Effect of midrotation fertilization on growth and specific gravity of loblolly pine

Abstract

Wood properties and growth were measured on breast-height cores and on disks collected at different heights from a thinned and fertilized midrotation loblolly pine (Pinus taeda L.) plantation in the lower Coastal Plain of North Carolina. The study was laid out in a randomized complete-block design receiving four levels of nitrogen (N) fertilizer: unfertilized control and 112, 224, and 336 kg/ha plus 28 kg/ha of phosphorus with each treatment. The effect of fertilization was analyzed for the whole-disk and for a 4 year average following fertilization on data collected from breast-height cores and from disks. The fertilization treatments did not significantly affect whole-disk wood properties but significantly increased radial growth. Fertilization rate of 336 kg/ha N significantly reduced 4 year average ring specific gravity and latewood specific gravity. Wood properties of trees that received 112 and 224 kg/ha N were not affected following treatment. There was no height related trend in wood property changes due to fertilization. Fertilization significantly increased ring basal area and earlywood basal area. In summary, there was a decline in wood properties and an increase in basal area growth immediately after fertilization; both depended on the rate of fertilizer applied irrespective of height.Résumé : Les auteurs ont mesuré les propriétés du bois et la croissance sur des carottes prélevées à hauteur de poitrine et des disques prélevés à différentes hauteurs dans une plantation à mi-révolution de pin à encens (Pinus taeda L.) éclaircie, fertilisée et située dans la basse plaine côtière de la Caroline du Nord. L'expérience était structurée en blocs complets aléa-toires dans lesquels quatre niveaux de fertilisant azoté ont été appliqués : témoin, 112, 224 et 336 kg/ha, et 28 kg/ha de phosphore ont été ajoutés à chaque traitement. L'effet de la fertilisation a été analysé sur les moyennes des disques entiers et les moyennes des 4 années suivant le traitement à partir des données mesurées sur les carottes et les disques. Les traitements de fertilisation n'ont pas eu d'effet significatif sur les propriétés du bois à l'échelle du disque entier mais ont causé une augmentation significative de la croissance radiale. Un taux de fertilisation azotée de 336 kg/ha a entraîné une réduc-tion significative de la densité relative moyenne des cernes annuels et du bois final des 4 années suivant le traitement. Les traitements de fertilisation azotée à 112 et 224 kg/ha n'ont pas eu d'effet sur les propriétés du bois. Les changements des propriétés du bois dus à la fertilisation n'ont suivi aucune tendance reliée à la hauteur dans l'arbre. La fertilisation a causé une augmentation significative de la surface terrière des cernes et du bois initial. En résumé, les propriétés du bois ont dé-cliné et la croissance en surface terrière a augmenté immédiatement après la fertilisation mais chacun de ces effets dépend-ait du taux de fertilisation utilisé peu importe la hauteur.[Traduit par la Rédaction]

Water availability and genetic effects on wood properties of loblolly pine (Pinus taeda)

“…Interestingly, the FL material evolved with greater water availability during the growing period compared with the SC material, with an evapotranspiration to precipitation ratio of 1.07 versus 1.39, suggesting that the SC family may be better adapted to water deficits because of its ability to make more latewood. No effect of irrigation was observed for V 2 or MOE in contrast with the significant effects reported for fertilization (Clark et al 2004;Antony et al 2009), fertilization combined with weed control (Clark et al 2004;Roth et al 2007), and initial plantation density (Roth et al 2007;Lasserre et al 2009). The stability of wood stiffness to different water availability shows that changes in V 2 are not related to LW% and are consistent with the observation that differences in V 2 are due predominately to changes in cellulose microfibril angle.…”

Growth responses of narrow or broad site adapted tree species to a range of resource availability treatments after a full harvest rotation

“…lowlands). As others have suggested, a focus on nutrient use and management is recommended for pine production (Haywood and Tiarks, 1990;Fox et al, 2007;Antony et al, 2009;Jokela et al, 2010).…”

Wood and Fiber Quality of Plantation-Grown Conifers: A Summary of Research with an Emphasis on Loblolly and Radiata Pine

“…Based on some of the studies on loblolly and radiata pine, SG of wood produced following fertilization is decreased when compared with that of unfertilized trees [79][80][81][82][83][84], with the effect lasting for 3-4 years post-fertilization. In radiata pine, nitrogen supply was shown to be an important factor affecting wood density [84,85].…”

“…Models explaining variation in wood properties following silvicultural treatments are rare, and more research is required. In loblolly pine, Antony et al [126] modeled responses in SG of LW following mid-rotation fertilization, as a function of the rate of fertilizer applied, and time since fertilization. In another study, Antony et al [55] modeled the effect of initial stocking on variation in wood stiffness within trees (Figure 4).…”