Comparisons of phenology and growth of Michigan and western North American sources of Populus tremuloides

1984 ◽  
Vol 14 (6) ◽  
pp. 789-793 ◽  
Author(s):  
John C. Brissette ◽  
Burton V. Barnes
Keyword(s):  
British Columbia ◽  
Populus Tremuloides ◽  
North American ◽  
Poor Performance ◽  
Growing Season ◽  
Early Growth ◽  
The Poor ◽  
Survival And Growth

Populustremuloides Michaux progeny from 13 local clones and 12 clones from five locations in Alaska, Alberta, and Utah were grown in southeastern Michigan to compare phenology and early growth. The progeny of western clones broke bud as much as 2 weeks before, and stopped growth up to 2 months earlier than local clones. After 2 years the western progeny averaged only 26–38% the height of the Michigan progeny. Survival and growth of ramets from 49 clones collected from British Columbia to Colorado and planted in southeastern Michigan were studied after 7 years. Only 30% of the 116 ramets and 39% of the clones survived. The poor performance of western clones in both experiments is probably due to their adaptation to longer photoperiods and (or) lower growing season minimum temperatures than occur in southeastern Michigan.

Soil temperatures and suckering response of trembling aspen (Populus tremuloides Michx.) following disposal of hog on winter-logged cutblocks

2004 ◽  
Vol 80 (6) ◽  
pp. 687-693 ◽  
Author(s):  
Timothy Conlin ◽  
Dave Cheyne ◽  
John Dymond
Keyword(s):  
British Columbia ◽  
Soil Temperature ◽  
Key Words ◽  
Populus Tremuloides ◽  
Growing Season ◽  
Soil Warming ◽  
Wood Residue ◽  
Application Rates ◽  
Soil Temperatures ◽  
Temperature Levels

Bark and wood residue, commonly referred to as "hog fuel" or "hog," from a portable pulp chipper was deposited on aspen cutblocks in replicated 10 x 10 m treatment plots during winter logging operations in northeastern British Columbia. The treatments emulated disposal of hog under conditions that simulated on-site chipping operations. Three different rates of hog disposal were applied; 34, 68 and 102 kg m-2, and three cutblocks were treated, one each during February of 1997, and March of 1998 and 1999. We originally hypothesized that the deposition of hog would lower soil temperatures in the treated plots and reduce aspen sucker density during the following growing season. However, our observations showed an initial lag in soil warming in the treatments followed by temperature levels that rose above that exhibited in the control plots. Higher soil temperatures were correlated with greater rates of hog disposal. Increased suckering was not observed in response to higher soil temperatures and stem densities decreased as hog application rates increased. Key words: in-woods, on-site, chipping, Populus tremuloides, hog fuel, soil temperature

Weekly xylem production in trembling aspen (Populus tremuloides) in response to artificial defoliation

2004 ◽  
Vol 82 (5) ◽  
pp. 590-597 ◽  
Author(s):  
Brin Jones ◽  
Jacques Tardif ◽  
Richard Westwood
Keyword(s):  
Populus Tremuloides ◽  
Radial Growth ◽  
Regression Models ◽  
Wood Anatomy ◽  
Ring Width ◽  
Growing Season ◽  
Early Growth ◽  
Trembling Aspen ◽  
Forest Sites ◽  
Significant Difference

The present study investigated the effect of artificial defoliation on weekly radial xylem production in trembling aspen (Populus tremuloides Michx.). It was hypothesized that defoliated trees would show reduced xylem and vessel production and thinner secondary walls in fibres. Two adjacent natural forest sites were selected within Winnipeg, Manitoba. Microcores were extracted weekly from the stems of 30 aspen trees from May to October 2002. Ten aspen trees were defoliated using pole pruners between 22 June and 6 July. Measurements included weekly xylem increment, annual vessel characteristics, and late growing season fibre dimensions. No significant difference in overall ring width was observed; however, trees from both groups showed a significant reduction in ring width in 2002. The ratio of radial growth in 2002 / radial growth in 2001 was significantly less in defoliated trees, suggesting a higher reduction in radial growth due to defoliation. Sigmoidal regression models suggested early growth cessation in defoliated trees. No significant differences in vessel characteristics were observed between groups; however, the diameter and lumen width of fibres was significantly reduced in defoliated trees. It is speculated that a shorter radial growing season may have led to a reduced cell elongation period. An early cessation of the radial growing season associated with a reallocation of carbohydrates to produce a second flush of leaves could explain the reduced size of fibres from defoliated trees.Key words: wood anatomy, diffuse porous, image analysis, radial growth, cell dimension, dendrochronology.

Establishment and Growth of Slash Pine on Grazed Cutover Range in Central Louisiana

1985 ◽  
Vol 9 (4) ◽  
pp. 232-236
Author(s):  
Harold E. Grelen ◽  
Henry A. Pearson ◽  
Ronald E. Thill
Keyword(s):  
Growing Season ◽  
Pinus Elliottii ◽  
Early Growth ◽  
Slash Pine ◽  
Heavy Grazing ◽  
Survival And Growth

Abstract Slash pine (Pinus elliottii) was established by both planting and seeding on cutover range units prescribe-burned and grazed yearlong. Paired fenced and unfenced plots were used to compare survival and growth on both heavily and lightly grazed range with ungrazed plots. On planted sites, survival was significantly lower on heavily grazed than on ungrazed sites by May of the first growing season. No significant differences in survival were found between lightly grazed and ungrazed sites. In seeded stands, survival was not significantly different between grazed and ungrazed sites. Trees were thinned at an average age of 18 years Prethinning measurements indicated that plantations subjected to heavy grazing throughout their existence had fewer trees per acre, but had larger dbh than the ungrazed. Consequently, differences in volume were not significant, showing regulated yearlong grazing to be compatible with the establishment and early growth of slash pine.

The Roma in Post-Communist Bulgaria: Growing Social Marginalization and State Policies

2020 ◽  
Vol 2 (1) ◽  
pp. 1-24
Author(s):  
Yorgos Christidis
Keyword(s):  
Political Parties ◽  
Social Exclusion ◽  
Hate Crime ◽  
Hate Speech ◽  
Poor Performance ◽  
State Policies ◽  
Social Marginalization ◽  
Popular Support ◽  
Economic Problems ◽  
The Poor

This article analyzes the growing impoverishment and marginalization of the Roma in Bulgarian society and the evolution of Bulgaria’s post-1989 policies towards the Roma. It examines the results of the policies so far and the reasons behind the “poor performance” of the policies implemented. It is believed that Post-communist Bulgaria has successfully re-integrated the ethnic Turkish minority given both the assimilation campaign carried out against it in the 1980s and the tragic events that took place in ex-Yugoslavia in the 1990s. This Bulgaria’s successful “ethnic model”, however, has failed to include the Roma. The “Roma issue” has emerged as one of the most serious and intractable ones facing Bulgaria since 1990. A growing part of its population has been living in circumstances of poverty and marginalization that seem only to deteriorate as years go by. State policies that have been introduced since 1999 have failed at large to produce tangible results and to reverse the socio-economic marginalization of the Roma: discrimination, poverty, and social exclusion continue to be the norm. NGOs point out to the fact that many of the measures that have been announced have not been properly implemented, and that legislation existing to tackle discrimination, hate crime, and hate speech is not implemented. Bulgaria’s political parties are averse in dealing with the Roma issue. Policies addressing the socio-economic problems of the Roma, including hate speech and crime, do not enjoy popular support and are seen as politically damaging.

Biomass Characterization in a Nitrification-Denitrification Biological Enhanced Phosphorus Removal (NDBEPR) Plant during Start-Up and Subsequent Periods of Good and Poor Phosphorus Removal

1994 ◽  
Vol 29 (7) ◽  
pp. 91-100 ◽  
Author(s):  
K. C. Lindrea ◽  
S. P. Pigdon ◽  
B. Boyd ◽  
G. A. Lockwood
Keyword(s):  
Phosphorus Removal ◽  
Poor Performance ◽  
Intracellular Distribution ◽  
Full Scale ◽  
Laboratory Scale ◽  
Plant Operation ◽  
The Poor ◽  
Start Up ◽  
Biomass Characterization

During commissioning and process stabilization of a NDBEPR plant at Bendigo intracellular distribution and movement of phosphorus, K+, Mg2+ and Ca2+ was followed to establish the nature of biomass development. The system was also monitored at the end of a period of breakdown of the BEPR process and during its return to phosphorus removal. Phosphorus (P) and Mg2+ distribution in the biomass were closely related during all phases of plant operation, and laboratory trials indicated that the poor performance of the full-scale plant was associated with seasonal reduction in influent Mg2+. Laboratory scale trials produced a similar effect when the influent Mg2+ was limited to concentrations much lower than those experienced in the full scale plant, but only after the Mg2+ and P reserves in the biomass were depleted. The distribution of P, K+, Mg2+ and Ca2+ in the biomass from the full scale plant was similar to that seen in the laboratory trials when cations in the feed were severely limited and recovery of the full scale plant also closely matched that of the laboratory scale system.

Trail Making Test Performance in Relation to Certain Experimenter, Test and Subject Variables

1964 ◽  
Vol 19 (1) ◽  
pp. 199-206 ◽  
Author(s):  
Oscar A. Parsons ◽  
Harriet I. Maslow ◽  
Freda Morris ◽  
J. Peter Denny
Keyword(s):  
Test Performance ◽  
Screening Test ◽  
Poor Performance ◽  
Trail Making Test ◽  
Psychiatric Disturbance ◽  
The Poor ◽  
Subject Variables ◽  
Trail Making ◽  
The Brain ◽  
Order Of Administration

The Trail Making Test, previously reported highly effective in differentiating brain-damaged from non-brain-damaged Ss, was administered to 21 brain-damaged Ss and 63 non-brain-damaged Ss. Since the latter Ss performed at a level indistinguishable from that of the brain-damaged Ss, several studies were designed in an attempt to “explain” the poor performance of the non-brain-damaged Ss. The possible effects of behavioral agitation, anxiety, examiner differences, facility with letters of the alphabet, order of administration, and ego-involvement were investigated. Only anxiety was found to be significantly related to performance. However, in other analyses age, education, vocabulary, and degree of psychiatric disturbance were significantly related to performance. Until these variables are considered in the scoring system, it seems unlikely that the TMT will be effective as a general screening test for brain-damage.

Cylindrocarpon and Fusarium root colonization of Douglas-fir seedlings from British Columbia reforestation sites

1998 ◽  
Vol 28 (8) ◽  
pp. 1198-1206 ◽  
Author(s):  
Paige E Axelrood ◽  
William K Chapman ◽  
Keith A Seifert ◽  
David B Trotter ◽  
Gwen Shrimpton
Keyword(s):  
British Columbia ◽  
Pseudotsuga Menziesii ◽  
Root Colonization ◽  
Linear Trend ◽  
Poor Performance ◽  
Douglas Fir ◽  
Root Infection ◽  
Significant Linear Trend ◽  
Conifer Seedlings ◽  
Cylindrocarpon Destructans

Poor performance of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) plantations established in 1987 has occurred in southwestern British Columbia. Affected sites were planted with 1-year-old container stock that exhibited some root dieback in the nursery. A study was initiated in 1991 to assess Cylindrocarpon and Fusarium root infection in planted and naturally regenerating (natural) Douglas-fir seedlings from seven affected plantations. Percentages of seedlings harboring Cylindrocarpon spp.and percent root colonization were significantly greater for planted seedlings compared with natural seedlings. A significant linear trend in Cylindrocarpon root colonization was observed for planted seedlings with colonization levels being highest for roots closest to the remnants of the root plug and decreasing at distances greater than 10cm from that region. This trend in Cylindrocarpon colonization was not observed for natural seedlings. Cylindrocarpon destructans (Zins.) Scholten var. destructans and C.cylindroides Wollenw. var. cylindroides were the only species isolated from planted and natural conifer seedlings. For most sites, percentage of seedlings harboring Fusarium spp.and percent Fusarium root colonization were less than for Cylindrocarpon. Recovery of Fusarium spp.from seedlings and root colonization levels were not significantly different for planted and natural seedlings from all sites.

scholarly journals Structural transformation and productivity in Latin America

2015 ◽  
Vol 15 (2) ◽  
Author(s):  
Pedro Cavalcanti Ferreira ◽  
Leonardo Fonseca da Silva
Keyword(s):  
Latin America ◽  
Structural Transformation ◽  
Productivity Growth ◽  
Equilibrium Model ◽  
Poor Performance ◽  
Services Sector ◽  
The Poor ◽  
Agriculture Industry ◽  
Key Factor ◽  
Modern Services

AbstractThis article examines the effects of sectorial shifts and structural transformation on the recent productivity path of Latin America. We use a four-sector (agriculture, industry, modern services and traditional services) general equilibrium model calibrated to the main economies in the region. The model very closely replicates labor reallocations across sectors and the growth of aggregate labor productivity from 1950 to 2005. Structural transformation explains a sizeable portion of the region’s convergence in the first decades. In most cases, the poor performance of the traditional services sector is the main cause of the slowdown in productivity growth observed in the region after the mid-1970s and is a key factor in explaining the divergence during this period.

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