Treesearch

Twenty-nine percent of motorists interviewed in an area where smoking was restricted were misinformed about, or didn't know of, the regulation prohibiting smoking while traveling. Familiarity with the regulation was related to whether the motorist smoked, frequency of use of the area, and place of residence. It was not related to the age and sex of the respondents.

The impact and recall value of a set of regularly used U.S. Forest Service fire prevention signs were compared with that of a set of improvised signs by interviews with typical forest users. The improvised signs generated a substantially greater impact. Although the regular signs have had past exposure to the general public, they demonstrated no significant difference from the experimental signs in the test of recall.

Patterns of susceptibility of pines to attack by certain species of Dendroctonus bark beetles suggest that a resistance mechanism exists. This situation was first called to my attention in 1949 by John M. Miller, entomologist at the Berkeley Forest Insect Laboratory. He was studying the resistance of pines to insects, at the Institute of Forest Genetics near Placerville, California. Miller worked closely with N. T. Mirov, who was studying differences in the volatile constituents of wood oleoresins of pine species. Miller, as others had suggested before, felt that differences in oleoresin...

Very little information has been reported on the time of pollen shedding of the many pines and firs native to Mexico and northern Central America. This kind of information is necessary for any breeding operation, and is often of considerable taxonomic and evolutionary interest as well. An example is the difference in pollination time of a month to six weeks between Pinus radiata D. Don and P. attenuata Lemmon, two closely related closed-cone pines native to California. This difference is a reliable means of distinguishing the two species, and is also the principal mechanism that limits...

Sequential sampling based on a negative binomial distribution of ribes populations required less than half the time taken by regular systematic line transect sampling in a comparison test. It gave the same control decision as the regular method in 9 of 13 field trials. A computer program that permits sequential plans to be built readily for other white pine regions is described.

Describes the climatic, edaphic, physiographic, and biotic habitat conditions of the natural range of bigcone Douglas-fir (Pseudotsuga macrocarpa [Vasey] Mayr) and how this tree reproduces, grows, and dies.

A major improvement and extension of the Map Information Assembly and Display System (MIADS) developed in 1964 is described. Basic principles remain unchanged, but the computer programs have been expanded and rewritten for a large computer, in Fortran IV and MAP languages. The code system is extended from 99 integers to about 2,200 alphanumeric 2-character codes. Hand-coding is reduced, and job preparation simplified. Total cost of using MIADS2 is about the same as that of using MIADS.

An anatomical study of ovule and conelet development was made on about 200 developing conelets in a plantation in the central Sierra Nevada of California, after an unseasonal April frost. Night temperatures as low as -6° C. were recorded. Conelets in pollination bags were most susceptible to cold damage; emerging conelets were the most badly damaged; conelets at maximum were only slightly damaged. Low temperatures did not affect final seed set of the surviving cones.

Aerial color photographs were taken at two scales over ash stands in New York State that were infected with ash dieback. Three photo interpreters then attempted to distinguish ash trees from other hardwoods and classify their disease condition. The scale of 1:7,920 was too small to permit accurate identification, but accuracy at the scale 1:1,584 was fair (60 to 70 percent) and disease classification was good (77 to 80 percent). Errors in identifying other species as ash were too numerous. Frequency of attack by ash dieback was positively correlated to increased diameter at breast height.

Immature sugar pine seeds were collected and ripened either in the cone or in moist vermiculate. Seeds collected before the second week of August could not be artificially ripened and the causes for these failures were investigated. After the second week of August, immature seeds could be brought to maturity. A practical method for a commercial operation should be possible.