Direct seeding techniques to regenerate white spruce in interior Alaska

1986 ◽  
Vol 16 (3) ◽  
pp. 660-664 ◽  
Author(s):  
William E. Putman ◽  
John C. Zasada
Keyword(s):  
Seedling Survival ◽  
Growing Season ◽  
White Spruce ◽  
Direct Seeding ◽  
Sowing Time ◽  
Interior Alaska

Direct seeding techniques for regenerating white spruce (Piceaglauca (Moench) Voss) were tested on 12 logged areas near Fairbanks, AK. Techniques examined included spot seeding on scarified seed spots with and without plastic cone shelters and spot seeding on nonscarified seed spots with and without plastic funnel shelters, all at three sowing times. After the second growing season, scarified treatments produced greater seedling survival. Cone shelters usually produced greater survival than unsheltered seeding on scarified seed spots and funnel shelters usually produced greater survival than unsheltered seeding on non-scarified seed spots. Sowing time had little effect on survival.

Embryo growth in Alaskan white spruce seeds

1988 ◽  
Vol 18 (1) ◽  
pp. 64-67 ◽  
Author(s):  
John C. Zasada
Keyword(s):  
Soil Moisture ◽  
Seed Dispersal ◽  
Embryo Development ◽  
Growing Season ◽  
White Spruce ◽  
High Elevation ◽  
Seed Collection ◽  
Interior Alaska ◽  
Lower Elevation ◽  
Soil Temperatures

Embryo development in white spruce seeds was studied in five stands in interior Alaska. Cones and seeds were collected at 10- to 14-day intervals starting in mid-July and continuing until just before seed dispersal began. Significant differences were found in embryo development between stands, between trees within stands, and between cones within trees. The four stands at lower elevations produced seeds that had embryos filling 95% or more of the embryo cavity; this percentage was significantly higher than the highest elevation stand where embryos filled about 75% of the embryo cavity at the end of the growing season. Relative cotyledon length was generally greater than 25% in the lower elevation stands and slightly less than 20% in the high elevation stand. Although seed collection can be started when embryos fill 75% of the embryo cavity, the results of this and other studies suggest that collecting seeds when embryos are more mature will result in better quality seeds. Air and soil temperatures and soil moisture levels associated with embryo development are presented.

Dynamics of CO2 emission from chernozems under agricultural use

2017 ◽  
Vol 4 (3) ◽  
pp. 43-49
Author(s):  
M. Miroshnychenko ◽  
O. Siabruk
Keyword(s):  
Carbon Dioxide ◽  
Agricultural Practices ◽  
Growing Season ◽  
Warm Period ◽  
Direct Seeding ◽  
Soil Tillage ◽  
Plant Residues ◽  
Hydrothermal Conditions ◽  
Organic Mineral ◽  
Mineral System

Aim. The comparison of the effect of hydrothermal conditions and various agricultural practices on the emission of CO 2 from chernozems in the Left-Bank Forest-Steppe of Ukraine. Methods. The dynamics of the intensity of carbon dioxide emissions from chernozem calcic (typical chernozem – in Ukrainian classifi cation) was studied during the growing season of 2011–2012. The observations were based on two fi eld experiments with various methods of soil till- age (6–7 years from the beginning of the experiment) and fertilization systems (21–22 years from the beginning of the experiment). Particularly, plowing at 20–22 cm, disking at 10–12 cm, cultivation at 6–8 cm and direct seeding using Great Plains drill were studied among the soil tillage methods. Mineral system (N 45 P 50 K 45 ), organic system (manure 8 t/ha) and combined organic-mineral system (manure 8 t/ha + N 45 P 50 K 45 ) were studied among fertilization systems. The intensity of CO 2 fl ux was determined using the non-stationary respiratory chambers by the alkaline absorption method, with averaging of the results during the day and the frequency of once a month. Results. During the warm period, the emission of carbon dioxide from the soil changes dynamically depending on temperature and humidity. The maximum of emission coincides with the periods of warm summer showers in June-July, the minimum values are characteristic for the late autumn period. The total emission losses of carbon in chernozems over the vegetation period ranged from 480 to 910 kg/ha and varied depending on the methods of tillage ± (4.0–6.0) % and fertilization systems ± (3.8–7.1) %. The changes in the intensity of CO 2 emission from the soil under different methods of soil tillage are associated with hydrothermal regime and the depth of crop residues location. The biggest difference is observed im- mediately after tillage, but in the spring period the differences are only 12–25 %, and after drying of the top layer of soil become even less. Direct seeding technology provides the greatest emission of CO 2 from chernozem, which is fa- cilitated by better water regime and more complete mineralization of plant residues on the soil surface. Annual losses of carbon are the least under disking of soil at 10–12 cm. The changes in the intensity of CO 2 emission from the soil under different fertilization systems are associated with the involvement of the additional organic matter from plant residues and manure to the microbiological decomposition. The greatest emission was observed under the organic- mineral fertilization system, which increased the loss of carbon by 7–8 % in comparison with the mineral system in the unfavorable hydrothermal year and by 11–15 % in the more favorable year. These differences are observed mainly during the fi rst half of the growing season when there is a clear tendency to increase the intensity of soil respiration. Conclusions. The hydrothermal conditions of the warm period of the year are decisive in the formation of the CO 2 emission fl ow from chernozems. Due to the improvement of agricultural practices, emissions might be reduced but not more that by 15 % of natural factor contribution.

scholarly journals Rattail fescue (Vulpia myuros) interference and seed production as affected by sowing time and crop density in winter wheat

Weed Science ◽  
2020 ◽  
pp. 1-10
Author(s):  
Muhammad Javaid Akhter ◽  
Per Kudsk ◽  
Solvejg Kopp Mathiassen ◽  
Bo Melander
Keyword(s):  
Winter Wheat ◽  
Grain Yield ◽  
Seed Production ◽  
Yield Components ◽  
Field Experiments ◽  
Growing Season ◽  
Sowing Time ◽  
Growing Seasons ◽  
Crop Density ◽  
Wide Range

Abstract Field experiments were conducted in the growing seasons of 2017 to 2018 and 2018 to 2019 to evaluate the competitive effects of rattail fescue [Vulpia myuros (L.) C.C. Gmel.] in winter wheat (Triticum aestivum L.) and to assess whether delayed crop sowing and increased crop density influence the emergence, competitiveness, and fecundity of V. myuros. Cumulative emergence showed the potential of V. myuros to emerge rapidly and under a wide range of climatic conditions with no effect of crop density and variable effects of sowing time between the two experiments. Grain yield and yield components were negatively affected by increasing V. myuros density. The relationship between grain yield and V. myuros density was not influenced by sowing time or by crop density, but crop–weed competition was strongly influenced by growing conditions. Due to very different weather conditions, grain yield reductions were lower in the growing season of 2017 to 2018 than in 2018 to 2019, with maximum grain yield losses of 22% and 50% in the two growing seasons, respectively. The yield components, number of crop ears per square meter, and 1,000-kernel weight were affected almost equally, reflecting that V. myuros’s competition with winter wheat occurred both early and late in the growing season. Seed production of V. myuros was suppressed by delaying sowing and increasing crop density. The impacts of delayed sowing and increasing crop density on seed production of V. myuros highlight the potential of these cultural weed control tactics in the long-term management programs of this species.

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

Hydrological implications of vegetation change in a subarctic, alpine catchment, Yukon Territory, Canada 

2021 ◽  
Author(s):  
Erin Nicholls ◽  
Gordon Drewitt ◽  
Sean Carey
Keyword(s):  
Soil Moisture ◽  
Interannual Variability ◽  
Sap Flow ◽  
Vegetation Change ◽  
Vegetation Type ◽  
Growing Season ◽  
White Spruce ◽  
Yukon Territory ◽  
Precipitation Regimes ◽  
Tall Shrub

<p>As a result of altitude and latitude amplified impacts of climate change, widespread alterations in vegetation composition, density and distribution are widely observed across the circumpolar north. The influence of this vegetation change on the timing and magnitude of hydrological fluxes is uncertain, and is confounded by changes driven by increased temperatures and altered precipitation (P) regimes. In northern alpine catchments, quantification of total evapotranspiration (ET) and evaporative partitioning across a range of elevation-based ecosystems is critical for predicting water yield under change, yet remains challenging due to coupled environmental and phenological controls on transpiration (T). In this work, we analyze 6 years of surface energy balance, ET, and sap flow data at three sites along an elevational gradient in a subarctic, alpine catchment near Whitehorse, Yukon Territory, Canada. These sites provide a space-for-time evaluation of vegetation shifts and include: 1) a low-elevation boreal white spruce forest (~20 m), 2) a mid-elevation subalpine taiga comprised of tall willow (Salix) and birch (Betula) shrubs (~1-3 m) and 3) a high-elevation subalpine taiga with shorter shrub cover (< 0.75 m) and moss, lichen, and bare rock. Specific objectives are to 1) evaluate interannual ET dynamics within and among sites under different precipitation regimes , and 2) assess the influence of vegetation type and structure, phenology, soil and meteorological controls on ET dynamics and partitioning.  Eddy covariance and sap flow sensors operated year-round at the forest and during the growing season at the mid-elevation site on both willow and birch shrubs for two years. Growing season ET decreased and interannual variability increased with elevation, with June to August ET totals of 250 (±3) mm at Forest, 192 (±9) mm at the tall shrub site, and 180 (± 26) mm at the short shrub site. Comparatively, AET:P ratios were the highest and most variable at the forest (2.4 ± 0.3) and similar at the tall and short shrub (1.2 ± 0.1).  At the forest, net radiation was the primary control on ET, and 55% was direct T from white spruce. At the shrub sites, monthly ET rates were similar except during the peak growing season when T at the tall shrub site comprised 89% of ET, resulting in greater total water loss. Soil moisture strongly influenced T at the forest, suggesting the potential for moisture stress, yet not at the shrub sites where there was no moisture limitation. Results indicate that elevation advances in treeline will increase overall ET and lower interannual variability; yet the large water deficit during summer implies a strong reliance on early spring snowmelt recharge to sustain soil moisture. Changes in shrub height and density will increase ET primarily during the mid-growing season. This work supports the assertion that predicted changes in vegetation type and structure will have a considerable impact on water partitioning in northern regions, and will also vary in a multifaceted way in response to changing temperature and P regimes.  </p>

Direct seeding of PinusSylvestris using microsite preparation and invigorated seed lots of different quality: 2-year results

1994 ◽  
Vol 24 (1) ◽  
pp. 77-86 ◽  
Author(s):  
Hans Winsa ◽  
Urban Bergsten
Keyword(s):  
Seed Quality ◽  
Seedling Survival ◽  
Seedling Emergence ◽  
Mineral Soil ◽  
Direct Seeding ◽  
Growing Seasons ◽  
Humus Layer ◽  
Negative Effect ◽  
Mean Germination Time ◽  
Better Than

Direct seeding of Pinussylvestris L. is a regeneration method, with potential for development considering scarification, microsite preparation, seed invigoration, and seed quality. Three seed lots of different quality concerning seed weight, germination percent, and mean germination time were used on two sites in northern Sweden. Microsite preparation, 2 cm deep pyramidal indentations, of the mineral soil improved seedling emergence on the two sites by 48 and 62%, respectively, compared with seeding without preparation other than removal of the humus layer. Microsite preparation in combination with invigorated seed, i.e., seed incubated at 30% moisture content for 7 days at 15 °C, resulted in seedling emergence of about 85% for the highest and about 50% for the lowest seed quality at both sites. Noninvigorated seed, seeded without microsite preparation, reached about 55% for the highest and 22% at one and 43% at the other for the lowest seed quality. Without microsite preparation there was no, or a negative, effect of seed invigoration on seedling emergence. Seedling survival after the first winter improved significantly with better seed quality. Survival averaged 92 and 72% at the two sites, with frost heaving causing most mortality. Seedlings from invigorated and redried seed survived better than seedlings from untreated seed. Seedlings from the best seed quality had higher values in seedling height, about 35%, shoot length, about 60%, and needle length, about 30%, after two growing seasons than seedlings from lower seed qualities. Invigoration and microsite preparation had no effect on measured growth characteristics.

A 200-Year Perspective of Climate Variability and the Response of White Spruce in Interior Alaska

2003 ◽  
Author(s):  
Glenn Patrick Juday ◽  
Valerie Barber
Keyword(s):  
Nineteenth Century ◽  
North America ◽  
Climate Variability ◽  
Tree Ring ◽  
Tree Growth ◽  
White Spruce ◽  
Boreal Region ◽  
The North ◽  
Interior Alaska ◽  
Summer Temperatures

The two most important life functions that organisms carry out to persist in the environment are reproduction and growth. In this chapter we examine the role of climate and climate variability as controlling factors in the growth of one of the most important and productive of the North American boreal forest tree species, white spruce (Picea glauca [Moench] Voss). Because the relationship between climate and tree growth is so close, tree-ring properties have been used successfully for many years as a proxy to reconstruct past climates. Our recent reconstruction of nineteenth- century summer temperatures at Fairbanks based on white spruce tree-ring characteristics (Barber et al. in press) reveals a fundamental pattern of quasi-decadal climate variability. The values in this reconstruction of nineteenth-century Fairbanks summer temperatures are surprisingly warm compared to values in much of the published paleoclimatic literature for boreal North America. In this chapter we compare our temperature reconstructions with ring-width records in northern and south-central Alaska to see whether tree-growth signals in the nineteenth century in those regions are consistent with tree-ring characteristics in and near Bonanza Creek (BNZ) LTER (25 km southwest of Fairbanks) that suggest warm temperatures during the mid-nineteenth century. We also present a conceptual model of key limiting events in white spruce reproduction and compare it to a 39-year record of seed fall at BNZ. Finally, we derive a radial growth pattern index from white spruce at nine stands across Interior Alaska that matches recent major seed crop events in the BNZ monitoring period, and we identify dates after 1800 when major seed crops of white spruce, which are infrequent, may have been produced. The boreal region is characterized by a broad zone of forest with a continuous distribution across Eurasia and North America, amounting to about 17% of the earth’s land surface area (Bonan et al. 1992). The boreal region is often conceived of as a zone of relatively homogenous climate, but in fact a surprising diversity of climates are present. During the long days of summer, continental interior locations under persistent high-pressure systems experience hot weather that can promote extensive forest fires frequently exceeding 100 kilohectares (K ha). Summer daily maximum temperatures are cooled to a considerable degree in maritime portions of the boreal region affected by air masses that originate over the North Atlantic, North Pacific, or Arctic Oceans.

Container Volume Affects Survival and Growth of White Spruce, Black Spruce, and Jack Pine Seedlings: A Literature Review

1988 ◽  
Vol 5 (3) ◽  
pp. 185-189 ◽  
Author(s):  
D. Craig Sutherland ◽  
Robert J. Day
Keyword(s):  
Literature Review ◽  
Seedling Growth ◽  
Black Spruce ◽  
Seedling Survival ◽  
White Spruce ◽  
Jack Pine ◽  
Greenhouse Production ◽  
Production Phase ◽  
Pine Seedlings ◽  
Survival And Growth

Abstract This paper is the first general review of the affects of container volume on the survival and growth of containerized white spruce, black spruce, and jack pine seedlings. The review shows that the literature on this topic is fragmentary and inconsistent. Seedling growth in the greenhouse production phase has been more completely quantified than subsequent establishment and growth after out-planting in the field. In the greenhouse production phase, seedling growth increased from 72 to 360% when the container volume was tripled in size. After outplanting in the field, seedling growth trends were more variable. Seedling height growth increased from 34 to 84% when container volume was tripled in size. Seedling survival was more difficult to assess because of limited data. Only white spruce showed a 10% increase in survival with an increase in container volume. The indications from this literature review suggest that nursery managers and practicing foresters should become more aware of the limitations imposed on seedling survival and growth due to container volume. To maintain optional survival and growth for white spruce, black spruce and jack pine, the container volume should range from 90 to 120 cm3. North. J. Appl. For. 5:185-189, Sept. 1988.

Consistent negative temperature sensitivity and positive influence of precipitation on growth of floodplain Picea glauca in Interior Alaska

2012 ◽  
Vol 42 (3) ◽  
pp. 561-573 ◽  
Author(s):  
Glenn Patrick Juday ◽  
Claire Alix
Keyword(s):  
Picea Glauca ◽  
Negative Relationship ◽  
Ring Width ◽  
Negative Temperature ◽  
White Spruce ◽  
Positive Influence ◽  
Monthly Precipitation ◽  
Temperature And Precipitation ◽  
Interior Alaska ◽  
Common Signal

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.

Root and shoot biomass and mycorrhizal development of white spruce seedlings naturally regenerating in interior Alaskan floodplain communities

1984 ◽  
Vol 14 (4) ◽  
pp. 554-558 ◽  
Author(s):  
M. E. Krasny ◽  
K. A. Vogt ◽  
J. C. Zasada
Keyword(s):  
Boreal Forest ◽  
Mycorrhizal Fungi ◽  
Growing Season ◽  
White Spruce ◽  
Shoot Biomass ◽  
Seedling Biomass ◽  
Mycorrhizal Development ◽  
Root:Shoot Ratios ◽  
Root And Shoot Biomass

Root and shoot biomass and mycorrhizal development were examined for white spruce (Piceaglauca (Moench) Voss) seedlings naturally regenerating in four floodplain communities in the boreal forest. Mean seedling biomass was highest in the open community and lowest in the spruce community. Seedlings growing in the open community had higher root:shoot ratios (0.50) compared with seedlings growing in the willow (0.34), alder (0.20), and spruce (0.24) communities. Essentially all short roots of spruce seedlings growing in all four communities were infected by mycorrhizal fungi throughout the growing season.

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