Hlp 1999 03 prsnttn ndwkshpresidualwoodstudy

Residual Wood Study • Objective: Estimate and compare the range of variability in the origin, abundance and condition of deadwood material and live trees recently disturbed by wildfire and by clearcut harvesting

7 study areas • 1 Mountain wildfire – 34 yr

• 3 Foothills wildfires – 35 - 40 yr

• 3 Foothills harvests – 23 - 27 yr 0 N

50

100 Kilometers

Paired design • Example of 2 sites: • Lynx Creek Burn (35 yr) & Adjacent cutblocks (23-27 yr)

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• 30 plots per site randomly located (almost)

Lynx Creek 0

5

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10 Kilometers

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Plot layout down deadwood standing dead standing live 390 m2

30 m

Wood present before disturbance No. pieces of down deadwood

(> 7 cm diameter) 100

Burned Logged

75 50 25 0 0

10

20

30

Time since disturbance (yr)

40

Wood generated after disturbance No. pieces of down deadwood

(> 7 cm diameter) 100

Burned Logged

75 50 25 0 0

10

20

30

Time since disturbance (yr)

40

Mean number of pieces per plot

Decay pattern of down wood

Burned

20 10 0 Logged

20 10 0 1

2

3

4

Log decay class

5

• In burns, hard logs are abundant 35 years after fire; probably recruited fromPre-disturbance falling snags.

Post-disturbance

• In cutblocks, most logs are soft 25 years after logging.

30 20 10 0

Burned

30 20 10 0

Logged

• In burns, falling snags get “hung up” above the ground.

Pre-disturbance

010 10 -2 0 20 -3 0 >3 0

Post-disturbance

0

Mean number of pieces per plot

Vertical distribution of down wood

Piece height (cm)

• In cutblocks, most logs are flush with the ground.

Summary: Residual wood • Burned stands (35 - 40 yr) – wood carried over from previous stand was highly variable, occasionally abundant • few standing dead trees • occasionally abundant down wood

• Logged stands (23 - 27 yr) – less (and less variable) wood carried over from previous stand • very few standing dead trees • fewer pieces of down wood