Coarse-scale Questions • • • •
Relevance of results Opportunities Constraints What do we need to proceed?
Relevance of Results / Opportunity • Coarse-filter component of biodiversity conservation strategy • Initially thought to be a fixed representative area by seral stage • Program results (rate and size functions) were used in stochastic modelling that led to understanding of: – “temporal age class variability” – range of natural variability
• Application in Forest Management Planning – assess landscapes produced by a harvest schedule against applicable ranges of natural variability
Application… developing natural ranges • Ranges of natural variability (nearly 200) were determined for combinations of: – Natural Subregions • Subalpine, Upper and Lower Foothills
– Geographic areas • 30,000 ha; 60,000 ha; 120,000 ha; 240,000 ha
– Leading Species • spruce, pine, mixedwood, deciduous
– Seral Stages • young, pole, mature, old
• e.g. UF 30k Spruce Old, 3 - 48%
Application… • 18 Upper Foothills Units • Wherever possible coincident with compartments (scheduling units) • aggregates of 30k units form larger units (60k, 120k, 240k)
Natural Variability Units
Application…
developing natural ranges
• Stochastic modelling was used to develop ranges of natural variability for combinations of: – Natural Subregions • Subalpine, Upper and Lower Foothills
– Geographic areas • 30,000 ha; 60,000 ha; 120,000 ha; 240,000 ha
– Leading Species • spruce, pine, mixedwood, deciduous
– Seral Stages • young, pole, mature, old
• e.g. UF 30k Spruce Old, 3 - 48%
Application…
Range of Natural Variability Old Seral Stage - Spruce Upper Foothills 30,000 ha Units 1 0.8 0.6 0.4
Historical Range
0.2
Time (decades) Outside Range
Natural Range
21
19
17
15
13
11
9
7
5
3
0 1
% Spruce Area
• Range represents the historical amount of spruce type in old seral stage • Old spruce varies between 3 and 48% of total spruce area
template for comparison
Application…
Scenario 1 Old Seral Stage - Spruce Upper Foothills 30,000 ha Units 1
Outside natural range 0.8 0.6 0.4 0.2
Time (decades) Outside Range
Natural Range
#1
21
19
17
15
13
11
9
7
5
3
0 1
% Strata Area
• Sample FMP Scenario results show increasing amount of old seral stage spruce • Caused by lack of disturbance in noncontributing area (riparian and low productivity black spruce)
comparing to forecast
Constraints / Considerations • Relationships for stochastic modelling may be difficult to acquire • Management interpretations - how to incorporate range of variability concept into the existing planning process? • Effects of natural range of variability on other resource values – Natural range may result in undesirable hydrologic or aesthetic effects
What do we need to proceed? • Research – refine stochastic modelling approach and data – continue to develop management interpretations
• Planning – latitude to use alternative management interpretations in Forest Management Plans