New Techniques For Pre-Commercial Thinning – Time Consumption and Tree Damage Parameters

This studyâs aim was to identify how the application season and the method of early cleaning (EC), the first stage of multistage pre-commercial thinning (PCT), affected the time consumption in EC and in the subsequent second PCT operation. The worktime in EC was recorded in the spring, summer, and autumn in 22 sites, which were either totally cleaned or point cleaned. Later, these sites were measured at the time of the second PCT. Time consumption was estimated in PCT, based on the removal of the sites. The time consumption in EC was 5.3 productive work hours (pwh) ha, 7.3 pwh ha, and 6.2 pwh ha respectively in the spring, summer, and autumn. EC in the spring instead of the summer saved 27â30% of working time, depending on the cleaning method. Point cleaning was 0.8 pwh ha quicker than total cleaning, but the difference was statistically insignificant. The second stage, PCT, was 1 pwh ha slower to conduct in sites which had been early cleaned in the spring instead of the summer. However, at the entire management program level, EC applied in the spring or autumn instead of the summer saved 11% or 5% respectively of the total discounted costs (3% interest rate) of multistage pre-commercial thinning. Today, the commonest time to conduct EC is in the summer, which was the most expensive of the analyzed management alternatives here. We can expect savings in juvenile stand management in forestry throughout boreal conifer forests by rethinking the seasonal workforce allocation.â1â1â1â1â1

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Time consumption and damage to the remaining stock in mechanised and motor manual pre-commercial thinning

Silva Fennica ◽

10.14214/sf.379 ◽

2005 ◽

Vol 39 (3) ◽

Cited By ~ 7

Author(s):

Daniel Ligné ◽

Lars Eliasson ◽

Tomas Nordfjell

Keyword(s):

Time Consumption ◽

Commercial Thinning

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Low cost prediction of time consumption for pre-commercial thinning in Finland

Silva Fennica ◽

10.14214/sf.10196 ◽

2020 ◽

Vol 54 (1) ◽

Author(s):

Karri Uotila ◽

Jari Miina ◽

Timo Saksa ◽

Ron Store ◽

Kauko Kärkkäinen ◽

...

Keyword(s):

Mixed Model ◽

Linear Mixed Model ◽

Low Cost ◽

Geographical Area ◽

Coefficient Of Determination ◽

Stand Age ◽

Validation Data ◽

Time Consumption ◽

Commercial Thinning ◽

Tc Model

The time consumption (TC) of pre-commercial thinning (PCT) varies greatly among sites, stands and forest workers. The TC in PCT is usually estimated by field-assessed work difficulty factors. In this study, a linear mixed model for the TC in PCT was prepared by utilizing forest resources data (FRD). The modelling data included 11â848 and validation data included 3035 worksites with TC information recorded by forest workers within the period of 2008â2018. The worksites represented a range of site and stand conditions across a broad geographical area in Finland. Site and stand characteristics and previous management logically explained the TC in PCT. The more fertile the site, the more working time was needed in PCT. On sites of medium fertility, TC in the initial PCT increased with stand age by 0.5 h ha yr. Site wetness increased the TC. PCT in summer was more time consuming than in spring. Small areas were more time consuming to PCT per hectare than larger ones. The between-forest worker variation involved in the TC was as high as 35% of the variation unexplained by the TC model. The coefficient of determination in validation data was 19.3%, RMSE 4.75 h ha and bias â1.6%. The TC model based on FRD was slightly less precise than the one based on field-assessed work difficulty factors (removal quantity and type and terrain difficulty): RMSE 4.9 h ha vs. 4.1 h ha (52% vs. 43%). The TC model could be connected to forest information systems where it would facilitate the predictions of the labour costs of PCT without field-assessing work difficulty factors.â1â1â1â1â1

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Stellar Evolution

Transactions of the International Astronomical Union ◽

10.1017/s0251107x00022343 ◽

1962 ◽

Vol 11 (02) ◽

pp. 137-143

Author(s):

M. Schwarzschild

Keyword(s):

Solar System ◽

Stellar Evolution ◽

Space Craft ◽

New Techniques ◽

Substantial Body ◽

Individual Stars ◽

The Past ◽

Evolution Of Galaxies ◽

History Of ◽

Fast Flow

It is perhaps one of the most important characteristics of the past decade in astronomy that the evolution of some major classes of astronomical objects has become accessible to detailed research. The theory of the evolution of individual stars has developed into a substantial body of quantitative investigations. The evolution of galaxies, particularly of our own, has clearly become a subject for serious research. Even the history of the solar system, this close-by intriguing puzzle, may soon make the transition from being a subject of speculation to being a subject of detailed study in view of the fast flow of new data obtained with new techniques, including space-craft.

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Microstructural characterization of CoPtCr/Cr thin film disks by cross-section TEM and elongated probe micro-diffraction

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100088129 ◽

1991 ◽

Vol 49 ◽

pp. 762-763

Author(s):

M.A. Parker ◽

K.E. Johnson ◽

C. Hwang ◽

A. Bermea

Keyword(s):

Magnetic Recording ◽

Electron Probe ◽

Microstructural Characterization ◽

Crystallographic Structure ◽

Recording Media ◽

Layer By Layer ◽

Cross Sectional ◽

New Techniques ◽

Polished Side

We have reported the dependence of the magnetic and recording properties of CoPtCr recording media on the thickness of the Cr underlayer. It was inferred from XRD data that grain-to-grain epitaxy of the Cr with the CoPtCr was responsible for the interaction observed between these layers. However, no cross-sectional TEM (XTEM) work was performed to confirm this inference. In this paper, we report the application of new techniques for preparing XTEM specimens from actual magnetic recording disks, and for layer-by-layer micro-diffraction with an electron probe elongated parallel to the surface of the deposited structure which elucidate the effect of the crystallographic structure of the Cr on that of the CoPtCr.XTEM specimens were prepared from magnetic recording disks by modifying a technique used to prepare semiconductor specimens. After 3mm disks were prepared per the standard XTEM procedure, these disks were then lapped using a tripod polishing device. A grid with a single 1mmx2mm hole was then glued with M-bond 610 to the polished side of the disk.

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Computer averaging of lattice images of poly-4-methyl-pentene-1 (P4mp1): Noise created artifacts

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100126731 ◽

1987 ◽

Vol 45 ◽

pp. 388-389

Author(s):

P. Pradère ◽

J.F. Revol ◽

R. St. John Manley

Keyword(s):

Low Dose ◽

Polymer Concentration ◽

Processing System ◽

Limiting Factor ◽

Dilute Solution ◽

New Techniques ◽

Dose Unit ◽

Lattice Images ◽

Dose Imaging ◽

Imaging Conditions

Although radiation damage is the limiting factor in HREM of polymers, new techniques based on low dose imaging at low magnification have permitted lattice images to be obtained from very radiation sensitive polymers such as polyethylene (PE). This paper describes the computer averaging of P4MP1 lattice images. P4MP1 is even more sensitive than PE (total end point dose of 27 C m-2 as compared to 100 C m-2 for PE at 120 kV). It does, however, have the advantage of forming flat crystals from dilute solution and no change in d-spacings is observed during irradiation.Crystals of P4MP1 were grown at 60°C in xylene (polymer concentration 0.05%). Electron microscopy was performed with a Philips EM 400 T microscope equipped with a Low Dose Unit and operated at 120 kV. Imaging conditions were the same as already described elsewhere. Enlarged micrographs were digitized and processed with the Spider image processing system.

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Serial thin sectioning for pre- and post-embedding immunohistochemistry: Achieving consistent and reliable results for a 3-D reconstruction

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010014748x ◽

1993 ◽

Vol 51 ◽

pp. 328-329

Author(s):

Antonia M. Milroy

Keyword(s):

Nervous System ◽

Computer Assisted ◽

Serial Sectioning ◽

Electron Microscopic ◽

High Quality ◽

New Techniques ◽

3 Dimensional ◽

Multiple User ◽

Thin Sectioning ◽

Subcellular Level

In recent years many new techniques and instruments for 3-Dimensional visualization of electron microscopic images have become available. Higher accelerating voltage through thicker sections, photographed at a tilt for stereo viewing, or the use of confocal microscopy, help to analyze biological material without the necessity of serial sectioning. However, when determining the presence of neurotransmitter receptors or biochemical substances present within the nervous system, the need for good serial sectioning (Fig. 1+2) remains. The advent of computer assisted reconstruction and the possibility of feeding information from the specimen viewing chamber directly into a computer via a camera mounted on the electron microscope column, facilitates serial analysis. Detailed information observed at the subcellular level is more precise and extensive and the complexities of interactions within the nervous system can be further elucidated.We emphasize that serial ultra thin sectioning can be performed routinely and consistently in multiple user electron microscopy laboratories. Initial tissue fixation and embedding must be of high quality.

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