Coarse Woody Debris
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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

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Coarse Woody Debris Missouri Ozark Forest Ecosystem Project

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Coarse woody debris missouri ozark forest ecosystem project

Coarse Woody Debris

Missouri Ozark Forest Ecosystem Project

Randy G. Jensen

Stephen R. Shifley

Brian L. Brookshire

David R. Larsen

Laura A. Herbeck


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

Snags and Down Wood--Who Cares?


Field procedures

Field Procedures

56.5’

100%

Inventory

Transects

0.5 acre plots

70+ per site; 648 total

(Snags, DDW% cover)

0.25 acre plots

11 per site, overlaid

(all DDW characteristics)


Variables observed

Down Wood

Volume

Surface Area

Percent of Ground Covered

Snags

Number per acre

Basal Area

Percent of Live Trees

Variables Observed


Down wood volume pre treatment

Down Wood Volume Pre-treatment

Volume (cu.ft/ac)


Down wood volume pre treatment1

Down Wood Volume Pre-treatment

No pre-treatment effects

Mean = 241

Volume (cu.ft/ac)


Anticipated 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

Anticipated Treatment Effects: Down Wood


Pre and post treatment

Pre- and Post-Treatment


Treatment summary by plot

Treatment Summary by Plot

cu.ft./ac


Relative size distribution

Relative Size Distribution


Key findings 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).

Key Findings (1)


Key findings 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.

Key Findings (2)


Future research 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.

Future Research (1)


Future research 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.

Future Research (2)


Future research 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.

Future Research (3)


Down wood volume

Down Wood Volume

Volume (cu.m/ha)


Snag to live ratio comparison

Snag-to-Live Ratio Comparison


Outline

Importance of Snags and Down Wood.

Initial Pre-treatment Conditions at MOFEP Sites.

Comparison of MOFEP sites to other locations.

Likely Changes Following Treatment.

Outline


Down wood volume comparison

Down Wood Volume Comparison


Change in down wood with stand age

Change in Down Wood with Stand Age

IN Second-growth

(Jenkins and Parker)

IN Old-Growth

(Spetich)

Volume (cu.ft/ac)

MOFEP

MO Old-Growth


Anticipated 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

Anticipated Treatment Effects: Snags


Conclusions

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.

Conclusions


Prognostications

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.

Prognostications


Down wood surface area

Down Wood Surface Area

Surface Area (sq.ft/ac)


Down wood ground cover

Down Wood % Ground Cover

Ground covered (%)


Snags per acre

Snags per Acre

Snags (n/ac)


Snag basal area

Snag Basal Area

Snag Basal Area (sq.ft/ac)


Study sites

Study sites

Sinkin (73)

MOFEP

Big Spring (30)


Snag ratio to live trees

Snag Ratio to Live Trees

Snag Ratio (%)


Was blocking effective down wood

Was Blocking Effective? (Down wood)

Down Wood Volume (cu.ft/ac)

Block 3

Block 1

Block 2


Was blocking effective snags

Was Blocking Effective? (Snags)

Snags per Acre

Block 3

Block 1

Block 2


Snag comparison

Snag Comparison


Down wood ground cover1

Down Wood Ground Cover


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