2.Interception

Question 1

___-___% of incoming precipitation goes back to the atmosphere without joining the soil-water balance leaving ___-___% avaialble at the surface

Answer 1

. 20-30% of precip coming down, goes back to atmos, never becomes part of the soil-water balance
.70-80% is available for use at surface

Question 2

Interception

Answer 2

• Effects – Decreases input of water at soil surface – Redistribution of input of water – Changes in chemical composition of water reaching the soil

Question 3

5 Factors affecting interception

Answer 3

• Factors – Interception storage – Interception loss – Rainfall duration – Rainfall frequency – Vegetation type

Question 4

.anytime water is in contact with dead or living plants, _____ ____ are released changing the chemical composition of the water

Answer 4

organic acids

Question 5

When the Interception storage fills until it cannot hold anymore and interception loss cant keep up

• at maximum, ____flow and _____fall can occur as the tree can no longer hold anymore
• this can be affected by whether rainfall starts when a tree’s canopy is already wet or dry, type and thickness of canopy, wind, sunlight, temp

Answer 5

stemflow

throughfall

Question 6

Vegetation removes __-__% of rainfall off the top

Answer 6

30-35

Question 7

______ a location, the more interception that can occurs

Answer 7

drier

Question 8

Interception percentage:

Coniferous:__ to __%

Deciduous: ___ %

Answer 8

30 to 35

15%

-deciduous is more spread out in its ability to hold water because there are so many different kinds of them
.conifers water is kept in separate droplets on needles 1 to 2 mm
-.decicuous (< 1mm) hold all the water together on leaf which means eventually it will fall off so conifer is better

Question 9

Grasses are similar to _____(conifer/deciduous) in terms of interception

Answer 9

.grasses are more like conifers but the open structure is not as important as wind is low at that level

Question 10

Gross rainfall=

____+_____

Answer 10

net rainfall+total interception loss

Question 11

Total Inception loss=

_____+-_____

Answer 11

canopy interception loss + litter interception loss

Question 12

Net rainfall=

____+____-____

Answer 12

throughfall+stemflow-litter interception loss

Question 13

T OR F

The higher the ammount of precipitation from a storm, the hgiher the interception ratio

Answer 13

F

the smaller the interception ratio

Question 14

higher intensity rainfall means ____ interception loss versus low intensity rainfall

Answer 14

lower

Question 15

______ have the higher interception ratio out of conifers and deciduous trees

Answer 15

conifers

Question 16

Interception:

Describe Conifers:

Describe Deciduous trees

Answer 16

• Conifers – lower leaf density – droplets stay on separate needles – higher storage capacity
• 1 to 2 mm
– open structure
• free circulation of air – uniform • little scatter

Broadleaves:
– higher leaf density 
– droplets run together 
– lower storage capacity 
• <1 mm – closed canopy structure • impedes circulation of air – diverse 
• substantial scatter

Question 17

Measuring Interception

Answer 17

When the tree gets wet, its mass increases and the trunk gets shorter under increased weight

• use 3 quartz tubes around the tree in order to know it was rain and not wind
• as water evaporates, the tree trunk lengthens again

-3 quartz tibes make triangle around tree at 120 degrees each

Question 18

Potentiometer

Answer 18

used to measure displacement changes in tree length

Question 19

How to measure Snow Interception

Answer 19

.hang tree(cut down) from load cell

.always important to know temp when measuring snow

Question 20

Interceptometer

Answer 20

: to measure tree trunk for snow interception similarly to rainfall measurement