Tree Biology & Mechanics: Wood Structure

Question 1

end-to-end, tube-like, water conducting cells in the xylem of angiosperms.

Answer 1

Vessel

Question 2

elongated, tapering xylem cell adapted for the support and transport of water and elements.

Answer 2

Tracheid

Question 3

rings of xylem that are visible in a cross section of the stem, branches, and roots of some trees. In temperate zones, the rings typically represent one year of growth.

Answer 3

Annual Rings

Question 4

thin-walled, living cells essential in photosynthesis, radial transport, energy storage, and production of protective compounds.

Answer 4

Parenchyma

Question 5

xylem produced to the interior of the vascular cambium during secondary growth.

Answer 5

Secondary Xylem

Question 6

main water- and mineral-conducting tissue in trees and other plants. Provides structural support.

Answer 6

Xylem

Question 7

thin layer(s) of meristematic cells that give rise (outward) to the phloem and (inward) to the xylem, increasing stem and root diameter.

Answer 7

Cambium

Question 8

organic substance that impregnates certain cell walls to thicken and strengthen the cell to reduce susceptibility to decay and pest damage.

Answer 8

Lignin

Question 9

parenchyma tissues that extend radially across the xylem and phloem of a tree and function in transport, storage, structural strength, and defense.

Answer 9

Rays

Question 10

portion of an annual ring (growth ring) that forms during summer, characterized by small-diameter cells with thick walls. Summer wood.

Answer 10

Latewood

Question 11

plant vascular tissue that transports photosynthates and growth regulators. Situated on the inside of the bark, just outside the cambium. Is bidirectional (transports up and down).

Answer 11

Phloem

Question 12

reaction wood in gymnosperms, and some angiosperms, that develops on the underside of branches or leaning trunks and is important in load bearing.

Answer 12

Compression wood

Question 13

plants with exposed seeds, usually within cones.

Answer 13

Gymnosperm

Question 14

lateral meristem from which secondary xylem and secondary phloem originate.

Answer 14

Vascular Cambium

Question 15

natural process during which an overly mature tree reduces its crown and increases its girth to consolidate resources and increase longevity; the deliberate process of reducing tree height to mimic natural processes.

Answer 15

Retrenchment

Question 16

new wood produced in response to loads to compensate for higher strain in outermost fibers; includes reaction wood (compression and tension), flexure wood, and woundwood.

Answer 16

Response growth

Question 17

the deformation resulting from a stress, measured as a change in specimen length per unit of total length.

Answer 17

Strain

Question 18

wood formed in leaning or crooked stems, or on upper or lower sides of branches, as a means of counteracting the effects of gravity.

Answer 18

Reaction wood

Question 19

a form of reaction wood in broadleaved trees (hardwoods) that forms on the upper side of branches or the trunks of leaning trees.

Answer 19

Tension wood

Question 20

lignified, differentiated tissues produced on woody plants as a response to wounding.

Answer 20

Woundwood

Question 21

inward curling formation of woundwood resembling the horns of a ram.

Answer 21

Ram’s horn