Treesearch

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...

Alternative futures planning is a generic name for a number of planning approaches which recognize that the future is uncertain. There is not one future, preordained and universally known, but rather a variety of possible futures, any one of which may occur. Mystic Mountain is an educational game which teaches wildland planners and managers important concepts in alternative futures planning while they attempt to manage a hypothetical national forest for 75 years. It combines education and fun in a few hours of playing time.

These 14 papers were submitted to a conference of Project Group P4.07 Division IV, International Union of Forestry Research Organizations. Topics discussed included the uses of simulations, analytical techniques, and mathematical programming techniques in land management planning, reforestation programs, intensive forestry, timber management and production, tree growth, wood transportation, and budgeting.

Two insects molt inhibitors, TH6038 N-[[4-cholorphenyl)amino]carbonyl]-2,6-dichlorobenzamide) and difluron (N-[[(4-chlorophenyl)amino]carbonyl]-2,6-difluorobenzamide), were tested for topical and feeding toxicity to the western spruce budworm, Choristoneura occidentalis Freeman, and the Douglas-fir tussock moth, Orgyia pseudotsugata (McDonnough). Both compounds showed little topical activity, but both were quite toxic when fed to insects in artificial diet. Difluron was most active when fed to early instars of both species. Difluron sprayed on Douglas-fir seedlings showed substantial...

Selected carbamate, chlorinated hydrocarbon, organophosphorous, and pyrethroid insecticides were tested on six Choristoneura species: conflictana (Walker), fumiferana (Clemens), lambertiana ponderosana Obraztsov, occidentalis Freeman, pinus Freeman, and virdis Freeman. When probit regression lines were compared by likelihood ration tests, the hypothesis of equality was uniformly rejected. The hypothesis of parallelism was accepted for some chemicals within each insecticide class except the chlorinated hydrocarbon. These results suggest that extrapolating the response of one species to...

Codes for automatic data processing (ADP) are provided for hazardous tree failure data submitted on Report of Tree Failure forms. Definitions of data items and suggestions for interpreting ambiguously worded reports are also included. The manual is intended to insure the production of accurate and consistent punched ADP cards which are used in transfer of the data to magnetic tapes. The codes and card format specified are compatible with the computer processing and analysis pro-grams provided in a user's guide, General Technical Report PSW-24. The guide covers use of the codes to specify...