Citations of plenary-session articles published in the Proceedings of the International Symposium on Veterinary Epidemiology and Economics

We measured the potential impact of articles representing the International Symposium on Veterinary Epidemiology and Economics (ISVEE) plenary-session presentations in subsequent published literature. Between July 1, 2004 and November 9, 2004, we searched the Web of Science for citations in the scientific literature to all 99 plenary-session articles published in the proceedings of the previous nine ISVEEs (or in journal special issues dedicated to the ISVEE plenary articles). We used a 4-year window around the publication of each of the ISVEE proceedings. We located 187 citations for 37 (of the 99) articles. We infer that the ISVEE proceedings represent an important resource for veterinary epidemiology.     

Regeneration of timber trees in a logged tropical forest in North Bolivia

For sustainable forest management, it is important to know the response of timber species to the change in environment caused by logging. We performed a 2-year study on germination, survival and growth of four timber species, Cedrela odorata, Swietenia macrophylla, Hymenaea courbaril, and Cariniana micrantha, and one non-commercial species Tachigali vasquezii. We sowed seeds of these species in five microenvironments: log landing, gap-crown and gap-trunk, skidder trail and understory, in a tropical lowland moist rain forest in northern Bolivia. We related seed and seedling performance to light availability, soil compaction, and plant competition. Germination did not differ significantly between microenvironments but survival of germinated seeds for most species was significantly higher (P < 0.05) in the log landing (46–100%) than in the understory (0–7%). After 2 years, the tallest plants were always found in the log landing (119–190 cm) and the smallest in the understory (12–26 cm) caused by a higher relative height growth rate (RHGR) in the log landing (0.003–0.004 cm cm⁻¹ per day) compared to the understory (0.000–0.001 cm cm⁻¹ per day). During the first year RHGR was positively related to canopy openness for all species and negatively to the number of overtopping competitors for three species. During the second year also water infiltration explained observed variation to RHGR. These results show that abandoned log landings and logging gaps are suitable environments for the regeneration of timber species studied. This finding suggests that the removal of competitors in log landings and logging gaps combined with leaving seed trees near these microenvironments or sowing seeds, will improve regeneration of timber species in tropical forests.     

Conservation value of dispersed tree cover threatened by pasture management

Trees dispersed in pastures are a prominent feature of many Central American landscapes, particularly in cattle producing regions where farmers retain trees to serve as shade, fodder, timber and firewood. The presence of dispersed trees in pastures is often considered as important for the conservation of biodiversity by providing habitat and enhancing landscape connectivity. However, despite their critical productive and environmental roles, little is known about tree distribution within pastures or how farmers’ management decisions influence the trees themselves and their impact on farm productivity and biodiversity conservation. Here, we present a synthesis of (a) the abundance, composition, and size of dispersed trees in four important cattle producing regions of Costa Rica (Caňas and Río Frío) and Nicaragua (Rivas and Matiguás), based on inventory of 18,669 trees on 1492 ha of pasture, (b) the local knowledge, management and use of trees by cattle farmers, and (c) opportunities for ensuring sustainable management of dispersed trees in pasture-dominated landscapes. Dispersed trees were common in all four landscapes, with mean frequency ranging from 8.0 trees ha⁻¹ in Caňas to 33.4 trees ha⁻¹ in Matiguás. A total of 255 tree species were found in pastures across the four landscapes. The total number of tree species per landscape varied from 72 in Rivas to 101 in Caňas and Rio Frio, with mean species richness per farm ranging from 22.9 in Rio Frio to 45.9 in Matiguás. In all four landscapes, a handful of tree species dominated the pastures, with the ten most abundant species in each landscape accounting for >70% of all trees recorded. Most of these common tree species provide fruits or foliage eaten by cattle, or are important timber or firewood species, and are deliberately retained by farmers for these uses. In all four landscapes, farmers had a detailed knowledge of tree attributes affecting pasture and animal productivity, and influenced tree cover through pasture management activities and occasional tree cutting. Current farm management practices are gradually decreasing the diversity of trees in pastures, and in some cases also tree density, reducing their contribution to farm productivity and biodiversity conservation. To reverse this trend, incentives are required to encourage cattle farmers to retain and enhance tree cover in pastures, through the adoption of pasture management practices that favor the regeneration and persistence of a diverse range of tree species.     

Parasitisme chez la vigne et consequences oenologiques

Sans résumé     

Sur quelques huiles essentielles nouvelles ou peu connues

Conclusions Douze essences sont étudiées, l'une, connue, celle de Vergerette du Canada et les autres, nouvelles. Les constituants principaux sont des terpènes, sauf pourNepeta mussini (alcool) etScrophularia lucida (cétone). Le terpène dominant, surtout dans les huiles essentielles de Composées, est l'-pinène droit; dans cette famille botanique, j'ai relevé deux fois (Phagnalon sordidum etCota tinctoria), la présence d'un sesquiterpène azulénogène, tel qu'on les trouve surtout dans l'absolue de Camomille romaine. L'acide valérianique, le plus souvent sous la forme combinée, est d'occurrence à peu près constante.Les méthyl-heptyl-cétone et méthyl-nonyl-cétone qui n'avaient guère été signalées que dans les essences de Rue ont été détectées, la première chezScrophularia lucida, la seconde chezAristolochia clematitis, plantes aussi éloignées botaniquement qu'elles le sont, l'une et l'autre, desRuta. Dans deux huiles essentielles, j'ai indiqué l'abondance de paraffines et, dans l'une d'elles, conjointement, celle de résines.

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On some new or less known essential oils

Summary The author gives the chemical and physical characteristics of the essential oils in the following plants:Erigeron canadensis, Phagnalon sordidum, Pulicaria dysenterica, Filaga spathulata, Achillea ageratum, Cota (Anthemis) tinctoria, Senecio erucifolius, Catanche coerulea, Salvia grahami. Nepeta mussini, Scrophularia lucida, Aristolochia clematitis. With the exception ofNepeta mussini (alcohol) andScrophularia lucida (cétone) terpenes are theprincipal constituents. The dominating terpene in the essential oils of the Compositae is the right pinene. Twice in this family, inPhagnalon sordidum and inCota tinctoria, the presence of a sesquiterpene, the azulogenene, has been proved, as it has been found specially in the Roman camomile. The valeric acid, mostly combined occurs nearly always. The methyl-heptyl-cetone and the methyl-nonyl-cetone which have been found until now only inRuta, were found, the former inScrophularia lucida and the latter inAristolochia. In two essential oils paraffines have been found abundantly in one of them, moreover the occurrence of resins has been proved.

     

Le genrePolygonum L. (Polygonacées)

Sans résumé