Carbon balance of the taiga forest within Alaska: present and future

2002 ◽  
Vol 32 (5) ◽  
pp. 757-767 ◽  
Author(s):  
John Yarie ◽  
Sharon Billings
Keyword(s):  
Boreal Forest ◽  
Black Spruce ◽  
White Spruce ◽  
Carbon Dynamics ◽  
Mean Annual Temperature ◽  
Century Model ◽  
Inventory Data ◽  
Balsam Poplar ◽  
Taiga Forest ◽  
Paper Birch

Forest biomass, rates of production, and carbon dynamics are a function of climate, plant species present, and the structure of the soil organic and mineral layers. Inventory data from the U.S. Forest Service (USFS) Inventory Analysis Unit was used to develop estimates of the land area represented by the major overstory species at various age-classes. The CENTURY model was then used to develop an estimate of carbon dynamics throughout the age sequence of forest development for the major ecosystem types. The estimated boreal forest area in Alaska, based on USFS inventory data is 17 244 098 ha. The total aboveground biomass within the Alaska boreal forest was estimated to be 815 330 000 Mg. The CENTURY model estimated maximum net ecosystem production (NEP) at 137, 88, 152, 99, and 65 g·m–2·year–1 for quaking aspen (Populus tremuloides Michx.), paper birch (Betula papyrifera Marsh.), balsam poplar (Populus balsamifera L.), white spruce (Picea glauca (Moench) Voss), and black spruce (Picea mariana (Mill.) BSP) forest stands, respectively. These values were predicted at stand ages of 80, 60, 41, 68, and 100 years, respectively. The minimum values of NEP for aspen, paper birch, balsam poplar, white spruce, and black spruce were –171, –166, –240, –300, and –61 g·m–2·year–1 at the ages of 1, 1, 1, 1, and 12, respectively. NEP became positive at the ages of 14, 19, 16, 13, and 34 for aspen, birch, balsam poplar, white spruce, and black spruce ecosystems, respectively. A 5°C increase in mean annual temperature resulted in a higher amount of predicted production and decomposition in all ecosystems, resulting in an increase of NEP. We estimate that the current vegetation absorbs approximately 9.65 Tg of carbon per year within the boreal forest of the state. If there is a 5°C increase in the mean annual temperature with no change in precipitation we estimated that NEP for the boreal forest in Alaska would increase to 16.95 Tg of carbon per year.

Potential changes in carbon dynamics due to climate change measured in the past two decades

2005 ◽  
Vol 35 (9) ◽  
pp. 2258-2267 ◽  
Author(s):  
John Yarie ◽  
Bill Parton
Keyword(s):  
Climate Change ◽  
Carbon Balance ◽  
Carbon Capture ◽  
Black Spruce ◽  
White Spruce ◽  
Carbon Dynamics ◽  
Age Classes ◽  
The Past ◽  
Interior Alaska ◽  
Taiga Forest

Evidence suggests that climate change dynamics have been occurring in the northern latitudes for the past two and a half decades. The CENTURY ecosystem model was used for a set of simulations related to the carbon dynamics of interior Alaska taiga forest types. The functional dynamics of three age-classes (young, middle, and mature) of three ecosystem types (white spruce (Picea glauca (Moench) Voss), black spruce (Picea mariana (Mill.) BSP), and hardwoods) were compared using an average climate that was present prior to 1980 and the climate record from 1980 to 2000. Estimates for total ecosystem production indicate a decrease in tree carbon capture for hardwood stands for all three age-classes summed across a 20-year climate change period. White spruce displayed increases in carbon capture for the three age-classes. Young and mid-aged black spruce stands showed a decrease in ecosystem productivity. The old-growth black spruce stand showed a small increase in carbon capture. Dynamics displayed for the entire ecosystem (soil organic matter, tree dynamics, dead wood, and forest litter) followed the same trends as vegetation productivity. For the same 20-year climate period and across all three age-classes, carbon capture decreased for hardwood ecosystems and increased for white spruce ecosystems. The young black spruce system showed a change from a positive carbon balance to a negative carbon balance. Based on the landscape area covered by each vegetation type, we suggest that the net effect of climate warming over the past 20 years has been a substantial decrease in carbon capture in the forests of interior Alaska.

Summary and Synthesis: Past and Future Changes in the Alaskan Boreal Forest

2006 ◽  
Author(s):  
Marilyn W. Walker ◽  
Mary E. Edwards
Keyword(s):  
Boreal Forest ◽  
Bark Beetles ◽  
Fire Regime ◽  
Black Spruce ◽  
Rapid Change ◽  
White Spruce ◽  
Late Glacial ◽  
Fire Frequency ◽  
Tree Resistance ◽  
Forest Sites

Historically the boreal forest has experienced major changes, and it remains a highly dynamic biome today. During cold phases of Quaternary climate cycles, forests were virtually absent from Alaska, and since the postglacial re-establishment of forests ca 13,000 years ago, there have been periods of both relative stability and rapid change (Chapter 5). Today, the Alaskan boreal forest appears to be on the brink of further significant change in composition and function triggered by recent changes that include climatic warming (Chapter 4). In this chapter, we summarize the major conclusions from earlier chapters as a basis for anticipating future trends. Alaska warmed rapidly at the end of the last glacial period, ca 15,000–13,000 years ago. Broadly speaking, climate was warmest and driest in the late glacial and early Holocene; subsequently, moisture increased, and the climate gradually cooled. These changes were associated with shifts in vegetation dominance from deciduous woodland and shrubland to white spruce and then to black spruce. The establishment of stands of fire-prone black spruce over large areas of the boreal forest 5000–6000 years ago is linked to an apparent increase in fire frequency, despite the climatic trend to cooler and moister conditions. This suggests that long-term features of the Holocene fire regime are more strongly driven by vegetation characteristics than directly by climate (Chapter 5). White spruce forests show decreased growth in response to recent warming, because warming-induced drought stress is more limiting to growth than is temperature per se (Chapters 5, 11). If these environmental controls persist, projections suggest that continued climate warming will lead to zero net annual growth and perhaps the movement of white spruce to cooler upland forest sites before the end of the twenty-first century. At the southern limit of the Alaskan boreal forest, spruce bark beetle outbreaks have decimated extensive areas of spruce forest, because warmer temperatures have reduced tree resistance to bark beetles and shortened the life cycle of the beetle from two years to one, shifting the tree-beetle interaction in favor of the insect (Chapter 9).

scholarly journals Splitting in Fire-Killed Trees in the Boreal Forest of Alberta

2003 ◽  
Vol 20 (4) ◽  
pp. 167-174
Author(s):  
Nobutaka Nakamura ◽  
Paul M. Woodard ◽  
Lars Bach
Keyword(s):  
Boreal Forest ◽  
Boreal Forests ◽  
Black Spruce ◽  
Lodgepole Pine ◽  
White Spruce ◽  
Balsam Fir ◽  
Crown Fire ◽  
In Fire ◽  
Solar Angle

Abstract Tree boles in the boreal forests of Alberta, Canada will split once killed by a stand-replacing crown fire. A total of 1,485 fire-killed trees were sampled, 1 yr after burning, in 23 plots in 14 widely separated stands within a 370,000 ha fire. Sampling occurred in the Upper and Lower Foothills natural subregions. The frequency of splitting varied by species but averaged 41% for all species. The order in the frequency of splitting was balsam fir, black spruce, white spruce and lodgepole pine. The type of splitting (straight, spiral, or multiple) varied by species, as did the position of the split on the tree bole. Aspect or solar angle was not statistically related to the type or occurrence of splitting.

An overview of the vegetation and soils of the floodplain ecosystems of the Tanana River, interior Alaska

1993 ◽  
Vol 23 (5) ◽  
pp. 889-898 ◽  
Author(s):  
L.A. Viereck ◽  
C.T. Dyrness ◽  
M.J. Foote
Keyword(s):  
Forest Succession ◽  
Black Spruce ◽  
White Spruce ◽  
Organic Layer ◽  
Organic Layers ◽  
Balsam Poplar ◽  
Feather Mosses ◽  
Successional Stages ◽  
Salt Affected Soils ◽  
Stochastic Events

The soils and vegetation of 12 stages of forest succession on the floodplain of the Tanana River are described. Succession begins with the invasion of newly deposited alluvium by willows (Salix spp.) and develops through a willow–alder (Alnustenuifolia Nutt.) stage to forest stands of balsam poplar (Populusbalsamifera L.), followed by white spruce (Piceaglauca (Moench) Voss), and finally black spruce (Piceamariana (Mill.) B.S.P.). The principal changes in substrate characteristics during the successional sequence are (i) change from sand to silt loam, (ii) increase in terrace height and distance from the water table, (iii) development of a forest floor, first of leaf litter and then live and dead feather mosses, (iv) burial of organic layers by flooding, and (v) the development of permafrost as soils are insulated by a thick organic layer. Soils and vegetation of six stands occurring in three successional stages used in the salt-affected soils study are described in detail: open willow stands (stage III), balsam poplar–alder stands (stage VI), and a mature white spruce stand (stage VIII). There is a general progression of plant species resulting from the modification of the environment by the developing vegetation and changes in soil characteristics. Life history and stochastic events are important in the early stages of succession, and biological controls such as facilitation and competition become more important in middle and late stages of succession.

scholarly journals Breeding Bird Communities in Boreal Forest of Western Canada: Consequences of “Unmixing” the Mixedwoods

The Condor ◽  
2000 ◽  
Vol 102 (4) ◽  
pp. 759-769 ◽  
Author(s):  
Keith A. Hobson ◽  
Erin Bayne
Keyword(s):  
Boreal Forest ◽  
Populus Tremuloides ◽  
Pinus Banksiana ◽  
Deciduous Forest ◽  
Black Spruce ◽  
Bird Species ◽  
White Spruce ◽  
Trembling Aspen ◽  
Vegetation Heterogeneity ◽  
Mixedwood Stands

Abstract Silvicultural practices following clearcutting in boreal forest may encourage the creation of monospecific, single-aged stands having less vegetation heterogeneity and diversity than original stands. We conducted point counts in central Saskatchewan, Canada, 1993–1995, in pure and mixedwood stands dominated by black spruce (Picea mariana), jackpine (Pinus banksiana), trembling aspen (Populus tremuloides), or white spruce (Picea glauca). Mixedwood stands supported more individuals and more species than pure stands. Higher abundance in mixedwood stands relative to pure stands was consistent among nesting guilds and migration strategies. Rarefaction revealed similar patterns, although pure trembling aspen stands were predicted to support more species than aspen-dominated mixedwood stands. Increased avian diversity in mixedwood stands was not solely the result of the mixing of bird species associated with coniferous or deciduous forest types. Chipping Sparrow (Spizella passerina), Pine Siskin (Carduelis pinus), White-winged Crossbill (Loxia leucoptera), Red-breasted Nuthatch (Sitta canadensis), Swainson's Thrush (Catharus ustulatus), and Tennessee Warbler (Vermivora peregrina) were more abundant in mixedwood stands than pure stands. Black-throated Green Warbler (Dendroica virens), Magnolia Warbler (D. magnolia), and Blackburnian Warbler (D. fusca) were abundant in stands dominated by white spruce but were absent from jackpine or black spruce. Other species such as American Redstart (Setophaga ruticilla) and Chestnut-sided Warbler (D. pensylvanica) relied exclusively on pure trembling aspen, particularly stands with dense shrub cover. Several bird species in the boreal forest will be adversely affected by forestry practices that target mature to old aspen and white spruce mixedwoods and promote reduction in mixedwood compositions of regenerating stands.

FOREST COMMUNITIES IN NORTHWESTERN ALBERTA

1953 ◽  
Vol 31 (2) ◽  
pp. 212-252 ◽  
Author(s):  
E. H. Moss
Keyword(s):  
Populus Tremuloides ◽  
Black Spruce ◽  
Abies Balsamea ◽  
White Spruce ◽  
Balsam Fir ◽  
Peat Moss ◽  
Mixed Stands ◽  
Natural Succession ◽  
Balsam Poplar ◽  
Feather Moss

Spruce, tamarack (larch), balsam fir, pine, and poplar communities of the region are described in terms of floristic composition and ecological relationships. The white spruce (Picea glauca) association is regarded as the climax type of the region. Of four phases or faciations presented by the white spruce association, the feather moss faciation appears to be the climax to which the other faciations tend to develop. Two black spruce (Picea mariana) communities are recognized, the black spruce – feather moss association and the black spruce–peat moss association. Of these, the former is characterized by "feather mosses" such as Hylocomium splendens and has developed on relatively level terrain without much peat formation, whereas the latter has a Sphagnum floor and has arisen in definite depressions through acid bog stages with the production of considerable peat. The black spruce – bog moss community is interpreted as subclimax, with natural succession to the black spruce – feather moss association. The tamarack (Larix laricina) community has many features in common with the black spruce – peat moss association but differs markedly, not only in its dominant species, but because of its development from a Drepano-cladus–Carex–Betula bog under persisting wet conditions. Succession to black spruce commonly occurs. Balsam fir (Abies balsamea) is relatively rare in the region and usually grows in mixed stands with white spruce, paper birch, aspen, and balsam poplar. Two divisions of the pine association are recognized, the jack pine (Pinus banksiana) and the lodgepole pine (P. contorta var. latifolia) consociations. For each of these, two phases are described, the pine – feather moss faciation on the more shaded sites and the pine–heath faciation on the more open and drier areas. Knowledge of the ranges of these two pines in northern Alberta and concerning hybrids between the species is extended. The poplar association, classified as aspen (Populus tremuloides) and balsam poplar (P. balsamifera) consociations, is considered in relation to other vegetation, especially prairie grassland and white spruce. Encroachment of aspen poplar upon native grassland is counteracted by various factors, notably burning. Natural succession of poplar and pine to white spruce is impeded chiefly by forest fires. Some attention is given to phytogeographical problems of this transition region.

Vegetation, soils, and forest productivity in selected forest types in interior Alaska

1983 ◽  
Vol 13 (5) ◽  
pp. 703-720 ◽  
Author(s):  
Leslie A. Viereck ◽  
C. T. Dyrness ◽  
Keith Van Cleve ◽  
M. Joan Foote
Keyword(s):  
Soil Moisture ◽  
Standing Crop ◽  
Environmental Gradient ◽  
Forest Type ◽  
Black Spruce ◽  
White Spruce ◽  
Forest Productivity ◽  
Balsam Poplar ◽  
Interior Alaska ◽  
Annual Productivity

Vegetation, forest productivity, and soils of 23 forest stands in the taiga of interior Alaska are described. The stands are arranged on an environmental gradient from an aspen (Populustremuloides Michx.) stand on a dry, steep south-facing bluff, to open black spruce (Piceamariana (Mill.) B.S.P.) stands underlain by permafrost on north-facing slopes. The coldest site is a mixed white spruce (Piceaglauca (Moench) Voss) and black spruce woodland at the treeline. Mesic upland sites are represented by successional stands of paper birch (Betulapapyrifera Marsh.) and aspen, and highly productive stands of white spruce. Several floodplain stands represent the successional sequence from productive balsam poplar (Populusbalsamifera L.) and white spruce to black spruce stands underlain by permafrost on the older terraces. The environmental gradient is described by using two soil factors: soil moisture and annual accumulated soil degree days (SDD), which range from 2217 SDD for the warmest aspen stand to 480 SDD for the coldest permafrost-dominated black spruce site. Soils vary from Alfie Cryochrepts on most of the mesic sites to Histic Pergelic Cryochrepts on the colder sites underlain by permafrost. A typical soil profile is described for each major forest type. A black spruce stand on permafrost has the lowest tree standing crop (15806 g•m−2) and annual productivity (56 g•m−2•year−1) whereas a mature white spruce stand has the largest tree standing crop (24 577 g•m−2) and an annual productivity of 540 g•m−2•year−1, but the successional balsam poplar stand on flood plain alluvium has the highest annual tree increment (952 g•m−2•year−1). The study supports the hypothesis that black spruce is a nutrient poor, unproductive forest type and that its low productivity is primarily the result of low soil temperature and high soil moisture.

Comparative drought sensitivity of co‐occurring white spruce and paper birch in interior Alaska

2021 ◽  
Author(s):  
Patrick F. Sullivan ◽  
Annalis H. Brownlee ◽  
Sarah B.Z. Ellison ◽  
Sean M.P. Cahoon
Keyword(s):  
White Spruce ◽  
Drought Sensitivity ◽  
Interior Alaska ◽  
Paper Birch
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