Annual Meeting

INTERMOUNTAIN FOREST

TREE NUTRITION COOPERATIVE

Annual Meeting

April 12, 1994

Riverbend Room, Schoenberg Center Gonzaga University

Spokane, Washington

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TABLE OF CONTENTS

Growth response to nitrogen fertilizer: results from the IFTNC region-wide

Douglas-fir experiments. - Peter Mika . . . • . . . • . . • . . . • . . . I Ten year within-stand distribution of growth response to nitrogen

fertilization. -Jim Moore 19

Ten year board foot response to nitrogen fertilization within Douglas-fir

case study stands. -Jim Moore 21

Ten year growth response to nitrogen fertilization versus pre-treatment

foliar potassium status for Douglas-fir. - Jim Moore . • • • . • . • . . . • . . . • 35 Four-year growth response to potassium fertilization versus pre-treatment

foliar potassium status for Douglas-fir. - Peter Mika 43

Evidence of links between nutrition and forest health. -Jim Moore . • • • . . . • . . 53 The effects of nutrition on Douglas-fIr root chemistry from a greenhouse

experiment. - Terry Shaw 63

The effect of nitrogen and potassium fertilization on Douglas-frr root

chemistry from the Grangemont root rot site. - John Schwandt 77 Ponderosa pine and mountain pine beetle response to nitrogen and potassium

fertilization in Montana. -John Mandzak . . . . 85 Nutritional differences between tree species. - Terry Shaw 91 Soils and tree nutrition in the Inland Northwest. -John Shumway . . . .. 113 Biomass removal, slash disposal, site preparation - effects on site

nutrient capital. -Dennis Parent . . . • . • . . . .. 125

Best management practices for nutrition. - John Bruna 133 _~

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INTERMOUNTAIN FOREST TREE NUTRITION COOPERATIVE

GROWTH RESPONSE TO NITROGEN FERTILIZER:

RESULTS FROM THE IFTNC REGION-WIDE DOUGLAS-FIR EXPERIMENTS

PETER MIKA UNIVERSITY OF IDAHO

MOSCOW, IDAHO

1

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N Fertilizer:

-Control -+-200#N/.

*400#N/.

1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6

Nitrogen Cone.

(%)

Foliar Nitrogen Distribution

One Year After 1

st

Treatment

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Nearly all Douglas-fir trees sampled on untreated control plots throughout the IFTNC region were below adequate (1.6%) foliar nitrogen concentration. Even afteradding 200 # of N per acre, more than 1/2 of the sampled trees still had inadequate (1.4%) foliar N concentration.

Only after fertilizing with 400 # of nitrogen did most sample trees show adequate foliar N concentration. These foliar diagnostics suggest that N is limited essentially everywhere in the region and that if N were supplied, growth increases of about 25% would be expected.

2

Control plot lO-year average volume growth was highest in northern Idaho and lowest in Montana and northeastern Oregon. Central and northeastern Washington were intermediate and they had about the same growth rates.

Growth response to the nitrogen fertilization treatments was not necessarily related to the untreated control plots' average growth rate.

10 Year Gross Volume Growth

By Region

3000

-r----.,...---.

FJ!

Control ~ 200#N/a .400#N/a (i2500

j;

-2000

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NI MO CI NEO CW NEW All

Region

3

Central Washington showed the largest growth response to both nitrogen treatments (200#N - = 360 cu. ft. and 400#N -

=

500 cu. ft.), and northeastern Oregon produced thelowest average N response. With the exception of northeastern Oregon, the 400 # N responsewas higher than the 200#N treatmentinallregions, although not significantly soinMontana and central Idaho.

10 Year Gross Volume Response

By Region

6 o 0 . . . . , . - - - - . . . , . - - - ,

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~200#N/a 11400#N/a

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Region

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All

2400 -200#N/8 +400#N/8

10 Year Net Volume Response

All Sites

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-2400 -1600 -800 0 800 1600

Net Volume Response (fP/a)

By design the IFTNC selected fertilization test sites that covered a wide range of site and soil conditions, with Douglas-fir site index ranging from 40 to 105 feet at SO years. We expected a wide rangeinresponse to nitrogen fertilization. This figure shows that we achieved a response range from minus 2400 to plus 2500 cu. ft. per acre. The trick is toaccount for the variation in response to nitrogen fertilization and screen out non-responding acres in an operational fertilization program.

600~---...,...---,

10 Year Gross Volume Response

By Parent Material

Mixed Sediment

Parent Material

Basalt Meta Granite

~200#N/a 11400#N/a

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~500 -

- i - - - '

: 400 c 8.300

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Sedimentary parent materials produced the largest response toboth nitrogen treatments (400 # N response averaged> 500 cu. ft.), and the granitics the lowest. The 400 # N response was greater than the 200 # N response for all parent materials exceptgranites.

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Granite parent materials showed negative net response toboth nitrogen fertilization treatments, this resulted from increased treatment related mort:.lity. The 400 , N net response on metamorphic soils was less than the 200 # N treatment , again due to higher mortality rates on the 400 # treatment.

10 Year Net Volume Response

By Parent Material

4 0 0 - , . - - - - . . . , . . . - - - . ,

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10 Year Gross Volume Response

By Parent Material

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-600 ·300 0 300 600 900 1200 1500

Gross Volume Response (ft3/a)

All of the large responders (greater than 500 cu. ft.perac.) toeither N treatment were on basalt and sedimentary soils. No large responders occurred on granitic soils. Soil parent material accounts for some of the wide variationin response to nitrogen fertilization.

8

2400

. . G,.nllo-200N

+ ...."

. . Sedimentary

+ ...."

. . Sedimentary

".' GRnla.--400N

10 Year Net Volume Response

By Parent Material

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·2400 ·1600 ·800 0 800 1600

Net Volume Response (fP/a)

Similar to gross cu. ft. response, no large responders occurred on granitic parent materials.

There were two large negative responders to the 400#N treatment on basalt soils. There were no negative responders on sedimentary soils.

9

···WRC

*WRC .•- GF-400N +DF

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10 Year Gross Volume Response

By Vegetation Series

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·600 ·300 0 300 600 900 1200 1500

Gross Volume Response (ft3/a)

Most of the large responders (greater than 500 cu. ft. per &c.) were located on grand fir and western redcedar habitat series. Two large negative responders on the western redcedar ^types greatly reduced the average response to the 200 # N treatment. Theoretically, if we could eliminateall sites that respond less than the median (50th %ti1e) then the new median response would be the current 75th %tile, or about 400 cu. ft. for grand firand western redcedartypes.

Habitat type series accounts for some of the wide variation in response to N fertilization.

10

Similarto gross volume response, the large responders to both nitrogen fertilization rates were on grand fir and western redcedar habitat types rather than on Douglas-fir types. The two largest negative responders resulted from the 400 # N treatment on Douglas-fir types.

Fertilizing with 400 # of N on Douglas-fir typesis not a good risk since there is a chance of producing large negative response but no chance of large positive response.

···GF-400N -GF-200N

2400 +DF

'-·WRC +DF

"WRC

10 Year Net Volume Response

By Vegetation Series

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-2400 -1600 -800 0 800 1600

Net Volume Response (ft³/a)

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11

Periodic Gross Volume Response

By Parent Material

Granite soils produce weak cu. ft. response of short duration and for the 400# N treatment response is negative during the last two growth periods due to treatment induced mortality.

However, on a relative basis, the surviving fertilized trees are growing faster than the control trees even in years 9 and 10after fertilization.

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N Rate: 2 4 2 4 2 4

Parent Material: Gran Basalt Sed

The graph on the left includes both direct and indirect N fertilization responses (ie. the extta wood that could be harvested), the total height of the bar is magnitude of response while the color codeswithineach bar represents duration of response. Graphs on the right represent direct N effect (this provides useful information on timing of N retreatments).

On the average, basalt soils showed moderate response to N fertilization that continues throughout the ten year period. The 400# N responsewas higher thanthe200 #N, primarily due to longer response duration. The 400#N treatment produces as much additional wood in 4 years as the 200# N does in 8. Either N treatment on basalt produces more additional wood in4 years than granitic soils do in 10 years.

Fertilization on soils derived from sedimentary rocks produced the highest N responses in the region. Their 10-year 200 #N response is the same as the 400 #N response on basalts. The 400 #N response is significantly higher than the 200 #N, with as much extra wood produced in 4 years on 400 # treatments as in 10 years from the 200 # N. The 400 # N response on sedimentary soils remains quite strong inyears 9 and 10.

This graph is arranged in a similarfashion as the previous soil parent material graph. The panel on the left represents both direct and indirect N treatment response, and the right panel shows direct N response only.

A ·stair-step" pattern is evident for both magnitude and duration of nitrogen cu. ft. growth response proceeding from the 200 # N on Douglas-fir habitattypes tothe 400 # N treatment on western redcedar types. The only exceptionto the pattern is the 200#N treatment on western redcedar habitats. The low response results from mortality on some 200 # N treated plots;

however, the surviving fertilized trees still show relatively faster growth (the panel on the right) than the untreated trees in years 9 and 10.

Both N treatments on grand fllhabitats and the 400# N on western redcedar produced equal or greater fertilization response in 4 years than Douglas-fir types do in 10 years.

Periodic Gross Volume Response

By Vegetation Series

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N Rate: 2 4 2 4 2 4 2 4 2 4 2 4

Series: DF GF WRC DF GF WRC

13

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The original 400 # N fertilization stillshows foliar N concentrations that are elevated over the control plots six years after the original treatments were applied. The increase in foliar N concentrations from the 200 # N retreatments (regardless of whether combined with K) was about the same as for the original 200 # N treatments. Nitrogen uptake is very consistent across a wide variety of sites even given differentyearsand associated variation in growing conditions.

Based only on these foliar diagnostics, we would expect about the same growth response to the retreatments as occurred after the original treatments (except for the original 400 # N treatments).

Foliar Nitrogen Distribution

One Year After 2nd Treatment

1.1 1.3 1.5 1.7 1.9 2.1 2.3

Nitrogen Cone.

(%)

14

The absolute cu.ft. response (both direct and indirect effects) to the 200#N retreatments (years 7-10) was less than for the original 200 # N treatments response (years 1-4) for all soil parent materials.

Comparison of Treatment and Retreatment Response

By Parent Material

2 0 0 , . . - - - - " " " " ' " T " - - - . IlmVee,.7·10

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Just as for absolute response, the relative (growth on fertilized plots/growth on control plots) response to the 200#N retreatments was also less than the original treatment response for all parent materials. Retreatment response was particularly less on those soils that produced the largest responsetothe original N treatments. This suggests that the original fertilization effects have not "worn off" and that six years is too soon toretreat withN to obtain the same growth

response per pound of N applied.

Comparison of Treatment and Retreatment Response

By Parent Material

3 5 - r - - - r - - - , CD ~years 7.10 • Years 1-4

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Granite Basalt Meta Sediment Mixed Parent Material

16

Similar to the retreatrnent comparisons for soil parent material, all habitat types showed less growth response to the N retreatrnents than to the original 200 # N treabllent. The retreatment response on redcedar habitat series was almost the same as for the original response.

Comparison of Treatment and Retreatment Response By Vegetation Series

2 5 0 . , . . . . - - - . . . . - - - ,

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Years 7-10 IIYears 1-4

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INTERMOUNTAIN FOREST TREE NUTRITION

COOPERATIVE

TEN YEAR WITHIN-STAND DISTRIBUTION OF GROWTH RESPONSE TO NITROGEN

FERTILIZATION

JIM MOORE UNIVERSITY OF IDAHO

MOSCOW, IDAHO

19

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Nitrogen Treatment Effect on Within-stand Relative-size Relative-growth Relationship

The nitrogen fertilization treatments had little effect on the characteristic within-stand relationship between individual tree relative growth and relative size. Ona relative basis, trees that were growing well before nitrogen fertilization responded well to the treatments.

There is a slight trend for large trees to grow relatively less afternitrogen fertilization.

20

INTERMOUNTAIN FOREST TREE NUTRITION COOPERATIVE

TEN YEAR BOARD FOOT RESPONSE TO NITROGEN FERTILIZATION FOR DOUGLAS-FIR

JIM MOORE UNIVERSITY OF IDAHO

MOSCOW. IDAHO

21

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The northern Idaho region shows the highest periodic growth rates for the untreated control plots. The other regions are all about the same.

Ten Year Average Gross Volume Growth

for Control Plots and by Region

1 2 , . . . - - - , 10

2

0'----

N.ID MT C.ID N.E. C.WA N.E. ALL

OR WA

Region

22

Ten Year Average Gross Volume Response

by Region and Treatment

Central Washington averaged about 2700 and 3000 bd. ft. per acre responseto the 200 and 400

# N treatments respectively. Central Idaho and northeastern Oregon showed low average response to N fertilization.

2N4N 2N4N 2N4N 2N4N 2N4N 2N4N 2N4N

N.ID MT C.ID NE-OR C.WA HE.WA ALL

2,500 3,000

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1.000 500

Treatment^O Region

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Granite soils showed negative average response to both nitrogen treatments. Basalt soils produced large average nitrogen growth response but no significant difference between the 200 and 400 #N treatments. The 400#N treatment response wassignificantlygreater than the 200

# N treatment on those soils derived fonn sedimentary rocks.

Ten Year Average Gross Volume Response

.by Soil Parent Material and Treatment

2 , 0 0 0 r - - - - = - - - ,

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_ S O O L . . . - - - J Treatment ^{2N .eN 2N .eN 2N .eN 2N .eN 2N .eN} Parent Material ^Granite Bass" Uetamorphlc Ulxed Sedimentary

24

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Ten Year Average Gross Volume Growth

by Habitat Type Series and Treatment

C 2N 4N

WRC

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Western red cedarhabitats grew faster than grand firtypeswhichintumgrew faster Douglas-frr habitat series.

Ten Year Average Gross Volume Response

by Habitat Type Series and Treatment

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Twenty-five percent of the sites on basalt, metamolphic, and sedimentary soils showed response to the 200 #N treatment greater than - 2000 bd. ft. per acre.

Ten Year Gross Response to the 200# N Treatment

by Soil Parent Material

AJ!",

°

^{1 2 3 4 5 6 7 8}

Response(MMbd.ft/ac)

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One-half of the sites on sedimentary rocks producedgrowthincreases of more than 2000 bd. ft.

peracre after the 400 # N treatment was applied. More than 1/2 of the metamorphic test sites showed negative growth response.

Ten Year Gross Response to the 400# N Treatment

by Soli Parent Material

~~~~~---

·2 ·1

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^{1 2 3 4 5 6 7 8 9 10}

Response(MMbd.ftlac}

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Some sites on basalt soils showed very high responseto the 200#N fertilization; however, no granite soils produced high growth response. MetamOIphic soils were highly variable in their fertilization response, while sedimentary soils were much less variable.

Ten Year Net Response to the 200# N Treatment

by Soli Parent Material

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Response (MMbd. ft/ac)

-Granite_~Basalt~MetamDrphlc-Sedimentary_~Mlxed

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Response(MMbd.ft/ac)

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Ten Year Net Response to the 400# N Treatment

by Soli Parent Material

30

There were no large responders tothe 200 # N treatment on Douglas-fir habitat series. Western

red cedar types are highly variablein their growth response.

Ten Year Gross Response to the 200# N Treatment

by Habitat Series

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10 Year Response (MMbd.ft./ac.)

I-Douglas-flr ..:...orand fir

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Ten Year Gross Response to the 400# N Treatment

by Habitat Series

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10 Rear Response (MMbd.ft./ac.)

I-Douglas-fir

~Grand

fir ...Westem Redcedar

I

32

None of the big responders to 200 #N treatments are on Douglas-fir habitat series, and about one-half of the Douglas-fir ^types showed negative net response.

Ten Year Net Volume to the 200# N Treatment

by Habitat Series

~ ' .00 r...-...---7---:::;~==:=:=:=:=~

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10-Year Response (MMbd.ft./ac.)

I-DouglaS-fir ---Grand fir"Western Redcedar

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Ten Year Net Response to the 400# N Treatment

by Habitat Series

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1O-year Response (MMbd.ft./ac.)

I-Douglas-fir

~Grand

^fir

"'Weste~

^Redcedar

I

34

INTERMOUNTAIN FOREST TREE NUTRITION COOPERATIVE

TEN YEAR GROWTH RESPONSE TO NITROGEN FERTILIZATION VERSUS PRE-TREATMENT FOLIAR

POTASSIUM STATUS FOR DOUGLAS-FIR

JIM MOORE UNIVERSITY OF IDAHO

MOSCOW, IDAHO

35

-.I

10 Year Gross Board Foot Volume Growth By Initial Potassium Condition

The untreated control plots on the good K-status plots averaged about 620 bd. ft. I ac. I year.

While the control plots on the poor K-status sites grew almost twice asfastaveraging over 1000 bd. ft. I ac. I year. Another illustration of the possibility that the soils were unable to supply sufficient K to support rapid growth rates on the poor K sites.

Poor

36

Good

Initial Potassium Condition

o

14~---r---....,---,

.. 1m

^Control ~200#N/a .400#N/a

~12.a ::E10

-

:i^{.r:. 8}

i

_o

~ 6 CJ

fit 4

e

fit ²

CJ

Good Poor

37

Initial Potassium Condition

fP1I200#N/a B400#N/a .

400~---,---,

o

10 Year Gross Volume Response

By Initial Potassium Condition

- ~

::'300 CDen c

&.200

enCD

a: = _e

¹⁰⁰

CI

- 4 0 0 . . . . L . . . - - - . . . J

~200#N/a .400#N/a

Poor Good

10 Year Net Volume Response

By Initial Potassium Condition

38

Initial Potassium Condition

Ci

400

;;0-

S.

CD 200

•

^C

a.o 0

=

II:

'S-200 Z

Some years after fertilizingwith nitrogen only, treesbegan dying aDthe poor X-status sites that received the 400 #N treatments withinthe confines of the plot boundaries. In contrast, on the good X-status sites the 400#fertilization rate produced significantly moregrowthresponse than the 200 # N treatment just as would be expected if nitrogen were the primary limiting element.

Nutrition is important for tree life (growth) and death. Small changes in nutrition can have a large impact on forest health.

, j

Periodic Gross Volume Response

By Initial Potassium Condition

The left panel includes both direct and indirect N fertilization response (ie. the extra wood that could be harvested), the right panel represents direct N effect (whichis useful for determining N retreatment timing). The 400 #N treatment cu. ft. response on the poor K-status sites (the left panel) was positive, although somewhat weak, for the first 4 years after treatment. The growth responseisnegative for the last six years due to treatment induced mortality which began in years 5 and 6 after N fertilization. However, on a relative basis (the right panel), the surviving trees on the poor K-status sites are still responding better than those on the good K sites. Perhaps another indication that the soil was unable to supply sufficient K to support higher growth rates on the poor K sites.

6 -

-

'f1.

6 ^CD

•

4 c0

~CD

3

!

2

_:; =

1 . .

a:

Ihea,.1-2 ~Vear.^3-4 .Ve.,."

8lh.a,.^{7-11 •} v••,.9-10

.r---r---...--...7

-

500

~

£400 CDCD

c 300

o~

CDCD 200

a::

CD

Z

¹⁰⁰

CJ

..

o 0

N Rate: 200 400 200 400 200 400 200 400

K Condillon: Poor Good Poor Good

39

-500 2,000

2 , 5 0 0 . . . - - - . ,

40

-1.000^L..-

-===-

^{- - J}

Treatment 2N 4N 2N 4N

K-status Poor Good

Ten Year Average Net Volume Response

by Pre-treatment Foliar K-status and Treatment

The good pre-treatment K-status sites showed good net response ^tothe 200 # N treatment and a significant further response increase from the 400 # N treatment. Thisisexactly the response pattern expected in a strongly N limited forest system. However, while the poor K-status sites produced good growth response to the 200 # N treatment, the average response to the 400 # fertilization was negative for the poor K category. There was significant treatment induced ttee

mortality from the 400 # N treatment.

- Poor-200#N +Poor~OO#N ... Good-200#N

+ ^Good-400#N

Two of the 400#N treatments on the poor X-status sites showed negative N treatment response of about 5000 and 7000 bd. ft. per ac. These were very definitely plots that exhibited the

IIsquare death syndrome".

10 Year Net Board Foot Volume Response

By Initial Potassium Condition

>01.0

,---r---:;:*=:t::==:::::t::==-.

uc

CD::I

.,.0.8 ---+-.~~:",.r...

~

~0.6

-

^CD

'5EO.4 U::I

~0.2CD

1i

..

II:0.0+-~-_r_"'_.,._-+___"'"""T'_...,,..._...,.-,...:0""'0'""T"...j

-8 -6 -4 -2 0 2 4 6 8 10 12 14

Net Volume Response (MMbf/a)

41

About 75% of the sites in the poor K-status showed negative net response to the 400# N treatment, while only about 5%of the good category were negative responders. Twenty-five percent of the good potassium sites responded greater than 4000 bd. ft. per acre in ten years.

Ten Year Net Response to the 400# N Treatment

by K Status

>-1.00r-=-=-=='='==-=-==-=-======-=-==?~:::::;:::~~

oc

~035 --- --- ---CD

~

!

CD 0.50 - - - -

~

'&i

~ ^0.25

=

o

O . O O L . . . - - - '

·6 -4 -2 0 2 4 6 8 10

10 Year Response (MMbd.ft./ac.)

I-poor

~Good I

42

INTERMOUNTAIN FOREST TREE NUTRITION COOPERATIVE

FOUR-YEAR GROWTH RESPONSE TO POTASSIUM FERTILIZATION VERSUS PRE-TREATMENT FOLIAR POTASSIUM STATUS FOR DOUGLAS-FIR

PETER MIKA UNIVERSITY OF IDAHO

MOSCOW, IDAHO

43

II

New N ~N + K . K Effect

At the time when the Douglas-fir installations were retreated with 200 lbsla of N, some of the plots were fertilized with a mixture of 200 Ibsla N and 200 IbslaK. This figure and the seven that follow show the influence of the addition of K on volume growth response 4 years after fertilization. Each figure shows the response tothe new N treatment, the response to the N

+

K treatment, and the K effect (the difference between the 2 responses).

There was no overall K effect on gross volume response, nor did any region show significant K effects. Central Idaho did have a K effect of 51 if/a due to the lack of any response to the N retreatment.

K Effect on Gross Volume Response

By Region

250.----~---_r_-_____,

- .!!.

200

5-

: 150 c

&.100

(I)

a:

CD ⁵⁰

enen

e

⁰

CJ

· 5 0 . . . . 1 . . . - - - '

NI MON CI NEO CW NEW All

Region

44

Means for net volume response indicate that K additions produce a positive effect in many regions. North Idaho, central Idaho, and northeast Oregon showed K effects of 86, 122, and 88 tria, respectively.

In addition to the 4 year response to retreatment, this figure also shows the 4 year response to the original N treatment. The regions with large K effects all experienced substantial declines in response to N from the first to the second treatment, with central Idaho and northeast Oregon actually showing negative responses. Without a K supplement, addition of N increased mortality rates beyond those occurring on non-retreated plots, but the K addition apparently prevented this.

In regions where N treatment did not lead to reduced response (central and northeast Washington), K additions had no effect.

K Effect on Net Volume Response

By Region

3 0 0 . . . - - - . - - - -

IllS

^{Old N}

II

^{New N} ~N + K • K Effect

- ~

²⁰⁰

CDfIJ

S

¹⁰⁰

a-U)

a::

CD 0 1) Z

·100 '---- ^--J

NI MON CI NEO CW NEW All

Region

45

DNew N ~N + K . K Effect

When sites are grouped according to parent material, no trends for differential gross volume response toK are apparent. IfK supplements does influence gross volume response on certain sites, the distinguishing characteristics of those sites are not related to the underlying rocktype.

K Effect on Gross Volume Response

By Parent Material

250

-.---r---.,---,

~200

-

e.

: 150 c 8.100 enCD

a:

⁵⁰

CDCD

e

⁰

CJ

· 5 0 . . . . 1 . . . - - - ' Granite Basalt Meta Sediment Mixed

Parent Material

46

Installations growing on granite and mixed (glacialtill)parent materials showed no reduction in response to N retreatment from the original response levels. These installations also failed to show any response to the K supplement.

Installations on basalt showed a large reduction in response to N (from 121 to -39 ft3/a) and a large K effect (115 fr/a). K and N nutrition may playa large role in mortality processes on these sites.

K Effect on Net Volume Response

By Parent Material

300

-r----r"---...---.

II

Old N

1'1

^{New N} ~N + K • K Effect -250

~

£200

CD~ 150

o

i

¹⁰⁰

a:

CD ⁵⁰

CDZ 0

-50~---J

Granite Basalt Meta Sediment Mixed Parent Material

47

Bl§Old N

II

^{New N} ~N + K • K Effect (!"

f"'!'"

~

f'l"

(!"""-

f'l"

~

~

f"'!"

(f'!f>I

~

f!"'"

~ (%I'

f!i"

fW'

(!'"

~

~

~

~

~

~ ("""

~

~ ('l"

f'P'

Grandfir sites showed substantial declines in gross volume responsetoN (from 17S toS4 fiJ/a) and also showed significant improvement (40 ft!/a) when K was added. Douglas-fir sites also declined in N response but failed to respondtoK supplements. Installations on western tedcedar' sites showed little declinein N response and noK effect.

Differences in species nutritional requirements maybe affecting these outcomes. Grand fir often makes upaconsiderable amount of the total basalarea inOUfGF and WRC sites: the difference in response behavior of GF and DF sites may reflecta tree species difference in response to K fertilization.

K Effect on Gross Volume Response

By Vegetation Series

300-r-~---.----.

-

.!!.

250

~-200

: g

¹⁵⁰

a.

: 100 a:

(I 50

(I

f

0 CJ

- 5 0 . . . . 1 . . . - - - '

GF DF WRC

Vegetation Series

48

While the net response to N retreatment was greatly reduced from original response rates onall vegetation series, only on grand firtypeswas the K effect substantial (127fiJ/a). Ifa schedule of repeated N fertilizations are being considered for stands on grand fir sites, addition of K to the fertilizer mix may be well justified.

K Effect on Net Volume Response

By Vegetation Series

250

-r---r---,,----., II

^Old N BNew N ~N +K BK Effect

-

~200

£

: 150 c

o

I:L eft 100

a:

CD

e

⁵⁰

z

o

GF DF WRC

Vegetation Series

49

250- , - - r - - - . - - - ,

K Effect on Gross Volume Response

By Initial K Condition

50

Poor Good

Initial K Condition

mOld N

II

New N ~N + K . K Effect

o

-

.!!

=200

-

^CD

!

¹⁵⁰

a.o

.! •

¹⁰⁰

e ••

⁵⁰

CJ

Sites exhibiting poor initial K conditions showed improved gross volume response ^to N retreatment when K was also included (K effect = 62 _~/a). Perhaps improved osmotic regulation could account for this: when provided with sufficient K, tree water use efficiency could improve and growing season length could be prolonged, thereby actually increasing individual tree growth.

Both good and poor K sites showed large reductions in net response to N treatment from previous N treatment response rates. And both types of sites also responded positively to K supplements (143 tria on poor K sites, 108 tria on good K sites). For both site types, N retreatment increased mortality rates, while N

+

K improved tree growth and minimized mortality.

K Effect on Net Volume Response

By

Initial

K

Condition

250~-r---r---,

II

Old N FJaNew N ~N + K . K Effect

m200

~

-150CD

ca

S

¹⁰⁰

a.en

~ ⁵⁰ ZCD 0

· 5 0 . . . . l . . - - - J

Poor Good

Initial K Condition

51

"'·:'1

INTERMOUNTAIN FOREST TREE NUTRITION COOPERATIVE

EVIDENCE OF LINKS BETWEEN NUTRITION AND FOREST HEALTH

JIM MOORE UNIVERSITY OF IDAHO

MOSCOW, IDAHO

53

(IW\

\

Obligate pathogens are those that require living tissue, while facultative can infect dead or dying tissue. Potassium nutrition has the same effect on both types of pathogens. High potassium levels result in low pathogen success. However, high nitrogen benefits facultative and reduces obligate pathogen success.

Potassium nutrition effects disease severity more than does nitrogen nutrition.

Effects of Nand K on the Severity of Diseases Caused by Parasites

5r---....,

H L H L H L H L

Obligate Facultative Obligate Facultative

N Level K Level

From Marschener 1986

o

4 4

54

1640 410

OL...---l

_o 82

K Supply (Kg/ha)

-

^'#._-60

II)

'tJG)

en

G) ⁴⁰

'tJ

~

.!

20

-

c

Effect of Potassium Supplied to Soybean on Percentage of Seeds Infected with Diaporthe

From Marschener 1986

As potassium supply increases, the percent of soybeanseeds infected withpod blight decreases significantly.

These kind of effects have been known and used inagriculture for many years.

55

Bryant 8tal. 1987

56

C= Control N= Nitrogen

140 '6j120

&100

-

~

!J!I80

~ ⁸⁰ i.~_:::I

CL 20

0 3.0 _2.11

~_.2.0 c:

'E1.5 c:

{!1.0 0.5 0.0 2.5

g2.0 '01.5

•

c:

1!1.o CL

0.5

0.0 C

Effects of Nitrogen Fertilization of Aspen on Phenol and Tannin Leaf Concentrations

and Tortrlx Larvae Weights

Fertilization with high nitrogen doses reduced leaf phenol and tannin concentrations which consequently produced higher average larvae weights for an aspen defoliator.

Phenols and tannins are plant defense chemicals.

High leaf phenolic concentrations result in low levels of leaf consumption by insects. Leaf

phenolic concentrations are significantly effected by changes in the trees' ( Salixsp.) light and nutrient environment.

Leaf Consumption

by

Beetles and Leaf Concentrations of Phenolic Compounds

1 . 2 0 . - - - , 1.00

" •

^{§ .0.00}

&.

~ ^10.0 E :::I

o CIl 8.0 U~

0"

^6.0

- -

-o ...CIl

c - 4.0 .cfI)

0.

0.0

1

r-·-...

-~-ml-HaIl-~--U}l-H9I-LlgN-1

~... maQp""~L""'"

From Larsson et 81 1986

57

58

_120 112

-

^C

.! 100

N"-a.

E 80

-

0_~ ⁶⁰

~

⁴⁰

.a

..

_CD

%: 20

0 Low Tannin High Tannin

From Coley 1986

t'''' rm'

~

(Pi' High leaf tannin concentration inhibits insect feeding on Cecropia ( a tropical tree) leaves.

f"'"

~

~

(IW"

Herbivory on Cecropia Trees with

rm"

High or Low leaf Tannin Content

~

~ (I"'"

rm

(I"'"

~

(f'h'\

~

Herbivory and Defense vs.

Tree Height Growth Rate

tr

~O.3

40 80 120

Growth Rate

From Coley 1988 3.5

3.0

~2.5

~ ^2.0

-

-e1.5 :J: 1.0

•

0.0 100

Q) 80

enc

Q) 60

-

^Q)

Q 40 20 0

Based on averages from 41 tropical tree species, as growth rate increases plant defense chemicals decrease, and as a consequence insect herbivory increases.

There is also evidence from other work that the same relationsQips hold for fast growing individuals within a species.

59 '~

( '

(A

~

~

fl""

~

f!!I

(%'"

~

~ (Ph>

~

~

~

~ fI'"

r:m'

~ (?!' ("'"

~

~

(f"""'

f"""

~

~

This study was conducted on Douglas-firin north Idaho. The X-axisisIQQ1 concentration of phenolics ( the energy to break down the molecules) divided byIQQl sugar concentration ( the energy supplied to the fungus by the sugar). Root phenolic/sugar ratios less than - 15 are good for the Armillaria and bad for the trees.

ARMILLARIA INFECTION RATE

Relationship to Thermochemical Budget

C 1.4

• •

;=0_u 1.3-

• ... ••

.!

^1.2-

.5

1.1 -

••

...

₀

_••

1 -

CD

•

U_C 0.9-

..

CD 0.8-

"a

•• •

13

_c ^0.7-

•

^•

• _•

- 0.6

S 10 1S 20 2S 30 35 40

EphenOI:Esugar (X 1o--')

Adapted from Entry et811991

60

Armillaria caused mortality is higherinthe poor pre-treatment foliar X-status compared to the good X-status. (1be same is also true when comparing the otherwise and good categories.)

MORTALITY RATES BY CAUSE,

TREATMENT, AND POTASSIUM STATUS

4~---'Cause of Mortality:

§l§Root Rot

I!iit

Bark Beetle • Other

N Treatment:

o

0 200 400 0 200 400 0 200 400

K Status: Poor Good Otherwise

61

"