Showing papers by "Forest Research Institute published in 1973"

Resistance of Paeonia cultivars to Cronartium flaccidum in Norway

Abstract: Cultivars of Paeonia differed widely in their resistance to Cronartium flaccidum in Norway; ‘Globe of Light’ and ‘Noemie Demay’ were found to be immune. The practical importance for silviculture and horticulture is discussed.

Demonstration of the applicability of satellite data to forestry

Abstract: The author has identified the following significant results. The experiments made with aerial photos and satellite pictures showed that there are distinct correlations between tone values of satellite pictures and the volume of forest growing stock. Field work is regarded as necessary in order to draw more detailed conclusions.

Bark Beetle Pheromones and their Potential Use in Forestry

Abstract: During the last decade our knowledge about the pheromones in bark beetles has been considerably increased due to research carried out in the United States. This paper outlines our present knowledge of pheromones in Dendroctonus species in North America and in Ips species in North America and Europe, based on information from the literature and on the author's studies with a research group in the USA. The pheromones in several species are mentioned and results are described on the practical use of synthetic compounds in forestry based on reports from field experiments in Texas and California. Summary The reasons behind the aggregation of large numbers of bark beetles on selected trees have always been of major interest to forest entomologists. The research on pheromones in recent years has elucidated the phenomenon and brought new aspects to light. Most of the work has been centred on species of the genera Ips and Dendroctonus which include the most aggressive beetles. Dendroctonus belongs to the Western Hemisphere, whereas Ips species can be found all over the Northern Hemisphere in America as well as in Eurasia. Pheromone compounds from several species have been isolated and identified and also synthesized. These synthetic products are used for the control of Dendroctonus in many parts of the United States. The attractive material is concentrated in the hindgut before or during the initiation of gallery construction. Bark beetle pheromones are associated with the alimentary system, and not with the reproductive apparatus as is usually true of sex attrac-tants in Lepidoptera. Two distinct functional types of pheromones seem to regulate aggregation among bark beetles: contact pheromones, produced and released upon contact with new host material; and frass pheromones, which require actual feeding in the new host's tissue. The aggregation of aggressive bark beetle species appears to be largely dependent on contact pheromones, whereas the host's suitability as food is indicated by the release of frass pheromones. In Dendroctonus species, six different pheromones have been isolated, identified, and synthesized. The synthetics have been studied in field bioassay and their biological significance has been investigated. In Ips species, four different pheromones have been identified. Gas chromatographic analyses of the European species I. sexdentatus, I. acuminatus, and I. typographies indicate that the same major pheromones are present in North American and European species, and are also common to many Ips species. Several field experiments in the Western and Southern United States indicate that synthetic compounds may be of great practical importance to forestry, but further work has to be done to develop methods for each single species according to their specific pheromones and behaviour. Resume Pheromones produites par les scolytides et possibilites d'utilisation en sylviculture Les rassemblements massifs de scolytides sur certains arbres ont toujours intrigue les entomologistes forestiers qui se sont efforces d'en deceler la cause. Ces dernieres annees, des recherches sur les pheromones ont apporte l'explication de ce phenomene tout en faisant ressortir de nouveaux elements. Les travaux ont porte notamment sur les genres Ips et Dendroctonus, qui component les especes les plus agressives. Dendroctonus est infeodea l'hemisphere occidental tandis que Ips se trouve partout dans l'hemisphere septentrional, en Amerique aussi bien qu'en Eurasie. Des pheromones composees, produites par plusieurs especes, ont pu etre isolees et identifiees, voire synthetisees. Ces produits synthetiques sont employes pour la lutte contre Dendroctonus dans beaucoup de regions des Etats-Unis. Les composes attractifs se concentrent dans la partie posterieure du tube digestif quand les coleopteres commencent a creuser leurs galeries. Les pheromones des scolytides sont en rapport avec les organes digestifs et non, comme cela se produit le plus souvent pour les attractifs sexuels des lepidopteres, avec les organes de reproduction. II apparait que deux types differents de pheromones regissent le rassemblement des scolytides: les pheromones de contact, produites et repandues quand les coleopteres rencontrent un nouveau specimen de la plante-hote, et les pheromones d'ingestion, engendrees seulement si le ravageur se nourrit des tissus de la nouvelle plante-hote. Le rassemblement des especes agressives de scolytides est largement lie aux pheromones de contact, tandis que la liberation de pheromones d'ingestion indique l'aptitude de l'hote a servir de nourriture. En ce qui concerne les especes de Dendroctonus, six pheromones differentes ont ete isolees, identifiees et synthetisees. Les composes synthetiques ont fait l'objet d'essais de plein champ et leur importance biologique a eteetudiee. Pour les especes d'Ips, quatre pheromones differentes ont ete identifiees. Des analyses de chromatographie en phase gazeuse portant sur les especes europeennes I. sexdentatus (Boerner), I. acuminatus Gyll. et I typographus L. ont fait ressortir que les memes pheromones principales se retrouvent dans les especes europeennes comme dans celles d'Amerique du Nord, et que leur presence est assez generale dans beaucoup d'especes d'Ips. Plusieurs experiences americaines menees dans les Etats de l'Ouest et du Sud ont indique que les composes synthetiques presentent une grande importance pratique pour la sylviculture; toutefois, les recherches doivent etre poursuivies afin d'elaborer des methodes particulieres pour chaque espece en tenant compte de ses pheromones specifiques ainsi que de son comportement.

Inhibitor levels associated with growth in seedlings of pinus radiata

Abstract: SUMMARY The conditioning of Pinus radiata D. Don seedlings to withstand transplanting stress involves the use of a mechanical root undercutting technique. Using the Avena coleoptile bioassay the differences in hormone levels in acidic extracts of the shoots and roots of conditioned and control seedlings were determined. Conditioned seedlings had roots with higher relative growth rates and lower levels of inhibitors per unit of root weight than non-conditioned seedlings.

Are the Present European Phytosanitary Regulations in Forestry Satisfactory

Abstract: The pathogens which present the greatest potential dangers to European and Mediterranean forest trees are mainly to be found in remote areas such as those parts of the American continent and East Asia where the climate and tree species are similar to those in Europe. In general, inspections are not sufficient to guarantee that a consignment is free from known, and especially from unknown, pathogens. Phytosanitary regulations should therefore be based on the prohibition of the importation of living plants (not seeds). The prohibition of the importation of all conifers (not seeds) from all countries outside Europe and the Mediterranean area is proposed. All European and Mediterranean countries should agree upon effective and co-ordinated phytosanitary regulations.

A procedure for parameterizing a constraint in linear programming

Abstract: A post-optimal procedure for parameterizing a constraint in linear programming is proposed. In the derivation of the procedure, the technique of pivotal operations (Jordan eliminations) is applied. The procedure is compared to another by Orchard-Hays [2], and a numerical example of the procedure is provided.