State and Federal Timber Stumpage Prices in Vermont

1992 ◽  
Vol 9 (3) ◽  
pp. 97-101
Author(s):  
Paul E. Sendak
Keyword(s):  
Sugar Maple ◽  
Weighted Average ◽  
National Forest ◽  
Green Mountain ◽  
Sale Price ◽  
Parks And Recreation ◽  
Timber Sales ◽  
The Difference ◽  
Significant Regression ◽  
Mean State

Abstract Timber sales data and stumpage prices were analyzed for the Green Mountain National Forest (federal) and the Vermont Department of Forests, Parks and Recreation (state). In all cases, state stumpage prices were higher on average, but significantly so only for the overall price (volume weighted average sale price per cunit), spruce sawtimber, and hardwood and softwood pulpwood. Differences between mean state and federal prices for sugar maple and yellow birch sawtimber were not significant. Regression analysis was used to examine the differences in overall stumpage price. The results suggest that the difference in sale prices can largely be explained by differences in sales characteristics, most notably timber quality. North. J. Appl. For. 9(3):97-101.

Logging Season Affects Hardwood Reproduction

1984 ◽  
Vol 1 (1) ◽  
pp. 5-7 ◽  
Author(s):  
Carl H. Tubbs ◽  
Bruce D. Reid
Keyword(s):  
Sugar Maple ◽  
Relative Proportion ◽  
National Forest ◽  
Green Mountain ◽  
Paper Birch ◽  
Winter Logging

Abstract The Rochester District of the Green Mountain National Forest has kept records of regeneration following clearcut and shelterwood harvesting since 1969. These records offered the opportunity to evaluate the effects of summer and winter harvesting on regeneration. Season of logging did not affect the number of stands with adequate stocking but winter logging resulted in somewhat better stocking of sugar maple and yellow and paper birch than summer logging. Shelterwoods were better stocked with sugar maple than clearcuts, which on average were better stocked with the birches. The year of cut seemed to have the greatest influence on the relative proportion of birches and sugar maple after clearcutting. Citation: Northern Journal of Applied Forestry, April 1984 NJ 1:5-7.

scholarly journals Evaluating the Impact of Floods on Housing Price Using a Spatial Matching Difference-In-Differences (SM-DID) Approach

2021 ◽  
Vol 13 (2) ◽  
pp. 804
Author(s):  
Jean Dubé ◽  
Maha AbdelHalim ◽  
Nicolas Devaux
Keyword(s):  
Housing Price ◽  
Hedonic Pricing ◽  
Environmental Amenities ◽  
Sale Price ◽  
Difference In Differences ◽  
Hedonic Pricing Model ◽  
The Difference ◽  
And Control ◽  
The Impact ◽  
The City

Many applications have relied on the hedonic pricing model (HPM) to measure the willingness-to-pay (WTP) for urban externalities and natural disasters. The classic HPM regresses housing price on a complete list of attributes/characteristics that include spatial or environmental amenities (or disamenities), such as floods, to retrieve the gradients of the market (marginal) WTP for such externalities. The aim of this paper is to propose an innovative methodological framework that extends the causal relations based on a spatial matching difference-in-differences (SM-DID) estimator, and which attempts to calculate the difference between sale price for similar goods within “treated” and “control” groups. To demonstrate the potential of the proposed spatial matching method, the researchers present an empirical investigation based on the case of a flood event recorded in the city of Laval (Québec, Canada) in 1998, using information on transactions occurring between 1995 and 2001. The research results show that the impact of flooding brings a negative premium on the housing price of about 20,000$ Canadian (CAN).

Perceived sleep need, cumulative sleep deficit, and associations with daily affect in adolescents: A 28-day study over school and vacation periods

2021 ◽  
Author(s):  
Lin Shen ◽  
Joshua F. Wiley ◽  
Bei Bei
Keyword(s):  
Sleep Duration ◽  
Multilevel Models ◽  
Weighted Average ◽  
Sleep Restriction ◽  
Positive And Negative Affect ◽  
The Past ◽  
Daily Affect ◽  
Day Of The Week ◽  
The Difference ◽  
Sleep Deficit

Study Objectives: To describe trajectories of daily perceived sleep need (PSNeed) and sleep deficit across 28 consecutive days, and examine if cumulative sleep deficit predicts next-day affect.Methods: Daily sleep and affect were measured over 2 weeks of school and 2 weeks of vacation in 205 adolescents (54.1% females, Mage = 16.9 years). Each day, participants wore actigraphs and self-reported the amount of sleep needed to function well the next day (i.e., perceived sleep need), sleep duration, and high- and low-arousal positive and negative affect (PA, NA). Cumulative actigraphy and diary sleep deficit were calculated as the weighted average of the difference between PSNeed and sleep duration over the past 3 days. Cross-lagged, multilevel models were used to test cumulative sleep deficit as a predictor of next-day affect. Lagged affect, day of the week, study day, and sociodemographics were controlled.Results: PSNeed was lower early in the school week, before increasing in the second half of the week. Adolescents accumulated sleep deficit across school days and reduced it during weekends. During weekends and vacations, adolescents’ self-reported, but not actigraphy sleep duration, met PSNeed. Higher cumulative actigraphy sleep deficit predicted higher next-day high arousal NA; higher cumulative diary sleep deficit predicted higher NA (regardless of arousal), and lower low arousal PA the following day.Conclusions: Adolescents experienced sustained cumulative sleep deficit across school days. Non-school nights appeared to be opportunities for reducing sleep deficit. Trajectories of sleep deficit during vacation suggested recovery from school-related sleep restriction.

scholarly journals Research on Improvement of the Combination Method for Conflicting Evidence Based on Historical Data

Symmetry ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 762
Author(s):  
Shuai Yuan ◽  
Honglei Wang
Keyword(s):  
Decision Rule ◽  
Historical Data ◽  
Evidence Theory ◽  
Weighted Average ◽  
Combination Method ◽  
Final Decision ◽  
Evidence Based ◽  
Combination Methods ◽  
Conflicting Evidence ◽  
The Difference

In a multi-sensor system, due to the difference of performance of sensors and the environment in which the sensor collects evidence, evidence collected will be highly conflicting, which leads to the failure of D-S evidence theory. The current research on combination methods of conflicting evidence focuses on eliminating the problem of "Zadeh paradox" brought by conflicting evidence, but do not distinguish the evidence from different sources effectively. In this paper, the credibility of each piece of evidence to be combined is weighted based on historical data, and the modified evidence is obtained by weighted average. Then the final result is obtained by combining the modified evidence using D-S evidence theory, and the improved decision rule is used for the final decision. After the decision, the system updates and stores the historical data based on actual results. The improved decision rule can solve the problem that the system cannot make a decision when there are two or more propositions corresponding to the maximum support in the final combination result. This method satisfies commutative law and associative law, so it has the symmetry that can meet the needs of the combination of time-domain evidence. Numerical examples show that the combination method of conflict evidence based on historical data can not only solve the problem of “Zadeh paradox”, but also obtain more reasonable results.

Black Bears Prefer Urea-Fertilized Trees

1989 ◽  
Vol 4 (1) ◽  
pp. 13-15 ◽  
Author(s):  
E. E. Nelson
Keyword(s):  
Pseudotsuga Menziesii ◽  
Dominant Species ◽  
Tree Mortality ◽  
Ursus Americanus ◽  
Douglas Fir ◽  
Black Bears ◽  
National Forest ◽  
Feeding Damage ◽  
Mount Hood ◽  
The Difference

Abstract Feeding damage by black bears (Ursus americanus) to urea-fertilized 25-yr-old Douglas-firs (Pseudotsuga menziesii) in the Mount Hood National Forest, Oregon, resulted in tree mortality four times as severe as among unfertilized trees. Damage was most apparent following application of urea at 448 kg N/ha in 1972, and 224 kg N/ha in 1977. Only Douglas-fir, the dominant species in the stand, was attacked. Attacked trees were somewhat larger than the stand average, but the difference was not significant. Bears appeared to be attracted to the more vigorous trees, which were on fertilized plots. West. J. Appl. For. 4(1):13-15, January 1989.

scholarly journals Mapping of Snow Depth by Blending Satellite and In-Situ Data Using Two-Dimensional Optimal Interpolation—Application to AMSR2

2019 ◽  
Vol 11 (24) ◽  
pp. 3049 ◽  
Author(s):  
Cezar Kongoli ◽  
Jeffrey Key ◽  
Thomas M. Smith
Keyword(s):  
North America ◽  
Snow Depth ◽  
Weather Prediction ◽  
Weighted Average ◽  
Optimal Interpolation ◽  
Horizontal Distance ◽  
Two Dimensional ◽  
In Situ Data ◽  
The Difference

The development of a snow depth product over North America is investigated by applying two-dimensional optimal interpolation to passive microwave satellite-derived and in-situ measured snow depth. At each snow-covered satellite footprint, the technique computes a snow depth increment as the weighted average of data increments, and updates the satellite-derived snow depth accordingly. Data increments are computed as the difference between the in-situ-measured and satellite snow depth at station locations surrounding the satellite footprint. Calculation of optimal weights is based on spatial lag autocorrelation of snow depth increments, modelled as functions of horizontal distance and elevation difference between pairs of observations. The technique is applied to Advanced Microwave Scanning Radiometer 2 (AMSR2) snow depth and in-situ snow depth obtained from the Global Historical Climatology Network. The results over North America during January–February 2017 indicate that the technique greatly enhances the performance of the satellite estimates, especially over mountain terrain, albeit with an accuracy inferior to that over low elevation areas. Moreover, the technique generates more accurate output compared to that from NOAA’s Global Forecast System, with implications for improving the utilization of satellite data in snow assessments and numerical weather prediction.

Shot-hole borer (Xyleborus fornicatus Eichh.) of tea in Ceylon II.—The effect of chemical control on the yield and manurial response of tea

1968 ◽  
Vol 57 (4) ◽  
pp. 619-641
Author(s):  
J. E. Cranham ◽  
P. Kanapathapillai ◽  
A. Kathiravetpillai
Keyword(s):  
Field Trials ◽  
First Year ◽  
Percentage Increase ◽  
Nitrogen Application ◽  
The Third ◽  
Prolonged Effect ◽  
Second Year ◽  
The Difference ◽  
Significant Regression ◽  
Effect On Yield

In 1960–65, six field trials were carried out on tea estates in Ceylon to assess the effect on yield, and on the response of the crop to fertilizer, of dieldrin sprays applied after pruning to control shot-hole borer (Xyleborus fornicatus Eichh.). Periodic sampling was carried out to assess the numbers of borers and their galleries. Yields were recorded by weekly or fortnightly weighings of the green leaf plucked, over pruning cycles of two to four years.The pattern of the yield increases on the sprayed plots was related to the difference in attack between the sprayed and unsprayed plots. Increases were, in general, small in the first year and much larger in the second year, reaching peak values of 32–58 per cent. (on the yields of successive three-monthly periods recorded) in the late second year, and declining thereafter through the third year as the difference in attack declined. Over the first two years there were marked yield increases in eight of the nine pruning cycles, and these ranged from 11·7 per cent, to 26·3 per cent. There was significant regression (P<0·001) of the percentage increase in yield on the maximum difference in gallery counts. Yield increases in the third year of pruning cycles were also considerable and the results evidence a prolonged effect of the heavy borer attack occurring in the second year.In one trial there was a significant interaction between the effects of dieldrin spraying and of nitrogen supplied. Control of the borer greatly improved the crop response to nitrogen. Nitrogen application increased the yield but resulted also in a proportionately larger loss of crop from borer attack. There was a small but significant increase in the number of borer galleries on the plots receiving nitrogen.The evidence on the size and pattern of crop losses caused by the borer suggests that these occur both from shoot breakages and from the direct effect of galleries on the growth of stems.The significance of the results in relation to estate practice, and the economics of spraying, are briefly discussed.

What is the role of tortuosity in the Kozeny-Carman equation?

2017 ◽  
Vol 5 (1) ◽  
pp. SB57-SB67 ◽  
Author(s):  
Nattavadee Srisutthiyakorn ◽  
Gerald M. Mavko
Keyword(s):  
Porous Media ◽  
Pore Space ◽  
Flow Simulation ◽  
Weighted Average ◽  
Rock Physics ◽  
Sample Length ◽  
Pore Throat ◽  
Binary Images ◽  
The Difference ◽  
Definition Of

Hydraulic tortuosity is an important parameter in characterizing fluid-flow heterogeneity in porous media. The most basic definition of tortuosity is the ratio of the average flow path length to the sample length. Although this definition seems straightforward, the lack of understanding and the lack of proper ways to measure tortuosity make it one of the most abused parameters in rock physics. Hydraulic tortuosity is often treated merely as a fitting factor, or worse, it is neglected by being combined with a geometric factor in the Kozeny-Carman (KC) equation. Often, the tortuosity is obtained from laboratory measurements of porosity, permeability, and specific surface area by inverting the KC equation. This approach has a major pitfall because it treats tortuosity as a fitting factor, and the inverted tortuosity is often unphysically high. In contrast, we obtained the tortuosity from 3D segmented binary images of porous media using streamlines extracted from a local flux, the output from the lattice Boltzmann method (LBM) flow simulation. After obtaining streamlines from each sample, we calculated the distribution of tortuosities and flux-weighted average tortuosity. With the tortuosity measurement from streamlines, every parameter in the KC equation can be measured accurately from 3D segmented binary images. We found, however, that the KC equation is still missing some important geometric information needed to predict permeability. With known parameters and without a fitting factor, the KC equation predicts permeability higher by one to two orders of magnitude than that predicted by the LBM. We searched for a missing parameter by exploring various concepts such as connected pore space and pore throat distribution. We found that the connected pore space does not contribute to the difference between the KC permeability and LBM permeability, whereas, as we learn with sinusoidal pipe examples, the pore throat distribution captures what is missing from the KC equation.

scholarly journals ImmuneDEX: a strategy for the genetic improvement of immune competence in Australian Angus cattle

2021 ◽  
Vol 99 (3) ◽  
Author(s):  
Antonio Reverter ◽  
Brad C Hine ◽  
Laercio Porto-Neto ◽  
Yutao Li ◽  
Christian J Duff ◽  
...  
Keyword(s):  
Immune Response ◽  
Genetic Improvement ◽  
Weighted Average ◽  
Real Data ◽  
Antibiotic Use ◽  
Alternative Methods ◽  
Immune Competence ◽  
Angus Cattle ◽  
The Difference ◽  
The Individual

Abstract In animal breeding and genetics, the ability to cope with disease, here defined as immune competence (IC), with minimal detriment to growth and fertility is a desired objective which addresses both animal production and welfare considerations. However, defining and objectively measuring IC phenotypes using testing methods which are practical to apply on-farm has been challenging. Based on previously described protocols, we measured both cell-mediated immune response (Cell-IR) and antibody-mediated immune response (Ab-IR) and combined these measures to determine an animal’s IC. Using a population of 2,853 Australian Angus steers and heifers, we compared 2 alternative methods to combine both metrics into a single phenotype to be used as a tool for the genetic improvement of IC. The first method, named ZMEAN, is obtained by taking the average of the individual metrics after subjecting each to a Z-score standardization. The second, ImmuneDEX (IDEX), is a weighted average that considers the correlation between Cell-IR and Ab-IR, as well as the difference in ranking of individuals by each metric, and uses these as weights in the averaging. Both simulation and real data were used to understand the behavior of ZMEAN and IDEX. To further ascertain the relationship between IDEX and other traits of economic importance, we evaluated a range of traits related to growth, feedlot performance, and carcass characteristics. We report estimates of heritability of 0.31 ± 0.06 for Cell-IR, 0.42 ± 0.06 for Ab-IR, 0.42 ± 0.06 for ZMEAN and 0.370 ± 0.06 for IDEX, as well as a unity genetic correlation (rg) between ZMEAN and IDEX. While a moderately positive rg was estimated between Cell-IR and Ab-IR (rg = 0.33 ± 0.12), strongly positive estimates were obtained between IDEX and Cell-IR (rg = 0.80 ± 0.05) and between IDEX and Ab-IR (rg = 0.85 ± 0.04). We obtained a moderately negative rg between IC traits and growth including an rg = −0.38 ± 0.14 between IDEX and weaning weight, and negligible with carcass fat measurements, including an rg = −0.03 ± 0.12 between IDEX and marbling. Given that breeding with a sole focus on production might inadvertently increase susceptibility to disease and associated antibiotic use, our analyses suggest that ImmuneDEX will provide a basis to breed animals that are both highly productive and with an enhanced ability to resist disease.

Sign in / Sign up

Export Citation Format

Share Document