EXPERIMENTAL STUDIES OF EXPERIMENTAL STUDIES OF RED ALDER NUTRITION ON RED ALDER NUTRITION ON

VANCOUVER ISLANDVANCOUVER ISLAND

Kevin Brown, KR Brown and Kevin Brown, KR Brown and Associates, Victoria, BCAssociates, Victoria, BC

Paul Courtin, BC Ministry of Forests, Paul Courtin, BC Ministry of Forests, Nanaimo, BCNanaimo, BC

But why nutrition? Alder fixes nitrogen !

Importance of fixing atmospheric N2 and its impact on red alder, coniferous associates, ecosystems has driven much research

Much less research on effects of nutrition on red alder

Do mineral nutrient deficiencies limit the growth of red alder on Vancouver Island ?

Rationale:Evidence relating site index and nutrient availability

Ongoing study of management regimes: density, pruning,thinning, mixtures in conjunction with HSC at OSU

E. Vancouver Island, Sunshine Coast identified as prime areas for intensified management

N

50 km

Glasshouse

Single tree plot

Stand-level

Previous work on alder nutrition and growth

Correlative studies: Courtin 1992; Harrington and Courtin 1994

Field studies: alder after alder or Douglas-firCole et al. 1990; Compton et al. 1997; Compton and Cole 2001

Seedling and young plantation studiesBinkley 1986; Radwan and DeBell 1994; Hurd and DeBell 2001

P seemed to be important

General Questions:

Is growth limited by deficiencies of mineral nutrients? If so, which ones and in which sites?

What are the long-term effects of adding those nutrients on different sites?

Experimental approaches:

Potted seedlingsSingle-tree plot fertilization experimentsMulti-tree plot experiments

Glasshouse—effects of P additions and liming

Rationale: indication that P supply might limit growth of alder in lower-pH soils

Grew seedlings in soils from alluvial alder stands on Vancouver Island: west of Cowichan Lake and north of Campbell River

All sites classified as having rich-very rich soil nutrient regimes4 sites “low pH” (4.5) 2 sites “high pH” (5.5)

Fertilized with P, dolomitic lime, grew for three months

Soil nutrient regime (SNR) and Soil Moisture Regime (SMR)

Integral part of BC biogeoclimatic ecosystem classification system – guide to forest management decisions

Determined using field-identifiable site and soil characteristics, composition of flora

Related to site index

SNR related to soil nutrient availability

Bray-P (ppm)5 10 15 20 25 30

Res

pons

e (%

)

0

100

200

300

400P1P2

Figure 3. projTM vs Bray-P (unfert)

Who

le-p

lant

mas

s (g

)

23456789

1011

KL

CL

SL

SY BT

NI

ns

Response to added P decreased with increasing Bray-P

Increase significant in 5 of 6 soils

Growth of unfertilized seedlings increased with Bray-P

Who

le-p

lant

Mas

s (g

)

2

4

6

8

10

12

P0 P1 P2 P0 P1 P2

"Low-pH" "High-pH"

Effect of P greaterin “low-pH” soils

Addition of dolomite increased pH, Mg uptake---did not affect growth

Conclude P deficiencies may limit growth of red alder even in sites classified as very rich

Field experiments: single-tree plot

Rationale:Confirm whether nutrient deficiencies existed in field

sites

Only very small plantations available

Disadvantage:Can’t assess long-term effects at stand level

Site AgeDominant Tree Species

Bray-P(ppm)

CEC(cmol/kg)

Malaspina (M) 4 P. menziesii 37.8 5.6

Bowser (B) 4 P. menziesii 11.4 4.3

French Creek (FC) 4 P. menziesii 91.6 2.8

Quinsam (Q) 3 P. menziesii 48.5 3.5

Hillcrest (Hill) 2 P. menziesii 118.5 4.1

FannyBayDry (FBD) 1 A. rubra 3 7.5

FannyBayWet (FBW) 1 A. rubra 6.8 10.8CampbellR Lower (CRL) 1

A. rubra / P.trichocarpa 3.5 5.7

CampbellRUpper(CRU) 1 P. menziesii 124.9 2.3

HarryRoad (HR) 0 A. rubra 6.8 9.1

SOIL NUTRIENT REGIME

MOISTURE Very poor Poor Medium Rich VeryRich

Very_Dry 0 02

Mod_Dry 1 03 04

Mod_Dry 2 Hill CRU FC M

Sl_Dry 3 B

Fresh 4 01 Q 05

Moist 5 06 FBD, HR 07

VeryMoist 6 FBW, CRL

Wet 7 11 12

TreatmentsAdded P with or without other elements: 0,10, 20, 30 g P

per tree in younger; 0, 20, 40 g P in older

Other elements added in appropriate proportion relative to P

Older plantations – removed understory and then banded fertilizers

Younger plantations: placed fertilizer in dibble holes

Responses measured for up to three years

Single-tree plot experiments:

Older plantations—little or no growth response to either P or blend fertilizer

Younger plantations—growth response to P, not to other added elements

3Y VOLUME BY SITE

Stem

Vol

ume

(dm

3 )

0

1

2

3

4

5

3Y HEIGHT

Hei

ght (

m)

0

3

4

5

Duncan Harry RdCR-U FB-DFB-W CR-L

n.c.

+45 %+ 56 %

+ 80 %+ 96 %

+ 64 %

0301 0505-07? 0707CDF CWHxm

Three year growth response; screening trials, young plantations

Best response on relatively moist, fertile sites

Single-tree plot experiment (cont’d)

P fertilizerincreased growth and Y1 foliar concentrations ofP, N (all sites) Ca, Mg, S (some sites)

decreased Zn (all sites) K, B, Cu, Mn (some sites)

Blend fertilizerincreased N, K, Mg, S, B, Zn but did not increase growth

Conclude P availability limited growth

Foliar P (g kg-1)

1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0

Stem

Vol

ume

(dm

3 )

0

1

2

3

4

5

FBDFBWCRLCRUHR

Stem

vol

ume

(dm

3)

2

4

6

8

10

12

14

16

18

MQBFC

a

b

Older plantations

Younger plantations

Why were older plantations less responsive?

Trees were bigger: volumes in 4 year old plantations 84X greater than in 1 year old, but P addition only 2X

Soil in older plantations had higher P levels

Foliage in older plantations had greater P concentrations

Multi-tree Plot Experiments

McColl Road (Bowser)

CWHxm ss 01/05 SMR: SD-F SNR: M-RpH: 5.3 Avail P: 10.7 mg kg-1

Planted fall 1999 / fill-planted in spring 2001

15 Plots 25m x 25m with 10m treated buffer and86 measurement trees per plot

Soil (Bray-extractable) P (mg kg-1)

2 4 6 8 10 12 14 16 18 20 22 24

Ste

m v

olum

e (c

m3 )

0

5

10

15

20

25

30

35

40

45

Y = 1.496P + 4.730 r2 = 0.49

Prior to P additions, stem volume increased with soil Bray-P

Treatments

0, 15, 30 g P per tree in spring 2001

Treatments randomly assigned

Attempt to maintain differences in foliar P

All trees re-fertilized in 2002, 2003, 2004; cumulative P additions of 0, 41, 88 g P/tree (0, 58, 124 kg P/ha)

Ste

m V

olum

e (c

m3 )

010002000300040005000600070008000

Y0 Y1Y2Y3Y4

planted 1999 planted 2001P0 P1 P2 P0 P1 P2

fall 2004

fall 2003

Volume increase with P additionsAbsolute increase greater in 1999 cohortRelative increase greater in 2001 cohort

1999 cohort

Mor

talit

y (%

)

05

1015202530

2002 2003 2004

2001 cohort

Mor

talit

y (%

)

05

1015202530

P0 P1 P2

Mortality greater in younger trees

Unaffected by P treatment through 4 years

Mortality greater in 2003, 2004, than in 2002; drought???

Month3 4 5 6 7 8 9 10

Prec

ipita

tion(

mm

)

0

20

40

60

80

100normal 2001200220032004

Growing season precipitation close to normal in 2001, 2002;Below-normal in 2003, early 2004

What we’ve learned…

P additions often increase growth of very young red alder

Growth responses are greatest at:addition rates of 20-30 g P / tree within year of

plantinglow soil P concentrations (< 15 ppm) or

• low foliar P concentrations (< 0.18 %)

Soil or foliar P is a better predictor of response than is BEC soil nutrient regime

Haven’t seen growth responses to addition of elements other than P

Some things we don’t know…

Why were bigger trees less responsive ?

How long do the effects of P fertilization last ?

Does P fertilization increase N accumulation?

Are of P-fertilized alders more susceptible to frost damage ?

Are P- fertilized alders more susceptible to moisture stress ?

At what rate does P fertilization induce deficiencies of other elements?