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

2010 samples

2011 samples

Study Areas -

Alberta

Variables

Predictor variables

• Date of Mortality

– Time since death

• Tree size (dbh)

• Site

– Subzone, soil moisture

regime

• Height along the stem

• Stand density

Response 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

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

3 Soil Moisture Regimes

3 Diameter Classes

4 TSD Categories

SBSdk (1-4)

SBSmc (3,4)

~ 600 sample trees

phase I and II

187 sample trees

Alberta

Field Measurements

• 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)

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

BEC TSD

(years) # plots

Average

stems/ ha % Pl % Down

SBSdk

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%

Upper,

Lower

Foothills

1-7 30 252-500 75, 69 <1%

DBH

10 20 30 40 50 60

Year

Die

d

1999

2000

2001

2002

2003

2004

2005

DBH

15 20 25 30 35 40 45 50

Year

Die

d

1997

1998

1999

2000

2001

2002

2003

2004

2005

SBS mc3

Stand group 3

SBS dk

Stand group 1

Progression of

mortality in a

stand by diameter

Sapwood moisture content grouped by

year of mortality

Years since death

0 2 4 6 8 10

Perc

ent

mois

ture

conte

nt

0

20

40

60

80

100

120

disc 1

disc 2

disc 4

disc 8

dk

Years since death

1 2 3 4 5

Perc

ent

mois

ture

conte

nt

0

20

40

60

80

100

120 disc 1

disc 2

disc 4

disc 8

mc

Time since death

-1 0 1 2 3 4 5

Pe

rce

nt m

ois

ture

co

nte

nt

0

50

100

150

Alberta-

mixed wood

Heartwood moisture content grouped by year

of mortality dkHeartwood

Years since death

0 2 4 6 8 10

Perc

ent

mois

ture

conte

nt

0

10

20

30

40

50

60

disc 1

disc 2

disc 4

disc 8

mcHeartwood

Years since death

1 2 3 4 5

Perc

ent

mois

ture

conte

nt

0

10

20

30

40

50

60

Years since death

-1 0 1 2 3 4 5

Pe

rce

nt

mo

istu

re c

on

ten

t

0

10

20

30

40

50

Alberta

dk dry dk mesic dk wet mc dry mc mesic mc wet

% M

oist

ure

Con

tent

0

20

40

60

80

100

120

disc1

disc2

disc4

disc8

BEC subzone, soil moisture regime

dk dry dk mesic dk wet mc dry mc mesic mc wet

% M

oist

ure

Con

tent

0

10

20

30

40

50

Sapwood

Heartwood

Moisture

content,

grouped by

bec unit

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

Year 1 Year 2 Year 3 Year 4

Disc1

Disc2Disc3

Alberta – bluestain depth D

ep

th (

cm

)

Years since death

Mixed wood Foothills

Percent of trees with 1 or more

checks – by disc height

Years since death

1 2 3 4 5

Perc

ent

0

20

40

60

80

disc 1

disc 2

disc 4

disc 8

Years since death

0 2 4 6 8 10

Pe

rce

nt

0

20

40

60

80

100

120

disc 1

disc 2

disc 4

disc 8

mc dk

Years since death

0 1 2 3 4 5

Perc

ent

trees w

ith c

hecks

0

20

40

60

80

100

Alberta

Time since death (years)

0 1 2 3 4 5 6 7 8 9 10

Num

ber

of checks

0.0

0.5

1.0

1.5

2.0

2.5

disc 1

disc 2

disc 4

disc 8

Time since death (years)

0 1 2 3 4 5 6 7 8 9 10

Check d

epth

(cm

)

0

2

4

6

8

10

disc 1

disc 2

disc 4

disc 8

Number and depth

of checks

BC samples

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

Time since death (years)

0 1 2 3 4 5 6 7 8 9 10

Pe

rce

nt tr

ee

s w

ith

no

sa

pro

t in

ba

sa

l d

isc (

%)

0

20

40

60

80

100

Time since death (years)

0 1 2 3 4 5 6 7 8 9 10

Pe

rce

nt tr

ee

s w

ith

no

w

oo

db

ore

re in

ba

sa

l d

isc (

%)

0

20

40

60

80

100

Time since death (years)

0 2 4 6 8 10

Pe

rce

nt tr

ee

s w

ith

no

ch

eckin

g a

t b

rea

st h

eig

ht (%

)

0

20

40

60

80

100

0 1 2 3 4 5 6 7 8 9 10

Sam

ple

siz

e

0

20

40

60

80

100

120

140

BC samples Alberta samples

Bark integrity category

1.0 2.0 3.0A

vera

ge d

epth

of

checks

0

1

2

3

4

5

bottom

middle

Condition of bark and effect on checking

Bark integrity category

1.0 2.0 3.0

Ave

rage

nu

mb

er

of

ch

ecks

0.0

0.2

0.4

0.6

0.8

bottom

middle

1 = tight

2 = loose

3 = missing

Diameter class (cm)

15 20 25 30 35

Pe

rce

nt d

ow

n

0

10

20

30

40

Percent down, 6-10 YSD, SBS

Years to fall, SBS

Number of years

2 4 6 8 10 12

Nu

mb

er

of

tre

es

0

2

4

6

8

10

12

14

16

years since death

years from death to fall

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).

Years post mortality 0 10

0-6

mo

nth

s, g

reen

wo

od

ch

ara

cte

risti

cs

0-2

years

Rap

id c

heckin

g i

ncre

ase

So

me s

ap

rot

develo

pm

en

t

2-8

years

Peri

od

of

sta

bil

ity i

n w

oo

d

qu

ali

ty

Mo

st

trees r

em

ain

sta

nd

ing

8+

years

Tre

es b

eg

in t

o f

all

Tre

es t

hat

rem

ain

sta

nd

ing

develo

p r

ot

an

d w

oo

db

ore

rs a

t

base