Treesearch

Investigations on complicated, complex, and not well-ordered systems are possible only with the aid of mathematical methods and electronic data processing. Simulation as a method of operations research is particularly suitable for this purpose. Theoretical and computational foundations of management class simulation must be integrated into the planning systems of forest management and must provide a large number of alternatives for action. A model already in wide use is described.

A computerized tree growth projection system has been developed for the Lake States Region as part of a larger Forest Resources Evaluation Program (FREP). Incorporating data from more than 1500 permanent growth plots throughout the Lake States, this system projects tree growth, mortality, regeneration, and removals in stands with any mixture of tree species and sizes, for the full range of sites encountered in the field. It incorporates the latest published timber management guides for the Lake States. It can identify silvicultural treatment opportunities now and in the future from the...

From the location of a fire lookout and the sites of past fires within a given radius about a lookout, an estimate of the fire distribution with respect to distance from the lookout can be obtained. The estimated distribution can include all fires located within a given number of feet below the last maximum line of sight from the lookout. Seen areas for the same lookout can be developed, stored, and plotted at a computer site for future work.

These Symposium papers cover bases of control, control planning and decisionmaking, control operations and accomplishments, refining and improving control techniques, and pest damage and integrated control. A program summary and a list of literature references on the dwarf mistletoes are included.

The depletion of soil moisture within the surface 7 m by a mixed conifer forest in the Sierra Nevada was measured by the neutron method every 2 weeks during 5 consecutive summers. Soil moisture recharge was measured periodically during the intervening winters. Groundwater fluctuations within the surface 17 m were continuously recorded during the same period.

The method proposed is derived from long experience of intensive management in forest stands of Central Europe and from our proposal for management in virgin Iranian forests of the Caspian Region. The method establishes the need for systematic planning of stand conversion to insure both sustained yield and the harvesting of sufficient timber to sustain economic development. The method also recognizes the need to integrate the planning of silvicultural activities with capital investments in roads and machinery.

Loss of tree root strength after timber cutting is a principal mechanism leading to slope failure and landslides. Measurement of root shear strength changes can be useful in evaluating effects of logging on slope stability. The simple apparatus described measures shear strength directly on roots up to 50 mm diameter. Tests on live roots showed excellent correlation between measurements of shear strength and tensile strength.

A data management system has been developed for storage and retrieval of tree failure and hazard data, with provision for computer analyses and presentation of results in useful tables. This system emphasizes important relationships between tree characteristics, environmental factors, and the resulting hazard. The analysis programs permit easy selection of subsets of data for examination of individual species, sites, and other categories of information. Use of this system allows site managers to control hazard at lower cost to both the site and the budget.

Two mechanical devices that are mainly used to print computer output in text form can simulate pictures of terrain and forests. The line printer, which is available for batch processing at many computer installations, can approximate halftones by using overstruck characters to produce successively larger "dots." The printer/plotter, which is normally used as an interactive terminal, permits fine adjustment of the space between characters in the plot mode. This control over blank space improves tonal appearance and permits solid black. The two types of printers have complementary uses. The...