Fertilizing Interior Forests: the scientific basis (and some informed speculation) Rob Brockley B.C. Ministry of Forests and Range Kalamalka Forestry Centre Vernon, BC

Why fertilize?

l Every tree to be harvested in the next years is in the ground today

Why fertilize? l Every tree to be harvested in the next years is in the ground today l Forest fertilization is a proven silvicultural treatment for accelerating the operability of established stands without sacrificing harvest volume

Why fertilize? l Every tree to be harvested in the next years is in the ground today l Forest fertilization is a proven silvicultural treatment for accelerating the operability of established stands without sacrificing harvest volume l Fertilization can be used strategically to impact the amount and timing of future harvest

How fertilization mitigates MPB mortality Conceptual Harvest volume Area age class distribution years from now2500 MPB mortality area

How fertilization mitigates MPB mortality Conceptual Area age class distribution years from now2500 MPB mortality area l Fertilizing 30- to 70-year-old stands (blue) can increase harvest volumes 20–40 years from now Harvest volume

How fertilization mitigates MPB mortality Conceptual Harvest volume Area age class distribution years from now2500 MPB mortality area l Fertilizing 30- to 70- year-old stands (blue) can increase harvest volumes 20–40 years from now l Fertilizing 15- to 30-year-old stands (yellow) can increase harvest volumes 40–70 years from now

Fertilization research in the BC interior l Lodgepole pine

Fertilization research in the BC interior l Lodgepole pine  ~ 70 screening trials

Fertilization research in the BC interior l Lodgepole pine  ~ 70 screening trials  ~ 50 area-based trials

Relative 6-year BA response following N fertilization Relative cumulative frequency distribution (n=46)

BA response following N and N+S fertilization Relative cumulative frequency distribution (n=26) N N+S

BA response following N and N+S fertilization Relative cumulative frequency distribution (n=26) N N+S

BA response following N and N+S fertilization Relative cumulative frequency distribution (n=26) N N+S

BA response following N and N+S fertilization Relative cumulative frequency distribution (n=26) N N+S

BA response following N and N+S fertilization Relative cumulative frequency distribution (n=26) N N+S

BA response following N and N+S fertilization Relative cumulative frequency distribution (n=26) N N+S

BA response following N and N+S fertilization Relative cumulative frequency distribution (n=26) N N+S

Effect of N and N+S fertilization on 6-year volume response of lodgepole pine in north-central B.C. EP (n=8)

Effect of N and N+S fertilization on 6-year volume response of lodgepole pine in south-central B.C. EP (n=7)

6-year relative BA response vs. initial foliar N

6-year relative BA response vs. initial foliar SO 4

Lodgepole pine foliar boron concentration Relative cumulative frequency distribution (n=58)

Effects of N and B fertilization on foliar B concentration EP critical value

Effects of N and B fertilization on foliar B concentration EP critical value

Fertilization research in the BC interior l Lodgepole pine  ~ 70 screening trials  ~ 50 area-based trials l Douglas-fir

Fertilization research in the BC interior l Lodgepole pine  ~ 70 screening trials  ~ 50 area-based trials l Douglas-fir  5 screening trials

Fertilization research in the BC interior l Lodgepole pine  ~ 70 screening trials  ~ 50 area-based trials l Douglas-fir  5 screening trials  6 area-based trials

Fertilization research in the BC interior l Lodgepole pine  ~ 70 screening trials  ~ 50 area-based trials l Douglas-fir  5 screening trials  6 area-based trials l Interior spruce

Fertilization research in the BC interior l Lodgepole pine  ~ 70 screening trials  ~ 50 area-based trials l Douglas-fir  5 screening trials  6 area-based trials l Interior spruce  14 screening trials

Fertilization research in the BC interior l Lodgepole pine  ~ 70 screening trials  ~ 50 area-based trials l Douglas-fir  5 screening trials  6 area-based trials l Interior spruce  14 screening trials  12 area-based trials

Douglas-fir fertilization research

l 5 screening trials (SBS, ICH)

Effects of individual and combined applications of N and “complete mix” fertilizer on 1 st year needle mass of Douglas-fir EP (n=5)

Effects of individual and combined applications of N and “complete mix” fertilizer on 1 st year foliar N/S ratio in Douglas-fir EP (n=5) critical level

Effects of individual and combined applications of N and “complete mix” fertilizer on 1 st year foliar N/S ratio in Douglas-fir EP (n=5) critical level

Douglas-fir fertilization research l 5 screening trials (SBS, ICH) l 6 area-based trials (ICH)

Douglas-fir fertilization research l 5 screening trials (SBS, ICH) l 6 area-based trials (ICH)  years

Douglas-fir fertilization research l 5 screening trials (SBS, ICH) l 6 area-based trials (ICH)  years  SI years

Effect of N and N+S fertilization on 9-year stand volume increment of Douglas-fir EP (n=5)

Foliar N/S ratio by treatment and year EP (Douglas-fir; n=5) critical level

Foliar N/S ratio by treatment and year EP (Douglas-fir; n=5) critical level

Effect of N and N+S fertilization on 9-year stand volume increment of Douglas-fir EP Inst. #25

Effect of N and N+S fertilization on 9-year stand volume increment of Douglas-fir EP Inst. #28

Effect of N and N+S fertilization on 9-year stand volume increment by initial foliar N class

Other relevant studies

Site and stand characteristics of the Inland NW Douglas-fir fertilizer installations (n=94) Moore et al. (1991)

Effects of fertilization on relative 6-year volume response of Douglas-fir Inland Northwest (Moore et al. 1991)

Effect of N fertilization on 6-year gross volume increment of Douglas-fir in the Inland NW Moore et al. (1991)

6-year net basal area response following N fertilization by N application rate and foliar K status (from Mika and Moore 1990) Poor Good Foliar K status

6-year net basal area response following N fertilization by N application rate and foliar K status (from Mika and Moore 1990) Poor Good Foliar K status

6-year net volume response following N fertilization by foliar K status (from Brockley 2006) Poor (n=1)Good (n=5) Foliar K status

Root tip phenolic:sugar concentration ratios in Douglas-fir seedlings supplied with different amounts of N and K (from Shaw et al. 1998)

Interior spruce fertilization research

Effects of broadcast burning on foliar N status of white spruce plantations in the B.C. interior Curran and Ballard (1990)

Interior spruce fertilization research l 14 screening trials (SBS, ICH, ESSF)

Effects of individual and combined applications of N and “complete mix” fertilizer on 1 st year needle mass of interior spruce (n=10) Swift and Brockley (1994)

Effects of individual and combined applications of N and “complete mix” fertilizer on 1 st year foliar N/S ratio in interior spruce (n=10) Swift and Brockley (1994) critical level

Effects of individual and combined applications of N and “complete mix” fertilizer on 1 st year foliar N/S ratio in interior spruce (n=10) Swift and Brockley (1994) critical level

Effect of fertilization on 3-year height increment of young Engelmann spruce in the ESSF dc (Brockley 1992) Year 3 Year 2 Year 1

Interior spruce fertilization research l 14 screening trials (SBS, ICH, ESSF) l 9 area-based “conventional” trials (SBS, ICH, ESSF)

Interior spruce fertilization research l 14 screening trials (SBS, ICH, ESSF) l 9 area-based “conventional” trials (SBS, ICH, ESSF)  19 to 30 years

Interior spruce fertilization research l 14 screening trials (SBS, ICH, ESSF) l 9 area-based “conventional” trials (SBS, ICH, ESSF)  19 to 30 years  SI years

Effect of N and N+S fertilization on 9-year stand volume increment of interior spruce EP (n=5)

Foliar N/S ratio by treatment and year EP (spruce; n=5) critical level

Foliar N/S ratio by treatment and year EP (spruce; n=5) critical level

Effect of N and N+S fertilization on 9-year stand volume increment of interior spruce EP Inst. #27 (ESSFwc4, SI 18)

Effect of N and N+S fertilization on 9-year stand volume increment of interior spruce EP Inst. #29 (ICHmc2, SI 18)

Effect of N and N+S fertilization on 9-year stand volume increment of interior spruce EP Inst. #21 (ICHmm, SI 23)

Effect of N and N+S fertilization on 9-year stand volume increment of interior spruce EP Inst. #22 (ICHwk1, SI 24)

Effect of N and N+S fertilization on 9-year stand volume increment of interior spruce EP Inst. #20 (SBSmc2, SI 19)

Foliar B concentration by treatment and year EP Inst. #20 critical level

Effect of N and N+S fertilization on 9-year stand volume increment by initial foliar N class

Interior spruce fertilization research l 14 screening trials (SBS, ICH, ESSF) l 9 area-based “conventional” trials (SBS, ICH, ESSF)  19 to 34 years  SI years l 3 area-based “maximum productivity” trials (SBS)

Interior spruce fertilization research l 14 screening trials (SBS, ICH, ESSF) l 9 area-based “conventional” trials (SBS, ICH, ESSF)  19 to 34 years  SI years l 3 area-based “maximum productivity” trials (SBS)  9 to 13 years

Effects of “single” vs. “repeated” fertilization Single fertilization Unfertilized Fertilize

Effects of “single” vs. “repeated” fertilization Single fertilization Unfertilized Multiple fertilization Fertilize

Treatments l Control l N+B l N+S+B l “Complete blend” l Optimum Nutrition 1 (1.3%N) l Optimum Nutrition 2 (1.6%N) every 6 years

Control Fall 2001 ON 2 Fall 2001

EP Inst. #3 (Crow Creek) Spruce (SBSmc2)

EP Inst. #3 (Crow Creek) Spruce (SBSmc2)

EP Inst. #3 (Crow Creek) Spruce (SBSmc2)

EP Inst. #5 (Lodi Lake) Spruce (SBSwk1)

EP Inst. #5 (Lodi Lake) Spruce (SBSwk1)

EP Inst. #5 (Lodi Lake) Spruce (SBSwk1)

EP Inst. #1 (Sheridan Creek) Lodgepole pine (SBSdw2)

EP Inst. #1 (Sheridan Creek) Lodgepole pine (SBSdw2)

EP Inst. #1 (Sheridan Creek) Lodgepole pine (SBSdw2)

Other relevant studies

Effect of N fertilization on 5-year stand volume increment of white spruce in Alberta (n=3) Krause et al. (1982)

Effect of N and N+K fertilization on 10-year stand volume increment of 35-year-old white spruce Gagnon et al. (1976)

Effect of repeated fertilization on 5-year tree BA increment of 70-year-old white spruce van Cleve and Zasada (1976)

Norway spruce fertilization response (m 3 /ha) Northern Sweden (from Pettersson 2001)

Effects of fertilization on the white pine weevil

Pissodes strobi

White pine weevil damage by treatment EP Installation #5 (Lodi Lake) vanAkker et al. (2005)

Effect of repeated fertilization on 9-year height increment of young interior spruce EP Inst. #5 (Lodi Lake) 7- to 9-year 4- to 6-year 1- to 3-year

White pine weevil damage by treatment EP Installation #9 (Hand Lake) L. vanAkker et al. (2005)

Summary

Douglas-fir

Summary Douglas-fir l stands in the ICH generally respond well to N fertilization

Summary Douglas-fir l stands in the ICH generally respond well to N fertilization l best responses (20-25 m 3 /ha or 30% over 9 years) are associated with low foliar N (< 1.15%)

Summary Douglas-fir l stands in the ICH generally respond well to N fertilization l best responses (20-25 m 3 /ha or 30% over 9 years) are associated with low foliar N (< 1.15%) l no apparent relationship between growth response and SI

Summary Douglas-fir l stands in the ICH generally respond well to N fertilization l best responses (20-25 m 3 /ha or 30% over 9 years) are associated with low foliar N (< 1.15%) l no apparent relationship between growth response and SI l little evidence of improved growth when S is combined with N in fertilizer prescriptions

Summary Douglas-fir l stands in the ICH generally respond well to N fertilization l best responses (20-25 m 3 /ha or 30% over 9 years) are associated with low foliar N (< 1.15%) l no apparent relationship between growth response and SI l little evidence of improved growth when S is combined with N in fertilizer prescriptions l additional area-based trials are needed in other BEC zones (SBS) and in older stands (> 40 years)

Summary Douglas-fir l stands in the ICH generally respond well to N fertilization l best responses (20-25 m 3 /ha or 30% over 9 years) are associated with low foliar N (< 1.15%) l no apparent relationship between growth response and SI l little evidence of improved growth when S is combined with N in fertilizer prescriptions l additional area-based trials are needed in other BEC zones (SBS) and in older stands (> 40 years) l effects of repeated fertilization need to be documented

Summary Interior spruce

Summary Interior spruce l fertilization response is more variable and, on average, smaller than D-fir

Summary Interior spruce l fertilization response is more variable and, on average, smaller than D-fir l best responses (20-25 m 3 /ha or 30-40% over 9 years) are associated with low foliar N (< 1.1%) and SI < 20

Summary Interior spruce l fertilization response is more variable and, on average, smaller than D-fir l best responses (20-25 m 3 /ha or 30-40% over 9 years) are associated with low foliar N (< 1.1%) and SI < 20 l smallest growth responses are associated with highest SI (> 23)

Summary Interior spruce l fertilization response is more variable and, on average, smaller than D-fir l best responses (20-25 m 3 /ha or 30-40% over 9 years) are associated with low foliar N (< 1.1%) and SI < 20 l smallest growth responses are associated with highest SI (> 23) l little evidence of improved growth when S is combined with N in fertilizer prescriptions

Summary Interior spruce l fertilization response is more variable and, on average, smaller than D-fir l best responses (20-25 m 3 /ha or 30-40% over 9 years) are associated with low foliar N (< 1.1%) and SI < 20 l smallest growth responses are associated with highest SI (> 23) l little evidence of improved growth when S is combined with N in fertilizer prescriptions l B deficiencies (< 10 ppm) may limit growth response to N and NS fertilization on some SBS sites

Summary Interior spruce l fertilization response is more variable and, on average, smaller than D-fir l best responses (20-25 m 3 /ha or 30-40% over 9 years) are associated with low foliar N (< 1.1%) and SI < 20 l smallest growth responses are associated with highest SI (> 23) l little evidence of improved growth when S is combined with N in fertilizer prescriptions l B deficiencies (< 10 ppm) may limit growth response to N and NS fertilization on some SBS sites l planted spruce is apparently very well suited to “high input” silviculture

Summary Interior spruce l fertilization response is more variable and, on average, smaller than D-fir l best responses (20-25 m 3 /ha or 30-40% over 9 years) are associated with low foliar N (< 1.1%) and SI < 20 l smallest growth responses are associated with highest SI (> 23) l little evidence of improved growth when S is combined with N in fertilizer prescriptions l B deficiencies (< 10 ppm) may limit growth response to N and NS fertilization on some SBS sites l planted spruce is apparently very well suited to “high input” silviculture l additional area-based trials are needed on N deficient sites in several BEC zones (ICH, ESSF, SBS) and in older stands (> 40 years)