iii.

Question 1

sapwood

Answer 1

living xylem, typically from the most-recent few years of the tree’s growth.

Question 2

living xylem

Answer 2

transports water from the soil up to the leaves

Question 3

the more leaves that a tree has …

Answer 3

the more sapwood it needs to get water to them

Question 4

The xylem in
sapwood is ____ and so ____

Answer 4

living; requires energy from maintenance respiration to keep it alive

Question 5

heartwood

Answer 5

older, dead xylem that had been sapwood when it was first created
waterproof because of being filled with secondary substances

Question 6

when the tree turned old sapwood into heartwood

Answer 6

the sapwood had its nutrient
reserves removed, and had secondary substances added that reduce the chance of it
decaying.

Question 7

secondary substances

Answer 7

tyloses, resins and dyes

Question 8

tyloses

Answer 8

deformed cells that fill vessels

Question 9

a tree does not need …

Answer 9

heartwood to be able to survive, because it is no longer functional

Question 10

hollow trees can

Answer 10

stand up fine as long as they are in closed-forests
that protect them from high winds

Question 11

Hollow trees growing in the open …

Answer 11

are more prone being blown down
the hollows in hollow tree-trunks concentrate the wind and that increases the chance they will be blown over

Question 12

annual tree-rings are typically much clearer in the

Answer 12

heartwood than they are in the
sapwood

Question 13

photosynthate

Answer 13

chemical energy created from photosynthesis

Question 14

trees typically allocate the photosynthate in the following ranking of abundance, from
most to least

Answer 14

maintenance respiration
producing leaves and fine roots
flower and seed production
primary growth
secondary growth

Question 15

maintenance respiration

Answer 15

the greatest amount of photosynthate is used to keep
existing tissues alive

Question 16

respiration increases as …

Answer 16

temperature increases

Question 17

producing leaves and fine roots …

Answer 17

to enable continued photosynthesis,
by replacing leaves that fall off seasonally

Question 18

flower and seed production …

Answer 18

to enable continued survival of a tree’s genes

Question 19

In years
when many seeds are produced …

Answer 19

trees have lower primary and secondary growth, due
to the energy put into making the seeds

Question 20

primary growth

Answer 20

elongation of terminal and lateral shoots and woody roots to enable a tree to compete with its neighbors for light and water

Question 21

secondary growth

Answer 21

new wood to conduct water

Question 22

trees growing vigorously in high quality habitat …

Answer 22

… have so much photosynthate that
maintenance respiration only takes up 25% of photosynthate, leaving 75% for growth

Question 23

trees in low quality habitat …

Answer 23

may need 75% of photosynthate for maintenance
respiration and only have 25% left for growth

Question 24

in very low quality habitats …

Answer 24

the photosynthate may go to maintenance respiration, leaving no energy to grow at all,
which results in those trees having missing rings over their whole surface

Question 25

sudden reduction in crown size …

Answer 25

can occur from people pruning leaves and branches from the tree
naturally by animals browsing (e.g. spruce budworm feed on needles and buds) or wind disturbance

Question 26

a sudden loss of >50% of the leaves typically results

Answer 26

in the tree dying

Question 27

the tree will survive if it
can …

Answer 27

quickly “abandon” (i.e. kill) much of the now unneeded xylem tissue, by removing the nutrients from the xylem and adding resins or tyloses to them

Question 28

how can trees survive
coppicing and pollarding?

Answer 28

they have their upper stem portions removed during winter when the plant is dormant and has stored most of its nutrients in the trunk and roots
trees must be first coppiced or pollarded when they are young and have a small diameter, and regularly coppiced or pollarded after that, to ensure that the trunk does not have a large amount of sapwood that would have a high maintenance respiration

Question 29

tree growth efficiency

Answer 29

the volume of wood grown per year per area of land on which the trees are grown

Question 30

as a tree ages …

Answer 30

its functional live crown stays the same size and thus so does its gross photosynthesis but, because the total tree size is
larger its respiration increases, and thus its net rate of photosynthesis decreases

Question 31

the tree growth efficiency for trees with strong apical control is highest …

Answer 31

for young trees when they are narrowly-spaced
for old trees when they are more widely spaced

Question 32

the tree growth efficiency for trees with weak apical control is highest …

Answer 32

for young trees if they are narrowly-spaced
for old trees when they are widely- spaced

Question 33

stability of decurrent tree stems

Answer 33

will be rapidly twisted by the wind which will cause it to split in half vertically (if hollow, growing in the open, and subject to high wind)

Question 34

stability of excurrent tree stems

Answer 34

if DBH is 1% of less of it’s height - will have much weight concentrated over a narrow based and may, as a result of
that weight, buckle, breaking horizontally several feet above the ground.

Question 35

dense stands of trees may support each other during wind because

Answer 35

their roots will be entwined and their crowns will be leaning on each other

Question 36

when trees are killed by disturbance or logging …

Answer 36

the environment for the remaining trees changes due to the loss of shading of their sides: the tree’s environment will change in terms of heat, moisture, light, and wind

Question 37

side-shade temperature increases

Answer 37

increased soil temperature increases nutrient availability in cold climates because the warmer temperatures increase the activity of bacteria and fungi in the soil

Question 38

side-shade moisture

Answer 38

the air typically becomes drier because there are no longer so many leaves transpiring moisture into the air

Question 39

side-shade brightness

Answer 39

thin shade-leaves may not be able to handle the sunlight and may thus die

Question 40

sun-scald

Answer 40

may develop on a tree released from side-shade
the sunlight might be strong enough to heat the dormant tree up enough to cause a part of the lateral meristem to become active; If the sunshine suddenly disappears, the temperature of the lateral meristem will suddenly drop, the tissues will
freeze, and that part of the lateral meristem will die leaving a crack or a scar

Question 41

if the tree was small when released (ages A or B)

Answer 41

it will grow to look like an open-growth tree, with its crown beginning low to the ground