Integration of nursery practices and vegetation management: economic and biological potential for improving regeneration

Abstract

Researchers in New Zealand, Scotland, South Africa, Texas, and Alabama provided data on growth responses owing to nursery management practices and weed control after outplanting. Nursery treatments included nitrogen fertilization (0 vs. 168 kg/ha), seedling grades (small-diameter vs. large-diameter seedlings), and a comparison of stock types. Weed-control treatments varied by study and included broadcast and spot applications. Interactions between nursery practices and weed control were examined. Regardless of location, growth (2–8 years after planting) was increased as seedling diameter increased. Practices that increase average seedling diameter in the nursery are typically less costly than silvicultural practices required to obtain similar growth responses from small-diameter stock. Although interactions were observed among sites, stock size, and intensity of weed control, large-diameter stock consistently grew better than small-diameter stock regardless of site or site-preparation method. Thus, increasing the investment of regeneration expenditures at the nursery, relative to that put into site preparation, will substantially improve financial returns on investment. Further research needs in this area are also discussed.

Interaction of initial seedling diameter, fertilization and weed control on Douglas-fir growth over the first four years After Planting

“…The benefit derived from planting larger stock was consistent with other published studies for Douglas-fir [11,27,35]. Similar trends have also been reported for other conifer species in dramatically different environments [17,[31][32][33].…”

“…However, in their study, fertilization and weed control interacted such that without weed control there were no fertilizer responses. In studies wherein the interactions between seedling size at planting and weed control were examined, the responses have been additive [13,17,31,32]. We are aware of only two published reports that compare planting different sized Douglas-fir seedlings that received similar nursery cultural histories in combination with fertilization treatments.…”

Évaluation de trois contenants pour la production de plants d'espèces feuillues de fortes dimensions

“…Parallklement B ces constatations, certains travaux ont dtmontrt l'amtlioration de la performance des plantations par l'utilisation de plants d'espkces rtsineuses de fortes dimensions (South et al 1993a(South et al , 1993b) pouvant dtvelopper des parties atriennes au-dessus de la vtgttation herbacte prtsente. Les espkces feuillues de haute valeur commerciale, pour leur part, sont plus vulnCrables envers la concurrence exercCe par la vtgttation herbade et consiquemrnent, le succks de l' Ctablissement de tels plants est fortement tributaire de la rtpression de cette compttition (Cogliastro et al 1990(Cogliastro et al , 1993von Althen 1987).…”

“…Parallklement B ces constatations, certains travaux ont dtmontrt l'amtlioration de la performance des plantations par l'utilisation de plants d'espkces rtsineuses de fortes dimensions (South et al 1993a(South et al , 1993b) pouvant dtvelopper des parties atriennes au-dessus de la vtgttation herbacte prtsente.…”

“…La production en contenant comporte plusieurs avantages, le principal Ctant qu'il conduit B l'ttablissement d'un systkme racinaire prottgt qui se dtveloppe avec un minimum de contraintes suite B la mise en tern (Sugden et Scarratt 1981). Cependant, les malformations mchaires ttant fkkluentes dans ce type de culture (Sheedy 1991), la conception de nouveaux modkles de contenant pouvant mieux contr6ler le dtveloppement des racines est en Cvolution (Appleton 1993; Gingras 1993).Parallklement B ces constatations, certains travaux ont dtmontrt l'amtlioration de la performance des plantations par l'utilisation de plants d'espkces rtsineuses de fortes dimensions (South et al 1993a(South et al , 1993b) pouvant dtvelopper des parties atriennes au-dessus de la vtgttation herbacte prtsente. Les espkces feuillues de haute valeur commerciale, pour leur part, sont plus vulnCrables envers la concurrence exercCe par la vtgttation herbade et consiquemrnent, le succks de l' Ctablissement de tels plants est fortement tributaire de la rtpression de cette compttition (Cogliastro et al 1990(Cogliastro et al , 1993von Althen 1987).…”