Eucalyptus populnea shrub woodlands. Control of regenerating trees and shrubs

In a Eucalyptus populnae shrub woodland, trees and shrubs more than 60 cm tall were killed by stem injections or basal stem applications of chemicals. Moody plants regenerated from seed following treatment of the original stand but numbers were fewer on plots sown to introduced grasses than on those sown to annual medics or left unsown. Intermittent heavy grazing with sheep controlled seedling regeneration of all woody species except the dominant tree, Eucalyptus populnae, and an unpalatable shrub, Pimelea pauciflora. After two years only 5 per cent (50 ha-1) of the trees and shrubs present at the commencement of grazing survived on plots sown to grasses and grazed intermittently by sheep. Burning two years after the application of the initial treatments reduced the number per hectare of the three most abundant shrubs, Eremophila mitchellii, Cassia nemophila, and Dodonaea viscosa, on ungrazed plots from 3665 to 90 ; the total number of trees was reduced from 4017 to 119 per hectare. Grazing after burning reduced shrub density to 55 per hectare. The results indicate the significance of heavy intermittent grazing by sheep for controlling shrubs that regenerate following thinning of Eucalyptus populnae shrub woodlands.

Herbage reponse to tree and shrub thinning in Eucalyptus populnea shrub woodlands

Effects of tree and shrub densities on production of native grasses and herbs in woodlands dominated by Eucalyptus populnea were investigated in two experiments. Densities were controlled experimentally by selectively killing individual trees and shrubs with chemical compounds. In an experiment in which girdling or ring barking was compared with chemical treatment, the herbage response was more rapid and of greater magnitude on plots treated chemically. Throughout the experiment the herbage biomass was always highest on chemically treated and lowest on untreated plots. The highest dry weight of herbage from areas in which trees were chemically treated was 2600 kg/ha; comparable yields from ring barked and untreated areas were 1540 and 820 kg/ha respectively. In a second experiment, living trees and shrubs were reduced to several density levels by chemical thinning. Herbage biomass fluctuated with season and with rainfall, but the relationship between herbage weight and woody plant density consistently had the same form and closely fitted a transition sigmoid curve. Trees had a greater effect than shrubs on herbage production: limits for maximum herbage biomass were 2–6 and 360 per hectare respectively. Practical implications of the findings for the management of E. populnea woodlands are discussed.

Pain and distraction in athletes and non-athletes

48 female Ss were divided into an athletic and a non-athletic group for the purpose of ascertaining differences on the parameters of pain threshold, pain tolerance, distracted pain tolerance, neuromuscular skill, and distracted neuromuscular skill. Distraction failed to raise tolerance to pain, although pain adversely affected the skill performance of both groups. Athletes demonstrated a higher pain tolerance than did non-athletes.

Behavioural science teaching and examining for postgraduate students in Glasgow

A course in behavioural science for the Diploma in Public Health at Glasgow University is described with details of the three parts of the course. The introduction of alternative choice questions is mentioned, together with some assessment of both essay and alternative choice methods of examining. A shortened version of this course in medical sociology and social and applied psychology has also been given to a day release course for Medical Officers of Health.

Absence from work in relation to length and distribution of shift hours

Walker, J., and de la Mare, Gwynneth (1971). Brit. J. industr. Med., 28, 36-44. Absence from work in relation to length and distribution of shift hours. A long period on night shift or even permanent night work has sometimes been suggested for those on continuous shift work to allow circadian rhythms to adapt. As the weekly hours of work have been reduced there is some evidence that a permanent night shift is practical, and about 12% of all shift workers are on this type of work. However, the case for permanent night shift must be established on grounds of both effectiveness and acceptability. The present study compares the absence experience, including sickness absence, of permanent day workers and permanent night workers matched for age and job in three undertakings which contained a range of working conditions. The question of the relationship between absence from work and total hours worked including overtime has been reopened, and in comparing absence from work according to the type of shift the total hours worked must also be taken into account. The relationship between the average hours when a man was at work and the amount of absence was tested. The men in the three undertakings worked a wide range of voluntary overtime. The results showed that in two undertakings long-term absence, mainly sickness absence, was higher on the night shift than on the day shift; and, in the third, absence was about the same on the two shifts. As the work load was less in the two undertakings with a higher absence on the night shift it was suggested that selective factors were operating. These results may be contrasted to studies which have compared the absence of rotating shift workers and day workers. In all three undertakings there was a tendency for absence to be less among high overtime workers than among those who worked medium or small amounts of overtime, although the trends were not consistent. There was no evidence at all that high overtime and absence from work were positively associated. The implications of these results are discussed.