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Wood degradation in standing lodgepole and hybrid lodgepole-jack pine killed by mountain pine beetle Kathy Lewis Kate Hrinkevich


Background • “Shelf-life” = Post-mortality rate of decay and degradation of wood quality and quantity variables • Rate of change of stand structure • Essential for strategic planning


Research Objectives • Quantify the relationship between time since death and measures of wood quality and quantity, in trees killed by mountain pine beetle. – Regression models

• Quantify the influence of site factors in wood deterioration • Determine rates of tree fall.


Other “shelf-life” factors • • • • •

Markets Cost of raw material Operating costs Manufacturing technology Log inventories - Biophysically-based


Multi-phased approach • Synthesis report – Literature review, interviews from Caribou Plateau outbreak – Report available (CFS, WP 2005-14)

• Phase I - BC – 0-5 years post-mortality (SBSdk and SBSmc3)

• Phase II - BC – 6-10 years post-mortality (SBSdk) – Phase I and II report available (CFS, WP 2008-30, Wood and Fiber Science 43:130-142)

• Phase III - Alberta – hybrid lodgepole/jack pine – boreal mixed wood – lodgepole


Study Area – Phase I and II - BC

SBS dk SBS mc3


Study Areas Alberta 2010 samples 2011 samples


Variables Response variables

Predictor variables

• Moisture content (hw/sw) • Wood density (hw/sw) • Penetration depth of blue stain fungi • Number, depth of checks • Penetration depth of saprot • Wood borer damage

• Date of Mortality – Time since death

• Tree size (dbh) • Site – Subzone, soil moisture regime

• Height along the stem • Stand density


Time Since Death – External Indicators, local information Four Categories 1. Red, bright needles, needles retained 2. Old Red, some needle loss 3. Early Grey, needle and some twig loss 4. Old Grey, all needles gone, most fine twigs gone Photo by Lorraine Maclauchlan


1. Stand-level surveys • • • •

Space – time distribution of mortality Fall rate Stand and tree attributes Select trees for destructive sampling


2. Tree Level

SBSdk (1-4)

3 Soil Moisture Regimes

SBSmc (3,4)

3 Diameter Classes 4 TSD Categories

~ 600 sample trees phase I and II 187 sample trees Alberta


Field Measurements 1

2

4

8

• Followed MOFR procedures for volume and decay studies (12 cookies (4 in Alberta)) • Each cookie: diameter, bluestain, number and depth of checks, saprot, woodborers • Moisture content and specific gravity (fresh weight discs 1,2,4,8)


Mortality dates via crossdating • Collect cores from live trees on sensitive sites • Prepare cores, measure rings • Standardize to remove age-related growth trend => master chronology • “Pattern match” dead trees to live chronology


Years to Tree Fall 1. Stand level surveys % down at time of surveying 2. Adjacent tree scar dates (BC only) – 30 pairs, phase I, II only – Date of death from fallen tree – Date of fall from scarred tree

Scarred live tree


Results – Stand Level TSD (years)

# plots

Average stems/ ha

% Pl

% Down

0-5

102

980-1225

68-90

<1%

6-10

15

500-1450

60-100

28% (range = 0-60%)

SBSmc3

0-5

81

1000 -1350

84-94

0

Foothills + mixed wood

0-4

17

840-2867

4-65

0-4%

1-7

30

252-500

75, 69

<1%

BEC

SBSdk

Upper, Lower Foothills


2005

Progression of mortality in a stand by diameter

SBS mc3

2004

Stand group 3

Year Died

2003 2002 2001 2000 1999 1998

SBS dk

2005

1997

Stand group 1

2004

15

25

30

35

DBH

2003

Year Died

20

2002

2001

2000

1999 10

20

30

40

DBH

50

60

40

45

50


Sapwood moisture content grouped by year of mortality 120

dk

disc 1 disc 2 disc 4 disc 8

disc 1 disc 2 disc 4 disc 8

mc

100

80

60

40

80

60

40

20

20

0

0 0

2

4

6

8

1

10

2

3

Years since death

Years since death

Albertamixed wood

150

Percent moisture content

Percent moisture content

100

Percent moisture content

120

100

50

0 -1

0

1

2

Time since death

3

4

5

4

5


Heartwood moisture content grouped by year of mortality dk Heartwood

mc Heartwood

60

60 disc 1 disc 2 disc 4 disc 8

Percent moisture content

50

40

30

20

10

40

30

20

10

0 0

2

4

6

8

0

10

1

2

Years since death

3

Years since death

50

Alberta

40

Percent moisture content

Percent moisture content

50

30

20

10

0 -1

0

1

2

Years since death

3

4

5

4

5


120

Sapwood disc1 disc2 disc4 disc8

% Moisture Content

100

80

Moisture content, grouped by bec unit

60

40

20

0 dk dry

dk mesic

dk wet

mc dry

mc mesic

mc wet

50

Heartwood

% Moisture Content

40

30

20

10

0 dk dry

dk mesic

dk wet

mc dry

mc mesic

BEC subzone, soil moisture regime

mc wet


Alberta â&#x20AC;&#x201C; bluestain depth Mixed wood

Foothills

Depth (cm)

8.0 7.0

Disc1

6.0

Disc 2 Disc 3

5.0 4.0 3.0

2.0 1.0 0.0 Year 1

Year 2

Year 3

Year 4

Years since death


Percent of trees with 1 or more checks â&#x20AC;&#x201C; by disc height 80

120 disc 1 disc 2 disc 4 disc 8

60

mc

disc 1 disc 2 disc 4 disc 8

100

dk

Percent

40

60

40 20

20

0

0 1

2

3

4

5

0

2

4

Years since death

6

Years since death

100

Alberta

80

Percent trees with checks

Percent

80

60

40

20

0 0

1

2

3

Years since death

4

5

8

10


2.5 disc 1 disc 2 disc 4 disc 8

Number of checks

2.0

Number and depth of checks

1.5

BC samples

1.0

0.5

0.0 0

1

2

3

4

5

6

7

8

9

10

Time since death (years)

10 disc 1 disc 2 disc 4 disc 8

Check depth (cm)

8

6

4

2

0 0

1

2

3

4

5

6

7

Time since death (years)

8

9

10


Number and depth of checks Alberta samples


DBH significantly related to number of checks and depth of checks, BC data Alberta data showed significant relationship only with check depth


Alberta samples 140

100

120

80

100

60

80 60

40 40 20

20 0

0 0

1

2

3

4

5

6

7

8

9

10

7

8

9

10

7

8

9

10

Percent trees with no saprot in basal disc (%)

Time since death (years)

100 80 60 40 20 0 0

1

2

3

4

5

6

Percent trees with no woodborere in basal disc (%)

Time since death (years)

100 80 60 40 20 0 0

1

2

3

4

5

6

Time since death (years)

Sample size

Percent trees with no checking at breast height (%)

BC samples


Condition of bark and effect on checking

5

0.8

Average depth of checks

Average number of checks

4 0.6 bottom middle

0.4

0.2

bottom middle 3

2

1

0

0.0 1.0

2.0

Bark integrity category

1 = tight 2 = loose 3 = missing

3.0

1.0

2.0

Bark integrity category

3.0


Percent down, 6-10 YSD, SBS 40

Percent down

30

20

10

0 15

20

25

Diameter class (cm)

30

35


Years to fall, SBS 16 14 years since death years from death to fall

Number of trees

12 10 8 6 4 2 0 2

4

6

8

Number of years

10

12


Conclusions • External indicators of tsd = inaccurate by 4-5 years, especially with smaller trees. • Mortality in a stand can take place over 5+ years. Pattern of mortality may vary between BC and Alberta – BC: early attacks = large (preceded by the small and weak) – More recent attacks = remaining small trees

• Only .25% of beetle-killed trees had fallen within the first 5 years, but rates of fall increased substantially after 5 years.


Conclusions continued • Biogeoclimatic unit and soil moisture regime did not predict decay and degrade in BC, but may be important with wider ranges of smr. • Most change in dependent variables occurred in the first 1-2 years. • Checks develop first and are worst in the middle sections of trees. • Response variables changed with height on the tree • Tree size (dbh or merchantable volume) is a good predictor of decay and degrade (BC).


0

Years post mortality 10

8+ years Trees begin to fall Trees that remain standing develop rot and woodborers at base

2-8 years Period of stability in wood quality Most trees remain standing

0-2 years Rapid checking increase Some saprot development

0-6 months, green wood characteristics


Mpbep 2012 04 prsnttn wooddegradationstandinglodgepolepinehybridlodgepolejackpinekilledbympb  

https://foothillsri.ca/sites/default/files/null/MPBEP_2012_04_Prsnttn_WoodDegradationStandingLodgepolePineHybridLodgepoleJackPineKilledByMPB...

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