Yellow-cedar decline is the accelerated decline and mortality of yellow cedar ( Chamaecyparis nootkatensis ) occurring in the Pacific Northwest Temperate Rainforest of Southeast Alaska and British Columbia in North America. This phenomenon has been observed on over 200,000 hectares of forest and is believed to be due to reduced winter snowpacks and increased soil freezing. [1]
Yellow cedar ranges from the Klamath Mountains of California to Prince William Sound in Alaska. [2] Limited to higher elevations throughout most of its natural range [3] The climate in Southeast Alaska and western British Columbia is hyper-maritime, with frequent low-intensity precipitation. [3] Snow levels in this area are highly variable due to near freezing temperatures in the winter time. [3] Forests here are dominated by Sitka spruce (Picea stichensis), western hemlock (Tsuga heterophylla), mountain hemlock (Tsuga mertensiana), shore pine (Pinus contorta), western redcedar (Thuja plicata), and yellow cedar. Decline of this species has affected over 200,000 hectares of forest in Alaska and 50,000 hectares in British Columbia, approximately 8% of the species range [2]
It is currently generally accepted that increased regional temperature and associated reduction in snow-pack depth and duration are some of the drivers behind yellow-cedar decline. [1] [2] [3] However, other causes of decline are being investigated by researchers. Current evidence suggests that yellow-cedar decline is not biologically driven or caused by direct anthropogenic pollution or atmospheric pollution. [4] Researchers have investigated the effects of soil saturation and soil chemistry on yellow-cedar decline [5] and have yet to reveal any conclusive data, other than the fact that these parameters may indirectly influence cedar mortality. Elevation also seems to play a role in cedar decline, as it was found in one study that yellow cedar trees growing above 130 meters were more cold hardy than those growing below 130 meters.[ citation needed ]
Yellow-cedar decline began in about 1880 which coincides with a warming of the climate after the Little Ice Age. [4] The mechanics of this process are still hypothetical, but evidence suggests that soil exposure to cold temperatures due to lack of canopy cover or wetness of soils can lead to freezing injury of yellow cedar. [3] Open canopy conditions in the forest expose soils to freezing temperatures. As regional temperatures warm, precipitation falls as rain more often than snow in the winter. Snow packs in the winter offer some insulation to root systems from freezing, the absence of this snow pack allows for soil freezing. As soils freeze, root tissues, especially those in wet soils, suffer damage and can lead to tree mortality. [3] Yellow cedar is found to be significantly less cold hardy than tree species surrounding it, such as the western hemlock, which was found to deharden at almost 13 °C less than the yellow cedar in comparable conditions. [3]
Management and conservation of yellow cedar in light of its declining state could be divided into three management areas: the maladapted, the persistent, and migration. [6] Maladapted being those areas in which yellow cedar will lose in competition with resident and exotic species. Persistent being those ecosystems in which yellow cedar has managed to compete with resident species that will require special attention for maintenance. And migration being those areas which are suitable, but do not presently contain yellow-cedar populations.[ citation needed ]
It is very important to recognize that conservation and restoration in areas that are maladapted for yellow cedar are futile. [6] Areas that have already been maladapted for yellow cedar are important as sources of economic value. Dead regions of yellow cedar are still available for harvest even 80 years after death. [6] Harvest of these areas represent a large opportunity for wood resources, shifting from logging of healthy yellow cedar in suitable habitat to those in maladapted regions could be beneficial to the conservation of this species. It seems that, following the decay of yellow cedar, western red cedar will succeed the dead forest. The red cedar offers many of the very same economic and ecological values as yellow cedar. Areas of lower elevation in Southeast Alaska and British Columbia that have seen yellow-cedar decay have been succeeded by red cedar. However, more research will need to take place as this problem persists to evaluate the economic and ecological value of subsidizing red cedar in these areas.[ citation needed ]
Areas that are predicted with future climate change models to be suitable for sustained yellow-cedar habitation could be considered persistent from a management standpoint. It is important to accurately model these areas in order to develop effective management strategies. At a landscape level, areas with well-drained soils are most likely to host yellow cedar into the future. These are the areas that see the highest rates of production among trees in the Pacific Northwest temperate rainforest, and are thusly the areas that are targeted for timber harvest. For this reason, these areas are hotspots for active management of yellow cedar into the future, as they represent the main areas that are able to achieve conservation goals. [6]
Some conservationists propose that assisted migration into areas uninhabited by yellow cedar will be an effective management strategy. Assisted migration is the introduction of species and genotypes into areas that are projected to be suitable for those species/genotypes. [6] This can be controversial, mainly because it is seen as introducing invasive species into ecosystems, which could bring undesirable results. Researchers have attempted the introduction of yellow cedar in areas that it does not grow, but are within its range. A trial planting in Yakutat, Alaska, yielded first-year survival rates of over 90%, meaning that targeted migration can be used as an effective management strategy. [6]
Taiga, generally referred to in North America as a boreal forest or snow forest, is a biome characterized by coniferous forests consisting mostly of pines, spruces, and larches.
Callitropsis nootkatensis, formerly known as Cupressus nootkatensis, is a species of tree in the cypress family native to the coastal regions of northwestern North America. This species goes by many common names including: Nootka cypress, yellow cypress, Alaska cypress, Nootka cedar, yellow cedar, Alaska cedar, and Alaska yellow cedar. The specific epithet nootkatensis is derived from its discovery by Europeans on the lands of a First Nation of Canada, the Nuu-chah-nulth people of Vancouver Island, British Columbia, who were formerly referred to as the Nootka.
Thuja plicata is a large evergreen coniferous tree in the family Cupressaceae, native to the Pacific Northwest of North America. Its common name is western redcedar in the U.S. or western red cedar in the UK, and it is also called pacific red cedar, giant arborvitae, western arborvitae, just cedar, giant cedar, or shinglewood. It is not a true cedar of the genus Cedrus. T. plicata is the largest species in the genus Thuja, growing up to 70 metres (230 ft) tall and 7 metres (23 ft) in diameter. It mostly grows in areas that experience a mild climate with plentiful rainfall, although it is sometimes present in drier areas on sites where water is available year-round, such as wet valley bottoms and mountain streamsides. The species is shade-tolerant and able to establish in forest understories and is thus considered a climax species. It is a very long-lived tree, with some specimens reaching ages of well over 1,000 years.
The tree line is the edge of a habitat at which trees are capable of growing. It is found at high elevations and high latitudes. Beyond the tree line, trees cannot tolerate the environmental conditions. The tree line is sometimes distinguished from a lower timberline, which is the line below which trees form a forest with a closed canopy.
Temperate rainforests are rainforests with coniferous or broadleaf forests that occur in the temperate zone and receive heavy rain.
The Pacific temperate rainforests of western North America is the largest temperate rain forest region on the planet as defined by the World Wildlife Fund. The Pacific temperate rainforests lie along the western side of the Pacific Coast Ranges along the Pacific Northwest Coast of North America from the Prince William Sound in Alaska through the British Columbia Coast to Northern California, and are part of the Nearctic realm, as also defined by the World Wildlife Fund. The Pacific temperate rain forests are characterized by a high amount of rainfall, in some areas more than 300 cm (10 ft) per year and moderate temperatures in both the summer and winter months.
Tsuga mertensiana, known as mountain hemlock, is a species of hemlock native to the west coast of North America, found between Southcentral Alaska and south-central California.
In hydrology, snowmelt is surface runoff produced from melting snow. It can also be used to describe the period or season during which such runoff is produced. Water produced by snowmelt is an important part of the annual water cycle in many parts of the world, in some cases contributing high fractions of the annual runoff in a watershed. Predicting snowmelt runoff from a drainage basin may be a part of designing water control projects. Rapid snowmelt can cause flooding. If the snowmelt is then frozen, very dangerous conditions and accidents can occur, introducing the need for salt to melt the ice.
The Northern Pacific coastal forests are temperate coniferous forest ecoregion of the Pacific coast of North America. It occupies a narrow coastal zone of Alaska, between the Pacific Ocean and the northernmost Pacific Coast Ranges, covering an area of 23,300 square miles, extending from the Alexander Archipelago in southeast Alaska along the Gulf of Alaska to the western Kenai Peninsula and eastern Kodiak Island. The Pacific Coastal Mountain icefields and tundra ecoregion lies inland, at higher elevations in the Coast Mountains. The ecoregion receives high rainfall, which varies considerably based on exposure and elevation. It contains a quarter of the world's remaining temperate rain forest.
Temperate deciduous or temperate broad-leaf forests are a variety of temperate forest 'dominated' by deciduous trees that lose their leaves each winter. They represent one of Earth's major biomes, making up 9.69% of global land area. These forests are found in areas with distinct seasonal variation that cycle through warm, moist summers, cold winters, and moderate fall and spring seasons. They are most commonly found in the Northern Hemisphere, with particularly large regions in eastern North America, East Asia, and a large portion of Europe, though smaller regions of temperate deciduous forests are also located in South America. Examples of trees typically growing in the Northern Hemisphere's deciduous forests include oak, maple, basswood, beech and elm, while in the Southern Hemisphere, trees of the genus Nothofagus dominate this type of forest. Temperate deciduous forests provide several unique ecosystem services, including habitats for diverse wildlife, and they face a set of natural and human-induced disturbances that regularly alter their structure.
The New England-Acadian forests are a temperate broadleaf and mixed forest ecoregion in North America that includes a variety of habitats on the hills, mountains and plateaus of New England and New York State in the Northeastern United States, and Quebec and the Maritime Provinces of Eastern Canada.
The biogeoclimatic zones of British Columbia are units of a classification system used by the British Columbia Ministry of Forests for the Canadian province's fourteen different broad, climatic ecosystems. The classification system, termed Biogeoclimatic Ecosystem Classification, exists independently of other ecoregion systems, one created by the World Wildlife Fund and the other in use by Environment Canada, which is based on one created by the Commission for Environmental Cooperation (CEC) and also in use by the US Environmental Protection Agency (EPA). The system of biogeoclimatic ecosystem classification was partly created for the purpose of managing forestry resources, but is also in use by the British Columbia Ministry of Environment and Climate Change Strategy and other provincial agencies. A biogeoclimatic zone is defined as "a geographic area having similar patterns of energy flow, vegetation and soils as a result of a broadly homogenous macroclimate."
The Ecology of the North Cascades is heavily influenced by the high elevation and rain shadow effects of the mountain range. The North Cascades is a section of the Cascade Range from the South Fork of the Snoqualmie River in Washington, United States, to the confluence of the Thompson and Fraser Rivers in British Columbia, Canada, where the range is officially called the Cascade Mountains but is usually referred to as the Canadian Cascades. The North Cascades Ecoregion is a Level III ecoregion in the Commission for Environmental Cooperation's classification system.
The North Central Rockies forests is a temperate coniferous forest ecoregion of Canada and the United States. This region overlaps in large part with the North American inland temperate rainforest and gets more rain on average than the South Central Rockies forests and is notable for containing the only inland populations of many species from the Pacific coast.
Climate change in Alaska encompasses the effects of climate change in the U.S. state of Alaska.
Climate change in Arizona encompasses the effects of climate change, attributed to man-made increases in atmospheric carbon dioxide, in the U.S. state of Arizona.
Climate change in Utah encompasses the effects of climate change, attributed to man-made increases in atmospheric carbon dioxide, in the U.S. state of Utah.
Climate change in Vermont encompasses the effects of climate change, attributed to man-made increases in atmospheric carbon dioxide, in the U.S. state of Vermont.
The North American inland temperate rainforest is a 7 million hectare disjunct temperate rainforest spreading over parts of British Columbia in Canada as well as Washington, Idaho and Montana on the US side. Its patches are located on the windward slopes of the Rocky Mountains and the Columbia Mountains, extending roughly over 1000km from 54° North to 45° North. It is one of the largest inland temperate rainforests in the world.
The Marine West Coast Forest is a Level I ecoregion of North America designated by the Commission for Environmental Cooperation (CEC) in its North American Environmental Atlas. The region includes parts of Alaska, the Yukon, British Columbia, Washington, Oregon, and California.