A species-specific, site-sensitive maximum stand density index model for Pacific Northwest conifer forests

2021 ◽  
pp. 1-12
Author(s):  
Ryan R. Heiderman ◽  
Mark J. Kimsey
Keyword(s):  
Species Composition ◽  
Pacific Northwest ◽  
Stochastic Frontier ◽  
Stand Density ◽  
Tsuga Heterophylla ◽  
The Self ◽  
Species Selection ◽  
Federal State ◽  
Density Index ◽  
Stand Density Index

Maximum stand density index (SDIMAX) models were developed for important Pacific Northwest conifers of western Oregon and Washington, USA, based on site and species influences and interactions. Inventory and monitoring data from numerous federal, state, and private forest management groups were obtained throughout the region to ensure a wide coverage of site characteristics. These observations include information on tree size, number, and species composition. The effects and influence on the self-thinning frontier of plot-specific factors such as climate, topography, soils, and geology, as well as species composition, were evaluated based on geographic location using a multistep approach to analysis involving linear quantile mixed models, random forest, and stochastic frontier functions. The self-thinning slope of forest stands dominated by Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) was found to be –1.517 and that of stands dominated by western hemlock (Tsuga heterophylla (Raf.) Sarg.) was found to be –1.461, leading to regionwide modelled SDIMAX values at the 95th percentile of 1728 and 1952 trees per hectare, respectively. The regional model of site-specific SDIMAX will support forest managers in decision-making regarding density management and species selection to more efficiently utilize site resources toward healthy, productive forests.

scholarly journals ESTIMATE OF STAND DENSITY INDEX FOR EUCALYPTUS UROPHYLLA USING DIFFERENT FIT METHODS

2016 ◽  
Vol 40 (5) ◽  
pp. 921-929 ◽  
Author(s):  
Ernani Lopes Possato ◽  
Natalino Calegario ◽  
Gilciano Saraiva Nogueira ◽  
Elliezer de Almeida Melo ◽  
Joyce de Almeida Alves
Keyword(s):  
Stochastic Frontier Analysis ◽  
Stochastic Frontier ◽  
Genetic Material ◽  
Stand Density ◽  
Model Parameters ◽  
Eucalyptus Urophylla ◽  
Frontier Analysis ◽  
Density Index ◽  
Number Of Stems ◽  
Stand Density Index

ABSTRACT The Reineke stand density index (SDI) was created on 1933 and remains as target of researches due to its importance on helping decision making regarding the management of population density. Part of such works is focused on the manner by which plots were selected and methods for the fit of Reineke model parameters in order to improve the definition of SDI value for the genetic material evaluated. The present study aimed to estimate the SDI value for Eucalyptus urophylla using the Reineke model fitted by the method of linear regression (LR) and stochastic frontier analysis (SFA). The database containing pairs of data number of stems per hectare (N) and mean quadratic diameter (Dq) was selected in three intensities, containing the 8, 30 and 43 plots of greatest density, and models were fitted by LR and SFA on each selected intensities. The intensity of data selection altered slightly the estimates of parameters and SDI when comparing the fits of each method. On the other hand, the adjust method influenced the mean estimated values of slope and SDI, which corresponded to -1.863 and 740 for LR and -1.582 and 810 for SFA.

scholarly journals Use of Modified Reineke’s Stand Density Index in Predicting Growth and Survival of Chinese Fir Plantations

2019 ◽  
Vol 65 (6) ◽  
pp. 776-783 ◽  
Author(s):  
Xiongqing Zhang ◽  
Quang V Cao ◽  
Lele Lu ◽  
Hanchen Wang ◽  
Aiguo Duan ◽  
...  
Keyword(s):  
Predictor Variable ◽  
Basal Area ◽  
Stand Density ◽  
Chinese Fir ◽  
The Self ◽  
Survival Models ◽  
Future Climate Change ◽  
Growth And Survival ◽  
Density Index ◽  
Stand Density Index

Abstract Stand density index (SDI) has played an important role in controlling stand stocking and modeling stand development in forest stands. Reineke’s SDI (SDI_R) is based on a constant slope of –1.605 for the self-thinning line. For Chinese fir plantations, however, it has been reported that the self-thinning slope varied with site and climate, rendering SDI_R questionable. Remeasured data from 48 plots distributed in Fujian, Jiangxi, Guangxi, and Sichuan provinces were used to develop models for prediction of stand survival and basal area, with SDI_R incorporated as a predictor variable. Also included in the evaluation were growth models based on self-thinning slopes estimated from two groups of sites (SDI_S) or from climate variables (SDI_C). Results indicated that models with climate-sensitive SDI (SDI_C) performed best, followed by SDI_S and SDI_R. The control models without SDI received the worst overall rank. Inclusion of climate-sensitive SDI in growth and survival models can therefore facilitate modeling of the relation between stand density and growth/survival under future climate-change conditions.

A Comparison of Diameter-and Volume-Based Stocking Guides for Red Alder

1989 ◽  
Vol 4 (4) ◽  
pp. 113-115 ◽  
Author(s):  
David E. Hibbs ◽  
Gary C. Carlton
Keyword(s):  
United States ◽  
Stand Density ◽  
The Self ◽  
Western United States ◽  
Alnus Rubra ◽  
Stem Density ◽  
Red Alder ◽  
Rule Based ◽  
Density Index ◽  
Stand Density Index

Abstract Stocking guides based on Reineke's stand density index concept (diameter vs stem density) and on the self-thinning rule (volume vs stem density) are currently in use in the western United States. A self-thinning rule-based guide has been developed for red alder (Alnus rubra). In this paper, we develop a Reineke-type guide for red alder and compare the growth of thinned and self-thinning stands in both systems. Stand density appears to be defined differently in the two systems, leading to differences in density management prescriptions. West. J. Appl. For. 4(4):113-115, October 1989.

Role of species composition in relative density measurement in Allegheny hardwoods

1986 ◽  
Vol 16 (3) ◽  
pp. 574-579 ◽  
Author(s):  
Susan Laurane Stout ◽  
Ralph D. Nyland
Keyword(s):  
Species Composition ◽  
Forest Type ◽  
Density Measurement ◽  
Basal Area ◽  
Stand Density ◽  
Area Ratio ◽  
Index Model ◽  
Density Index ◽  
Species Groups ◽  
Stand Density Index

Two frequently used measures of relative stand density, the tree area ratio and the stand density index, were fitted to data from Allegheny hardwood stands. Both were modified to reflect the influence of species composition, since the proportion of the basal area in different species groups had an important effect on the measurement of relative stand density in this mixed species forest type. The tree area ratio model provided a better fit to the data than the stand density index model, particularly when adapted to include three species groups: one based on Prunusserotina Ehrh. and Liriodendrontulipifera L., one based on Acerrubrum L., and one based on Acersaccharum Marsh, and Fagusgrandifolia Ehrh.

Comparing productivity of pure and mixed Douglas-fir and western hemlock plantations in the Pacific Northwest

2006 ◽  
Vol 36 (6) ◽  
pp. 1484-1496 ◽  
Author(s):  
M M Amoroso ◽  
E C Turnblom
Keyword(s):  
Pacific Northwest ◽  
Stand Density ◽  
Tsuga Heterophylla ◽  
Douglas Fir ◽  
Western Hemlock ◽  
Mixed Stand ◽  
Mixed Stands ◽  
Individual Tree ◽  
The Pacific ◽  
Increase In Productivity

We studied pure and 50/50 mixtures of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and western hemlock (Tsuga heterophylla (Raf.) Sarg.) plantations to compare attained total yields between mixed-species stands as opposed to monocultures of equal densities. Whether overall stand density influences this outcome has not been adequately investigated, and to address this we included three density levels (494, 1111, and 1729 trees/ha) in the analysis. At age 12, as components of the mixed stands, Douglas-fir exhibited greater height, diameter, and individual-tree volume than western hemlock at all densities. At 494 and 1111 trees/ha the monocultures had a higher volume per hectare than the mixed stand, but at 1729 trees/ha the mixed stand appeared to be just as productive as the pure stands. The increase in productivity by the mixture at high densities seems to have resulted from the partial stratification observed and most likely also from better use of the site resources. Because of this, less interspecific competition was probably experienced in the mixed stand than intraspecific competition in the pure stands. This study shows the important role density plays in the productivity of mixed stands and thus in comparing mixed and pure stands.

scholarly journals Auf dem Weg zum Gebirgsplenterwald: Kurzzeiteffekte von Durchforstungen auf die Struktur subalpiner Fichtenwälder | On the way to a mountain selection forest:Short-term effects of thinning on the structure of subalpine spruce forests (reviewed paper)

2005 ◽  
Vol 156 (12) ◽  
pp. 456-466 ◽  
Author(s):  
Hansheinrich Bachofen ◽  
Andreas Zingg
Keyword(s):  
Spatial Distribution ◽  
Stand Density ◽  
Stand Development ◽  
Protective Function ◽  
Spruce Forests ◽  
Density Index ◽  
Thinning Operations ◽  
Stand Density Index ◽  
Improve Stability

Stand structures and stand stability in unmanaged Norway spruce forests in the Swiss mountains may decline and their protective function against natural hazards will thus be put at risk. They are being subjected to thinning operations to improve stability and, in the long-term, to transform them into mountain selection forests. On pairs of research plots – thinned and not thinned – we will closely follow the stand development. Preliminary results indicate that the best variables to describe the effectiveness of the applied treatment to the stand structures are the h/d ratio,the spatial distribution and the stand density index.

scholarly journals Effects of Western Balsam Bark Beetle on Spruce-Fir Forests of North-Central Wyoming

2003 ◽  
Vol 18 (4) ◽  
pp. 259-266 ◽  
Author(s):  
Joel D. McMillin ◽  
Kurt K. Allen ◽  
Daniel F. Long ◽  
Jeri Lyn Harris ◽  
José F. Negrón
Keyword(s):  
Bark Beetle ◽  
Basal Area ◽  
Stand Density ◽  
Herbaceous Plant ◽  
North Central ◽  
Subalpine Fir ◽  
Dryocoetes Confusus ◽  
Density Index ◽  
Stand Density Index ◽  
Stand Conditions

Abstract Western balsam bark beetle, Dryocoetes confusus (Coleoptera: Scolytidae), has caused widespread mortality of subalpine fir (Abies lasiocarpa) in western North America throughout the past decade. The objectives of this study were to document the effects of this mortality, relate mortality to pre-existing stand conditions, and investigate the role of storm-damaged fir in beetle population dynamics in north-central Wyoming. Transect cruise lines and pairs of infested and uninfested plots were installed to detect changes in the forest overstory and understory and to determine associations between stand conditions and beetle-caused fir mortality. On average, beetles killed more than 70 trees/ac over the last several years. This mortality resulted in significant decreases in: subalpine fir basal area, trees per acre, stand density index, and the percentage of subalpine fir stems in the overstory. Small, but significant increases were detected in the understory; herbaceous plant abundance increased in the infested plots compared with the noninfested plots. Moreover, significant positive linear relationships were found between the amount of fir mortality and the percentage of subalpine fir trees in a stand, subalpine fir basal area, and subalpine fir stand density index. In addition, a significant positive linear relationship was found between the percentage of wind-caused downed fir logs in an area and the percentage of logs utilized by western balsam bark beetle. The blowdown events that occurred in the mid-1990s in combination with a high percentage of fir component has provided ideal conditions for continued beetle expansion. West. J. Appl. For. 18(4):259–266.

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