CENTRAL CASCADES ADAPTIVE CENTRAL CASCADES ADAPTIVE MANAGEMENT PARTNERSHIPMANAGEMENT PARTNERSHIP

An intersection of state and federal organizations, sharing and focusing science and management resources to elevate our understanding of natural resources.

YOUNG STAND THINNING AND DIVERSITY STUDY

A management study evaluating the ecological, operational, social, and economic consequences of alternative methods of managing 30-50 year-old plantations.

TREATMENTS 

Control (uncut, avg. 261 tpa) : Blue outline

Light thin (thinned to 105 tpa) : Yellow outline

Heavy thin (55 tpa) : Green outline

Light Thin with Gaps (same as light thin but with additional 0.5 acre gaps over 20% of the treatment) : Red Outline

The Young Stand Study targeted stands 35-50 years old

LIGHT THIN W/GAP TREATMENT

This treatment mimics mortality patterns of •small fires •root-rot outbreaks•Insects

Gaps planted

HEAVY THIN TREATMENT

This treatment opens the canopy dramatically allowing

•Rapid diameter growth

•More understory development

LIGHT THIN TREATMENT

This treatment is similar to a standard commercial thin. 

• ~ 1/2 stems were removed

• 110 trees per acre left

MONITORING• Small Mammals pre twice; post 2 & 3, 11 & 12• Amphibians pre twice; post 11 + cover boards• Birds pre twice; post 3, 4, 5, 7, 11, 12 • Vegetation pre stand exams, post 1, 3, 5, 11 • Logging Costs post• Soil Impacts post• Snags/down wood post 2, 11• Stand Damage post• Public Perceptions post• Arthropods post 5 and 6

Chanterelle’s

MONITORING -- one year pre (1994), post 1996-7, 1999

KEY FINDING:• Chanterelle productivity significantly declined (but was

not eliminated) immediately after thinning • the level of decline was greater in the heavily thinned

stands than in those lightly thinned

NO DATA COLLECTED TO SEE IF RECOVERED OVER TIME

Chanterelle’s

1996 1997 1999 2001

MushroomsAv

g.C

hant

erel

les

per a

cre

0

100

200

300

400

Col 2 Col 2: 199 Col 2: 25 Col 2: 280 Col 2: 95 Col 2: 20 Col 2: 85 Col 2: 20 Col 2: 5 Col 2: 350 Col 2: 320 Col 2: 110

Pilz et al. 2006

www.pbase.com/ladislav/image/33934414

Short-term reductions

LOGGING DAMAGE

Compared tractor, cut-to-length, skyline, & helicopter

KEY FINDINGS: • Most typical damage was scarring

• Ground-based systems more severe

• Skyline and helicopter: larger scars, gouging, and root damage

• Damaged concentrated w/in 15 ft of skid trails / skyline corridor centerlines.

• Cut-to-length systems -- harvester caused more wounding (70%) than forwarder (30%), but forwarder scars were larger and sustained severe gouging.

Litter Dwelling Arthropods Affects of thinning complex!

• Key Findings:– Seasonal affects override treatment affects– Indirect affects on litter moisture decreases

abundance and diversity proportional to thinning

– Control vs light thin – no difference– Light thin w/gaps – no difference from heavy

PUBLIC PERCEPTIONSPost-Thin, Heavy and Light

KEY FINDINGS:

• Both Treatments - low visual impacts

met moderate scenic integrity standards

COMPACTION

• KEY FINDINGS: CABLE

– 0.5% of area was disturbed

– Compaction negligible, but some sites

-- decreased bulk density

–From tilling of dragging tops??

COMPACTION – SLASH DEPTHS

KEY FINDINGS: HARVESTER FORWARDER• 3-5 passes, compaction raised soil strength

– no further increase in compaction

• Existing OM, particularly rotten logs, cushioned and reduced compaction

• Compaction was 21% at 4” depth, 12% at 8”

• High levels of slash reduced compaction to a small extent

• There was very little change in bulk density in the middle of skid trails at 8” depth

COMPACTION

KEY FINDINGS: CUT TO LENGTH (harvester forwarder)

• Difficult to reuse old skid trails due to difference in the systems used 50 years ago

• New skid trail showed same compaction as old trails

• Bulk density increased 12%

• Over 20% oF area of compacted, still within FS guidelines

THE REST OF THE STORY…