scholarly journals To Thin or Not to Thin: Using the Forest Vegetation Simulator to Evaluate Thinning of Aspen

2003 ◽  
Vol 20 (1) ◽  
pp. 14-18 ◽  
Author(s):  
Daniel W. Gilmore
Keyword(s):  
Site Index ◽  
Forest Vegetation ◽  
Forest Vegetation Simulator ◽  
Precommercial Thinning ◽  
Simulation Tools ◽  
Tree Diameter ◽  
Time Period ◽  
Younger Age ◽  
Volume Production ◽  
A Site

Abstract Thinning experiments are costly to install and take decades of monitoring. Computer simulation tools, however, allow for the creation of “virtual” thinning experiments that forest managers can use as a guide in prescribing thinnings. The Forest Vegetation Simulator (FVS) was used to conduct a “virtual” thinning experiment to a range of residual densities (8, 10, 12, 15, and 20 ft spacings) at a range of thinning ages (5, 10, 25, and 40 yr) over a 50 yr time period. Stand level volume production was not enhanced through precommercial thinning, but average tree diameter was increased. Stand level volume was less after commercial thinnings but total volume production was increased if volumes removed during thinnings were considered. Tree diameter growth was greater when thinnings were performed at a younger age at and at a wider spacing. The greatest total volume production (removed during thinning and standing at age 50) was found to be nearly equal at 8 ft and 10 ft spacing with thinnings occurring at ages 10 or 25 on a site index of 80. North. J. Appl. For. 20(1):14–18.

Testing the Lake States variant of FVS (Forest Vegetation Simulator) for the main forest types of northern Ontario

2004 ◽  
Vol 80 (4) ◽  
pp. 495-506 ◽  
Author(s):  
V. Lacerte ◽  
G R Larocque ◽  
M. Woods ◽  
W J Parton ◽  
M. Penner
Keyword(s):  
Black Spruce ◽  
Basal Area ◽  
Stand Density ◽  
Site Index ◽  
Forest Vegetation ◽  
Forest Vegetation Simulator ◽  
Consistency Analysis ◽  
Northern Ontario ◽  
Individual Tree ◽  
Stand Basal Area

The Lake States variant of the FVS (Forest Vegetation Simulator) model (LS-FVS), also known as the LS-TWIGS variant of FVS, was validated for black spruce (Picea mariana (Mill.) BSP), white spruce (Picea glauca (Moench) Voss), jack pine (Pinus banksiana Lamb.) and trembling aspen (Populus tremuloides Michx.) forests in northern Ontario. Individual-tree data from 537 remeasured sample plots were used. This dataset included different combinations of site index, stand density and age. It was possible to compare observations and predictions for different projection length periods. The validation exercise included a biological consistency analysis, the computation of mean percent difference (MPD) for stand density, stand basal area, top height and quadratic mean diameter (QMD) and the comparison of observed and predicted individual-tree dbh. The biological consistency analysis indicated that LS-FVS logically predicted the effect of site index on top height, stand basal area and QMD for black spruce and jack pine. However, the decrease in stand basal area at young ages was inconsistent with the normal development pattern of the forest stands under study and was attributed to deficiencies in the prediction of mortality. LS-FVS was found to underpredict stand density, stand basal area and top height and to over-predict QMD. Even though there were large errors in the prediction of change in stand density, LS-FVS was nevertheless consistent in the prediction of the shape of the dbh size distribution. Key words: FVS, Forest Vegetation Simulator, validation, biological consistency analysis

scholarly journals Incorporation of Genetic Gain into Growth Projections of Douglas-Fir Using ORGANON and the Forest Vegetation Simulator

2010 ◽  
Vol 25 (2) ◽  
pp. 55-61 ◽  
Author(s):  
Peter J. Gould ◽  
David D. Marshall
Keyword(s):  
Pacific Northwest ◽  
Genetic Gain ◽  
Growth Models ◽  
Regional Growth ◽  
Site Index ◽  
Douglas Fir ◽  
Forest Vegetation ◽  
Planting Density ◽  
Forest Vegetation Simulator ◽  
Stand Management

Abstract Growth models for coast Douglas-fir (Pseudotsuga menziesii var. menziesii [Mirb.] Franco) are generally based on measurements of stands that are genetically unimproved (or woods-run); therefore, they cannot be expected to accurately project the development of stands that originate from improved seedlots. In this report, we demonstrate how early expected gain and genetic-gain multipliers can be incorporated into growth projection, and we also summarize projected volume gains and other aspects of stand development under different levels of genetic gain, site productivity, and initial planting density. Representative tree lists that included three levels of productivity (site index = 100, 125, and 150 ft; base = 50 years)and three initial planting densities (302, 435, and 602 trees/ac) were projected from ages 10 to 60 years under three scenarios using two regional growth models (Stand Management Cooperative version of ORGANON and the Pacific Northwest variant of the Forest Vegetation Simulator). The two models projected similar percentage volume gains for improved seedlots. Seedlots with a genetic worth (GW) of 5% for height and diameter growth were projected to have volume gains of 3.3–5.8% over woods-run stands at 40 years and 2.1–3.2% at 60 years. Volume gains were projected to approximately double when GW was increased from 5 to 10%.

scholarly journals Comorbid disease burden among MS patients 1968–2012: A Swedish register–based cohort study

2020 ◽  
pp. 135245852091049 ◽  
Author(s):  
Kelsi A Smith ◽  
Sarah Burkill ◽  
Ayako Hiyoshi ◽  
Tomas Olsson ◽  
Shahram Bahmanyar ◽  
...  
Keyword(s):  
General Population ◽  
Age Groups ◽  
Comorbid Disease ◽  
Hazard Ratios ◽  
Time Period ◽  
Younger Age ◽  
Cardiovascular Depression ◽  
Prevalence Prevalence ◽  
Time Periods ◽  
Prevalence Ratios

Background: People with multiple sclerosis (pwMS) have increased comorbid disease (CMD) risk. Most previous studies have not considered overall CMD burden. Objective: To describe lifetime CMD burden among pwMS. Methods: PwMS identified using Swedish registers between 1968 and 2012 ( n = 25,476) were matched by sex, age, and county of residence with general-population comparators ( n = 251,170). Prevalence, prevalence ratios (PRs), survival functions, and hazard ratios by MS status, age, and time period compared seven CMD: autoimmune, cardiovascular, depression, diabetes, respiratory, renal, and seizures. Results: The magnitude of the PRs for each CMD and age group decreased across time, with higher PRs in earlier time periods. Before 1990, younger age groups had higher PRs, and after 1990, older age groups had higher PRs. Male pwMS had higher burden compared with females. Overall, renal, respiratory, and seizures had the highest PRs. Before 2001, 50% of pwMS received a first/additional CMD diagnosis 20 years prior to people without MS, which reduced to 4 years after 2001. PwMS had four times higher rates of first/additional diagnoses in earlier time periods, which reduced to less than two times higher in recent time periods compared to people without MS. Conclusion: Swedish pwMS have increased CMD burden compared with the general population, but this has reduced over time.

Assessment of landslide hazard under combined loading

2003 ◽  
Vol 40 (4) ◽  
pp. 821-829 ◽  
Author(s):  
Tien H Wu
Keyword(s):  
Pore Pressure ◽  
Failure Probability ◽  
Threshold Value ◽  
Landslide Hazard ◽  
Combined Loading ◽  
Rational Approach ◽  
Root Reinforcement ◽  
Load Combination ◽  
Time Period ◽  
A Site

A method for assessing landslide hazard under combined loading is described. The loads are considered as pulses that occur randomly in time. The method accounts for the rate of occurrence and the duration of the loads and calculates the rate of coincidence of two or more loads. This is used to calculate the failure probability, which is equal to the probability that the load combination will exceed a threshold value during a given time period. The method was applied to a site in the Cascade Mountains of Washington. The loads considered include those as a result of gravity, pore pressure from infiltration of rainfall plus snowmelt, loss of root reinforcement through fire or logging, and earthquakes. The example demonstrates a rational approach that accounts for the properties of the loads and the different loading conditions that may be expected.Key words: earthquake, failure probability, landslide hazard, load coincidence, load combination, pore pressure, root reinforcement.

Othello as a play-within-the-film in post-independence Indian cinema1

2021 ◽  
Vol 5 (1) ◽  
pp. 43-58 ◽  
Author(s):  
Rosa García-Periago
Keyword(s):  
College Performance ◽  
Political Issues ◽  
Time Period ◽  
Racial Dynamics ◽  
Main Plot ◽  
A Site

This article aims to explore the appropriation of Othello as a play-within-the-film in three Indian movies: Anbu (Natesan 1953), Saptapadi (Kar 1961) and Ratha Thilagam (Mirasi 1963). Anbu and Ratha Thilagam are Tamil movies, whereas Saptapadi is an example of Bengali cinema. In the three films, the same scene from Shakespeare’s Othello – the murder scene – is performed as part of college theatricals. Although the films immediately associate Shakespeare with education, their appropriation of Othello goes beyond a college performance and provides insight on the main plot. The performance of the murder scene foreshadows the rest of the plot (Anbu and Ratha Thilagam), and explores racial dynamics and miscegenation in relation to the protagonists in Saptapadi. Anbu, Saptapadi and Ratha Thilagam introduce variations to the plot to add new layers of meaning. As the three films are set in postcolonial India, the use of the Shakespearean play inevitably becomes a site of negotiation between colonizers and colonized; the three films negotiate changing controversial political issues across the time period to which they all belong. Anbu, Saptapadi and Ratha Thilagam generate then a new understanding of Othello, which becomes paramount to trace the evolution of Shakespeare in postcolonial India.

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