DEVELOPMENT OF WHITE SPRUCE AND ALPINE FIR SEEDLINGS ON CUT-OVER AREAS IN THE CENTRAL INTERIOR OF BRITISH COLUMBIA

1965 ◽  
Vol 41 (4) ◽  
pp. 419-431 ◽  
Author(s):  
Slavoj Eis

Germination of white spruce and alpine fir was similar on mineral soil at all forest sites studied and averaged 33 per cent for spruce and 6 per cent for alpine fir.Mortality of seedlings in mineral soil was confined to the period of summer droughts. During this period maximum air temperatures approached 100° F., mineral soil exceeded 120° F. and humus 135° F. Water content of the upper 20 to 40 mm. of mineral soil was reduced below the wilting point and approximately 45 per cent of the seedlings died. The average root length of seedlings which died was 18 mm.; of those which survived, 37 mm. Greatest mortality occurred on fully exposed plots of dry habitats.On undisturbed seedbeds, germination of both species was very low. Seeds remained suspended and had insufficient contact with humic particles. Radicles of seeds which did germinate failed to reach compacted moist horizons. At the depth of root penetration, raw humus was at wilting point a few days after rain. A negligible number of seedlings of either species survived on raw humus to the end of the growing season.Shoot growth of both species ended at the beginning of August, while roots kept increasing in length until late in fall. The depth of root penetration on mineral seedbeds was greatest on sandy soils. At the end of the growing season alpine fir seedlings were larger than spruce seedlings.The main cause of seedling mortality on both types of seedbed appears to be the water deficit in the root zone. Increased mortality on fully exposed plots can be attributed to the direct heating of the living tissue under water stress.

2018 ◽  
Vol 48 (4) ◽  
pp. 324-332 ◽  
Author(s):  
Nicola A. Kokkonen ◽  
S. Ellen Macdonald ◽  
Ian Curran ◽  
Simon M. Landhäusser ◽  
Victor J. Lieffers

Given a seed source, the quality of available substrates is a key factor in determining the success of white spruce (Picea glauca (Moench) Voss) natural regeneration. We examined the influence of substrate and competing vegetation on survival and growth of natural regeneration of white spruce up to 4 years following harvesting in deciduous-dominated upland boreal mixedwood sites. Feather moss, thick soil surface organic layers, litter, and solid wood were poor substrates for establishment. Early successional mosses establishing on mineral soil, thin organics, and rotten wood were generally favourable microsites but were not highly available on postharvest sites. Mineral soil substrates were not as suitable as expected, likely because on a postlogged site, they are associated with unfavourable environmental characteristics (e.g., low nutrient availability, exposure). There was some evidence that survival and growth of seedlings were improved by surrounding vegetation in the first years, but heavy competing vegetation had a negative impact on older seedlings. Burial by aspen litter greatly increased seedling mortality, especially when combined with a brief period of submergence due to heavy spring snowmelt. The results provide insight into conditions under which natural regeneration could be an option for establishing white spruce following harvesting of deciduous-dominated boreal mixedwood forests.


2005 ◽  
Vol 35 (3) ◽  
pp. 667-673 ◽  
Author(s):  
G. Geoff Wang ◽  
Kevin J Kemball

Experimental seeding of balsam fir (Abies balsamea (L.) Mill.) and white spruce (Picea glauca (Moench) Voss) was implemented in three mature trembling aspen (Populus tremuloides Michx.) stands in southeastern Manitoba to test (i) the effect of vegetation (light) competition and seedbed type (undisturbed forest floor, exposed mineral soil, and rotten logs) on seedling recruitment over the first 2 years and (ii) the effect of broadleaf litter exclusion on seedling mortality during the first winter. The study indicated that, with adequate seed supply, seedbed type was the most important factor limiting seedling recruitment, especially the recruitment of white spruce, in trembling aspen stands. Seedling recruitment on the best and the worst seedbeds differed by 1.8 times for balsam fir but by 19 times for white spruce. Significant differences in soil moisture and temperature were found between seedbed types. Broadleaf litter exclusion also facilitated the recruitment of balsam fir and white spruce, but only on undisturbed forest floor. Vegetation (light) competition, however, did not limit seedling recruitment. On the contrary, the presence of understory vegetation benefited seedling recruitment on rotten logs. Compared with white spruce, balsam fir is better adapted to regenerate in trembling aspen stands. Balsam fir was about 4, 12, and 36 times better than white spruce when regenerating on exposed mineral soil, rotten log, and undisturbed forest floor, respectively.


HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 451a-451
Author(s):  
Eric J. Biddinger ◽  
Robert D. Berghage ◽  
David J. Beattie

There is an increasing interest in the use of fiber pots to grow containerized nursery plants. Of particular interest is the ability to incorporate chemicals to modify plant growth, reduce microbial decomposition, and alter fiber structure. Four perennial plants Forsythia `Spring Glory', Baptisia australis, Ilex × meserveae `Blue Girl', and Coreopsis rosea were grown in 2.3-L fiber containers. Containers were treated with Cu(OH)2 (Spin Out®, Griffin Corp.) at 1500 or 3000 ppm, TCMBT (Busan® 30WB fungicide, Buckman Lab.) at 1700 or 3400 ppm, and combinations of Cu(OH)2 and TCMBT. Untreated plastic and untreated fiber pots were used as controls. Plants were grown in a commercial nursery in central Pennsylvania for 5 months during the 1997 growing season. Plants were harvested in the fall. Data included: root penetration of pot walls, plant growth, pot strength, medium root distribution, and root zone temperatures. Results with TCMBT were inconclusive. However, Cu(OH)2-treated pots had fewer penetrating roots and were stronger. Root zone temperatures in fiber pots were lower.


1967 ◽  
Vol 43 (2) ◽  
pp. 174-177 ◽  
Author(s):  
S. Eis

Survival and growth of white spruce seedlings and juvenile trees were compared on two seedbeds, three forest sites, and a range of light conditions in the central interior of British Columbia. For germination, the most favourable seedbed was mineral soil in shade on moist and wet sites; for survival, mineral soil, dry habitats, partial shade; for growth, mineral soil, moist habitats, full light exposure.


2005 ◽  
Vol 22 (3) ◽  
pp. 154-161 ◽  
Author(s):  
Juha Heiskanen ◽  
Heli Viiri

Abstract The European pine weevil (Hylobius abietis L.) is not found in northern America so far but is the major pest in conifer reforestation in northern Europe. The effects of mounding on pine-weevil damage and growth in planted Norway spruce (Picea abies (L.) Karst.) seedlings were studied on two clearcut forest sites in Finland. Three different mounding treatments (spot mounding with or without mixing and inverting) were compared to three unscarified treatments with or without vegetation control (mulch or herbicide). Mounding significantly decreased pine-weevil damage, mortality, and growth losses of planted Norway spruce seedlings even if insecticide was used before planting. Seedling growth and survival were poorest with the heaviest feeding by the pine weevil. After the first growing season, the proportion of gnawed seedlings was higher on unscarified spots (76% gnawed), whereas seedlings on mounded spots had hardly any feeding (1%). Seedling mortality was lower on mounded (1%) than on unscarified spots, where it was higher in 1-year-old (27%) than 2-year-old seedlings (10%). After the second growing season, mortality and proportion of gnawed seedlings increased on both mounded and unscarified spots. The study indicates that mounding can provide an effective method of decreasing pine-weevil damage and improving plantation success.North. J. Appl. For. 22(3):154 –161.


2021 ◽  
Vol 165 (3-4) ◽  
Author(s):  
Maria Vorkauf ◽  
Christoph Marty ◽  
Ansgar Kahmen ◽  
Erika Hiltbrunner

AbstractThe start of the growing season for alpine plants is primarily determined by the date of snowmelt. We analysed time series of snow depth at 23 manually operated and 15 automatic (IMIS) stations between 1055 and 2555 m asl in the Swiss Central Alps. Between 1958 and 2019, snowmelt dates occurred 2.8 ± 1.3 days earlier in the year per decade, with a strong shift towards earlier snowmelt dates during the late 1980s and early 1990s, but non-significant trends thereafter. Snowmelt dates at high-elevation automatic stations strongly correlated with snowmelt dates at lower-elevation manual stations. At all elevations, snowmelt dates strongly depended on spring air temperatures. More specifically, 44% of the variance in snowmelt dates was explained by the first day when a three-week running mean of daily air temperatures passed a 5 °C threshold. The mean winter snow depth accounted for 30% of the variance. We adopted the effects of air temperature and snowpack height to Swiss climate change scenarios to explore likely snowmelt trends throughout the twenty-first century. Under a high-emission scenario (RCP8.5), we simulated snowmelt dates to advance by 6 days per decade by the end of the century. By then, snowmelt dates could occur one month earlier than during the reference periods (1990–2019 and 2000–2019). Such early snowmelt may extend the alpine growing season by one third of its current duration while exposing alpine plants to shorter daylengths and adding a higher risk of freezing damage.


Author(s):  
Mireia Fontanet ◽  
Daniel Fernàndez-Garcia ◽  
Gema Rodrigo ◽  
Francesc Ferrer ◽  
Josep Maria Villar

AbstractIn the context of growing evidence of climate change and the fact that agriculture uses about 70% of all the water available for irrigation in semi-arid areas, there is an increasing probability of water scarcity scenarios. Water irrigation optimization is, therefore, one of the main goals of researchers and stakeholders involved in irrigated agriculture. Irrigation scheduling is often conducted based on simple water requirement calculations without accounting for the strong link between water movement in the root zone, soil–water–crop productivity and irrigation expenses. In this work, we present a combined simulation and optimization framework aimed at estimating irrigation parameters that maximize the crop net margin. The simulation component couples the movement of water in a variably saturated porous media driven by irrigation with crop water uptake and crop yields. The optimization component assures maximum gain with minimum cost of crop production during a growing season. An application of the method demonstrates that an optimal solution exists and substantially differs from traditional methods. In contrast to traditional methods, results show that the optimal irrigation scheduling solution prevents water logging and provides a more constant value of water content during the entire growing season within the root zone. As a result, in this case, the crop net margin cost exhibits a substantial increase with respect to the traditional method. The optimal irrigation scheduling solution is also shown to strongly depend on the particular soil hydraulic properties of the given field site.


Agriculture ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 67
Author(s):  
Piotr Żurawik

Crustaceans, including shrimps, are an important group of marine products processed in over 50 countries around the world. It is one of the most profitable and fast-growing processing branches. About 30 to 40% of crustaceans are used immediately after fishing, while 60–70% are processed. This generates thousands of tons of waste, proper management of which becomes increasingly important. The study was conducted in the years 2015–2017. Planting material included rhizomes of Miscanthus sinensis and Miscanthus × giganteus. Shrimp shells, dried and fragmented into 2–3 mm long pieces, were added to the soil at a dose of 5%, 10% and 15%. Mineral soil without the dried waste served as control. pH and substrate salinity were determined both before and after the growing season, and vegetative and generative traits of the plants were assessed. Shrimp biowaste is rich in N, P, K, Ca and Mg, has alkaline pH and high salinity. Its effects on plants depend on its dose and plant species. Miscanthus sinensis turned out more sensitive to the substrate salinity but in both species shrimp biowaste improved their ornamental value. For Miscanthus sinensis the most beneficial dose was 5%, while for Miscanthus × giganteus it was 15%.


2003 ◽  
Vol 18 (2) ◽  
pp. 109-114 ◽  
Author(s):  
Steven J. Stein ◽  
Diana N. Kimberling

Abstract Information on the mortality factors affecting naturally seeded conifer seedlings is becoming increasingly important to forest managers for both economic and ecological reasons. Mortality factors affecting ponderosa pine (Pinus ponderosa) seedlings immediately following natural germination and through the following year were monitored in Northern Arizona. The four major mortality factors in temporal order included the failure of roots to establish in the soil (27%), herbivory by lepidopteran larvae (28%), desiccation (30%), and winterkill (10%). These mortality factors were compared among seedlings germinating in three different overstory densities and an experimental water treatment. Seedlings that were experimentally watered experienced greater mortality than natural seedlings due to herbivory (40%), nearly as much mortality due to the failure of roots to establish in the soil (20%), less mortality due to winterkill (5%), and no mortality due to desiccation. The seedling mortality data through time were summarized using survivorship curves and life tables. Our results suggest that managers should consider using prescribed burns to decrease the percentage of seedlings that die from failure of their roots to reach mineral soil and from attack by lepidopteran larvae. West. J. Appl. For. 18(2):109–114.


1994 ◽  
Vol 70 (2) ◽  
pp. 151-158 ◽  
Author(s):  
R. L. Fleming ◽  
D. S. Mossa

A series of spot seeding experiments was set out on coarse-textured upland sites in northwestern Ontario to investigate how black spruce (Picea mariana [Mill.] B.S.P.) seedling establishment and growth could be improved by site selection and seedbed preparation. Virtually all germination occurred within the first growing season. Annual seedling mortality rates were greatest during the first year, then declined steadily and stabilized at low levels (<10%) after the third year. The highest fifth-year establishment ratios (seedlings/viable seed sown) were found on seedbeds derived from materials near the mineral soil/humus interface. On wetter sites (i.e., higher Soil Moisture Regimes) the best seedbeds occurred closer to the soil surface. Mean fifth year establishment ratios for the best seedbeds were 0.032 on moderately fresh to fresh sites, 0.146 on very fresh to moderately moist sites, and 0.082 on moist to very moist sites. On adjacent lowland sites, slow-growing, compact Sphagnum mosses had a mean establishment ratio of 0.179. Mean fifth-year seedling heights on upland sites ranged from 12 to 14 cm, and were not strongly correlated with site or seedbed type. Key words: direct seeding, black spruce, seedbed, seedling establishment, site type and germination


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