal wood decay

Question 34

Mass dampening

Answer 34

Acts to reduce dangerous harmonic sway motion of the trunk which minimizes loads and increases stability.

Question 35

Trees can have internal decay and remain stable do not apply when:

Answer 35

Tree is not essentially circular in cross section, decay is not centrally located, loading potential is low.

Question 36

Trees respond to wind by

Answer 36

Streamlining leaves, twigs, and branches Reducing height and or increasing diameter Altering root growth Developing smaller leaves and shorter internodes Forming thicker branch unions Forming reaction wood

Question 37

Cross sectional strength formulas limitations

Answer 37

Assumes round stems and centered cavities Does not account large diameter trees or strong wood Cavity openings are not considered Load on shell wall and strength of response wood are not considered

Question 38

Retrenchment

Answer 38

Overly mature tree reduces its crown and increases girth to harbor resources and increase longevity. Crown dieback, adventitious shoots, decreased vigor, new wood at slower rate.

Question 39

Long lived vs short lived trees

Answer 39

Adapt biologically to overcome defects. Weaker response to defects, relys on vigor.

Question 40

Sapwood rot

Answer 40

Rotting from bark. Likelihood of failure increases due to rapid reduction

Question 41

Load and likelihood of failure

Answer 41

Branch strength, location of load, wind exposure, changes in load.

Question 42

Assessing loads for likelihood of failure

Answer 42

Wind, precipitation, tree weight, crown size, foliage density, cross section areas.

Question 43

Trees with smaller height/diameter ratios

Answer 43

Typically have more significant taper

Question 44

Large h/d ratios

Answer 44

Combined with site exposure can cause failure

Question 45

During the load assessment, consider

Answer 45

Crown density, stress raisers, wind strength and direction, precipitation, length of lever arm, load location, response growth.

Question 46

Earlywood Latewood

Answer 46

Tree comes out of dormancy, new wood normally has thin cell walls. Intercellular space is larger Later in the season, cell walls get thicker. Intercellular space is smaller

Question 47

Distribution of new wood is determined

Answer 47

Large part to mechanical stresses, tree health as well.