structural root architecture of some New Zealand native...
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A peek down under: structural root architecture of some New Zealand native plants Chris Phillips Mike Marden, Jagath Ekanayake & Alex Watson
Transcript of structural root architecture of some New Zealand native...
A peek down under:
structural root architecture of some New Zealand native plants
Chris Phillips
Mike Marden, Jagath Ekanayake & Alex Watson
Disclaimer
We are not botanists!
We are not plant ecologists!
We are on the edge!
We play in the dirt!
We are statistically challenged!
Wadda ya know?
•• Context Context –– 3 strands3 strands•• What weWhat we’’ve done ve done –– 2 trials2 trials•• How we do itHow we do it•• What weWhat we’’ve foundve found•• How we use the informationHow we use the information•• Wrap upWrap up
In this talk….
•• Plantation forests for erosion controlPlantation forests for erosion control•• Pinus radiata and other exoticsPinus radiata and other exotics•• 19801980’’s to 1990s to 1990’’ss•• Effectiveness, densities, harvesting etcEffectiveness, densities, harvesting etc
Context 1 – hillslope stability
Context 1 – hillslope stability
Context 1 – hillslope stability
Context 1 – hillslope stability
•• Off the hills and into the rivers Off the hills and into the rivers –– ICM ICM •• Riparian restoration/rehabilitation effortsRiparian restoration/rehabilitation efforts•• Natives Natives vsvs exotics, Ecology exotics, Ecology vsvs function function •• Performance, build the K basePerformance, build the K base
Context 2 – river bank stabilisation
Context 2 – river bank stabilisation
• MAF – Govt policies - convergence• Climate change mitigation & Sustainable land
management (SLM) >> HCE• What to use, how effective, how much C,
what rate, where, management etc
Context 3 – Carbon & SLM
The Big Question?Can our New Zealand native plants perform E & SC Can our New Zealand native plants perform E & SC
functions as well as introduced plants?functions as well as introduced plants?
In geotechnical terms, how do we quantify the benefits of In geotechnical terms, how do we quantify the benefits of vegetation to soil stabilisation? vegetation to soil stabilisation?
Shear displacement
Without roots
With roots
What we’ve been doing
• Exotic species• 2 native trials • 1 MSc. on Cordyline
Riparian plant trial Cabbage trees
Czernin (2002) Czernin & Phillips (2005)
Marden, Rowan, Phillips (2007; 2005)Phillips & Marden (2006)
Common nameKaramu RibbonwoodKowhaiLemonwoodKohuhuLacebark MapouFivefingerCabbage treeRewarewaManukaTutu
Common nameKauri RimuKahikateaMiroTotaraMataiPuririTitoki
Sedge grass NZ Mountain flaxToe toe
Podocarp trial
What we’ve been doing - natives
Still in progress
The old The newThe hard
How we do it
• General growth patterns• Biomass• Root length• Root depth• Site occupancy• Root strength
What we’ve found
Root architecture
Root definitions
Root bole
Sinker
Sinker
Taproot
Lateral
Root architecture
• plateroot
• heartroot
• taproot
Tree root forms
5
7
25
13
What we’ve found – growth
Cabbage tree
(Cordyline australis)
Czernin (2002) Czernin & Phillips (2005)
1 year old 2 year old 3 year old4 year old
3.35 mWhat we’ve found – growth
(Psuedopanax arboreus)m
m
1 m
What we’ve found – growth
Kauri
Totara4 yr old
0
3 year oldsToe toe
Flax Carex
Kahikatea & Puriri
4m
What we’ve found – growth
1m
Coprosma robusta (karamu)
Pittosporum tenuifolium (kohuhu)
What we’ve found – root spread
5 year old
Mean max. root spread – 5 year old
What we’ve found – root spread
0
1
2
3
4
mapou
reware
wafiv
e.fing
erman
uka
karam
uko
whai
lacebark
cabb
age.tre
eko
huhu
ribbo
nwood tutulemon
wood
Roo
t Spr
ead
(m)
Mean max. root depth – 5 year old
50
45
40
35
30
25
20
15
10
5
0
mapou
five.f
inger
kohu
huko
whai
lemon
wood
manuk
arew
arewa
laceb
arktut
u
karam
urib
bonw
ood
cabb
age.t
ree
(cm)
What we’ve found – root depth
What we’ve found – root depth
RibbonwoodCabbage tree
5 year old
4202468
101214
mapou
reware
wafiv
e.fing
erman
uka
kowha
ilac
ebark
kohu
hulem
onwoo
dka
ramu
ribbo
nwoo
dtut
uca
bbag
e.tree
(kg)
Above-ground
Below-ground
What we’ve found – biomass
What we’ve found – root length
3 year old - woody
What we’ve found – root length
3 year old - all
What we’ve found – root length
3-5 year old - all
What we’ve found – variation
What we’ve found – variation
What we’ve found – variation
What we’ve found – variation
Data range – max, mean, min5 year old - woody
0
10
20
30
40
50
60
RataLac
ebark
Hard bee
chKowhai
Manuka
-1Man
uka-2
Red bee
chKan
ukaKohuhuKam
ahi
Fivefin
gerRew
arewa
Cabbag
e tree
Mountain bee
chDouglas
firRibbonwoodRad
iata p
ineLem
monwood
TutuKara
mu
Mea
n m
ax. t
ensi
le s
tren
gth
(MPa
)
Exotics
Watson & Marden (2005)
Willows 30 - 125 MPa
(1-4 mm diameter)
Riparian plant trial
What we’ve found – root tensile strength
Old FRI data
How we use it – Knowledge delivery
http://icm.landcareresearch.co.nz/
Planting types – radiata pine 3 yr old
Watson & Tombleson (2004)
How we use it – management
y = 4.8813xr2 = 0.9617
0255075
100125150175200
0 10 20 30 40
Mean root collar diameter (cm)
Roo
ting
dept
h (c
m)
11 yrGisborne plant trial
Cabbage tree root depth
How we use it – Allometry
1. Kanuka 16000 spha
2. Radiata 1250 spha
3. Radiata 800 spha
4. Radiata 500 spha
How we use it – relative root reinforcement
“Window of vulnerability”
Watson, Phillips, Marden (1999)
100% root site occupancy
Root site occupancy
How we use it – Models
100% root site occupancy
What about these bits?
Root site occupancy
How we use it – Models
Poplars5 yr
7 yr
9.5 yr
McIvor et al (2007)
Cabbage tree
Czernin & Phillips (2005)
4 yr 8 yr 25 yr
Totara
Marden & Phillips (unpub.)4 yr
?
?
?
?
?
Site occupancy
Mean maximum root length radius
100%
0%
“Effective” root spread radius
Root reinforcement index (RFI) = Root surface area
Root spread area
??
How we use it – root site occupancy model
Effective root spread measured & predicted using model equation
0
20
40
60
80
100
120
2 3 4 5Time (years)
Effe
ctiv
e R
oot S
prea
d di
stan
ce fr
om s
tum
p(c
m)
5-Finger5-FingerCabage_TreeCabage treeKaramauKaramauKohuhKohuhuKowhaiKowhaiLacebarkLacebarkLemonwoodLemonwoodmanukaManukaMapouMapouRewarewaRewarewaRibbonwoodRibbonwoodTutu
)exp(5.0 xc
xbay ++=
Site occupancy (%) for planting density 1m x 1m
25
50
75
100
2 3 4 5 6 7Time (years)
Site
occ
upan
cy (%
)
5-FingerCabage treeKaramauKohuhuKowhaiLacebarkLemonwoodRewarewaRibbonwoodTutuMapou
How we use it – root site occupancy & density
Site occupancy (%) for planting density 2m x 2m
0
25
50
75
100
2 3 4 5 6
Time (years)
Site
occ
upan
cy (%
)
5-FingerCabage treeKaramauKohuhuKowhaiLacebarkLemonwoodRewarewaRibbonwoodTutu
How we use it – root site occupancy & density
Avondale Stream, existing channel, May 2004How we use it – Visualisation
Avondale Stream, Carex added
Avondale Stream, Juncus added
Avondale Stream, native trees added
Existing channel has little in-stream cover
Riparian grasses provide cover & spawning habitat
Cabbage trees suitable above the wetland grasses
Tree ferns also suitable above wetland grasses
Chockie fish time…
• What native had the greatest tensile root strength?
• What do we call the gadget we use to expose the root systems of plants?
• What’s so special about the root systems of cabbage trees?
Fivefinger
• We know more than we did before• Hard won data• Natives can grow quickly • Maybe need to look more at function• Opportunities for further research
– Optimisation for site reinforcement– Carbon modelling …..– Modelling in general…
Wrap up
“The unhealthiness in our world today is in direct proportion to our inability to see it as a whole.”
Peter Senge
