Exam 1 Vocabulary

Question 1

wood

Answer 1

secondary xylem of a tree

Question 2

vascular cambium/lateral meristem

Answer 2

a thin layer of meristematic tissue located between the xylem and phloem of tree stems; sheaths the twigs, branches, trunk, and roots

Question 3

fusiform initials

Answer 3

long, slender cells in the lateral meristem that divide repeatedly to form new xylem and phloem longitudinal cells

Question 4

ray initials

Answer 4

short, rounded cells that divide to create either xylem or phloem rays or new ray initials

Question 5

periclinal division

Answer 5

Division parallel to the stem surface in a tangential plane to Form either new xylem or phloem

Question 6

anticlinal division

Answer 6

Division on the radial plane to Form new cambial initials and increase the circumference of the vascular cambium

Question 7

wood rays

Answer 7

Radially oriented groups of cells extending from the vascular cambium in both the xylem and the phloem

Question 8

earlywood

Answer 8

Early spring, rapid growth, larger radial cell diameter, thinner cell wall, lower density, generally lighter in color

Question 9

late wood

Answer 9

Mid summer, slower growth, smaller radial cell diameter, thicker wall, higher density, generally darker

Question 10

intergrown knot

Answer 10

Aka tight, sound, or black. Growth rings are continuous between branch and stem wood

Question 11

encased knot

Answer 11

Stem growth increments encase branch, often surrounded by bark

Question 12

quarter sawn

Answer 12

Rings perpendicular to narrow side

Question 13

flat sawn

Answer 13

Rings parallel to narrow side

Question 14

primary wall

Answer 14

Thin, membrane like and pectin rich wall that forms around new wood cells

Question 15

microfibril

Answer 15

Larger structures within the cell wall when the highly crystalline network of cellulose unifies

Question 16

apical meristem

Answer 16

Branch tips, results in height growth

Question 17

tree

Answer 17

20 ft. Usually single stem

Question 18

angiosperm

Answer 18

Produces seeds within ovaries

Question 19

gymnosperm

Answer 19

Naked seeds

Question 20

xylem

Answer 20

Wood

Question 21

phloem

Answer 21

Inner layer of bark

Question 22

outer bark

Answer 22

Outer protective layer

Question 23

meristematic regions

Answer 23

Regions in which cells divide repeatedly to Form new cells

Question 24

procambium

Answer 24

Near the center of the stem, cells undergo development in size and shape, eventually form an unbroken ring around the stem center.

Question 25

pith

Answer 25

Very Center of the stem

Question 26

epidermis

Answer 26

Tissues at outer edge of young stem, one layer of cells, thick wax covered walls protecting from moisture loss

Question 27

sapwood

Answer 27

Light colored outer zone of a tree stem cross section, contains the living cells, part of it serves to conduct water upward

Question 28

heartwood

Answer 28

Cells in this region are no longer alive, and function mostly as structural support

Question 29

softwood

Answer 29

Naked seeds, usually evergreen, Form tends to be excurrent, lower average density, simple homogeneous cell structure

Question 30

hardwood

Answer 30

Seeds enclosed in fruit, mostly deciduous, dendritic or deliquesent Form, higher average density, more complex cells

Question 31

growth ring

Answer 31

Alternating variations in cell characteristics seen with the unaided eye on the transverse surface of wood

Question 32

tangential surface/direction

Answer 32

Result from cutting perpendicular to a radius or a tangent to the growth rings

Question 33

radial surface/direction

Answer 33

Made by cutting longitudinally along the radius of a cross section

Question 34

longitudinal direction

Answer 34

Vertical within stem

Question 35

cross section

Answer 35

Horizontal surface of cut stem

Question 36

interlocked grain

Answer 36

Regular reversal in right and left spiral grain in successive growth increments, more resistant to splitting, more difficult to dry

Question 37

spiral grain

Answer 37

Helical orientation of wood cells in tree stem, reduced strength and stiffness

Question 38

diagonal grain

Answer 38

Grain is not parallel to the long Axis of the piece, result of not sawing parallel to the bark

Question 39

cellulose

Answer 39

Chemical component synthesized within living tree cells from a glucose based sugar nucleotide, principal chemical constituent, long linear polymer chains

Question 40

hemicelluloses

Answer 40

Lower Molecular weight polysaccharides, branched chain polymers

Question 41

lignin

Answer 41

Complex and high Molecular weight polymer built upon phenylpropane units, not a carbohydrate, phenolic in nature

Question 42

extractives

Answer 42

General name for various compounds that develop during heartwood formation, give wood odor, color, taste, durability, etc.

Question 43

pectins

Answer 43

Complex colloidal substances of hough Molecular weight found within and between cell walls that, upon hydrolysis, usually yields galacturonic acid and small amounts of arabinose and galactose

Question 44

polysaccharide

Answer 44

Multiple sugar units

Question 45

crystalline

Answer 45

Diamond shaped

Question 46

discontinuous rings

Answer 46

When growth rings fail to Form around the complete cross section, due to the cambiamos remaining dormant in one or more places around the stem

Question 47

false rings

Answer 47

Occur when normal growth is interrupted by external events

Question 48

secondary metabolites

Answer 48

Substances that do not participate directly in tree growth and development

Question 49

ribbon stripe figure

Answer 49

Alternating grain directions cause light to reflect in various patterns across radially cut wood

Question 50

polymer

Answer 50

Many parts