Do lichens prevent pine stand

reclosure in the boreal forest?

Marine Pacé PhD student in environmental sciences

Nicole Fenton, David Paré, Yves Bergeron

Introduction

Pine stands on sandy soil in the boreal forest

Productive pine stand

1/15

Introduction

Canopy opening

Pine stands on sandy soil in the boreal forest

Productive pine stand

1/15

Introduction

Lichen woodland Stable alternative state*

Pine regeneration

deficit

Pine stands on sandy soil in the boreal forest

Productive pine stand Canopy opening

* Jasinsky and Payette 2005 1/15

Lichen woodland

Productive pine stand

Introduction

Feather mosses including Pleurozium

Lichens

Pine stands on sandy soil in the boreal forest

Canopy opening

Stable alternative state

Pine regeneration

deficit

1/15

Introduction

Do lichens play a role in maintaining open lichen woodlands in the boreal forest?

Suspect 001

Pine stands on sandy soil in the boreal forest

Productive pine stand Canopy opening

Lichen woodland Stable alternative state

Pine regeneration

deficit

Introduction

Do lichens affect jack pine germination and/or growth?

Question :

And if so, how?

2/15

Experimental design

Tree Ground cover Fertilization

Jack pine

bare soil

vs

Feather mosses

vs

Lichen

Control vs Fertilized

Application of various treatments…

X

3/15

Stage of growth Design

Germination Ex situ*

Seedling growth Ex situ*

Young tree growth

In situ Ex situ*

… at different stages of pine development

* Substrate from the field

Experimental design

4/15

Stage of growth Design Treatment application

Germination Ex situ*

Direct exposition

Seedling growth Ex situ*

Young tree growth

In situ Ex situ*

Direct exposition

Indirect exposition

Experimental design

… at different stages of pine development

* Substrate from the field 4/15

Germination

Results G

erm

inat

ion

su

cces

0.

00.

20.

40.

60.

81.

0

Index

Réu

ssite

ger

min

atio

n

0.0

0.2

0.4

0.6

0.8

1.0

Index

Réu

ssite

ger

min

atio

n

0.0

0.2

0.4

0.6

0.8

1.0

Index

Ré

uss

ite g

erm

ina

tion

5/15

Germination

Positive effect of the ground cover

*

0.0

0.2

0.4

0.6

0.8

1.0

Index

Réu

ssite

ger

min

atio

n

0.0

0.2

0.4

0.6

0.8

1.0

Index

Réu

ssite

ger

min

atio

n

0.0

0.2

0.4

0.6

0.8

1.0

Index

Ré

uss

ite g

erm

ina

tion

A B

Ge

rmin

atio

n s

ucc

es

Results

5/15

Seedling growth D

ry b

iom

ass

(g/p

ot)

0.0

0.2

0.4

0.6

0.8

1.0

Index

Bio

ma

sse

sè

ch

e(g

/pla

ntu

le)

Results

6/15

0.0

0.2

0.4

0.6

0.8

1.0

Index

Bio

ma

sse

sè

che

(g/p

lan

tule

)

0.0

0.2

0.4

0.6

0.8

1.0

Index

Bio

ma

sse

sè

ch

e(g

/pla

ntu

le)

Results Seedling growth

Dry

bio

mas

s (g

/po

t)

6/15

0.0

0.2

0.4

0.6

0.8

1.0

Index

Bio

ma

sse

sè

che

(g/p

lan

tule

)

***

Positive effect of feather mosses

0.0

0.2

0.4

0.6

0.8

1.0

Index

Bio

ma

sse

sè

ch

e(g

/pla

ntu

le)

a

b b

Results Seedling growth

Dry

bio

mas

s (g

/po

t)

6/15

Young tree growth ex situ

Index

Rela

tive d

iffe

rence b

etw

een initia

l and f

inal bio

masses (

%)

C- C+ M- M+ L- L+-15

-10

-50

5

Rel

ativ

e gr

ow

th (

SU)

6

4

Ro

ots

0

Ab

ove

2

Results

7/15

Index

Rela

tive d

iffe

rence b

etw

een initia

l and f

inal bio

masses (

%)

C- M- L-

-6-4

-20

2

Negative effect of lichens on root growth

A A A

ab

a b

≈

Index

Rela

tive d

iffe

rence b

etw

een initia

l and f

inal bio

masses (

%)

C- M- L-

-6-4

-20

2

Results Young tree growth ex situ

Rel

ativ

e gr

ow

th (

SU)

6

4

Ro

ots

0

Ab

ove

2

7/15

R

elat

ive

gro

wth

(SU

)

3

Ro

ots

0

A

bo

ve

3

Young tree growth in situ

Index

Rela

tive d

iffe

rence b

etw

een initia

l and f

inal bio

masses (

%)

C CO M MO L LO

-3-2

-10

12

3

Index

Rela

tive d

iffe

rence b

etw

een initia

l and f

inal bio

masses (

%)

C M L

-3-2

-10

12

3

Results

8/15

Index

Rela

tive d

iffe

rence b

etw

een initia

l and f

inal bio

masses (

%)

C CO M MO L LO

-3-2

-10

12

3

Index

Rela

tive d

iffe

rence b

etw

een initia

l and f

inal bio

masses (

%)

C M L

-3-2

-10

12

3

Negative effect of lichens on pine growth

A B

?

Results R

elat

ive

gro

wth

(SU

)

3

Ro

ots

0

A

bo

ve

3

Young tree growth in situ

8/15

Index

Rela

tive d

iffere

nce

betw

een in

itial a

nd f

inal b

iom

ass

es

(%)

C M L-8-6

-4-2

02

4

Index

Rela

tive d

iffe

rence b

etw

een initia

l and f

inal bio

masses (

%)

C M L-8-6

-4-2

02

4

Rel

ativ

e gr

ow

th (

SU)

-8

Ro

ots

-

2

0

A

bo

ve

4

Young tree growth ex situ – indirect exposition

Results

9/15

Index

Rela

tive d

iffere

nce

betw

een in

itial a

nd f

inal b

iom

ass

es

(%)

C M L-8-6

-4-2

02

4

Index

Rela

tive d

iffe

rence b

etw

een initia

l and f

inal bio

masses (

%)

C M L-8-6

-4-2

02

4

A A A

a a

b * ≈

Results

Negative effect of the lichen leachates on root growth

Rel

ativ

e gr

ow

th (

SU)

-8

Ro

ots

-

2

0

A

bo

ve

4

Young tree growth ex situ – indirect exposition

9/15

Young tree growth ex situ

Index

Rela

tive d

iffe

rence b

etw

een initia

l and f

inal bio

masses (

%)

C- C+ M- M+ L- L+-15

-10

-50

5

Index

Rela

tive d

iffe

rence b

etw

een initia

l and f

inal bio

masses (

%)

C- C+ M- M+ L- L+-15

-10

-50

5

Negative effect of lichens on root growth

A A A

ab

a b

Rel

ativ

e gr

ow

th (

SU)

1

5

10

R

oo

ts

0

A

bo

ve

5

≈

Results

10/15

≈

Index

Rela

tive d

iffe

rence b

etw

een initia

l and f

inal bio

masses (

%)

C- C+ M- M+ L- L+-15

-10

-50

5

Index

Rela

tive d

iffe

rence b

etw

een initia

l and f

inal bio

masses (

%)

C- C+ M- M+ L- L+-15

-10

-50

5

A A A

ab

a b

Rel

ativ

e gr

ow

th (

SU)

1

5

10

R

oo

ts

0

A

bo

ve 5

Results Young tree growth ex situ

10/15

≈

Young tree growth ex situ

Index

Rela

tive d

iffe

rence b

etw

een initia

l and f

inal bio

masses (

%)

C- C+ M- M+ L- L+-15

-10

-50

5

Index

Rela

tive d

iffe

rence b

etw

een initia

l and f

inal bio

masses (

%)

C- C+ M- M+ L- L+-15

-10

-50

5

***

A A A

ab

a b

B B B

c c

abc

Results

Positive effect of fertilisation regardless of the cover

Rel

ativ

e gr

ow

th (

SU)

1

5

10

R

oo

ts

0

A

bo

ve 5

10/15

Suspect 001

* Reference = bare soil

Results Lichen and feather moss effects on pine growth*

11/15

Suspect 001

Results

* Reference = bare soil

Lichen and feather moss effects on pine growth*

11/15

Suspect 001

Results

* Reference = bare soil

Lichen and feather moss effects on pine growth*

11/15

Suspect 001

Results Lichen and feather moss effects on pine growth*

* Reference = bare soil 11/15

Lichen has a globally negative effect on pine growth: some clues on is M.O.?

Suspect 001

Results

* Reference = bare soil

Lichen and feather moss effects on pine growth*

11/15

Suspect 001

Results

* Reference = bare soil

Lichen has a globally negative effect on pine growth: some clues on is M.O.?

Lichen and feather moss effects on pine growth*

11/15

Discussion Effect via soil moisture

Higher moisture under lichens …

12/15

Discussion

… Related to different rates of evapotranspiration …

Effect via soil moisture

12/15

Discussion

… But also to the emission by lichens of a slimy substance that reduced the drainage …

Effect via soil moisture

12/15

Discussion

… Contrasted effects depending on the stage of pine development.

Effect via soil moisture

12/15

Discussion Effect via soil moisture

… Contrasted effects depending on the stage of pine development.

12/15

Discussion

NPK

Overall less soil nutrients under lichens …

NPK

Effect via soil nutrients

13/15

Discussion

High fertilization = should reduce the difference between lichens and feather mosses

NPK NPK

Soil nutrients

13/15

Discussion

… However, the positive effect of fertilization is the same regardless of the ground cover …

NPK NPK

Soil nutrients

13/15

Discussion

… And tree growth on lichen ground cover remains lower despite the fertilization …

NPK NPK

Effect via soil nutrients

13/15

Discussion

The negative effects of lichen are not only linked to soil nutrients.

NPK NPK

Effect via soil nutrients

13/15

Discussion

Negative effect of lichen leachates on tree growth Direct effect …

Effect via soil solution

14/15

Discussion

…Or indirect via the soil biological communities

Effect via soil solution

14/15

Conclusion

Suspect 001

• Lichens affect jack pine development at different stages

• Effect via nutrients, but not only… • Effect via the soil solution, allelopathy ?

15/15

Conclusion

Suspect 001

Lichens are likely to contribute to the absence of stand reclosure in the boreal forest.

• Lichens affect jack pine development at different stages

• Effect via nutrients, but not only… • Effect via the soil solution, allelopathy ?

15/15

Thanks for your attention !

Aknowlegments

Hugues, Linda, Nicole, Franck, Denis, Sylvie, Armand, Michel, Marie-

Hélène, Serge, Sébastien, Jacques, Fanny, Laurence, Samuel, Jonathan, Pauline, Lili, Benjamin, Roch, Danielle, Danièle, Marc, Raynald, Marie…

And to all the people who have contributed to this study… Thanks !