coarse woody debris missouri ozark forest ecosystem project
DESCRIPTION
Coarse Woody Debris Missouri Ozark Forest Ecosystem Project. Randy G. Jensen Stephen R. Shifley Brian L. Brookshire David R. Larsen Laura A. Herbeck. Wildlife habitat Birds.......... 36 Species Mammals...11 Species Reptiles........8 Species Nutrient cycling - PowerPoint PPT PresentationTRANSCRIPT
Coarse Woody DebrisCoarse Woody Debris Missouri Ozark Forest Ecosystem ProjectMissouri Ozark Forest Ecosystem Project
Randy G. Jensen Randy G. Jensen Stephen R. ShifleyStephen R. ShifleyBrian L. BrookshireBrian L. BrookshireDavid R. LarsenDavid R. LarsenLaura A. HerbeckLaura A. Herbeck
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Snags and Down Wood--Who Cares?Snags and Down Wood--Who Cares?
• Wildlife habitat– Birds.......... 36 Species– Mammals...11 Species– Reptiles........ 8 Species
• Nutrient cycling– Substrate for fungi and vascular plants– Slow release of nutrients back into the system– Carbon storage
• Soil stability
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Field Field ProceduresProcedures
56.5’Transects
100%Inventory
0.5 acre plots0.5 acre plots70+ per site; 648 total70+ per site; 648 total(Snags, DDW% cover)(Snags, DDW% cover)
0.25 acre plots0.25 acre plots11 per site, overlaid11 per site, overlaid
(all DDW characteristics)(all DDW characteristics)
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Variables Variables ObservedObserved
• Down Wood– Volume– Surface Area– Percent of Ground Covered
• Snags– Number per acre– Basal Area– Percent of Live Trees
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Down Wood Volume Pre-treatmentDown Wood Volume Pre-treatment
0
100
200
300
400
Noharvest
Even-aged
Uneven-aged
Block 1Block 2Block 3
1 96 3 5 72 48
Volu
me
(cu.
ft/ac
)
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Down Wood Volume Pre-treatmentDown Wood Volume Pre-treatment
0
100
200
300
400
Noharvest
Even-aged
Uneven-aged
Block 1Block 2Block 3
1 96 3 5 72 48
Volu
me
(cu.
ft/ac
)
Mean = 241Mean = 241
No pre-treatment effectsNo pre-treatment effects
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Anticipated Treatment Effects: Down WoodAnticipated Treatment Effects: Down Wood
• No harvesting– Gradual increase in the amount of dead wood– Perhaps double the current volume
• Harvested Stands (EAM or UAM)– Dramatic increase in the amount of down wood– Thinning (some)– Regeneration harvesting (substantial)– Because boles are removed increase % cover faster than volume
• Down wood should increase on all sites• Snags eventually become down wood
– Short term increase in snags = long term increase in down wood
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Pre- and Post-Pre- and Post-TreatmentTreatmentTreatment Mean, 1992
cu.ft./acMean, 2000
cu.ft./acNo harvest 291 527
Uneven-aged 162 671
Even-aged 270 636
Mean 241 611
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Treatment Summary by Treatment Summary by PlotPlot
0 500 1000 1500 2000 2500
Clearcut
Single tree w/Group
Single tree
Intermediatethinning
No harvest
cu.ft./ac
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Relative Size Relative Size DistributionDistribution
0
10
20
30
40
50
6 10 14 18 22 26 30Dbh class (in)
Rel
ativ
e fr
eque
ncy
(%)
Live treesSnags
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Regression, Conf. & Pred.
Age (years)0 50 100 150 200 250
Dead
wood
Vol
ume
(m3 /h
a)
-20
0
20
40
60
80
100
120
140
J
J
J
JMV
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Key Findings Key Findings (1)(1)
• Down coarse woody debris (CWD) is an important but little-studied indicator of forest structure, fire risk, habitat quality, nutrient cycling, and carbon storage.
• Snags (standing dead trees) are closely linked to CWD because snags ultimately add to the pool of CWD.
• CWD was inventoried in 1990-1991, 1994-1995 and 1999-2000 (post-treatment) using line transects .
• Total combined length of transects was 27.75 miles of which about 1 mile of transect (total) passed through clearcuts. The 8,855 pieces of measured down wood covered about 1 mile of transect length or roughly 3.6 percent of the ground area (all MOFEP sites combined).
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Key Findings Key Findings (2)(2)
• Down wood volume associated with individual silvicultural treatments sorted out in a logical order with total CWD for clearcut plots > group selection > single tree > intermediate thinning > no harvest.
• Prior to the 1997 harvest treatments there were no significant differences among treatment groups . The volume and percent coverage of CWD approximately doubled before and after harvest treatments, even on the control plots.
• Prior to harvest treatments, snags comprised about 5 sq.ft. basal area/ac with roughly 1 snag for every 10 to 12 live trees by dbh class.
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Future Research Future Research (1)(1)
• Snags and CWD should continue to be periodically measured, particularly before and after harvest treatments. This will allow scientists to better quantify the magnitude and variability of the accumulation of snags and CWD in untreated stands.
• Little is known about rates of decomposition for snags and down wood.
• Periodic harvesting, particularly uneven-aged management with periodic thinning treatments, may eliminate trees that are prone to die and thus over time reduce the number of snags relative to untreated stands.
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Future Research Future Research (2)(2)
• The volume of coarse woody debris of various sizes is indicative of fuel loading and ultimately of fire intensity if ignited. The MOFEP results could be used to support fire research and modeling efforts in the Ozarks.
• The Forest Service Forest Inventory and Analysis (FIA) program is now collecting CWD data on a small proportion of plots as part of their on-going state-wide inventories. The FIA CWD sampling is just beginning, and results from the periodic MOFEP CWD inventories can serve as a reference point from which to evaluate the early FIA results.
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Future Research Future Research (3)(3)
• Inventories of snags and CWD present sampling challenges because they are highly variable at small spatial scales. Moreover, snags are relatively rare events. Recent work related to cavity tree estimation indicates that appropriate spatial scales can be determined for estimating current and predicted levels of cavity trees. A similar approach would likely be productive if applied to estimation and prediction of snag density or CWD at stand and landscape scales.
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Down Wood Down Wood VolumeVolume
0
10
20
30
40
50
Dark HollowEngelmannSchnabelBig SpringRoaring SinkinMOFEP
Volu
me
(cu.
m/h
a)
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Snag-to-Live Ratio Snag-to-Live Ratio ComparisonComparison
0
4
8
12S
nag
to L
ive
Tree
Rat
io (%
) MOFEPSinkinBig Spring
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OutlinOutlinee• Importance of Snags and Down Wood.• Initial Pre-treatment Conditions at MOFEP
Sites.• Comparison of MOFEP sites to other locations.• Likely Changes Following Treatment.
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Down Wood Volume Down Wood Volume ComparisonComparison
0
100
200
300
400
500Vo
lum
e (c
u.ft/
ac) MOFEP
SinkinBig Spring
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Change in Down Wood with Stand AgeChange in Down Wood with Stand Age
0
300
600
900
1200
1500
0 20 40 60 80 100 120 140
MO Old-Growth
IN Old-Growth (Spetich)
MOFEP
IN Second-growth(Jenkins and Parker)
Volu
me
(cu.
ft/ac
)
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Anticipated Treatment Effects: SnagsAnticipated Treatment Effects: Snags
• No harvesting– No change in ratio of snags to live trees.– Modest increase in mean snag size.
• Thinning (EAM or UAM)– Reduce number of snags in long run.– Girdling nonmerchantable stems will increase snags in the short run.
• Regeneration harvesting (EAM or UAM)– Felling snags during harvesting will greatly decrease snags...BUT– Girdling nonmerchantable stems could greatly increase snags in short term
• Any harvesting will alter the ratio of snags to live trees
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ConclusionConclusionss
• No pre-treatment differences in snags or down wood.– GOOD!
• Blocking probably not very helpful in grouping treatment areas for these characteristics.
– Too bad, but not a big deal.
• Dead wood flows from overstory to understory.– Snags and down wood volumes vary with stand age/condition– Management allows opportunity to control rates of snag
accumulation and movement of wood from overstory to forest floor.
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PrognosticationPrognosticationss• Any harvesting will rapidly increase the amount of down wood
in the short term, but in the long term harvested sites will probably have less down wood than the No Harvest treatment.
• Felling nonmerchantable stems will decrease the number of snags and increase the relative amount of down wood on the forest floor.
• Girdling nonmerchantable stems will increase snags and delay input of some down wood.
• Any harvesting will alter the ratio of snags to live trees.
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Down Wood Surface Down Wood Surface AreaArea
0
500
1000
1500
2000
Noharvest
Even-aged
Uneven-aged
Block 1Block 2Block 3
1 96 8 3 5 72 4Surf
ace
Are
a (s
q.ft/
ac)
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Down Wood % Ground Down Wood % Ground CoverCover
0.0
0.5
1.0
1.5
2.0
Noharvest
Even-aged
Uneven-aged
Block 1Block 2Block 3
1 96 8 3 5 72 4Gro
und
cove
red
(%)
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Snags per Snags per AcreAcre
0
5
10
15
20
25
Noharvest
Even-aged
Uneven-aged
Block 1Block 2Block 3
1 96 8 3 5 72 4
Snag
s (n
/ac)
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Snag Basal Snag Basal AreaArea
0
2
4
6
8
10
Noharvest
Even-aged
Uneven-aged
Block 1Block 2Block 3
1 96 8 3 5 72 4
Snag
Bas
al A
rea
(sq.
ft/ac
)
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Study sitesStudy sites
Big Spring (30)MOFEP
Sinkin (73)
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Snag Ratio to Live Snag Ratio to Live TreesTrees
0
5
10
15
20
Noharvest
Even-aged
Uneven-aged
Block 1Block 2Block 3
1 96 8 3 5 72 4
Snag
Rat
io (%
)
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0
100
200
300
400
500
1 2 3 4 5 6 7 8 9
Was Blocking Effective? (Down wood)Was Blocking Effective? (Down wood)
Dow
n W
ood
Volu
me
(cu.
ft/ac
)
BlockBlock 1 1 BlockBlock 2 2 BlockBlock 3 3
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0
5
10
15
20
25
1 2 3 4 5 6 7 8 9
Was Blocking Effective? Was Blocking Effective? (Snags)(Snags)Sn
ags
per A
cre
BlockBlock 1 1 BlockBlock 2 2 BlockBlock 3 3
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Snag Snag ComparisonComparison
0
5
10
15
20S
nags
per
acr
eMOFEPSinkinBig Spring
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Down Wood Ground Down Wood Ground CoverCover
0.0
0.5
1.0
1.5
2.0D
own
Woo
d G
roun
d C
over
(%)
MOFEPSinkinBig Spring