A Comparison of Wood Properties of Coastal and Interior Provenances of Lodgepole Pine Pinus contorta Dougl. ex Loud

At the Millbuie Lodgepole pine intensive provenance plots incrementborings were extracted at similar fractional heights in treesof a central Interior and a southern Coastal provenance andthe properties of the same five growth-rings were compared.Scanning microphotometry was used to measure ring width, percent earlywood, and earlywood density. Tracheid length and width,nominal density, and latewood density were also determined.For each of these wood properties significant differences werefound between the average values for the two provenances. Inthe Coastal provenance nominal density was about 20 per centhigher than in the Interior provenance, the incidence of compressionwood was much higher, but tracheid length was about 20 per centshorter. The probable effects of these results on the propertiesof sawn timber and pulp are discussed. Average tree heightsand diameters were similar, and the earlier growth of the treeswas analysed. The relation between nominal density and ringwidth (vigour) was investigated, and a low correlation (r² of0·054 and 0·17) was found between the two quantities.Furthermore the regression lines show density decreasing slowlywith increased ring width. Both these results are in contrastwith published results for Sitka spruce.     

PHOTOLYSIS OF FLUORODIFEN

Summary. A dry film or p. -nitrophenyl-α,α,α:-trifluoro-2-nitro-2-tolyl ether (fluorodifen) decomposed rapidly under ultraviolet (2537 run) irradiation in the laboratory. Photolysis under growth chamber lights was slower. One major photolysis product (probably a polymer of fluorodifen) and several minor products were detected.
Photolyse du flurodifene
Résumé. Un film sec de p -nitrophényl-α,α,α-trifluoro-2-nitro- p -tolyl äther (fluorodifènc) a été rapidement décomposé sous une irradiation dans l'ultra-violet (253,7 nm) au laboratoire. La photolyse sous l'éclairage des chambres elimatisées fut plus lente. Un produit important de la photolyse (probablement un polyméie du fluorodiféne) et plusieurs produits secondaires ont été détectés.
Photolyse von Fluorodifen
Zusammenfassung. Ein trockener Film von p -Nitrophenyl-α,α,α-trifiuor-2-nitro- p -tolyläther (Fluorodifen) zersetzte sich im Laboratorium schnell bei Bestrahlung mit ultraviolettem Licht (253,7 nm). Unter Klimakammerlampen war die Photolyse lang-samer. Es konnten ein Hauptprodukt der Photolyse (wahrscheinlich ein Polymer von Fluorodifen) sowie mehrere Nebenprodukte festgestellt werden.     

Problems in Monocultures

In the author's opinion, modern farm management techniques compel a critical evaluation of established concepts of the use of rotations in arable farming as rapid changes have put many formerly accepted reasons for their use in doubt. From literature, examples are cited which show clearly that monocultures of cereals, or cereals grown in narrow rotations, can attain economically acceptable yield levels. From his own personal work in this field the author cites results which demonstrate that with adequate husbandry techniques, even monocultures of wheat can reach normal yields. In the conclusion, the need for close co-operation between specialists in order to obtain results, which can be applied to a wider scale of farming conditions, is stressed.