1. CWD (COARSE
WOODY DEBRIS)
AMY AMUQUANDOH
SWARTHMORE COLLEGE
SWARTHMORE, PA
SCHOOL FOR FIELD STUDIES
YUNGABURRA, QLD
What does CWD volume tell us about
secondary forest recovery to pre-disturbance
levels in FNQ?

2. What is it?
 CWD is an essential component of forest
ecosystems
 Fallen branches, logs, and standing trees
(snags) ≥ 10cm in diameter
 Habitat provision for organisms
 Long term carbon storage

3. Secondary Succession
 Induced by natural and anthropogenic
disturbances, these forest ecosystems function
differently from old growth
 Successional patterns largely determined by
land use history
 Above ground biomass (AGB) can serve as
indication of intensity of previous land use

4. How do these connect?
 Tree mortality and fallen branches generate
large volumes of dead wood which accumulate
as succession advances
 CWD is a part of the above ground biomass!
 Often overlooked in conservation/restoration
management schemes

5. Objectives
 Find out if volume of CWD varies between
secondary and primary forest
 Use results to determine if CWD volume is an
indication of secondary forest recovery to pre-
disturbance levels
 Prediction: increasing total volume with forest
age due to disturbance history

6. Sites
 Simple notophyll vine forests
 Less fertile soil/less complex than most forests
 Granite and metamorphic rock
 Secondary growth & Primary growth
 Unassisted secondary ecosystem recovery after
clearcutting and agricultural abandonment
 Chronosequence with range of 17-67 years
 Data used from 2014 & 2015

9. Methods
 50 m transect line within
each study site
 5m distance from that
transect line
 Measure all fallen logs and
branches ≥10cm diameter
 Void space
 length
 Measure snags ≥10cm
diameter at breast height
(DBH)
 Void space
 Height (up to 10cm diameter)
Photo Credit: Sophia

10. Plot Methods
50 m
All snags ≥10 cm
DBH
All CWD (fallen &
suspended) ≥ 10 cm
Diameter
10m

11. Formulas
 Smalian’s formula for volume (Baker and Chao
2011):
 𝑉 = 𝐿
(𝜋(D1/2)+ 𝜋(D2/2)2]
2
× void space
“where L (m) is the length (or height) of the piece of
CWD, and D is the diameter (m), at either end”

12. Total CWD Volume (m3) in
Secondary Forests
Correlation of the total volume (m3) of CWD in secondary forests (17-
67 years) versus age. (r= 0.76221; p = 0.0104).

13. Cont.
Kruskal-Wallis comparison of total volumes of CWD among different
age classes.

14. CWD in ABG
Correlation of CWD biomass percentage of total ABG with forest
age. (r= .57318; p= 0.083248).

15. Conclusion
 CWD volumes increase with age between
secondary and primary forests
 Important for conservation purposes
 Volume difference with age suggests CWD is
good recovery indicator
 Separate yet valuable component of AGB
 Abundance of CWD adds conservation value to
secondary forests

16. Limitations
 Chronosequence, may not be accurate
representation of site and type of forest;
longitudinal study is better
 Wood density estimation
 Volume calculation

17. Future Studies
 Look at decay class difference within these
forest
 further differences between the non significant
MS and P succession classes?

18. Acknolwedgements
 Fellow researchers
 My research advisor, Dr. Catherine Pohlman
 Private land owners of sites used in study
 Interns Kylie Vanchena and Carina Easley-
Appleyard
 SFS for funding

19. References
Baker T.R. & Chao K.J. (2011) Manual for coarse woody
debris measurement in RAINFOR plots. Rainfor 2, 1–8.
Carmona M.R., Armesto J.J., Aravena J.C. & Perez C.A.
(2002) Coarse woody debris biomass in successional
and primary temperate forests in Chiloe Island, Chile.
Forest Ecology and Management 164, 265–27.
Letcher S. G. & Chazdon R. L. (2009) Rapid Recovery
of Biomass, Species Richness, and Species
Composition in a Forest Chronosequence in
Northeastern Costa Rica. Biotropica 41(5), 608–617.

20. Questions
?
FIN.