Developing relative stand density index for structurally complex mixed species cypress and pine forests

2018 ◽  
Vol 409 ◽  
pp. 425-433 ◽  
Author(s):  
Ting-Ru Yang ◽  
Tzeng Yih Lam ◽  
John A. Kershaw
Keyword(s):  
Stand Density ◽  
Pine Forests ◽  
Mixed Species ◽  
Density Index ◽  
Stand Density Index

scholarly journals Can an Exponential Function Be Applied to the Asymptotic Density–Size Relationship? Two New Stand-Density Indices in Mixed-Species Forests

Forests ◽  
2018 ◽  
Vol 10 (1) ◽  
pp. 9 ◽  
Author(s):  
Gerónimo Quiñonez-Barraza ◽  
Hugo Ramírez-Maldonado
Keyword(s):  
Mortality Rate ◽  
Initial Density ◽  
Stand Density ◽  
Species Group ◽  
Mixed Species ◽  
Management Objectives ◽  
Density Index ◽  
Density Indices ◽  
Species Groups ◽  
Stand Density Index

This study presents two stand-density indices (SDIs) based on exponential density decline as a function of quadratic mean diameter for all species combined in mixed-species forests with 22 species mix grouped in four species groups. The exponential-based density–diameter relationship, as well the density index corresponding to the slope or instantaneous mortality rate parameters, was compared with those based on power-law density–diameter relationship. A dataset of 202 fully stocked circular plots at maximum density was used for fitting the models, and a dataset of 122 circular plots was used for validation stand density index for all species combined of mixed-species stands. The dataset for validation was independent of dataset for model development. The first stand-density index showed a density management graphic (DMG) with a variable intercept and common instantaneous mortality rate, and the second index showed a DMG with common intercept and variable mortality rate. Additionally, the value of the initial density of the fitted line was more realistic than those generated by the potential model for all species combined. Moreover, the density management diagrams showed a curvilinear trend based on the maximum stand density index in graphical log–log scale. The DMGs could be interpreted as forest scenarios based on variable initial density and common management objectives or the same density and different management objectives for forest-rotation periods involving all species combined in mixed-species stands. The fitting of exponential and potential equations for species or species groups showed that the density–size relationships in mixed-species forests should be modeled for all species combined because the disaggregation of mixture species represented a weak tendency for each species or species group and the resultant fitted equations were unrealistic.

Determining maximum stand density index in mixed species stands for strategic-scale stocking assessments

2005 ◽  
Vol 216 (1-3) ◽  
pp. 367-377 ◽  
Author(s):  
Chris W. Woodall ◽  
Patrick D. Miles ◽  
John S. Vissage
Keyword(s):  
Stand Density ◽  
Mixed Species ◽  
Density Index ◽  
Stand Density Index

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.

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 Rapid Assessment of Relative Density in Mixed-Species Stands of the Northeastern United States

2010 ◽  
Vol 2010 ◽  
pp. 1-8
Author(s):  
M. J. Ducey ◽  
R. A. Knapp
Keyword(s):  
United States ◽  
Specific Gravity ◽  
Rapid Assessment ◽  
Basal Area ◽  
Stand Density ◽  
Sampling Technique ◽  
Northeastern United States ◽  
Mixed Species ◽  
Stand Density Index ◽  
Simple Tree

Basal area has shortcomings as a measure of stand density, but it is often preferred for operational assessments because it is easy to measure. Previous work has demonstrated that an additive version of Reineke's stand density index can be estimated by a simple tree count using a modified horizontal point sampling technique. We show that this technique can be extended further to estimate a mixed-species density measure that has been developed for complex stands in the northeastern United States, using wood specific gravity to harmonize the density contributions of different species. The sampling technique provides design-unbiased estimates of stand density from a weighted tree count, where the weights depend on specific gravity but not on diameter. Rounding the specific gravity values for different species in the calculation of estimates introduces a trivial amount of bias but streamlines the procedure for rapid use in the field.

Sign in / Sign up

Export Citation Format

Share Document