Thinking and acting differently for sustainable management of the boreal forest

Sustainable forest management has replaced sustained yield as the new management strategy for most countries and forest companies. This concept has generated a lot of interest and discussion, and a great deal of effort is being made to modify current forestry practices to be sustainable. In this paper, we argue that the still somewhat vague concept of sustainable forest management calls for a substantial modification in our way of thinking about and practicing forestry. To move toward that goal, we recognize important social and economic challenges to sustainable management and suggest nine essential notions: 1) manage the forest ecosystem as a whole and not in parts nor only for the crop species; 2) conserve a significant proportion of the boreal forest (i.e., at least 12%); 3) practice intensive forestry on a small portion of the land to recover the fibre lost from notions 1 and 2; 4) strive for innovation in thinking and acting; 5) foster research and development to support notion 4; 6) balance regional needs with that of the global community; 7) encourage public participation; 8) consider the impact of substantial change in climate over the next 100 years (or next rotation); and 9) substitute regulations that are adaptive for those that are restrictive. An example of the kind of silviculture that could be used in ecosystem management for the black spruce forest is also discussed

Development of an improved model estimating the nutrient content of the bole for four boreal tree species

An improved model for estimating nutrient contents of the commercial portion of tree boles was developed for four boreal tree species (Populus tremuloides Michx., Betula papyrifera Marsh., Picea glauca (Moench) Voss, and Abies balsamea (L.) Mill.). This model considers the spatial pattern of variation of nutrient concentrations inside the bole and its relationships with tree size. For all species-nutrient combinations, no significant pattern was found for vertical variations in nutrient concentrations, while two types of nonlinear models, using distance from the tree periphery as the independent variable, fit the pattern of horizontal (or radial) variations. These patterns of variability were used to estimate the global nutrient concentration of the bole by using mathematical integration. The values obtained with this method were generally lower, especially for large stems, than values obtained with traditional methods that do not consider the variability of nutrient concentrations inside the bole. This improved model would permit better estimates of the mounts of nutrients lost in biomass upon forest harvesting, as well as internal cycling of nutrients within the bole

Probing Relativity using Space-Based Experiments

An overview of space tests searching for small deviations from special relativity arising at the Planck scale is given. Potential high-sensitivity space-based experiments include ones with atomic clocks, masers, and electromagnetic cavities. We show that a significant portion of the coefficient space in the Standard-Model Extension, a framework that covers the full spectrum of possible effects, can be accessed using space tests. Some remarks on Lorentz violation in the gravitational sector are also given.Comment: 12 pages, invited talk at International Workshop, From Quantum to Cosmos, Warrenton, VA, USA, May 22-24, 200

Comparative Winter Habitat Use and Associations among Herbivores in the High Arctic

We studied winter habitat use and interspecific associations among large- and medium-sized herbivores on southeastern Victoria Island, Arctic Canada, by documenting the deposition of feces in relation to vegetation. Associations between ptarmigan (Lagopus spp.), arctic hares (Lepus arcticus), caribou (Rangifer tarandus), and muskoxen (Ovibos moschatus) were assessed using the Jaccard Index (JI) and chi² at two scales, i.e., with 1 m² and 1 ha as sampling units. JI values for species pairs were greater at the larger scale, but chi² revealed significant (positive) associations only at the smaller scale and only between arctic hares and caribou and between arctic hares and ptarmigan. Comparative use of habitats was described with respect to vegetation by canonical correspondence analysis (CCA). Ptarmigan and muskoxen were most strongly correlated with lowland vegetation and caribou with upland vegetation; arctic hares were intermediate. CCA also indicated rather wide separation in the multivariate space, further suggesting distinct patterns of habitat use. The results imply that these species were segregated in their use of resources in this High Arctic environment.On a étudié l'utilisation de l'habitat hivernal et les associations biotiques parmi les grands et moyens herbivores du sud-est de l'île Victoria située dans l'Arctique canadien, en étudiant l'emplacement des crottes par rapport à la végétation. À l'aide de l'index Jaccard (IJ) et de chi² à deux échelles (c.-à-d. en prenant 1 m² et 1 ha comme unités d'échantillonnage), on a évalué les associations entre le lagopède (Lagopus spp), le lièvre arctique (Lepus arcticus), le caribou (Rangifer tarandus) et le boeuf musqué (Ovibos moschatus). Les valeurs de IJ pour les paires d'espèces étaient plus élevées à grande échelle, mais chi² ne montrait des associations notables (positives) qu'à petite échelle et seulement entre le lièvre arctique et le caribou ainsi qu'entre le lièvre arctique et le lagopède. On a décrit l'utilisation comparative des habitats en rapport avec la végétation par analyse de correspondance canonique (ACC). Le lagopède et le boeuf musqué étaient corrélés le plus fortement avec la végétation des basses-terres et le caribou avec celle des hautes-terres; le lièvre arctique se situait au milieu. L'ACC montrait aussi une séparation relativement importante dans l'espace à plusieurs variables, ce qui laisse suggérer des modèles distincts d'utilisation de l'habitat. Les résultats indiqueraient qu'il existait pour ces espèces une ségrégation dans l'utilisation des ressources au sein de cet environnement extrême-arctique

Blending of nanoscale and microscale in uniform large-area sculptured thin-film architectures

The combination of large thickness ($>3$ $\mu$m), large--area uniformity (75 mm diameter), high growth rate (up to 0.4 $\mu$m/min) in assemblies of complex--shaped nanowires on lithographically defined patterns has been achieved for the first time. The nanoscale and the microscale have thus been blended together in sculptured thin films with transverse architectures. SiO$_x$ ($x\approx 2$) nanowires were grown by electron--beam evaporation onto silicon substrates both with and without photoresist lines (1--D arrays) and checkerboard (2--D arrays) patterns. Atomic self--shadowing due to oblique--angle deposition enables the nanowires to grow continuously, to change direction abruptly, and to maintain constant cross--sectional diameter. The selective growth of nanowire assemblies on the top surfaces of both 1--D and 2--D arrays can be understood and predicted using simple geometrical shadowing equations.Comment: 17 pages, 9 figure

Demography of the George River Caribou Herd: Evidence of Population Regulation by Forage Exploitation and Range Expansion

The George River caribou herd in northern Quebec/Labrador increased from about 5000 animals in 1954 to 472,200 (or 1.1 caribou/km) prior to the 1984 calving season. The range used by the herd expanded from 160,000 to 442,000 sq km for the period 1971-84. The exponential rate of increase (r) was estimated at 0.11 in the 1970s. Calf:female ratio in autumn was relatively constant (x=0.52) from 1973 to 1983, but decreased to about 0.39 in 1984-86. The harvest rate was relatively low in the 1970s (about 3%/y), but seemingly increased in the mid-1980s to 5-7% as a result of more liberal regulations and a greater impetus to exploit caribou for subsistence. The cumulative impact of lower calf recruitment and more intensive hunting may have appreciably depressed the growth rate of the herd in 1984-86. A greater year-round competition for food resources and a greater energy expenditure associated with range expansion are presented as probable regulatory factors for the George River herd. It is argued that the nature of caribou-habitat interactions in continental regions generate long-term fluctuations in caribou numbers if human exploitation remains low. At present, wolf predation does not appear to be an important mortality factor capable of regulating the George River herd.Key words: caribou, population regulation, food limitation, northem Quebec, Labrador, wolf predationMots clés: caribou, régulation de la population, limitation de la nourriture, nord du Québec, Labrador, prédation des loup