CWD (COARSE WOODY DEBRIS)AMY AMUQUANDOH

SWARTHMORE COLLEGESWARTHMORE, PA

SCHOOL FOR FIELD STUDIESYUNGABURRA, QLD

What does CWD volume tell us about secondary forest recovery to pre-disturbance levels in FNQ?

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

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

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

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

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

Peeramon

Barrine Crater/Lake Barrine

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 Siciliano

Plot Methods

50 m

All snags ≥10 cm DBH

All CWD (fallen & suspended) ≥ 10 cm Diameter

10 m

Formulas Smalian’s formula for volume (Baker and

Chao 2011):

“where L (m) is the length (or height) of the piece of CWD, and D is the diameter (m), at either end”

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).

Cont.

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

CWD in ABG

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

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

Limitations Chronosequence, may not be accurate

representation of site and type of forest; longitudinal study is better

Wood density estimation Volume calculation

Future Studies Look at decay class difference within

these forest

further differences between the non significant MS and P succession classes?

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

ReferencesBaker 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.

Questions?

FIN.