scholarly journals A Comparison of Logging Planning, Felling, and Skyline Yarding Costs Between Clearcutting and Five Group-Selection Harvesting Methods

1996 ◽  
Vol 11 (3) ◽  
pp. 90-96 ◽  
Author(s):  
Loren D. Kellogg ◽  
Pete Bettinger ◽  
Richard M. Edwards
Keyword(s):  
Pseudotsuga Menziesii ◽  
Group Selection ◽  
Douglas Fir ◽  
Total Cost ◽  
Silvicultural Treatment ◽  
Cable Yarding ◽  
Selection Harvesting ◽  
Set Up ◽  
Manual Felling ◽  
The Cost

Abstract Logging planning, felling, and cable yarding costs were determined for five group-selection treatments and a clearcut in a 90 yr old Douglas-fir (Pseudotsuga menziesii) stand in western Oregon. The harvesting system included manual felling and a yarder rigged in a standing skyline configuration with a mechanical slackpulling carriage. The clearcut treatment had the lowest total harvest cost; costs of the group-selection treatments were 7.3 to 31.5% higher than the clearcut. Yarding cost associated with road and landing changes, plus the cost of equipment moving, set up, and tear down allocated over different treatment volumes removed had the biggest influence on total cost for each silvicultural treatment. West. J. Appl. For. 11(3):90-96.

Longevity and dynamics of fatally and nonfatally topped Douglas-fir in the Coast Range of Oregon

2009 ◽  
Vol 39 (11) ◽  
pp. 2224-2233 ◽  
Author(s):  
Tristan D. Huff ◽  
John D. Bailey
Keyword(s):  
Pseudotsuga Menziesii ◽  
Group Selection ◽  
Regression Models ◽  
Forest Ecosystems ◽  
Structural Heterogeneity ◽  
Douglas Fir ◽  
Coast Range ◽  
Logistic Regression Models ◽  
Explanatory Variables ◽  
Ground Slope

Worldwide, snags are an important, but often lacking, component of forest ecosystems. We revisited artificially topped Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco) trees 16–18 years after treatment in a replicated experiment in western Oregon. Some trees had been topped such that no live crown was retained (fatally topped), while others retained some portion of their live crown after topping (nonfatally topped). Topped trees were created under three different silvicultural regimes: clearcut, two story, and group selection. Twenty-three percent (61 of 262) of nonfatally topped trees remained living 16–18 years after treatment; 4% (19 of 482) of fatally topped trees had broken at some point up the bole by 16–18 years after treatment. Silvicultural regime, post-treatment height, stem diameter, stem lean, and ground slope were considered as potential explanatory variables in logistic regression models explaining mortality and breakage. A nonfatally topped tree’s odds of surviving 16–18 years after treatment was greater in the mature matrix of group selection stands than in clearcuts or two-story stands. A fatally topped tree’s odds of breaking within 16–18 years of treatment decreased as DBH increased. If carefully created, artificially topping trees can be a useful silvicultural tool to increase structural heterogeneity.

CFIRP: What we learned in the first ten years

1999 ◽  
Vol 75 (3) ◽  
pp. 431-434 ◽  
Author(s):  
Carol L. Chambers ◽  
William C. McComb ◽  
John C. Tappeiner II ◽  
Loren D. Kellogg ◽  
Rebecca L. Johnson ◽  
...  
Keyword(s):  
Pseudotsuga Menziesii ◽  
Group Selection ◽  
Structural Features ◽  
Human Dimensions ◽  
Douglas Fir ◽  
Small Scale ◽  
Tree Retention ◽  
Green Tree Retention ◽  
Patch Group

In response to public dissatisfaction with forest management methods, we initiated the College of Forestry Integrated Research Project (CFIRP) to test alternative silvicultural systems in Douglas-fir (Pseudotsuga menziesii) stands in western Oregon. We compared costs and biological and human responses among a control and three replicated silvicultural alternatives to clearcutting that retained structural features found in old Douglas-fir forests. Treatments were applied within 8- to 15-ha stands and attempted to mimic crown fires (modified clearcut), windthrow (green tree retention), and small-scale impacts such as root rot diseases (small patch group selection). We also compared costs in three unreplicated treatments (large patch group selection, wedge cut, and strip cut). Each treatment included differences in the pattern of retained dead trees (snags), as either scattered individuals or as clumps. Good communication among researchers and managers, a long-term commitment to the project, and careful documentation of research sites and data are important to the success of long-term silvicultural research projects. To date, over 30 publications have resulted from the project. Key words: alternative silviculture, data management, Douglas-fir, green tree retention, harvesting costs, human dimensions, Oregon, Pseudotsuga menziesii, recreation, wildlife

scholarly journals Pathogenicity and Virulence of Pythium Species Obtained from Forest Nursery Soils on Douglas-Fir Seedlings

Plant Disease ◽  
2013 ◽  
Vol 97 (6) ◽  
pp. 744-748 ◽  
Author(s):  
Jerry E. Weiland ◽  
Bryan R. Beck ◽  
Anne Davis
Keyword(s):  
Pseudotsuga Menziesii ◽  
Seedling Survival ◽  
The United States ◽  
Douglas Fir ◽  
Tree Seedlings ◽  
Pythium Species ◽  
Forest Nursery ◽  
Damping Off ◽  
Greenhouse Study ◽  
Forest Nurseries

Pythium species are common soilborne oomycetes that occur in forest nursery soils throughout the United States. Numerous species have been described from nursery soils. However, with the exception of P. aphanidermatum, P. irregulare, P. sylvaticum, and P. ultimum, little is known about the potential for other Pythium species found in nursery soils to cause damping-off of tree seedlings. A greenhouse study was conducted to evaluate the pathogenicity and virulence of 44 Pythium isolates representing 16 species that were originally recovered from soil at three forest nurseries in Washington and Oregon. Seeds of Douglas-fir (Pseudotsuga menziesii) were planted into soil infested with each of the isolates. Seedling survival, the number of surviving seedlings with necrotic root lesions, and taproot length were evaluated 4 weeks later. Responses of Douglas-fir to inoculation varied significantly depending on Pythium species and isolate. Eight species (P. dissotocum, P. irregulare, P. aff. macrosporum, P. mamillatum, P. aff. oopapillum, P. rostratifingens, P. sylvaticum, and P. ultimum var. ultimum) significantly reduced the number of surviving seedlings compared to the noninoculated treatment. However, all Pythium species caused a greater percentage of seedlings to develop root lesions (total mean 40%) than was observed from noninoculated seedlings (17%). Taproot length varied little among Pythium treatments and was not a useful character for evaluating pathogenicity. Results confirm the ability of P. irregulare, P. mamillatum, and P. ultimum var. ultimum to cause damping-off of Douglas-fir seedlings, and are indicative that other species such as P. dissotocum, P. aff. macrosporum, P. aff. oopapillum, P. rostratifingens, and P. sylvaticum may also be responsible for seedling loss.

scholarly journals The Development of Patient Scheduling Groups for an Effective Appointment System

2016 ◽  
Vol 07 (01) ◽  
pp. 43-58 ◽  
Author(s):  
Yu Li Huang
Keyword(s):  
Access To Care ◽  
Treatment Time ◽  
Optimization Technique ◽  
Urgent Care ◽  
Patient Scheduling ◽  
Total Cost ◽  
Patient Type ◽  
Clinic Efficiency ◽  
The Cost ◽  
The Impact

SummaryPatient access to care and long wait times has been identified as major problems in outpatient delivery systems. These aspects impact medical staff productivity, service quality, clinic efficiency, and health-care cost.This study proposed to redesign existing patient types into scheduling groups so that the total cost of clinic flow and scheduling flexibility was minimized. The optimal scheduling group aimed to improve clinic efficiency and accessibility.The proposed approach used the simulation optimization technique and was demonstrated in a Primary Care physician clinic. Patient type included, emergency/urgent care (ER/UC), follow-up (FU), new patient (NP), office visit (OV), physical exam (PE), and well child care (WCC). One scheduling group was designed for this physician. The approach steps were to collect physician treatment time data for each patient type, form the possible scheduling groups, simulate daily clinic flow and patient appointment requests, calculate costs of clinic flow as well as appointment flexibility, and find the scheduling group that minimized the total cost.The cost of clinic flow was minimized at the scheduling group of four, an 8.3% reduction from the group of one. The four groups were: 1. WCC, 2. OV, 3. FU and ER/UC, and 4. PE and NP. The cost of flexibility was always minimized at the group of one. The total cost was minimized at the group of two. WCC was considered separate and the others were grouped together. The total cost reduction was 1.3% from the group of one.This study provided an alternative method of redesigning patient scheduling groups to address the impact on both clinic flow and appointment accessibility. Balance between them ensured the feasibility to the recognized issues of patient service and access to care. The robustness of the proposed method on the changes of clinic conditions was also discussed.

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 A MEAN FIELD GAME ANALYSIS OF SIR DYNAMICS WITH VACCINATION

2020 ◽  
pp. 1-18
Author(s):  
Josu Doncel ◽  
Nicolas Gast ◽  
Bruno Gaujal
Keyword(s):  
Mean Field ◽  
Vaccination Strategy ◽  
Game Analysis ◽  
Total Cost ◽  
Mean Field Game ◽  
Vaccination Behavior ◽  
Switching Curve ◽  
The One ◽  
The Cost ◽  
Vaccination Period

We analyze a mean field game model of SIR dynamics (Susceptible, Infected, and Recovered) where players choose when to vaccinate. We show that this game admits a unique mean field equilibrium (MFE) that consists in vaccinating at a maximal rate until a given time and then not vaccinating. The vaccination strategy that minimizes the total cost has the same structure as the MFE. We prove that the vaccination period of the MFE is always smaller than the one minimizing the total cost. This implies that, to encourage optimal vaccination behavior, vaccination should always be subsidized. Finally, we provide numerical experiments to study the convergence of the equilibrium when the system is composed by a finite number of agents ( $N$ ) to the MFE. These experiments show that the convergence rate of the cost is $1/N$ and the convergence of the switching curve is monotone.

The Mitigation of the French Nuclear Option: New Industrial Realism and Technical Democracy

2002 ◽  
Vol 13 (2) ◽  
pp. 263-279 ◽  
Author(s):  
Dominique Finon
Keyword(s):  
Waste Management ◽  
Electricity Markets ◽  
Social Preferences ◽  
Public Inquiry ◽  
The Future ◽  
Parliamentary Committee ◽  
Set Up ◽  
The Stability ◽  
The Cost ◽  
Phase Out

Nuclear phase-out policies and the European obligation to liberalise electricity markets could put the French nuclear option dramatically at risk by influencing social preferences or by constraining power producers' investment choices in the future. So far, the particular institutional set-up which has allowed the efficient build-up and operation of several series of standardised reactors preserves the stability of the main elements of the option. However, important adaptations to the evolving industrial and political environment occur and contribute to changing the option. Some institutional changes (such as local public inquiry, creation of a Parliamentary committee, independence of safety authorities) and divergence between industrial interests already allow debates on internal options such as reprocessing, type of waste management deposits, ordering of an advanced PWR. These changes improve the cost transparency, even if internalisation of nuclear externalities (cost of insurance, provisions for waste management) is still incomplete. However, when effective, this internalisation would not affect definitively the competitive position of the nuclear production because of the parallel internalisation of CO2 externalities from fossil fuel power generation in the official rationale. Consequently the real issue for the future of the nuclear option in France remains the preservation of social acceptability in the perception of nuclear risks.

Contarinia pseudotsugae. [Distribution map].

2020 ◽  
Author(s):  
Keyword(s):  
British Columbia ◽  
North America ◽  
Geographical Distribution ◽  
Pseudotsuga Menziesii ◽  
Douglas Fir ◽  
Distribution Map ◽  
New Distribution ◽  
Distribution In Europe

Abstract A new distribution map is provided for Contarinia pseudotsugae Condrashoff (Diptera: Cecidomyiidae). Hosts: Douglas fir (Pseudotsuga menziesii). Information is given on the geographical distribution in Europe (Belgium, France, Germany and Netherlands) and North America (Canada, British Columbia, USA, California, Idaho, Michigan, Montana, Oregon, Pennsylvania and Washington).

Penetapan Tarif Ambulans Untuk Evakuasi Medis Berbasis Unit Cost

2021 ◽  
Vol 7 (1) ◽  
pp. 167-173
Author(s):  
Kelvin Riupassa ◽  
Narizma Nova ◽  
Endah Lestari ◽  
Sri Juniarti Azis ◽  
Wahyu Sulistiadi
Keyword(s):  
Recovery Rate ◽  
Unit Cost ◽  
Cost Recovery ◽  
Maintenance Costs ◽  
Total Cost ◽  
Medical Evacuation ◽  
Operational Costs ◽  
Emergency Ambulance ◽  
The Cost ◽  
Cost Components

Background: An ambulance is a vehicle designed to be able to handle emergency patients, provide first aid and carry out intensive care while on the way to a referral hospital. Ambulance operations require a large amount of funds obtained from APBD funds through tariffs that were passed through the DKI Jakarta Governor Regulation five years ago. For this reason, a new tariff is required to adjust to current conditions. Objectives: The purpose of this study is to calculate the unit cost of ambulance services in DKI Jakarta to be a consideration in the tariff setting policy in DKI Jakarta province. Research Metodes: This study uses a quantitative descriptive approach to obtain information about the unit cost of the Jakarta ambulance production unit. The method used is the calculation of real cost using the basis of the causes of costs. This research was conducted at the DKI Jakarta Emergency Ambulance using secondary data on investment costs, operational costs and maintenance costs in 2018. Results: The total cost of emergency ambulance in 2018 is known that the proportion of three cost components, namely operational costs, is 76%, followed by investment costs of 20% and maintenance costs of 3%. The calculation of the total cost of medical evacuation using the double distribution method is Rp. 98,915,016,805.00 divided by the number of medical evacuations in 2018 of 37,564 activities, the unit cost of medical evacuation for the AGD of DKI Jakarta Health Office is Rp. 2,633,215.00 without subsidies. APBD costs, while if the subsidy component is included in the calculation, the unit cost for one trip to the AGD of the Health Office is Rp. 604,071.00. This is still far above the current tariff of Rp. 450.00, so the cost recovery rate (CRR) is still below. 100%. Conclusion: From the three cost components consisting of investment, operational and maintenance costs,the largest proportion was operational costs at 76%. The Cost Recovery Rate has not reached 100% so that the existing rates have not covered the costs incurred.   Keywords: ambulance; price fixing; unit cost

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