Effects of Intensive Fertilization on
the Growth of Interior Spruce
Presentation to:
Interior Fertilization Working Group
February 5/13 (revised March 4/13)
Typical pattern of growth response following
“conventional” fertilization
3
Total stand volume (m /ha)
Type 1 response
Unfertilized
“Conventional” fertilization (Type 1)
Fertilize
Age
Typical pattern of growth response following
“conventional” fertilization
3
Total stand volume (m /ha)
Type 1 response
Unfertilized
“Conventional” fertilization (Type 1)
Fertilize
Age
Typical pattern of growth response following
“intensive” fertilization
3
Total stand volume (m /ha)
Type 2 response
Unfertilized
“Conventional” fertilization (Type 1)
“Intensive” fertilization (Type 2)
Fertilize
Age
Effects of yearly fertilization on the growth of
Norway spruce in northern Sweden
from Bergh et al. (2005)
3
Total stand volume (m /ha)
200
175
150
Control
125
Fertilized
100
75
50
25
0
0
5
10
Years following trial establishment
15
Stem volume production
(m3/ha/yr)
Relationship between stem wood production and
light interception by forest canopy
Absorbed sunlight during the growing season (GJ/m2)
How can light interception be maximized?
How can light interception be maximized?
 Increase the length of the growing season
How can light interception be maximized?

Increase the length of the growing season
 Increase the amount of leaf area
How can light interception be maximized?

Increase the length of the growing season

Increase the amount of leaf area
 Leaf area is strongly influenced by nutrient
availability
Volume growth (m3/ha/yr)
Relationship between annual volume growth and
leaf area
Leaf area index (m2/m2)
Volume growth (m3/ha/yr)
Relationship between annual volume growth and
leaf area
Leaf area index (m2/m2)
Volume growth (m3/ha/yr)
Relationship between annual volume growth and
leaf area
Leaf area index (m2/m2)
“Maximum Productivity” fertilization research
EP 886.13
 Objectives
 determine the effects of different regimes and
frequencies of repeated fertilization on the
growth and development of young, managed
interior spruce and lodgepole pine forests
“Maximum Productivity” fertilization research
EP 886.13
 Objectives

determine the effects of different regimes and
frequencies of repeated fertilization on the growth and
development of young, managed interior spruce and
lodgepole pine forests

document the long-term effects of intensive,
repeated fertilization on above- and belowground timber and non-timber resources
Interior spruce study sites
Crow Creek
 SBSmc2
 10 years old, planted
Interior spruce study sites
Crow Creek

SBSmc2

10 years old, planted
Lodi Lake
 SBSwk1
 11 years old, planted
Interior spruce study sites
Crow Creek

SBSmc2

10 years old, planted
Lodi Lake

SBSwk1

11 years old, planted
Hand Lake
 SBSmk1
 14 years old, planted
Treatments
 Control
 N+B
 N+S+B
every 6 years
 “Complete blend”
 Optimum Nutrition 1 (1.3%N)
 Optimum Nutrition 2 (1.6%N)
Foliar nitrogen by treatment and year
Crow Creek (Brockley 2010)
1.8
Control
Foliar N (%)
1.6
ON1
ON2
1.4
1.2
1.0
0.8
0.6
0
1
2
3
4
5
6
Year
7
8
9
10
11
12
Foliar nitrogen by treatment and year
Lodi Lake (Unpubl. data)
2.0
Control
1.8
ON1
ON2
Foliar N (%)
1.6
1.4
1.2
1.0
0.8
0.6
0
1
2
3
4
5
6
Year
7
8
9
10
11
12
Foliar nitrogen by treatment and year
Hand Lake (Brockley unpubl.)
1.8
Control
Foliar N (%)
1.6
ON1
ON2
1.4
1.2
1.0
0.8
0.6
0
1
2
3
4
5
6
Year
7
8
9
10
11
12
Foliar nitrogen by treatment and year
Crow Creek (Brockley 2010)
2.4
Foliar N (%)
2.0
Control
NSB
1.6
1.2
0.8
0.4
0.0
0
1
3
6
Year
7
9
12
Foliar nitrogen by treatment and year
Lodi Lake (Unpubl. data)
2.4
Control
Foliar N (%)
2.0
NSB
1.6
1.2
0.8
0.4
0.0
0
1
3
6
Year
7
8
12
18-year tree height increment by treatment
Height increment (m/tree)
Crow Creek (Unpubl. data)
14
13- to 18-year
7- to 12-year
1- to 6-year
12
c
b
10
8
a
30%
29%
NSB
Comp
40%
47%
ON1
ON2
17%
6
4
2
0
Control
NB
Treatment
12-year tree height increment by treatment
Height increment (m/tree)
Lodi Lake (Unpubl. data)
9
8
7
6
5
4
3
2
1
0
7- to 12-year
1- to 6-year
c
b
34%
14%
18%
16%
20%
NB
NSB
Comp
ON1
a
Control
Treatment
ON2
18-year stand volume increment by treatment
250
13- to 18-year
c
7- to 12-year
3
Volume increment (m /ha)
Crow Creek (Unpubl. data)
200
247%
1- to 6-year
b
168%
150
123%
110%
65%
100
a
50
0
Control
NB
NSB
Comp
Treatment
ON1
ON2
12-year stand volume increment by treatment
3
Volume increment (m /ha)
Lodi Lake (Unpubl. data)
140
120
7- to 12-year
1- to 6-year
c
204%
100
80
60
40
136%
b
55%
67%
70%
NSB
Comp
a
20
0
Control
NB
Treatment
ON1
ON2
18-year stand volume development by treatment
Crow Creek (Unpubl. data)
3
Stand volume (m /ha)
200
175
150
125
Control
100
75
50
25
0
0
1
2
3
4
5
6
7
8
9 10 11 12 13 14 15 16 17 18
Years following establishment
18-year stand volume development by treatment
Crow Creek (Unpubl. data)
3
Stand volume (m /ha)
200
175
150
Control
125
100
NB
75
50
25
0
0
1
2
3
4
5
6
7
8
9 10 11 12 13 14 15 16 17 18
Years following establishment
18-year stand volume development by treatment
Crow Creek (Unpubl. data)
3
Stand volume (m /ha)
200
175
150
Control
125
NB
100
NSB
Complete
75
50
25
0
0
1
2
3
4
5
6
7
8
9 10 11 12 13 14 15 16 17 18
Years following establishment
18-year stand volume development by treatment
Crow Creek (Unpubl. data)
3
Stand volume (m /ha)
200
175
Control
150
NB
125
NSB
100
Complete
ON1
75
50
25
0
0
1
2
3
4
5
6
7
8
9 10 11 12 13 14 15 16 17 18
Years following establishment
18-year stand volume development by treatment
Crow Creek (Unpubl. data)
3
Stand volume (m /ha)
200
175
150
Control
125
NSB
NB
Complete
100
ON1
75
ON2
50
25
0
0
1
2
3
4
5
6
7
8
9 10 11 12 13 14 15 16 17 18
Years following establishment
12-year stand volume development by treatment
Lodi Lake (Unpubl. data)
3
Stand volume (m /ha)
160
140
120
100
Control
80
60
40
20
0
0
1
2
3
4
5
6
7
8
9 10 11 12
Years following establishment
12-year stand volume development by treatment
Lodi Lake (Unpubl. data)
3
Stand volume (m /ha)
160
140
120
Control
100
80
NB
60
40
20
0
0
1
2
3
4
5
6
7
8
9 10 11 12
Years following establishment
12-year stand volume development by treatment
Lodi Lake (Unpubl. data)
3
Stand volume (m /ha)
160
140
Control
120
NB
100
80
NSB
60
Complete
40
20
0
0
1
2
3
4
5
6
7
8
9 10 11 12
Years following establishment
12-year stand volume development by treatment
Lodi Lake (Unpubl. data)
160
Stand volume (m3/ha)
140
Control
120
NB
100
NSB
80
Complete
60
ON1
40
20
0
0
1
2
3
4
5
6
7
8
9 10 11 12
Years following establishment
12-year stand volume development by treatment
Lodi Lake (Unpubl. data)
160
Stand volume (m3/ha)
140
Control
NB
NSB
Complete
ON1
ON2
120
100
80
60
40
20
0
0
1
2
3
4
5
6
7
8
9 10 11 12
Years following establishment
Effects of yearly fertilization on the growth of
Norway spruce in northern Sweden
3
Stand volume (m /ha)
from Bergh et al. (2005)
200
180
160
140
120
100
80
60
40
20
0
Control
0
5
10
Years following establishment
15
Effects of yearly fertilization on the growth of
Norway spruce in northern Sweden
3
Stand volume (m /ha)
from Bergh et al. (2005)
200
180
160
140
120
100
80
60
40
20
0
Control
Fertilized
0
5
10
Years following trial establishment
15
Effects of 20 years of annual fertilization on the
growth of Norway spruce in central Sweden
Tamm (1991)
3
Stand volume (m /ha)
400
350
296%
305%
N2PK
N3PK
300
250
199%
200
150
100
50
0
Control
N1PK
Treatment
But …
12-year tree height increment by treatment
Height increment (m/tree)
Hand Lake (Unpubl. data)
10
7- to 12-year
8
1- to 6-year
6
a
3%
1%
Control
NB
NSB
a
b
11%
12%
12%
Comp
ON1
ON2
4
2
0
Treatment
12-year stand volume increment by treatment
3
Volume increment (m /ha)
Hand Lake (Unpubl. data)
200
175
7- to 12-year
1- to 6-year
b
a
150
125
100
13%
19%
25%
33%
38%
a
75
50
25
0
Control
NB
NSB
Comp
Treatment
ON1
ON2
12-year stand volume development by treatment
Hand Lake (Unpubl. data)
3
Stand volume (m /ha)
160
140
120
100
Control
80
60
40
20
0
0
1
2
3
4
5
6
7
8
9 10 11 12
Years following establishment
12-year stand volume development by treatment
Hand Lake (Unpubl. data)
3
Stand volume (m /ha)
160
140
120
Control
100
80
NB
60
40
20
0
0
1
2
3
4
5
6
7
8
9 10 11 12
Years following establishment
12-year stand volume development by treatment
Hand Lake (Unpubl. data)
3
Stand volume (m /ha)
160
140
Control
120
NB
100
80
NSB
60
Complete
40
20
0
0
1
2
3
4
5
6
7
8
9 10 11 12
Years following establishment
12-year stand volume development by treatment
Hand Lake (Unpubl. data)
160
Stand volume (m3/ha)
140
Control
120
NB
100
NSB
80
Complete
60
ON1
40
20
0
0
1
2
3
4
5
6
7
8
9
Years following establishment
10 11 12
12-year stand volume development by treatment
Hand Lake (Unpubl. data)
160
Stand volume (m3/ha)
140
Control
NB
NSB
Complete
ON1
ON2
120
100
80
60
40
20
0
0
1
2
3
4
5
6
7
8
9
Years following establishment
10 11 12
Volume growth (m3/ha/yr)
Relationship between annual volume growth and
leaf area
Leaf area index (m2/m2)
Volume growth (m3/ha/yr)
Relationship between annual volume growth and
leaf area
Leaf area index (m2/m2)
Leaf area index by treatment at year 12
5
2
2
Leaf area index (m /m )
Crow Creek (Brockley 2010)
4
268%
3
176%
2
84%
93%
95%
NB
NSB
Comp
1
0
Control
Treatment
ON1
ON2
12-year stand volume increment by treatment
3
Volume increment (m /ha)
Crow Creek (Brockley 2010)
140
120
284%
100
196%
80
60
130%
123%
NSB
Comp
77%
40
20
0
Control
NB
Treatment
ON1
ON2
Leaf area index by treatment at year 9
Hand Lake (Unpubl. data)
Leaf area index (m2/m2)
6
5
4
12%
35%
38%
42%
Comp
ON1
ON2
20%
3
2
1
0
Control
NB
NSB
Treatment
12-year stand volume increment by treatment
3
Volume increment (m /ha)
Hand Lake (Unpubl. data)
200
175
150
125
13%
19%
25%
33%
38%
100
75
50
25
0
Control
NB
NSB
Comp
Treatment
ON1
ON2
Effects of frequency of fertilization on the growth of
Norway spruce in central Sweden – 5-year results
Bergh et al. (2008)
3
Stand volume (m /ha)
80
F1 – 75-100 kg N every year
F2 – 125-150 kg N every 2 years
F3 – 150-180 kg N every 3 years
70
60
50
91%
83%
40
48%
30
20
10
0
Control
F1
F2
Treatment
F3
Summary of results to date
 Young, nutrient deficient Sx plantations
apparently respond well to repeated
fertilization
Summary of results to date

Young, nutrient deficient Sx plantations apparently respond
well to repeated fertilization
 Potentially large effects on rotation length
or harvest volume
Summary of results to date

Young, nutrient deficient Sx plantations apparently respond
well to repeated fertilization

Potentially large effects on rotation length or harvest volume
 Magnitude of gains directly related to
frequency of application
Modelling the effects of repeatedly fertilizing interior
spruce
 Age of unfertilized and fertilized stands at
minimum operability (e.g., 200 m3/ha
merchantable volume)
Modelling the effects of repeatedly fertilizing interior
spruce

Age of unfertilized and fertilized stands at minimum
operability (e.g., 200 m3/ha merchantable volume)
 Merchantable volume of unfertilized and
fertilized stand at a given stand age (e.g.,
20 years in future)
Merchantable volume (m3/ha))
Modelled effects of fertilization at 5-year intervals
500
450
400
350
300
250
200
150
100
50
0
SI=20
Fertilize every 5 years, starting @ age 20
50% total volume response per fertilization
Unfertilized
Fertilized
39 years
48 years
96 m3/ha
Fertilize
0
5 10 15 20 25 30 35 40 45 50 55
Stand age
Merchantable volume (m3/ha))
Modelled effects of fertilization at 5-year intervals
500
450
400
350
300
250
200
150
100
50
0
SI=20
Fertilize every 5 years, starting @ age 20
75% total volume response per fertilization
Unfertilized
Fertilized
37 years
48 years
140 m3/ha
Fertilize
0
5 10 15 20 25 30 35 40 45 50 55
Stand age
Cautionary Notes
 Repeated fertilization may negatively
impact:
Wood quality

Cautionary Notes
 Repeated fertilization may negatively
impact:

Wood quality

Forest health
Cautionary Notes
 Repeated fertilization may negatively
impact:



Wood quality
Forest health
Non-timber values (e.g., understory,
water, wildlife)
Cautionary Notes

Repeated fertilization may negatively impact:

Wood quality

Forest health

Non-timber values (e.g., understory, water, wildlife)
 Future competition mortality may reduce
net volume gains
Cautionary Notes

Repeated fertilization may negatively impact:

Wood quality

Forest health

Non-timber values (e.g., understory, water, wildlife)

Future competition mortality may reduce net volume gains
 Only short-term (18-yr) local data available
Cautionary Notes

Repeated fertilization may negatively impact:

Wood quality

Forest health

Non-timber values (e.g., understory, water, wildlife)

Future competition mortality may reduce net volume gains

Only short-term (18-yr) local data available
 All stands are not equally responsive
Cautionary Notes

Repeated fertilization may negatively impact:

Wood quality

Forest health

Non-timber values (e.g., understory, water, wildlife)

Future competition mortality may reduce net volume gains

Only short-term (18-yr) local data available

All stands are not equally responsive
 Small number of research trials
Recommended approach
 Proceed cautiously with repeated fertilization every
4-6 years on select SBS sites
Recommended approach

Proceed cautiously with repeated fertilization every 4-6 years on select SBS
sites
 Site/stand attributes



young (15-25 yrs)
broadcast burned
N deficient (<1.1% N)
Recommended approach

Proceed cautiously with repeated fertilization every 4-6 years on select SBS
sites

Site/stand attributes
young (15-25 yrs)
broadcast burned
N deficient (<1.1% N)



 Apply N at ~175 kg/ha
Recommended approach

Proceed cautiously with repeated fertilization every 4-6 years on select SBS
sites

Site/stand attributes
Young (15-25 yrs)
Broadcast burned
N deficient (<1.1% N)




Apply N at ~175 kg/ha
 Apply other nutrients (S, B) as needed (every 2nd
application?)
Recommended approach

Proceed cautiously with repeated fertilization every 4-6 years on select SBS
sites

Site/stand attributes
Young (15-25 yrs)
Broadcast burned
N deficient (<1.1% N)




Apply N at ~175 kg/ha

Apply other nutrients (S, B) as needed (every 2nd application?)
 Monitor foliar nutrients, forest health and water
quality
Recommended approach

Proceed cautiously with repeated fertilization every 4-6 years on select SBS
sites

Site/stand attributes
Young (15-25 yrs)
Broadcast burned
N deficient (<1.1% N)




Apply N at ~175 kg/ha

Apply other nutrients (S, B) as needed (every 2nd application?)

Monitor foliar nutrients, forest health and water quality
 Continue measurement and re-treatment of
existing research trials