Land and Watershed Management

Genetic and Silvicultural Foundations for Management

Selected Studies

Tips to Consider in Applying Variable Density Management

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1. In the past, one funding source may have paid for a project that had benefits to more than one resource area. With declining budgets that may be less feasible. If projects have multiple benefits, consider if it is possible to use multiple funding sources or people from different resource areas to help in accomplishing the work. This approach will be most successful if involvement by others is initiated early in the planning stages.

2. It may be possible to add heterogeneity to a unit without spending a lot of extra time on planning or layout if you use a combination of uniform methods and methods which increase random assignment of treatment. For example, varying size of opening to be created or species to be planted could be done by pacing on a grid and then at the grid point shaking dice, pulling tokens out of a pocket, or using a handheld computer to select treatment size, shape, or species. We have successfully done this operationally with several people involved and it worked very well.

3. If there will be more than one thinning entry into the stand, the first entry might be keyed into laying out openings on N:S lines and the next entry on E:W lines. Although it is important to reuse roads and landings, it may still be possible to add variation into a treatment just by deliberately changing the orientation of treatment layouts.

4. When consistent with the project objectives, consider ways to vary spacing or species without a lot of pre-planning. For example, it may be possible to give some members of a crew marking trees for a timber sale different marking guidelines from others or give tree planters different mixes of species in the planting bag. Rather than vary the size of openings (or spacing for a thinning) within a particular project, another approach would be to select one size opening (or spacing) for each project but vary the target from project to project so each one was internally consistent. If you keep prescriptions for small areas fairly simple it may help minimize the effort involved in setting up and monitoring contracts.

5. It has been suggested that you can vary prescriptions by using easy ways to break up a unit. For example, if you know about how many trees can be painted with a can of paint, it may be possible to develop guidelines for in-house crews such as "mark this area to spacing X by X until the can you are using runs out, then switch to another spacing or add openings". Or "mark using this prescription or guideline until noon, then switch to this one". Although this approach to project layout takes getting used to, it may be a cost-effective way to increase variability in on-the-ground activities without a lot of detailed planning.

6. Or, instead of using arbitrary breaks such as a paint can or time for lunch, consider using natural breaks such as streams, ridges or roads to delineate units for a treatment or portion of a treatment. This will allow the area of the treated unit to be determined without additional measurement.

7. When planning variable treatments such as openings within a stand, plan to use round areas as much as possible as they are much easier for one person to lay out in the field.

8. Don't underestimate employees or contractors, many can accomplish multiple tasks on a site so different parts of a project don't have to be laid out or contracted differently. This may initially take some training, field trips, extra work with people or just a different way of thinking about a project. It is important to explain the purpose of the job rather than concentrate on specifications.

9. Consider using simple flagging codes for projects with different aspects so that for example, the type of flagging (solid vs. striped vs. dotted) means one thing and the color means something else. We used this on a project where the type of flagging indicated the size of the opening to be created and the color indicated which species or group of species was to be planted.

10. Consider how the use of new technology and tools might increase efficiency. For example, it may be possible to use low elevation photography or GPS to identify possible cut or leave spots on one field visit, then decide in the office how many, what size, or which ones to select and produce a map in GIS. This might be much more efficient than using one field visit to look at the area, then plan in the office, followed by another field visit to flag areas, and then hand-draw maps of locations.

11. Stratify the cruise needed to determine the volume to be offered in a timber sale by the types of prescriptions used. Consider if areas which represent a small portion of the likely volume need to have the same accuracy as areas which represent a larger portion (depending on your employer, there may not be much flexibility in how the cruising work is done).
    

12. Consider if centers of activities rather than boundaries can be flagged. Or even if they have to be marked on the ground or if marking on a map or photo would be sufficient.

13. Be prepared for the people who will be implementing the work not to understand what you want done when it is a new job. Consider setting up a demonstration area or mark a small portion of the area with more flagging/paint/string than usual to make your intentions clear.
    

14. Use as many information sources as possible when starting new practices. Talking with co-workers, going to workshops and on tours, reading technical publications and newsletters, and surfing the internet can all be productive ways to add to your information base.
    

USDA Forest Service - GenSilv Team
Last Modified: Wednesday, 14 March 2012 at 21:39:03 EDT