“Multiple-Stable States”

Changes in:

Species diversity

Opportunistic species

Incidence of disease

Tightness of nutrient cycling

Net Primary Production

Natural Range of Stable States

Degraded/ Loss of integrity

Degraded/ Loss of integrity

0

0.5

1

1400 1500 1600 1700 1800 1900

Year

Prop

ortio

n of

Lan

dsca

pe in

Old

-gro

wth

HRV

Historical Range of Variability

Figure from Aplet and Keeton (1999)

Multiple Pathways of Succession:

f (Timing, Type, and Intensity of Disturbances + Masting and Seed Availability)

From Hemstrom and Logan (1986), in Spies (1997)

IUCN Cat. 2:

National Park

IUCN Cat. I:

Nature preserve

IUCN Cat. 3:

Natural Monument

IUCN Cat. 4:

Habitat/ Species Mgt. Area

IUCN Cat. 5:

Protected Landscape

IUCN Cat. 6:

Managed Resource Area

Low Vegetation Management Intensity

Protected Areas Unprotected Areas

Matrix Management

Intermediate Vegetation Management Intensity

High Vegetation Management Intensity

Certified Non-Industrial Private Forests

Certified Industrial Forests

Uncertified Non-Industrial Private Forests

Uncertified Industrial Forests

The Forest Management Spectrum

Climate

Direct Indirect

Effects on Organisms(Physiological, etc.)

Effects on DisturbanceRegimes

Ecosystem Composition and Function

Figure courtesy of Ray Drapek,

Oregon State University

Multiple stressors produce a vulnerable landscape*

*Text and figure reprinted with permission

from D.L. Peterson et al. 1999.

300

0

Bio

mas

s (M

g/ha

)

Stand Age (years)

0 100 200 400300

?

Empirical Data from Keeton et al. (2007) and others

Empirical Data from Bormann and Likens (1979)

Theoretical Projections from Bormann and Likens (1979)

0

50

100

150

200

250

300

350

400

0 5 10 15 20 25 30 35 40 45 50 55

Years

Ab

ov

eg

rou

nd

Tre

e B

iom

as

s (

Mg

/ha

)

SCE Units (No Treatment)

Uneven-Aged Units (No Treatment)

SCE (With Treatment)

Uneven-Aged (With Treatment)

SCE (Multiple Entries)

Uneven-Aged (Multiple Entries)

304.5 Mg/ha

216.6 Mg/ha

292.3 Mg/ha

178.9 Mg/ha

251.6 Mg/ha

223.8 Mg/ha

55.9 Mg/ha

80.7 Mg/ha