Residence Time of Coarse Woody Debris on the Forest Floor in Southeastern Indiana Forests

M. Ross Alexander and Darrin L. RubinoBiology Department, Hanover College, Hanover, IN

What is CWD?

• Downed branches and boles – greater than 10 cm

diameter – longer than 1 m in length

• Divided into classes based on degree of rot (punkiness)

• Why?

Decay Classes

• Common classes defined by Pyle and Brown (1998)

• 5 classes– Class I

Freshly fallen logs

– Class II Bark still present, solid

– Class IIIBark typically absent,

wood: Spongy, flaky

– Class IV• No longer solid• Crushes when struck (no

flaking)

– Class V• Predominantly powder

wood• Typically flattened shape

Goals

• Determine death dates of logs within decay classes

• Determine how long different species reside on forest floor

• Are there a differences in the decay rates of different hardwood species?

Methods

• Several forests in Southeastern Indiana were sampled.

• Purposefully chose samples that had either bark or wane.• Wane = outermost growth ring

• “Cookie” samples were taken using a chain saw

Surface Preparation

• Sanding– Finer grits of sandpaper

– 50, 80, 120, 180, 220, 320, 400, 600

– Table sanders– Palm (orbital) sanders– Hand sanding

1

Dating

• Place arbitrary years on sanded sample• Skeleton plots

Dating

• Measure sample

• Allows for “Crossdating”

19901980

1971 – 2003

Crossdating Process

19901980

? – ?

1971 – 2003

19901980

1971 – 2003

? – ?

1990

1960 1970

1980

1971 – 2003

1953 – 1979

Results

• 88 samples from 8 species (LITU, FRAX, SAAL, FAGR, ROPS, Red and White Oak, PRSE, ) were analyzed

• ANOVA analysis was performed where appropriate

• Analysis was not performed on PRSE, SAAL, or the Oaks

Class n

I 29

II 13

III 39

IV 7

I II III0

1

2

3

4

5

Oaks

Decay Class

Num

ber o

f sam

ples

I III0

2

4

6

LITU

Decay ClassNum

ber o

f Sam

ples

I II III05

101520

ROPS

Decay Class

Num

ber o

f Sam

ples

I II III IV05

101520

FAGR

Decay Class

Num

ber o

f Sam

ples

I II III0123456789

FRAX

Decay Class

Num

ber o

f Sam

ples

Beech

I II III IV0

2

4

6

8

10

12

Decay Class

Mea

n Ye

ars

dead

a

c c

b

F = 19.07P < 0.001n = 40

Decay Class III

FAGR FRAX LITU ROPS0

5

10

15

20

25

Species

Mea

n Ye

ars

Dea

d

ab

a

b

F = 5.70P = 0.03n = 35

a

Conclusions

• Decay rates are different from species to species

• More sampling is needed to increase depth

• Future work: Chemical analysis to determine nutrient release among different species.

Acknowledgements

• Biology Dept. at Hanover College• Patricia Walne Student Research Fund• Cassie Lothery• Abby Simpson