Biodiversity across the forest cycle in ash and Sitka spruce plantations:

Stand structure and vegetation change

Laura French, George Smith, Saoirse O’Donoghue, Anne-Marie McKee, Sue Iremonger, Daniel Kelly,

Fraser Mitchell

Department of Botany, Trinity College Dublin

University College, Cork

University of Dublin, Trinity College

Coillte Teoranta

Forestry and biodiversity

• Forestry an increasing land use in Ireland

Forestry and biodiversity

• Forestry an increasing land use in Ireland

• Can represent a threat to existing biodiversity

Forestry and biodiversity

• Forestry an increasing land use in Ireland

• Can represent a threat to existing biodiversity

• Can be an opportunity to enhance biodiversity at local and landscape scales

Forestry and biodiversity

• What is the biodiversity of commercial forestry plantations?

OR?

Objectives

• How does stand structure develop in plantations?

Objectives

• How does stand structure develop in plantations?

• How does species richness change over the forest cycle?

Objectives

• How does stand structure develop in plantations?

• How does species richness change over the forest cycle?

• How does tree species influence vegetation species richness?

Objectives

• How does stand structure develop in plantations?

• How does species richness change over the forest cycle?

• How does tree species influence vegetation species richness?

• How does species richness of typical woodland plants change?

Study sites

• 20 Sitka spruce• 12 ash• 12 spruce-ash mix

• Spruce 5 - 46 yr old• Ash 5 - 80 yr old

• 3 100m2 plots per site / species combination

######

###

###

###

###

####

######

######

#########

###

#####

###

####

######

###

######

#######

######

######

############

###

###

###

######

###

######

###

###

######

###

###

#####

######

######

###

###

######

######

#####

###

Sitka spruce

ash

Sitka spruce structural typesPCA Ordination

Axis 1 (Var Expl = 73%)

Axi

s 2

(Var

Exp

l = 2

1%)

Prethicket

30% Canopy Cover

Prethicket spruce site: Brackloon, Co. Galway

Sitka spruce structural typesPCA Ordination

Axis 1 (Var Expl = 73%)

Axi

s 2

(Var

Exp

l = 2

1%)

Thicket

80% Canopy Cover

Sitka spruce structural typesPCA Ordination

Axis 1 (Var Expl = 73%)

Axi

s 2

(Var

Exp

l = 2

1%)

Closed-maturing

87% Canopy Cover

Closed-maturing spruce site: Buffanoky, Co. Limerick

Sitka spruce structural typesPCA Ordination

Axis 1 (Var Expl = 73%)

Axi

s 2

(Var

Exp

l = 2

1%)

Reopening

71% Canopy Cover

Sitka spruce structural typesPCA Ordination

Axis 1 (Var Expl = 73%)

Axi

s 2

(Var

Exp

l = 2

1%)

Mature

55% Canopy Cover

Mature spruce site: Union Wood, Co. Sligo

Species richness over the Sitka spruce forest cycle

Me

an

sp

eci

es

ric

hn

es

s

pe

r plo

t

Vascular plants Bryophytes

0

5

10

15

20

25

Pre Thk Clo Reo Mat

A

B

C

BC

A

0

5

10

15

20

25

Pre Thk Clo Reo Mat

A

BCC

BCB

Canopy cover and species richness

y = -0.6162x + 63.062

R2 = 0.71

0

5

10

15

20

25

30

35

40

45

30 50 70 90

Canopy cover (% cover per 100 m2 quadrat)

Me

an

to

tal s

pe

cie

s

ric

hn

es

s p

er

plo

t

Ash canopy cover

0

20

40

60

80

100

Pre Pole Clo Semi Mat

Can

op

y C

ove

r (%

)

Pole ash site: Coolross, Co. Tipperary

Ash canopy cover

0

20

40

60

80

100

Pre Pole Clo Semi Mat

Can

op

y C

ove

r (%

)

Closed-maturing ash site: Sinnot’s Bog, Co. Wexford

Ash canopy cover

0

20

40

60

80

100

Pre Pole Clo Semi Mat

Can

op

y C

ove

r (%

)

Species richness over the ash forest cycle

0

5

10

15

20

25

Pre Pol Clo Semi MatMe

an

sp

eci

es

ric

hn

es

s

pe

r plo

t

Vascular plants Bryophytes

A A

BBB

0

5

10

15

20

25

Pre Pol Clo Semi Mat

A

ABB B

AB

Ash compared with Sitka spruce

Me

an

sp

eci

es

ric

hn

es

s

pe

r plo

t

Ash Sitka spruce

0

5

10

15

20

25

30

Vascular Plants Bryophytes Total

A

B

A

A A

B

Woodland species over the forest cycle

0

2

4

6

8

10

Pre Thk Clo Reo MatMe

an

sp

eci

es

ric

hn

es

s

pe

r plo

t

Ash Sitka spruce

AAB

C

B

A

0

2

4

6

8

10

Pre Pol Clo Semi Mat

A AB

CD

D

BC

Conclusions

• Species richness changes significantly over the forest cycle

Conclusions

• Species richness changes significantly over the forest cycle

• Ash forests have higher species richness of vascular plants

Conclusions

• Species richness changes significantly over the forest cycle

• Ash forests have higher species richness of vascular plants

• Sitka spruce forests have higher species richness of bryophytes

Conclusions

• Species richness changes significantly over the forest cycle

• Ash forests have higher species richness of vascular plants

• Sitka spruce forests have higher species richness of bryophytes

• Species richness of woodland vascular plants increases along forest cycle

Conclusions

• Plantations of ash and Sitka spruce are not necessarily “ecological deserts”

Conclusions

• Plantations of ash and Sitka spruce are not necessarily “ecological deserts”

• Not “oases of biodiversity” either

The BIOFOREST project is funded by the National Development Plan through the EPA and COFORD as part of the Environmental RTDI Programme 2000-2006

Project Website:

http://bioforest.ucc.ie