Global vegetation models predict that boreal forests are particularly sensitive to a biome shift during the 21st century. This shift would manifest itself first at the biome's margins, with evergreen forest expanding into current tundra while being replaced by grasslands or temperate forest at the biome's southern edge. We evaluated changes in forest productivity since 1982 across boreal Alaska by linking satellite estimates of primary productivity and a large tree-ring data set. Trends in both records show consistent growth increases at the boreal-tundra ecotones that contrast with drought-induced productivity declines throughout interior Alaska. These patterns support the hypothesized effects of an initiating biome shift. Ultimately, tree dispersal rates, habitat availability and the rate of future climate change, and how it changes disturbance regimes, are expected to determine where the boreal biome will undergo a gradual geographic range shift, and where a more rapid decline.

No abstract

This paper calibrates climate controls over radial growth of floodplain white spruce ( Picea glauca (Moench) Voss) and examines whether growth in these populations responds similarly to climate as upland trees in Interior Alaska. Floodplain white spruce trees hold previously unrecognized potential for long-term climate reconstruction because they are the source of driftwood that becomes frozen in coastal deposits, where archeological timbers and beach logs represent well-preserved datable material. We compared ring width chronologies for 135 trees in six stands on the Yukon Flats and Tanana River with temperature and precipitation at Fairbanks from 1912–2001. Our sample contains a stable common signal representing a strong negative relationship between summer temperature and tree growth. We developed a floodplain temperature index (FPTI), which explains half of the variability of the composite chronology, and a supplemental precipitation index (SPI) based on correlation of monthly precipitation with the residual of the temperature-based prediction of growth. We then combined FPTI and SPI into a climate favorability index (CFI) in which above-normal precipitation partially compensates for temperature-induced drought reduction of growth and vice versa. CFI and growth have been particularly low since 1969. Our results provide a basis for building longer chronologies based on archeological wood and for projecting future growth.

ABSTRACT. Discussions of the development of past hunting equipment generally focus on lithic and bone projectile points and foreshafts, as these are often the only elements remaining in archaeological sites. In the last 15 years, the archaeology of alpine ice patches has provided a unique opportunity to analyze hunting equipment over time and gain knowledge of the wooden elements on which the points are hafted. This paper describes the wood and morphometrical analysis of a collection of 27 arrow shafts from two ice patch regions of the western Canadian Subarctic. In both regions, two main categories of arrow shafts show the selection of specific pieces of wood, spruce (Picea sp.) on the one hand and birch (Betula sp.) on the other, with associated morphometrical characteristics. These shafts also share some characteristics that are distinct from those of Arctic and coastal arrow shafts. Shafts of pine (Pinus sp. sec. ponderosa) and hemlock (Tsuga sp.) were also identified in the southwestern Yukon Territory. The absence of correlation between the arrow shaft types and 14 C dating raises the question of the significance of the arrow types and the potential for function, trade, or travel to explain the variation.Key words: archery, arrow shafts, ice patch archaeology, wood analysis, xylology, Subarctic, Arctic, Southwest Yukon, Northwest Territories RÉSUMÉ. Les discussions sur le développement des armes de chasse se concentrent généralement sur les pointes de projectile et les préhampes en matières lithiques et osseuses car ce sont ces éléments qui sont les plus souvent retrouvés dans les sites archéologiques. Ces quinze dernières années, l'archéologie des névés alpins nous donne l'opportunité unique d'analyser des équipements de chasse sur le long terme et de documenter les éléments en bois au bout desquels les pointes sont emmanchées. Dans cet article, nous décrivons l'analyse d'une collection de vingt-sept hampes de flèche en bois végétal provenant de deux régions de névés du Subarctique canadien. Dans les deux régions, on définit deux catégories principales de hampes de flèche qui montrent une sélection spécifique de pièces de bois d'épicéa (Picea sp.) et de bouleau (Betula sp.) auxquelles correspondent des caractéristiques morphométriques propres. Ces hampes partagent aussi des caractéristiques qui les distinguent de celles plus nordiques des côtes de l'Arctique. Des hampes faites en bois de pin (Pinus sp. sec. ponderosa) et de pruche (Tsuga sp.) ont également été identifiées dans le Sud-ouest du Territoire du Yukon. L'absence de corrélation entre les types de hampe de flèche et les dates radiocarbone soulève la question du sens à donner à ces types de flèche. Des facteurs tels que la fonction, les échanges ou des déplacements de personne sont envisagés.

No abstract

The NWT Ice Patch Study was developed in partnership with the Shúhtagot'ine residents of Tulita, Northwest Territories, Canada. This paper explores how Shúhtagot'ine traditional knowledge, collected through the direct participation of Elders in our archaeological fieldwork, science camps with Elders and youth, Elder interviews, and traditional land-use mapping, is informing our interpretation of archaeological data collected at alpine ice patches in the Selwyn Mountains. While knowledge of bow-and-arrow and snare technologies persists in Shúhtagot'ine culture, Shúhtagot'ine oral history does not contain detailed knowledge of throwing dart technology. Using data collected in our traditional land-use mapping project, we consider the role of ice patches in the broader context of Shúhtagot'ine land use. We propose that resource harvesting on high alpine plateaus and adjacent ice patches in the summer was more important in late precontact times than it was after contact. Shúhtagot'ine land-use practices involve long-distance travel in all seasons. Safe travel in the alpine landscape requires detailed knowledge of environmental conditions, such as snow and ice conditions, and respectful engagement with the spiritual entities inhabiting the landscape.RÉSUMÉ. L'étude des névés des Territoires du Nord-Ouest a été réalisée en collaboration avec les Shúhtagot'ine de Tulita, dans les Territoires du Nord-Ouest, au Canada. Le présent article explore comment le savoir traditionnel des Shúhtagot'ine, recueilli lors de la participation directe des aînés à nos fouilles archéologiques, à des camps de sciences où aînés et plus jeunes participaient, à des entrevues avec les aînés et au relevé cartographique de l'utilisation traditionnelle des terres influence et éclaire notre interprétation des données archéologiques recueillies dans les névés alpins de la chaîne de Selwyn . Bien que le savoir relatif aux techniques de l'arc et de la flèche et de la chasse au collet est encore bien présent dans la culture des Shúhtagot'ine, leur histoire orale ne fait aucune allusion à la technique du tir au propulseur. En nous appuyant sur les données recueillies dans le cadre de notre projet de cartographie de l'utilisation traditionnelle des terres, nous considérons le rôle des névés dans le plus contexte plus large de l'utilisation du territoire par les Shúhtagot'ine. Nous proposons que la récolte estivale des ressources sur les hauts plateaux alpins et les névés adjacents était plus importante à la période juste avant le contact qu'à celle qui a suivi. Les pratiques d'utilisation des terres par les Shúhtagot'ine impliquent des déplacements s ur de longues distances à toutes saisons. La sûreté des déplacements en milieu alpin nécessite une connaissance détaillée des conditions environnementales, telles que l'état de la neige et de la glace, de même qu'une interaction respectueuse avec les entités spirituelles qui habitent le milieu.

No abstract

Ground-penetrating radar (GPR) offers many advantages for assessing archaeological potential in frozen and partially frozen contexts in high latitude and alpine regions. These settings pose several challenges for GPR, including extreme velocity changes at the interface of frozen and active layers, cryogenic patterns resulting in anomalies that can easily be mistaken for cultural features, and the difficulty in accessing sites and deploying equipment in remote settings. In this study we discuss some of these challenges while highlighting the potential for this method by describing recent successful investigations with GPR in the region. We draw on cases from Bering Land Bridge National Preserve, Cape Krusenstern National Monument, Kobuk Valley National Park, and Gates of the Arctic National Park and Preserve. The sites required small aircraft accessibility with light equipment loads and minimal personnel. The substrates we investigate include coastal saturated active layer over permafrost, interior well-drained active layer over permafrost, a frozen thermo-karst lake, and an alpine ice patch. These examples demonstrate that GPR is effective at mapping semi-subterranean house remains in several contexts, including houses with no surface manifestation. GPR is also shown to be effective at mapping anomalies from the skeletal remains of a late Pleistocene mammoth frozen in ice. The potential for using GPR in ice and snow patch archaeology, an area of increasing interest with global environmental change exposing new material each year, is also demonstrated.