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Danger Tree Mitigation Guidelines for Managers


Blasting, mechanical felling, and manual felling all are useful methods for mitigating danger trees. Each method has advantages and disadvantages.

Due to cost and efficiency, blasting usually is employed only when other mitigation methods cannot safely be used.

Mechanized equipment can treat large areas quickly, but may not be cost effective for smaller jobs. Mechanized equipment use also results in less overall exposure to the hazards associated with work under and around danger trees. Mechanized equipment usually is operated by only one person and can be outfitted with features designed to protect the operator from falling objects.

Using chain saws to fell danger trees often is the most convenient mitigation method, especially for smaller jobs. Most national forests have a workforce of trained sawyers. Felling with sawyers is considerably slower than felling with mechanized equipment. Felling also increases overall exposure to danger trees for more people over longer periods of time. Manual felling is the only mitigation method that requires a worker to be standing next to the tree as it starts to fall.

Variables such as worker safety; forest conditions; availability of equipment, workers, or contractors; expected results; available funding; job size; location; and proximity to a forest products mill are factors that help managers determine the best mitigation method. Correctly matching a mitigation method to a danger tree situation can increase employee safety, improve project results, and increase cost efficiency. Table 3 compares production rates, estimated costs, and associated variables for each mitigation method.

Safety considerations, such as operator proficiency, communication consistency, and familiarity with local terrain, will increase the safety of employees mitigating danger trees.

Table 3—Expected Production Rates, Estimated Costs, and Production/Cost Variables of Danger Tree Mitigation Methods and Techniques.
  Production Rates Estimated Costs Variables
Blasting 1 to 3 trees per hour when blasting single trees $100 to $2,000 per tree Pay level, number of guards required, when blasting single amount and types of explosives, tree trees complexity and location, and terrain
Mechanical Felling 3 to 4 acres per day $3,000 to $5,000 per day Tree size, species, and stand density; ground conditions; cutting prescription; job size; slope; site access; and transportation of felling machines
Mechanical Mulching 2 to 4 acres per day $300 to $500 per acre Type of mulching machine, stand density, tree size and species, site conditions, and desired size and distribution of mulch
Mechanical Crushing 2 to 4 acres per day $150 to $200 per acre Terrain type, tree size and species, and stand density
Mechanical Pushing, Toppling, and Grubbing 2 to 4 acres per day Less than $200 per acre Site access, machine size, rooting pattern and mass, other subsurface variables, and tree size species, age and condition
Manual Felling About 30 (12-inch d.b.h.) trees per day for each sawyer About $2,000 per 100 trees, which includes felling, bucking, piling, and burning Tree complexity and size, terrain type, weather conditions, sawyer experience, season, and whether the trees must be felled in a specific direction
Avoidance N/A Signage and closure enforcement as needed N/A