You can readily identify low priority sites by determining which areas are not feasible to treat. These include areas that are so steep and/or inaccessible that treatments would be excessively difficult and expensive. Areas that are not practical to treat can be removed from further consideration.
Among sites that could be treated, the ease of treatment and likelihood of obtaining acceptable levels of disease control will vary due to the factors shown in table 2-7. By assessing these factors, you should be able to rank potential sites based on their overall SOD management opportunities.
Table 2-7—Prioritization matrix: Factors to consider when prioritizing stands for SOD management activities
| Category | Factors | Priority for management action | |
|---|---|---|---|
|
|
High Priority | Low Priority |
Management |
Ease of access for treatment (slope, roads, etc) |
Near level |
Excessively steep |
Adjacent to roads |
No road access |
||
Position of treatment area |
A rea is discrete unit, little or no likely contribution of inoculum from adjacent areas beyond treated zone |
Area is adjacent to areas that cannot be treated |
|
SOD impact stage |
No or low percentage of trees with cankers or SOD mortality |
High percentage of trees dead or with severe SOD symptoms |
|
Relative cost of treatment |
Low cost per unit treated |
High cost per unit treated |
|
Overall likelihood of success |
L ikely to be successful due to combination of favorable site and/or logistical factors |
Low probability of success due to difficult site and/or logistical factors |
|
California bay presence/density/sizeclasses |
Bays mostly understory saplings and small trees |
Bays are large overstory trees |
|
Bays are low percentage of total tree cover |
Bays are majority of tree cover |
||
California bay continuity |
Bay distribution discontinuous in local area or could be made discontinuous with limited tree removal |
Continuous bay distribution over large area, little or no possibility of creating significant gaps in distribution |
|
Disease Risk: |
California bay density |
Low to moderate density in overstory and/or understory |
None present within stand |
Proximity to known P. ramorum infestations |
P. ramorum present in stand |
Nearest known P. ramorum at least 8-16 km (5-10 mi) away |
|
Risk of pathogen introduction (if not present) |
High number of visitors and vehicles |
Infrequently used site |
|
Climate / microclimate conditions |
Wet -rainy, foggy, north facing slope, dense tree canopy |
Dry - fog uncommon, south facing slope, open canopy |
|
|
Tree variables |
Large, dominant, vigorous trees with thick, expanding bark (bark fissures with brown, unweathered tissue) |
Small, overtopped/suppressed, and/or water- stressed trees with thin bark, slow bark expansion (bark fissures weathered and grayish) |
Resource benefits: |
Stand condition without SOD |
Sustainable stand, trees mostly fair to good condition |
Stand declining due to other factors |
Stand uniqueness |
Stand unusual due to species composition, age structure |
Widespread and common stand type |
|
Historical / cultural value |
Significant trees or stand |
No special significance |
|
Aesthetic /amenity/ visual values |
Significant scenic resource |
Stand not within a viewshed |
|
Strongly contributes to property value |
Low or no specific contribution to property value |
||
Serves as visual buffer (e.g., screening, privacy) |
No visual buffer effects |
||
Habitat value |
Essential or preferred habitat of rare or special status species. |
Unsuitable habitat for rare or special status species, none present. |
|
Important habitat for other locally significant or desirable species |
Poor habitat quality for species of interest |
||
Special habitat features/areas present (e.g., riparian, wetland, old growth, unique soils) |
No special habitat features |
||
High native species biodiversity |
Low native biodiversity (e.g., highly disturbed site) |
||
Important corridor or connection between different habitats |
Doesn't function as corridor (e.g., isolated forest fragment) |
||
Soil stability and water quality |
SOD-susceptible species in critical location providing slope stability / erosion protection |
SOD-susceptible species not important contributors to soil stability at site |
|
SOD-susceptible species present along watercourse and providing important bank stabilization |
SOD-susceptible species not near watercourse or don't contribute to bank stability |
||
SOD-related liabilities |
Hazards posed by infected and dead trees to persons and properties |
Failures would affect occupied structures |
Not near structures |
Failures would affect heavily used roads or trails |
Not near roads or trails |
||
Failures would affect other built infrastructure (utility lines, drainage structures, etc) |
Not near infrastructure |
||
Contribution to fire hazard |
Defensible space fire hazard significantly increased by fuels associated with dead standing or down trees |
SOD-related mortality poses little or no change to overall fire hazard within or near defensible space |
|
Conversion to exotic-dominated or other undesirable vegetation type |
Highly susceptible to invasion by undesirable exotics |
Invasion by exotics unlikely |
|
Gaps likely to be converted to undesirable vegetation type |
No undesirable changes likely due to species mix and small or no gaps |
||
Assessing factors that influence SOD risk can help you determine which sites to prioritize for treatment. If the risk that SOD will develop in a given stand is small, that stand will have a very low priority for SOD management activities. Disease risk may change over time as conditions change, so priority rankings based on disease risk need to be reevaluated periodically.
Sites with at-risk SOD canker hosts can be prioritized by considering the various ecosystem services they provide. Highest priority sites provide the most important benefits and values. Table 2-7 lists a number of potential factors to consider. To develop a list that matches your management objectives and interests, add or delete items from table 2-7 and adjust the definitions of the high and low priority categories. The weight of factors can also be shifted.
The presence of many SOD-killed trees on a landscape may pose a number of hazards. Consider the degree to which you can avoid these hazards by preventing or minimizing SOD-related mortality when prioritizing sites for treatment.
For large parcels, data from maps or GIS databases may be used to identify sites that can be eliminated from consideration (e.g., inaccessible areas) or to identify areas to examined in detail (e.g., significant areas with uncertain vegetation composition). Targeted surveys or observations may be used to obtain information needed to assess priority (e.g., the amount of SOD present).