Disturbance -Based Management Landscape-Level – Pattern and complexity – Stand age class distributions – Patch distributions: type, size, – shape, and continuity – Habitat representation – Historic range of variability Stand-Level – Vertical structure – Horizontal structure – Cohorts – Tree age class distributions – Biological legacies

Figure adapted from Franklin and Spies (1991). Structural Change Through Stand Development

Photos courtesy of Jerry F. Franklin, University of Washington Recovery facilitated by biological legacies at Mount St. Helens

Large-scale Windthrow: Hurricanes Fine-scale Windthrow Ice Storms Insect and Pathogens Outbreaks

Coarse Woody Debris in Northern Hardwood Forests Even-agedSingle-tree SelectionOld-Growth Habitat Nitrogen Fixation Soil organic matter Mycorrhizal fungi Nurse logs Erosion reduction Riparian functions Figure from McGee et al. (1999)

Teakettle Ecosystem Experiment Forest Ecosystem Research Network

0 % 100 %80 % 20 %80 % 20 % Removal at Harvest Retention at Harvest Entries per Rotation Age Classes or more Even-aged (1 class) Multi-aged (2-3 classes) Uneven-aged (4 or more classes) Figure from Franklin et al. (1997) Variable Retention Harvest System

“Demonstration of Ecosystem Management Options”

Weyerhaeuser Co. Variable Retention Adaptive Management (VRAM) Experiment

Weyerhaeuser Co. Variable Retention Forestry in B.C.

VRAM

Year 0 Year 15

Long-Term Implications ?

What have we learned about natural disturbance effects? Scale and frequency of disturbance

Figures from Seymour et al Mimicking scale and frequency of disturbances

HRV Historical Range of Variability Figure from Aplet and Keeton (1999)

HRV Scale: Small Watershed Scale: Drainage Basin Scale: Region Hurricane Hurricanes Source: Aplet and Keeton (1999)

HRV Historical Range of Variability Figure modified from Aplet and Keeton (1999) using data from Cogbill (2000) Year Proportion of Landscape in Early-Succession

What have we learned about natural disturbance effects? Coarse-woody debris: snags and downed wood

Coarse Woody Debris in Northern Hardwood Forests Even-agedSingle-tree SelectionOld-Growth Habitat Nitrogen Fixation Soil organic matter Mycorrhizal fungi Nurse logs Erosion reduction Riparian functions Figure from McGee et al. (1999)

What have we learned about natural stand development? Importance of large trees as structural elements

Crown Release to Increase the Representation of Large Trees Age (Years) DBH (cm) No release Partial crown releaseFull crown release Data from Singer and Lorimer (1997)

What have we learned about natural stand development? Vertical complexity Horizontal complexity

Structural Complexity Index (Zenner 2000) A) B) = Ratio of 3D area in A to 2D area in B

Uneven-aged Forestry Single-tree selection Group selection BDq prescriptions are based on the desired: 1. residual basal area 2. maximum dbh 3. q-factor

Single-Tree Selection Prescription for Mt. Mansfield Unit 4: q-factor of 1.3, maximum diameter of 24", and residual basal area of 80 ft 2 /acre Diameter Class in Inches # Stems per Acre

Diameter Distributions Figure from Goodburn and Lorimer (1999)

Unbalanced Diameter Distributions: Figure from Goodburn and Lorimer (1999) Density-dependent mortality reduced with fewer stems in smaller size classes Equal allocation of growing space not found consistently

Figure from Seymour 2005 Multi-modal distributions due to old- tree legacy

Rotated Sigmoid Diameter Distribution Shift in basal area allocation to larger size classes Often found in old-growth northern hardwoods and mixed-woods Varies with disturbance history, stand composition, and competitive dynamics Theoretical silvicultural utility proposed (O’Hara 1999, Leak 2003); tested experimentally by Keeton (2005). # of Trees Diameter Class

Yield vs. Big Tree Structure in Northern Hardwoods 40 cm max. 50 cm max cm max. Data from Hansen and Nyland (1987)Data from Goodburn and Lorimer (1999) Maximized volume production Selection harvest + old-growth structure after multiple cutting cycles Maximized large sawtimber volume and value growth

An Alternative: Multi-aged Silviculture Recognizes that “reverse J” is limiting Other stand structures are sustainable Ecological functions more closely associated with canopy structure All-aged stands exceedingly rare in actuality Management based on the desired number of canopies provides a better alternative Set objectives based on canopy strata  two-aged and multi-aged are possibilities

Multi-aged distributions resulting from multiple disturbances Diameter Class Trees/ha

–Leaf area index –Stand density index – MASAM model (O’Hara 1998) Growing space allocation approaches

Shift in growing space from one strata to another also shifts growth increment High Low Understory growth Overstory growing space occupied (%) Overstory growth High Low Understory Overstory Figure from O’Hara (1998) Conversion to Multi-Aged or Multi-Canopied

Managing for Canopy Strata Fewer and longer cutting cycles Management across multiple spatial scales –Need combination of single and multi-layered stands to maximize biodiversity potential

Independant Geomorphology Geology GPM type Mode of deposition Intial static conditions Hydrology Waterways Watershed Topography slope, orientation, altitude Meteorology Temperature, precipitation Climate Climatic zone Non-forested Agricultural land, roads Natural disturbances Dynamic processes Fire Size, Intensity, Frequency Epidemics Size, Intensity, Frequency Windthrow Size Landscape Watershed Stand Scale Stand Watershed Landscape Imposed Status quo Harvesting scenarios Management scenarios Multiple pass Partial cutting Triad Scale Stand Watershed Landscape Constraints expressed in terms of indicators Sustainable forest management SoilsRegenerationBiodiversityAquatic Rotation period, geology, stand type, harvesting method Age structure, composition, configuration, roads, bird monitoring mineral soil, stocking and growth of seedlings, compétition Distance to seed trees, age and species of seed trees % watershed harvested, dissolved P and C, transparency Government standards Forested land Initial dynamic conditions Productive Initial Forest Conditions Poor soils, slow growing species Unproductive Barren, semi-barren, Marginal Modelling elements

Indicators of biodiversity Crit1: Maintenance of ecosystem diversity –Ind1.1: Age structure of the forest (P) –Ind1.2: Forest species composition (P) –Ind1.3: Configuration of the forest (P) Crit2: Maintenance of species diversity –Ind2.1: Road density (P) –Ind2.1: Monitoring bird populations (M)

100 year forest rotation 100 year fire cycle Proposed age class distribution for managed forest Ind1.1: Age class structure

Extended Rotations Mean annual increment Periodic annual increment Stand age Cubic ft./acre/year 0 300

Advantages of extended rotations: Reduced land area in regeneration and early- development stages, hence: 1.Reduced visual impacts 2.Lower regeneration and respacing costs 3.Less need for herbicides, slash burning, etc. 4.Reducing frequency of intense disturbance Large tree and higher-quality wood Adjust precently unbalanced age distributions Higher quality habitat for species associated with late-successional forest structure Hydrologic benefits Increased carbon stock associated with increased net biomass/larger growing stock Preservation of options for future adaptive management

Landscape Management System (LMS)

Simulated landscape based on individual stand structures + important features (e.g. roads, streams, etc.)