Effect of shelterwood removal methods on established regeneration in an Alaska white spruce stand

1990 ◽  
Vol 20 (9) ◽  
pp. 1378-1381 ◽  
Author(s):  
Andrew P. Youngblood

Seedling damage during overstory removal was compared among different yarding methods; almost three times more mortality was associated with rubber-tired ground skidding than with skyline cable yarding. Seedlings ranging in height from 0.4 to 1.0 m generally received less damage or had lower mortality rates from cable yarding than did shorter or taller seedlings. Snowpack disturbance and percentage of seedling mortality were positively correlated. Results suggested that with attention to seedling height growth and yarding method, the shelterwood regeneration system is a viable option for white spruce (Piceaglauca (Moench) Voss) stand regeneration in interior Alaska.

1967 ◽  
Vol 43 (4) ◽  
pp. 365-371
Author(s):  
A. K. Hellum

A one-year phenological study with white spruce seedlings in central Alberta has shown that seasonal height growth is positively correlated with length of growing period, size of terminal bud, and length of terminal. Bud size is closely related to seedling height but is also affected by factors of the environment and genetic variability among seedlings.


1983 ◽  
Vol 13 (2) ◽  
pp. 339-343
Author(s):  
S. Eis ◽  
D. Craigdallie

Survival and height growth of planted white spruce, Piceaglauca (Moench) Voss, and alpine fir, Abieslasiocarpa (Hook.) Nutt., seedlings, the growth of competing shrubs, and height, diameter, and volume growth of spruce and fir up to about 130 years of age were studied on Alluvial and Aralia sites in the central interior of British Columbia to assess the suitability of alpine fir for restocking the sites where shrub competition causes heavy seedling mortality of spruce. Alpine fir regenerated successfully under heavy shrub competition where spruce generally failed, and its growth up to almost 100 years was better than that of spruce. Spruce maintained its growth longer. Spruce should be favored where its regeneration can be assured. Where shrubs prevent regeneration of spruce, however, alpine fir may provide a viable and even economically justifiable alternative.


2021 ◽  
Author(s):  
Patrick F. Sullivan ◽  
Annalis H. Brownlee ◽  
Sarah B.Z. Ellison ◽  
Sean M.P. Cahoon

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.


2009 ◽  
Vol 16 (10) ◽  
pp. 1527-1528 ◽  
Author(s):  
Rafael Zaragoza ◽  
Javier Pemán ◽  
Guillermo Quindós ◽  
Jose R. Iruretagoyena ◽  
María S. Cuétara ◽  
...  

ABSTRACT The influence of kinetic patterns of Candida albicans germ tube antibodies (CAGTA) on mortality was analyzed in six intensive care units. Statistically significant lower mortality rates were found in patients with patterns of increasing CAGTA titers who had been treated with antifungal agents. Thus, antifungal treatment should be considered when CAGTA titers are increasing in critically ill patients.


1984 ◽  
Vol 14 (6) ◽  
pp. 909-913 ◽  
Author(s):  
Y. S. Park ◽  
D. P. Fowler ◽  
J. F. Coles

Natural inbreeding and relatedness among neighboring trees were studied in several central New Brunswick populations of white spruce (Piceaglauca (Moench) Voss). Coefficients of relationship (r) were estimated by comparing the self-, neighbor-, open-, and unrelated-pollination effects on percent full seed. The estimates were 0.29 and 0.28 for neighbor and open pollinations, respectively. The effects of natural inbreeding on juvenile traits, e.g., germination and early growth, were slight while the effect on height growth increased with age at least to age 7 years. Neighboring white spruce trees growing in natural stands appear to be related at about the half-sib level (r = 0.25). Based on percent full seed, open-pollination approximates a level of inbreeding expected from trees related at a level well above that of half-sibs. Differential selection at the pre-embryo to early seedling stages results in progenies again related at the half-sib level. It is suggested that an inbreeding equilibrium exists in natural stands of white spruce and that this equilibrium approximates that expected from half-sib matings (F = 0.125). The inbreeding equilibrium is controlled, at least in part, by the frequency of lethal genes in the populations.


Author(s):  
Glenn Patrick Juday ◽  
Valerie Barber

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.


2007 ◽  
Vol 24 (4) ◽  
pp. 296-300 ◽  
Author(s):  
Yuhui Weng ◽  
Kathy Tosh ◽  
Yill Sung Park ◽  
Michele S. Fullarton

Abstract Polycross-pollinated white spruce (Picea glauca [Moench] Voss) families were evaluated in field and retrospective nursery tests in 1989, 1991, and 1992, respectively. Height growth was measured at age 10 for the field tests and at ages 1 to 6 for the retrospective nursery tests. Except for a few cases, the family mean correlations between nursery and field heights were significant for the 1989 and 1992 series, and their corresponding genetic correlations ranged from low to medium (from 0.37 to 0.74). Because of heavy noncrop competition, height growth in the 1991 nursery series showed consistently lower heritabilities and correlations with field performance compared with those of the other two series. Early nursery selection by theoretical prediction was generally efficient for the 1989 and 1992 series. Rank classification analysis indicated that application of early nursery selection should be used with caution for identifying elite families but could be used to cull inferior families or clones, apply multiple-stage selection, or perform positive assortative mating.


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