Thinning and Harvesting Regimes for Yellow-Poplar

1990 ◽  
Vol 14 (3) ◽  
pp. 101-103 ◽  
Author(s):  
Carlyle Franklin ◽  
Dennis W. Hazel ◽  
Randal R. Rucker ◽  
Gary D. Kronrad
Keyword(s):  
North Carolina ◽  
Discount Rate ◽  
Development Model ◽  
Site Quality ◽  
Stand Age ◽  
Stand Development ◽  
Discount Rates ◽  
Yellow Poplar

Abstract Grade 1 yellow-poplar logs were recently selling for $150/mbf, three times the price for grade 2 logs in North Carolina. A computerized stand development model was used to examine the profitability of thinning and holding yellow-poplar stands for increased diameter and grade. Analyses were done over wide ranges in stand age, site quality, and stocking, at 5% and 10% discount rates. At a 5% discount rate, the maximum net present stumpage value was obtained by thinning in most regimes. Lower stand age, higher initial stocking, and higher site indices favored thin-clearcut regimes over regimes with no initial thinning. At a 10% discount rate, thinning was optimal only at initial age 30 on the highest quality sites at the highest initial stockings. All other combinations of variables favored clearcutting immediately or with a 10-year delay. Thinning options with net values within 50% of maximum were numerous at a 5% discount rate in younger stands but decreased rapidly as initial age increased. Only a few such options were available at the 10% discount rate. South. J. Appl. For. 14(3):101-103.

Yellow-Poplar Site Quality Related to Slope Type in Mountainous Terrain

1987 ◽  
Vol 4 (4) ◽  
pp. 189-192 ◽  
Author(s):  
W. Henry McNab
Keyword(s):  
Land Surface ◽  
Appalachian Mountains ◽  
Site Index ◽  
Important Variable ◽  
Surface Shape ◽  
Site Quality ◽  
Stand Age ◽  
Mountainous Terrain ◽  
Yellow Poplar ◽  
Southern Appalachian

Abstract Site index and topographic variables were measured on 112, ¼-ac sample plots with yellow-poplar overstory in the Blue Ridge Province of the Southern Appalachian Mountains. The plots were grouped by slope type—nose, side, or head—and multiple regression analysis was used to develop equations for predicting height at 50 years. Estimated site index was significantly less on side slopes than on head slopes. Stand age was the most important variable in both equations, followed by aspect and land surface shape. The equations accounted for 79% of the variation of yellow-poplar height on head slopes and 84% on side slopes. North. J. Appl. For. 4:189-192, Dec. 1987.

Relation between the permeability and the anatomy of jack pine sapwood with stand development

1989 ◽  
Vol 19 (12) ◽  
pp. 1564-1570 ◽  
Author(s):  
David Pothier ◽  
Hank A. Margolis ◽  
Jean Poliquin ◽  
Richard H. Waring
Keyword(s):  
Jack Pine ◽  
Site Quality ◽  
Stand Age ◽  
Stand Development ◽  
Pit Membrane ◽  
Relative Water ◽  
Poiseuille's Law ◽  
Shallow Soils ◽  
Mature Stands ◽  
Poiseuille’S Law

The anatomical characteristics of sapwood from the base of the live crown of trees from 11 jack pine stands (Pinusbanksiana Lamb.) of different age and site quality were related to the patterns of change of longitudinal sapwood permeability (k) previously observed to occur among these stands. Tracheid length (Lt) increased rapidly from a minimum of 1.9 mm to a plateau of around 3.6 mm as stand age and site quality (productivity class) increased. Sapwood relative water content (Rs) measured before saturation ranged from 78 to 85% for the majority of trees. Samples taken from trees growing on poor sites, however, exhibited significantly lower values of Rs, which probably resulted in their remaining below saturation during the determination of sapwood permeability. The lower Rs values were assumed to be reflective of more adverse water balances during the growing season associated with rapidly drained and (or) shallow soils. Tracheid lumen diameter (Dl) was positively correlated with k within age-classes 15 and 35, but not thereafter. The initial relation between Dl, and k is thought to be associated with corresponding increases in the area of pit membranes, which determines the number of pores within a pit membrane. Values of k were never more than 60% of the values calculated by Poiseuille's law for ideal capillaries (kc) and were generally less than 40%. Values of k tended to approach kc with increasing Lt and decreasing Dl. Overall, Poiseuille's law by itself could not explain the changes in the hydraulic properties of jack pine sapwood with stand development. However, Lt and Rs could together account for 72% of the variation in k. Young stands that had different k depending on site quality generally had corresponding differences in Lt, Rs, and (or) Dl. Mature stands that had reached maximum k on all quality sites no longer showed differences in Lt, Rs, or Dl.

scholarly journals Changes in Soil Arthropod Abundance and Community Structure across a Poplar Plantation Chronosequence in Reclaimed Coastal Saline Soil

Forests ◽  
2018 ◽  
Vol 9 (10) ◽  
pp. 644 ◽  
Author(s):  
Yuanyuan Li ◽  
Han Chen ◽  
Qianyun Song ◽  
Jiahui Liao ◽  
Ziqian Xu ◽  
...  
Keyword(s):  
Community Dynamics ◽  
Stand Age ◽  
Stand Development ◽  
Soil Arthropods ◽  
Total Abundance ◽  
Soil Arthropod ◽  
Plantation Development ◽  
Poplar Plantations ◽  
Hill Numbers ◽  
One Year

Poplar plantations have the capacity to improve the properties of soils in muddy coastal areas; however, our understanding of the impacts of plantation development on soil arthropods remains limited. For this study, we determined the community dynamics of soil dwelling arthropods across poplar plantations of different ages (5-, 10-, and 21-years) over the course of one year in Eastern Coastal China. The total abundance of soil arthropods differed with stand development. Further, there were some interactions that involved the sampling date. On average, total abundance was highest in the 10-year-old stands and lowest in the 5-year-old stands. Total abundance exhibited strong age-dependent trends in June and September, but not in March or December. The abundance of Prostigmata and Oribatida increased in the 5- to 21-year-old stands, with the highest levels being in the 10-year-old stands. The abundance of Collembola increased with stand development; however, the stand age had no significant impact on the abundance of epedapic, hemiedaphic, and euedaphic Collembola. Order richness (Hill number q = 0) curve confidence intervals overlapped among three stand ages. Shannon and Simpson diversity (Hill numbers q = 1 and q = 2) differed between 10- and 21-year-old stand age. They showed almost similar trends, and the highest and lowest values were recorded in the 21- and 10-year-old stand ages, respectively. Permutational multivariate analysis of variance demonstrated that composition also varied significantly with the sampling date and stand age, and the 10-year-old stands that were sampled in June stood well-separated from the others. Indicator analysis revealed that Scolopendromorpha and Prostigmata were indicators in June for the 10-year-old stands, while Collembola were indicators for the 21-year-old stands sampled in September. Our results highlight that both stand development and climate seasonality can significantly impact soil arthropod community dynamics in the reclaimed coastal saline soils of managed poplar plantations.

High Discounts and High Unemployment

2017 ◽  
Vol 107 (2) ◽  
pp. 305-330 ◽  
Author(s):  
Robert E. Hall
Keyword(s):  
Labor Market ◽  
Stock Market ◽  
Discount Rate ◽  
Job Creation ◽  
Discount Rates ◽  
Present Value ◽  
High Unemployment ◽  
Business Income ◽  
New Hire

Unemployment is high when financial discounts are high. In recessions, the stock market falls and all types of investment fall, including employers' investment in job creation. The discount rate implicit in the stock market rises, and discounts for other claims on business income also rise. A higher discount implies a lower present value of the benefit of a new hire to an employer. According to the leading view of unemployment—the Diamond-Mortensen-Pissarides model—when the incentive for job creation falls, the labor market slackens and unemployment rises. Thus high discount rates imply high unemployment. (JEL E24, E32, E44, J23, J31, J63)

scholarly journals Stationary Forestry with Human Interference

2018 ◽  
Vol 10 (10) ◽  
pp. 3662 ◽  
Author(s):  
Petri Kärenlampi
Keyword(s):  
Management Practices ◽  
Small Volume ◽  
Development Model ◽  
Financial Sustainability ◽  
Stand Development ◽  
Forest Stands ◽  
Human Interference ◽  
Return Rates ◽  
Appreciation Rate ◽  
Capital Return

Here, we present stationarity criteria for forest stands and establish ecological embodiments using an empirical stand development model. We introduced human interference in terms of diameter-limit cutting. Financial sustainability was investigated as a function of the cutting limit diameter. It was found that nonoperative capitalization along with its appreciation rate dictates the sustainability of management practices. In the absence of nonoperative capitalization, stationary forestry produces high capital return rates at a rather small volume of growing trees. In the case of large but constant nonoperative capitalization, a large operative capitalization resulting in a large harvesting yield provides the best capital returns. A high nonoperative appreciation rate requires a small volume of growing trees.

scholarly journals Influences of Forest Type, Stand Age, and Weather on Deer Weights and Antler Size in the Southern Appalachians

1997 ◽  
Vol 21 (1) ◽  
pp. 11-18 ◽  
Author(s):  
William M. Ford ◽  
A. Sydney Johnson ◽  
Philip E. Hale ◽  
James M. Wentworth
Keyword(s):  
Age Structure ◽  
Forest Type ◽  
Site Index ◽  
Forest Stand ◽  
Site Quality ◽  
Stand Age ◽  
Southern Appalachians ◽  
Study Region ◽  
Pinus Spp ◽  
Percent Area

Abstract We analyzed correlations of forest type, age structure, and site index data with weights and antler characteristics of yearling white-tailed deer (Odocoileus virginianus) bucks from specific localities in the Chattahoochee, Cherokee, Nantahala, and Pisgah national forests in Georgia, Tennessee, and North Carolina. Areas in the northern part of the study region produced larger deer with larger antlers than those in the southern portion of the region. These northern areas differed from those to the south in having more diverse ownership and land use and in origins of deer stock. Weights and antler characteristics were significantly correlated (P < 0.05) with percent area in the cove hardwood type, but otherwise were poorly correlated with forest stand type and site index. Percent area in young (0-8 yr old) cove hardwood and in mid-successional (9-20 and 21-40) cove hardwood, pine (Pinus spp.), and upland oak (Quercus spp.) were significantly correlated (P < 0.05) with deer variables, particularly in years following a poor mast crop. Much of the quantifiable habitat influences on deer in the Southern Appalachians probably is masked by low deer densities and the small site quality differences among areas examined. Because much of the forest consists of mature mast-producing oaks and abundant forage is produced in both mature and younger aged stands, deer numbers seem to be below any threshold of quantifiable effects due to forest stand age structure. South. J. Appl. For. 21(1):11-18.

Managing Appalachian Hardwood Stands Using Four Regeneration Practice—34-Year Results

1987 ◽  
Vol 4 (4) ◽  
pp. 180-185 ◽  
Author(s):  
H. Clay Smith ◽  
Gary W. Miller
Keyword(s):  
Sugar Maple ◽  
Growth Response ◽  
Black Locust ◽  
Control Area ◽  
Stand Development ◽  
Yellow Poplar ◽  
Single Tree ◽  
Single Tree Selection ◽  
Intensively Managed ◽  
Future Management

Abstract Adjacent Appalachian hardwood stands in West Virginia established on excellent growing sites were managed for a 34-year period using four regeneration practices. These practices included a commercial clearcut, 15.5-in diameter-limit, and two single-tree selection practices. An uncut area was maintained as a control. Stand development, growth response, and some stumpage revenue data were summarized for each treatment. At 34 years after the initial treatments, the commercial clearcut stand had the greatest variety of tree species for future management. This stand was dominated primarily by yellow-poplar and black locust. Selection and 15.5-in diameter-limit treatments promoted sugar maple on these excellent sites. Stand quality improved through management. After 34 years, the control area was worth $1,554/ac, and an intensively managed selection area was worth $1,214/ac, but the control area contained twice the sawtimber volume. Other preliminary value comparisons indicate that landowners benefit from some type of management compared to doing no management. North. J. Appl. For. 4:180-185, Dec. 1987.

scholarly journals A Nonlinear Mixed-Effects Height-to-Diameter Ratio Model for Several Tree Species Based on Czech National Forest Inventory Data

Forests ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 70 ◽  
Author(s):  
Ram Sharma ◽  
Zdeněk Vacek ◽  
Stanislav Vacek ◽  
Miloš Kučera
Keyword(s):  
Forest Inventory ◽  
Stand Density ◽  
Development Stage ◽  
National Forest Inventory ◽  
Mixed Effects ◽  
Site Quality ◽  
National Forest ◽  
Stand Development ◽  
Inventory Data ◽  
Canopy Layer

Height-to-diameter at breast height (DBH) ratio (HDR) is an important tree and stand stability measure. Several factors such as stand dynamics, natural and anthropogenic disturbances, and silvicultural tending significantly affect HDR, and, therefore, in-depth investigation of HDR is essential for better understanding of ecological processes in a forest. A nonlinear mixed-effects HDR model applicable to several tree species was developed using the Czech national forest inventory data comprising 13,875 sample plots and 348,980 trees. The predictive performance of this model was evaluated using the independent dataset which was originated from 25,146 trees on 220 research sample plots. Among various tree- and stand-level variables describing tree size, site quality, stand development stage, stand density, inter-tree spacing, and competition evaluated, dominant height (HDOM), dominant diameter (DDOM), relative spacing index (RS), and DBH-to-quadratic mean DBH ratio (dq) were identified as the most important predictors of HDR variations. A random component describing sample plot-specific HDR variations was included through mixed-effects modelling, and dummy variables describing species-specific HDR variations and canopy layer-specific HDR variations were also included into the HDR model through dummy variable modelling. The mixed-effects HDR model explained 79% of HDR variations without any significant trends in the residuals. Simulation results showed that HDR for each canopy layer increased with increasing site quality and stand development stage (increased HDOM) and increasing competition (increased RS, decreased DDOM and dq). Testing the HDR model on the independent data revealed that more than 85% of HDR variations were described for each individual species (Norway spruce, Scots pine, European larch, and European beech) and group of species (fir species, oak species, birch and alder species) without significant trends in the prediction errors. The HDR can be predicted with a higher accuracy using the calibrated mixed-effects HDR model from measurements of its predictors that can be obtained from routine forest inventories. To improve the prediction accuracy, a model needs to be calibrated with the random effects estimated using one to four randomly selected trees of a particular species or group of species depending on the availability of their numbers per sample plot. The HDR model can be applied for stand stability assessment and stand density regulation. The HDR information is also useful for designing a stand density management diagram. Brief implications of the HDR model for designing silviculture strategies and forest management planning are presented in the article.

scholarly journals Anomalies: Intertemporal Choice

1989 ◽  
Vol 3 (4) ◽  
pp. 181-193 ◽  
Author(s):  
George Loewenstein ◽  
Richard H Thaler
Keyword(s):  
Decision Making ◽  
Time Delay ◽  
Discount Rate ◽  
Intertemporal Choice ◽  
Discount Rates ◽  
Market Rate ◽  
Money Flows ◽  
Speed Up ◽  
The Way

We examine a number of situations in which people do not appear to discount money flows at the market rate of interest or any other single discount rate. Discount rates observed in both laboratory and field decision-making environments are shown to depend on the magnitude and sign of what is being discounted, on the time delay, on whether the choice is cast in terms of speed-up or delay, on the way in which a choice is framed, and on whether future benefits or costs induce savoring or dread.

Changes to the growth and discount rates and asset impairment

2020 ◽  
Vol 33 (4/5) ◽  
pp. 577-592
Author(s):  
Maxeem Georges
Keyword(s):  
Growth Rate ◽  
Discount Rate ◽  
Discount Rates ◽  
Estimation Model ◽  
Content Type ◽  
Listed Firms ◽  
Opportunistic Behaviour ◽  
Asset Impairment ◽  
Asset Impairments ◽  
Insight Into

Purpose With timeliness and measurement of asset impairments as well as management opportunistic behaviour being topical, since the issuance of Australian Accounting Standards Board (AASB) 136, this study aims to examine whether assumptions about growth and discount rates made about asset recoverable amounts determine asset impairments. Design/methodology/approach This study uses a sample of 450 firm-year observations representing 133 Australian listed firms from 2015 to 2018. An estimation model is used where asset impairments is the dependent variable, growth and discount rates are the variables of interest and several impairment indicators are included as controls. Findings The results show that the decrease in growth rate but not the increase in discount rate affects the recognition of large asset impairments, where firms decrease the growth rate in the year of recognition. A change in discount rate affects asset impairments only when it is higher than the industry average. Hence, the growth rate is the management’s tool of choice in the recognition of asset impairments. Originality/value This study provides additional insight into how AASB 136 is used in practice. This includes investigating the tools used by firms in the calculation of asset recoverable amount and whether firms provide important information, as a part of disclosure. The results are of interest to investors and policymakers because they highlight the need for more restrictions around growth rate assumptions and less variation in disclosure.

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