Herbicide technology has evolved with forest management in North America over the past 60 years and has become an integral part of modern forestry practice. Forest managers have prescribed herbicides to increase reforestation success and long‐term timber yields. Wildlife managers and others interested in conserving biodiversity, however, have often viewed herbicide use as conflicting with their objectives. Do herbicides increase forest productivity, and are they compatible with the objectives of wildlife management and biodiversity conservation? Results from the longest‐term studies (10–30 years) in North America suggest that the range of wood volume yield gains from effectively managing forest vegetation (primarily using herbicides) is 30–450% in Pacific Northwest forests, 10–150% in the southeastern forests, and 50–450% in northern forests. Most of the 23 studies examined indicated 30–300% increases in wood volume yield for major commercial tree species and that gains were relatively consistent for a wide range of site conditions. Meeting future demands for wildlife habitat and biodiversity conservation will require that society's growing demand for wood be satisfied on a shrinking forestland base. Increased fiber yields from intensively managed plantations, which include the use of herbicides, will be a crucial part of the solution. If herbicides are properly used, current research indicates that the negative effects on wildlife usually are short‐term and that herbicides can be used to meet wildlife habitat objectives.

No abstract

Realized gains from selection of the first-generation breeding population of slash pine (Pinus elliottii Engelm. var. elliottii) were estimated using data from 38 field trials planted in large rectangular plots in the southeastern United States. The trials consisted of material selected for volume growth and planted by the Cooperative Forest Genetics Research Program at the University of Florida (19 trials) and by the Plantation Management Research Cooperative at the University of Georgia (19 trials). All trials contained slash pine seedlots collected from unrogued or lightly rogued first-generation seed orchards. Analyses of variance detected, on average, moderate gains in rust resistance (I50 = 43.1%) and site index (4.3%) and important gains in individual tree volume (7.7%) and stand yield (10.2%). Silvicultural treatments and age by realized gains interactions were never significant, but significant interactions between seedlots and trials showed that realized gains are not consistent at all sites. Overall results were highly consistent with predicted breeding values for rust resistance, but lower than expected for volume. On average, realized gain in stand yield for first-generation material was approximately 10%, or an extra inside-bark volume of 25 m 3 ·ha -1 (357 feet 3 ·acre -1 ) at 25 years.Résumé : Les gains réalisés par la sélection dans la population de première génération de pin d'Elliott typique (Pinus elliottii Engelm. var. elliottii) ont été estimés à l'aide de données provenant de 38 essais au champ plantés dans de grandes parcelles rectangulaires dans le sud-est des États-Unis. Les essais étaient constitués de matériel sélectionné pour la croissance en volume et planté dans le cadre du programme coopératif de recherche en génétique forestière de l'Université de Floride (19 essais) et par la Coopérative de recherche sur l'aménagement des plantations de l'Université de Georgie (19 essais). Tous les essais contenaient des lots de pin d'Elliott typique collectés dans des vergers à graines de première génération légèrement ou non éclaircis. Les analyses de variance ont détecté en moyenne des gains modérés pour la résistance à la rouille (I50 = 43,1 %) et l'indice de station (4,3 %) ainsi que des gains importants dans le volume des arbres (7,7 %) et le rendement des peuplements (10,2 %). Les interactions entre les gains réalisés et les traitements sylvicoles ou l'âge n'étaient jamais significatives mais il y avait des interactions significatives entre les lots de graines et les essais indiquant que les gains réalisés ne sont pas les mêmes dans tous les sites. Dans l'ensemble, les gains réa-lisés sont très consistants avec les valeurs en croisement prédites pour la résistance à la rouille mais plus faibles que prévu pour le volume. En moyenne, les gains réalisés dans le rendement des peuplements avec le matériel de première génération étaient approximativement de 10%, ou un volume sans écorce supplémentaire de 25 m 3 ·ha -1 (357 pieds 3 ·acre -1 ) à 25 ans.[Traduit par la Rédaction] Vergara et al. 2600

Timber inventory data is the basis for many monetary transactions related to timber and timberland sale and (or) purchase as well as for development of timber management plans. The value of such data is well known and much appreciated for sale and (or) purchase of standing merchantable timber. Unfortunately, the value of timber inventory data for planning purposes is less well understood. We report on the results of a large simulation study that was undertaken to evaluate the utility and value of timber inventory data for timber management plan development for a typical timberland ownership in the southern United States. Our results indicate that timberland managers are likely producing management plans that do not maximize the profitability of their timberland holdings. Specifically, our results indicate it is likely that timber management organizations that develop timber management plans with stand level data that has a sampling error of 25% are experiencing expected losses in net present value in excess of 170 US$·ha–1 on a large proportion of the acreage found on typical timberland parcels in the southern United States.

No abstract