Landscape-Scale Thresholds of Early

Successional Habitat Reconciling Biodiversity, Public Perception, and

Timber Yield in Managed Forests

Susan Loeb, Beverly Collins, Laura DeWald, Jeremy Hyman, Thomas Straka, Elizabeth Baldwin, Jonathan Brooks, Thomas Green

Early Successional Habitat

• Recently disturbed sites • Sparse canopy• Dominated by grasses, forbs, and shrubs • Contain unique communities

Trani et al. 2001

Trani et al. 2001

Decline of ES•Farm abandonment •Urban/Suburban Development •Suppression of natural disturbances

• Fire • Beaver activity• Flooding

Dettmers 2003

How can we best restore early successional (ES) habitat?

Questions1) Does opening size affect use, abundance, or ecological relationships of early successional species?

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Questions2) Can changing the aggregation of harvests more effectively increase abundance of early successional species at the stand and landscape levels?

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Questions2) Can changing the aggregation of harvests more effectively increase abundance of early successional species at the stand and landscape levels?

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Questions•If so, can we retain acceptable timber yield?

•Will smaller cuts be more favorably looked upon than larger cuts by the public?

Great Smoky Mountains National Park

zzzzzzzzzzzzzzzzzzzzzzzControl

(no cutting) zzzzzzzzzzzz

20-25 ac2-age harvest

zzzzzzzzzzzzzzzzzzzzzzzzzzzzzz

zzzzzzzz5 1-ac harvestsAggregated

5 1-ac harvestsDispersed

2 9-ac harvestsAggregated

2 9-ac harvestsDispersed

zzzzzzzzzzzzzzzzzzzzzzzControl

(no cutting) zzzzzzzzzzzz

20-25 ac2-age harvest

zzzzzzzzzzzzzzzzzzzzzzzzzzzzzz

zzzzzzzz5 1-ac harvestsAggregated

5 1-ac harvestsDispersed

2 9-ac harvestsAggregated

2 9-ac harvestsDispersed

Installed 2016

Currently beingcut

Currently beingcut

Approaches To-Date•Pre-treatment assessment of plants, birds, and bats

•Effects of patch size on bats & plants using existing ESH

•Initial studies of aggregation effects on plants, bird, bats

•Harvesting economics modeling•Public perception baseline info

Effects of Size on Biodiversity-Plants

<3 ha 3-6 ha 6-10 ha

Green, in prep

Woody plant functional traits in relation to edge• No significant difference in the relationship between seed size and distance from edge between opening sizes (p = 0.659)

• No significant difference in relationship between shade tolerance and distance from edge by opening size (p = 0.248)

Effects of Opening Size on Nocturnal Insect Abundance

Mea

n in

sect

abu

ndan

ce

Small Medium Large

Opening size

0

200

400

600

8000

200

400

600

800

2015

2014

Brooks 2016

Small = 0.2-1.6 ha Medium = 2.1-5.6 ha Large = 6.2-18.5 haP > 0.10

Effects of Opening Size on Bat Activity

Mea

n ba

t act

ivity

Small Medium Large

Opening size

0

20

40

60

80

1000

20

40

60

80

100

2015

2014

Brooks 2016

P > 0.10

Mea

n ba

t act

ivity

Interior Edge

Location

0

100

200

300

400

500

0

100

200

300

400

500

2015

2014

Positive Effects of EdgeP = 0.08

Size Effects on Birds

Common Name TotalBlack-throated Green Warbler 76Red-eyed Vireo 94Hooded Warbler 68Tufted Titmouse 68Worm-eating Warbler 60Black-and-white Warbler 55Ovenbird 34Scarlet Tanager 48Indigo Bunting 6Carolina Wren 25American Crow 12Northern Parula 16Carolina Chickadee 23Blue-headed Vireo 38Blue-gray Gnatcatcher 18Northern Cardinal 10Blue Jay 16Yellow-billed Cuckoo 6Downy Woodpecker 3Pileated Woodpecker 10Eastern Wood-Pewee 5White-breasted Nuthatch 14Wood Thrush 9Yellow-throated Warbler 36Eastern Towhee 18Red-bellied Woodpecker 13

American Redstart 0Ruby-throated Hummingbird 2Wild Turkey 0American Robin 1Rose Breasted Grosbeak 0Broad-winged Hawk 7Yellow-throated Vireo 0Turkey Vulture 1Mourning Dove 7Red-breasted Nuthatch 0American Goldfinch 1Acadian Flycatcher 0Brown Thrasher 0White-Eyed Vireo 0Cedar Waxwing 1Red-tailed Hawk 0Northern Flicker 2Hairy Woodpecker 0Ruffed Grouse 0American Robin 2Yellow-breasted Chat 14Blackburnian Warbler 1Eastern Phoebe 1Great Crested Flycatcher 1Black-throated Blue Warbler 7Swainson's Warbler 5Red Headed Woodpecker 2

Red: Edge & Successional Species

Bird Counts in 1 Acre Plots

Summer ‘16 – Initial ecosystem, plant, avian, insect, and bat responses

open edg

e

forest open

edge

Aggregation Effects – Preliminary Results

Soil M

oisture

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

OpenEdgeForest

6/06 6/13 6/21 6/27 7/04

Soil Tem

perature (C)

15

16

17

18

19

20

21

22

23

CenterEdgeForest

6/06 6/13 6/21 6/27 7/04

Soil moisture

- Higher in forest than edge and open

Soil temperature

- Highest in open, lowest in forest

i.e., openings are hot and dry compared to the forest

Soil C

O2 Flux um

ol/m2

/s

2

4

6

8

10

OpenEdgeForest

6/06 6/13 6/21 6/27 7/04

Soil respiration highest in forest, lower in edge, and lowest in open- Contrary to hypothesis that cutting would increase soil

respiration- Suggests harvesting during hot, dry weather could

partially mitigate the increased soil respiration that typically occurs when openings are created

Soil respiration values similar to values (ca. 4.5-5.1 µmol m-2 s-1) reported for a forested area at Coweeta in June

Num

ber of Visitors

0

5

10

15

20

25

30

AggregatedDisaggregated

Open Edge Forest

Species R

ichness

0

2

4

6

8

10

12

14

- Significant (P<0.001) interaction between location and aggregation;

- Insects higher in aggregated forests

- no significant difference between treatments or among locations

Diurnal Pollinating

Insects

Economic Consequences of Harvesting Configurations – Costs

Economic Consequences of Harvesting Configurations – Revenue

Economic Consequences of Harvesting Configurations – Net Present Value

Net Present Value of Each Prescription

A B C D E

-$120.00-$100.00-$80.00-$60.00-$40.00-$20.00

$0.00$20.00$40.00$60.00$80.00

$100.00$120.00

NPV

Dol

lars

1 acreAggregated

1 acreDispersed

9 acreAggregated

9 acreDispersed 20 acre

Summary & Conclusions• ESH patch size: little effect on plants & bats

• May need larger patches for ES birds

• ESH aggregation: still exploring

• Economic analysis suggests that larger, aggregated patches provide the best return