Báo cáo khoa học: Differences in vegetation cover resulting from various methods of site preparation for pine plantations in South Africa

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Báo cáo khoa học: "Differences in vegetation cover resulting from various methods of site preparation for pine plantations in South Africa" article Original Differences in vegetation cover resulting from various methods of site preparation for pine plantations in South Africa JB Zwolinski DGM Donald 1 School of Forestry, Auburn University, Auburn, AL 36849-5418, USA; 2 Faculty of Forestry, University of Stellenbosch, Stellenbosch, South Africa November 1993; accepted 5 October (Received 25 1994)Summary — Species composition, height, cover, and biomass of vegetation were examined inresponse to forest regeneration methods applied in exotic tree plantations of Pinus radiata in South Africa.The experimental treatments involved 4 soil cultivation techniques (pitting, augering, ripping and disk-ing) and 2 levels of weed control (standard and intensive). Both species cover and composition weresignificantly affected by the experimental treatments. However, the most important weed speciesremained common irrespective of the site preparation technique applied. More research is neededto find methods for selective control of weed species. plantations / biodiversity / competing vegetation / weed control / soil cultivationtreeRésumé — Effet des méthodes de préparation de site sur la couverture végétale dans les plan-tations de pin en Afrique du Sud. La diversité des espèces, la hauteur, la couverture et la biomassevégétale des plantations exotiques de Pinus radiata ont été examinées en fonction des méthodes derégénération de forêt en Afrique du Sud. Les traitements expérimentaux comprennent 4 méthodes depréparation du sol, et 2 niveaux de contrôle des mauvaises herbes (standard et intensif). Les traitementsexpérimentaux ont un effet sur la couverture et la diversité des espèces. Pourtant, les espèces adven-tices les plus importantes restent présentes quelle que soit la technique utilisé pour préparer le site. Desrecherches supplémentaires sont requises pour trouver des méthodes de contrôle sélectif des espècesadventices.plantations forestières / diversité biologique / compétition végétale / contrôle des mauvaisesherbes / préparation du solINTRODUCTION ber production from indigenous forests was not sufficient to satisfy the demand. Estab- lishment of exotic tree plantations duringThere about 7 000 species of plants, of are the last century resulted in suppression of than half are endemic, in thewhich more natural vegetation (weeds) on extensive Province of South Africa. EndemicCape areas. Large areas of fynbos have beenfamilies include: Bruniaceae (12 genera, 75 invaded by aliens introduced for land recla-species), Geisolomataceae (1 species), mation or timber production, but most dis-Grubbiaceae (2 genera, 5 species), Penae- turbance occurred at afforestation whenceae (5 genera, 25 species), Retziaceae (5 indigenous vegetation was burnt and thegenera, 12 species). The other character- land ploughed. Not only did it take longeristic families are, Ericaceae (c 650 endemic for the vegetation to re-establish itself, butspecies), Proteaceae (c 320 endemic also a single society returned on thespecies), Restionaceae (c 180 endemic ploughed ground compared to at least 6species), Rutaceae-Diosmeae (c 150 societies after spot hoeing (pitting) (Donaldendemic species) (White, 1983). The preva- and Schönau, 1963). Species diversity oflent vegetation in the Cape region is fyn- indigenous vegetation was further reducedbos, occurring in the form of 1-3 m tall scle- ...