Decay dynamics of coarsewood habitat in old-growth spruce and pine stands

Eileen L. Jones and Lori D. DanielsDepartment of Geography,

University of British Columbia

Coarsewood Pathways

Terrestrial Coarsewood Functions

substrate for plants and fungus

wildlife habitat

habitat for invertebrates and microorganisms

nutrient and carbon cycles

geomorphology

Research Questions

1. (a) How abundant are spruce and pine snags and logs on the landscape?

(b) What is their distribution of decay classes and wildlife habitat functions?

2. (a) When did the snags and logs die?

(b) How does time since death vary among decay classes?

Conservation and management implications?

MethodsSA

Hinton

SB

SC, SD, SE

PA, PB

PE

PC, PD

Methods

Coarsewood Census

SNAGS

Spruce: 508 ± 188 per ha

Pine: 298 ± 259 per ha

LOGS

Spruce: 468 ± 113 per ha

Pine: 545 ± 73 per ha

Coarsewood Census

Perc

ent

020406080 (b) Site SB (n=91)

(f) Site PA (n=38)

(g) Site PB (n=53)

(h) Site PC (n=9)

(i) Site PD (n=14)

Decay Class3 4 5 6

(j) Site PE (n=5)

Decay Class3 4 5 6

Perc

ent

020406080 (e) Site SE (n=23)

Perc

ent

020406080 (d) Site SD (n=15)

Per

cent

020406080 (c) Site SC (n=40)

Perc

ent

020406080 (a) Site SA (n=34)

SNAGS

Coarsewood Census

(f) Site PA (n=43)

(g) Site PB (n=50)

(h) Site PC (n=49)

(i) Site PD (n=39)

Decay Class1 2 3 4 5

(j) Site PE (n=37)

Decay Class1 2 3 4 5

Perc

ent

020406080 (e) Site SE (n=32)

Perc

ent

020406080 (d) Site SD (n=53)

Perc

ent

020406080 (c) Site SC (n=34)

Perc

ent

020406080 (b) Site SB (n=31)

Perc

ent

020406080 (a) Site SA (n=37)

LOGS

potential c

avities

existin

g cavit

iescra

cks/l

oose bark

nest su

pports

feedinghuntin

g perches

conce

aled space

s

Freq

uenc

y

0

10

20

30

40

50D ecay C lass 3D ecay C lass 4 D ecay C lass 5

Snag Census: Wildlife Use

SPRUCE

potential c

avities

existin

g cavit

iescra

cks/l

oose bark

nest su

pports

feedinghuntin

g perches

conce

aled space

s

Freq

uenc

y

0

10

20

30

40

50D ecay C lass 3D ecay C lass 4 D ecay C lass 5

Snag Census: Wildlife Use

decay-softened inner wood for cavity excavation

http://fishandgame.idaho.govSPRUCE

potential c

avities

existin

g cavit

iescra

cks/l

oose bark

nest su

pports

feedinghuntin

g perches

conce

aled space

s

Freq

uenc

y

0

10

20

30

40

50D ecay C lass 3D ecay C lass 4 D ecay C lass 5

Snag Census: Wildlife Use

cracks or loose bark for reproduction and resting

http://fireflyforest.net

SPRUCE

potential c

avities

existin

g cavit

iescra

cks/l

oose bark

nest su

pports

feedinghuntin

g perches

conce

aled space

s

Freq

uenc

y

0

10

20

30

40

50D ecay C lass 3D ecay C lass 4 D ecay C lass 5

Snag Census: Wildlife Use

large branches or broken tops to support large nests

http://ecotravel.ctaudubon.orgSPRUCE

Snag Census: Wildlife Use

SPRUCE

PINE

poten

tial c

avitie

sex

isting

cavit

iescra

cks/l

oose

bark

nest

supp

orts

feedin

ghu

nting

perch

esco

ncea

led sp

aces

Freq

uenc

y

0

10

20

30

40

50Decay Class 3Decay Class 4 Decay Class 5

poten

tial c

avitie

sex

isting

cavit

iescra

cks/l

oose

bark

nest

supp

orts

feedin

ghu

nting

perch

esco

ncea

led sp

aces

Freq

uenc

y

0

10

20

30

40

50Decay Class 3Decay Class 4 Decay Class 5

large

spac

es

small

spac

es

long s

pace

s

trave

l lane

s

feedin

g

Freq

uenc

y

0

50

100

150

200Decay Class 1Decay Class 2 Decay Class 3 Decay Class 4

Log Census: Wildlife Use

SPRUCE

large

spac

es

small

spac

es

long s

pace

s

trave

l lane

s

feedin

g

Freq

uenc

y

0

50

100

150

200Decay Class 1Decay Class 2 Decay Class 3 Decay Class 4

Log Census: Wildlife Use

small concealed spaces for reproduction and resting

SPRUCE http://www.premiumpestmanagement.com

large

spac

es

small

spac

es

long s

pace

s

trave

l lane

s

feedin

g

Freq

uenc

y

0

50

100

150

200Decay Class 1Decay Class 2 Decay Class 3 Decay Class 4

Log Census: Wildlife Use

exposed, raised travel lanes

SPRUCE http://www.crcd.org

large

spac

es

small

spac

es

long s

pace

s

trave

l lane

s

feedin

g

Freq

uenc

y

0

50

100

150

200Decay Class 1Decay Class 2 Decay Class 3 Decay Class 4

Log Census: Wildlife Use

invertebrates in wood

SPRUCE http://fishandgame.idaho.gov

large

spac

es

small

spac

es

long s

pace

s

trave

l lane

s

feedin

g

Freq

uenc

y

0

50

100

150

200Decay Class 1Decay Class 2 Decay Class 3 Decay Class 4

Log Census: Wildlife Use

SPRUCE

PINE

large

spac

es

small

spac

es

long s

pace

s

trave

l lane

s

feedin

g

Freq

uenc

y

0

50

100

150

200Decay Class 1Decay Class 2 Decay Class 3 Decay Class 4

Year of Death (YOD) = calendar year of outer ring

Time Since Death = 2008 – YOD = snag or log age

“old” = snag or log that has been dead for a long time

Time Since Death (years since 2008)

0 40 80 120 160 200

pine snags (n=40)

Time Since Death (years since 2008)

0 40 80 120 160 200

Freq

uenc

y

0

2

4

6

8

10spruce snags (n=37)

Time Since Death (years since 2008)

0 40 80 120 160 200

pine logs (n=46)

Time Since Death (years since 2008)

0 40 80 120 160 200

Freq

uenc

y

0

2

4

6

8

10spruce logs (n=44)

Time Since Death

Time Since Death: Variability Across Decay Classes

Decay Class 3 Decay Class 4 Decay Class 5

Tim

e Si

nce

Dea

th (y

ears

prio

r to

2008

)

0

50

100

150

200snags

An=17

Bn=39

Cn=21

Decay Class 1 Decay Class 2 Decay Class 3 Decay Class 4Ti

me

Sinc

e D

eath

(yea

rs p

rior t

o 20

08)

0

50

100

150

200logs

Cn=27

Cn=40

Bn=17

An=6

SNAGS LOGS

poten

tial c

avitie

sex

isting

cavit

iescra

cks/l

oose

bark

nest

supp

orts

feedin

ghu

nting

perch

esco

ncea

led sp

aces

Freq

uenc

y

0

10

20

30

40

50Decay Class 3Decay Class 4 Decay Class 5

poten

tial c

avitie

sex

isting

cavit

iescra

cks/l

oose

bark

nest

supp

orts

feedin

ghu

nting

perch

esco

ncea

led sp

aces

Freq

uenc

y

0

10

20

30

40

50Decay Class 3Decay Class 4 Decay Class 5

REMINDERCoarsewood Census: Wildlife Use

SNAGS LOGS

SPRUCE

PINE

large

spac

es

small

spac

es

long s

pace

s

trave

l lane

s

feedin

g

Freq

uenc

y

0

50

100

150

200Decay Class 1Decay Class 2 Decay Class 3 Decay Class 4

large

spac

es

small

spac

es

long s

pace

s

trave

l lane

s

feedin

g

Freq

uenc

y

0

50

100

150

200Decay Class 1Decay Class 2 Decay Class 3 Decay Class 4

Decay Class 3 Decay Class 4 Decay Class 5

Tim

e Si

nce

Dea

th (y

ears

prio

r to

2008

)

0

50

100

150

200

An=17

Bn=39

Cn=21

Snag Decay Class 2

Time Since Death: 3-19 years

11% of habitat function:

• cavities for reproduction and

resting

• nest supports

Time Since Death: 7-34 years

1% of habitat function:

• hunting perches

Decay Class 3 Decay Class 4 Decay Class 5

Tim

e Si

nce

Dea

th (y

ears

prio

r to

2008

)

0

50

100

150

200

An=17

Bn=39

Cn=21

Snag Decay Class 4

Time Since Death: 54-180 years

8% of habitat function:

• cavities for reproduction and

resting

• feeding substrates

Time Since Death: 40-142 years

51% of habitat function:

• cavities for reproduction and

resting

• nest supports

• feeding substrates

• hunting perches

Decay Class 3 Decay Class 4 Decay Class 5

Tim

e Si

nce

Dea

th (y

ears

prio

r to

2008

)

0

50

100

150

200

An=17

Bn=39

Cn=21

Snag Decay Class 3

Time Since Death: 2-168 years

73% of habitat function:

• cavities for reproduction and

resting

• nest supports

• feeding substrates

• hunting perches

• concealed spaces

Time Since Death: 6-64 years

48% of habitat function:

• cavities for reproduction and

resting

• nest supports

• feeding substrates

• hunting perches

• concealed spaces

Decay Class 1 Decay Class 2 Decay Class 3 Decay Class 4

Tim

e Si

nce

Dea

th (y

ears

prio

r to

2008

)

0

50

100

150

200logs

Cn=27

Cn=40

Bn=17

An=6

Log Decay Class 2

Time Since Death: 0-24 years

7% of habitat function:

• large concealed spaces

Time Since Death: 6-76 years

8% of habitat function:

• large concealed spaces

Log Decay Class 4

Time Since Death: 20-125 years

26% of habitat function:

• small concealed spaces

• long concealed spaces

• feeding substrates

Time Since Death: 23-133 years

28% of habitat function:

• small concealed spaces

• feeding substrates

Decay Class 1 Decay Class 2 Decay Class 3 Decay Class 4

Tim

e Si

nce

Dea

th (y

ears

prio

r to

2008

)

0

50

100

150

200logs

Cn=27

Cn=40

Bn=17

An=6

Log Decay Class 3

Time Since Death: 15-175 years

65% of habitat function:

• small concealed spaces

• large concealed spaces

• travel lanes

• feeding substrate

Time Since Death: 12-95 years

64% of habitat function:

• small concealed spaces

• large concealed spaces

• travel lanes

• feeding substrate

Decay Class 1 Decay Class 2 Decay Class 3 Decay Class 4

Tim

e Si

nce

Dea

th (y

ears

prio

r to

2008

)

0

50

100

150

200logs

Cn=27

Cn=40

Bn=17

An=6

Habitat Conservation

intermediate decay classes = most function

94% logs, 33% snags at least one function

....only 11% snags have more than one function

.... 91% logs have more than one function

Habitat Conservation

• abundance and diversity

• rare functions

Management Implications

• long-term planning

• decision-support tool

• old forests

Acknowledgements

Evan Henderson, Amy Nicoll, Julia Maddison, Kylie McLeod, Abha Parajulee, Raphael Chavardes

Lori Daniels, Valerie LeMay, R. Dan Moore