scholarly journals Models for diameter distribution and tree height in hybrid aspen plantations in southern Finland

Silva Fennica ◽  
2021 ◽  
Vol 55 (5) ◽  
Author(s):  
Daesung Lee ◽  
Jouni Siipilehto ◽  
Jari Hynynen
Keyword(s):  
Goodness Of Fit ◽  
Basal Area ◽  
Tree Height ◽  
Diameter Distribution ◽  
Weibull Function ◽  
Hybrid Aspen ◽  
Recovery Method ◽  
Parameter Recovery ◽  
Mean Diameter ◽  
Median Diameter

Hybrid aspen ( L. × Michx.) is known with outstanding growth rate and some favourable wood characteristics, but models for stand management have not yet been prepared in northern Europe. This study introduces methods and models to predict tree dimensions, diameter at breast height (dbh) and tree height for a hybrid aspen plantation using data from repeatedly measured permanent sample plots established in clonal plantations in southern Finland. Dbh distributions using parameter recovery method for the Weibull function was used with Näslund’s height curve to model tree heights. According to the goodness-of-fit statistics of Kolmogorov-Smirnov and the Error Index, the arithmetic mean diameter () and basal area-weighted mean diameter () provided more stable parameter recovery for the Weibull distribution than the median diameter () and basal area-weighted median diameter (), while showed the best overall fit. Thus, Näslund’s height curve was modelled using with Lorey’s height (), age, basal area (), and tree dbh (Model 1). Also, Model 2 was tested using all predictors of Model 1 with the number of trees per ha (). All predictors were shown to be significant in both Models, showing slightly different behaviour. Model 1 was sensitive to the mean characteristics, and , while Model 2 was sensitive to stand density, including both and as predictors. Model 1 was considered more reasonable to apply based on our results. Consequently, the parameter recovery method using and Näslund’s models were applicable for predicting tree diameter and height.Populus tremulaP. tremuloidesDDGDMDGMDGDGHGBATPHDGHGBATPHDG

scholarly journals Predicting Diameter Distributions for Young Longleaf Pine Plantations in Southwest Georgia

2009 ◽  
Vol 33 (1) ◽  
pp. 25-28 ◽  
Author(s):  
Lichun Jiang ◽  
John R. Brooks
Keyword(s):  
Distribution Function ◽  
Goodness Of Fit ◽  
Longleaf Pine ◽  
Pinus Palustris ◽  
Cumulative Distribution ◽  
Diameter Distribution ◽  
Weibull Function ◽  
Recovery Method ◽  
Parameter Recovery ◽  
Diameter Distributions

Abstract Parameter prediction equations for the Weibull distribution function were developed based on four percentile functions and a parameter recovery method for longleaf pine (Pinus palustris Mill.) in Southwest Georgia. Four percentiles were expressed as functions of stand-level characteristics based on stepwise regression and seemingly unrelated regression. Using a percentile-based parameter recovery method (PCT), estimated diameter distributions were obtained from available stand-level variables. The PCT method was also compared with a cumulative distribution function (CDF) regression method. The PCT method produced consistently better goodness-of-fit statistics than the CDF method. The results indicate that diameter distribution in longleaf pine stands can be successfully characterized with the Weibull function.

Eastern cottonwood clonal mixing study: predicted diameter distributions

1994 ◽  
Vol 24 (2) ◽  
pp. 405-414 ◽  
Author(s):  
Steven A. Knowe ◽  
G. Sam Foster ◽  
Randall J. Rousseau ◽  
Warren L. Nance
Keyword(s):  
Weibull Distribution ◽  
Basal Area ◽  
Diameter Distribution ◽  
Minimum Diameter ◽  
Quadratic Mean ◽  
Parameter Recovery ◽  
Eastern Cottonwood ◽  
Mean Diameter ◽  
Quadratic Mean Diameter ◽  
Diameter Distributions

A parameter recovery procedure for the Weibull distribution function was modified to incorporate monocultures and mixtures of eastern cottonwood (Populusdeltoides Bartr.) clones planted in Mississippi and Kentucky. Components of the system included functions to predict stand-level basal area and four percentiles (0th, 25th, 50th, and 95th) of the cumulative diameter distribution. Basal area was predicted as a function of surviving number of trees, dominant height, age, planting location, and the proportion of each clone planted. Clonal proportions, which accounted for 3.6% of the variation in observed basal area, were more important than differences in planting locations, which accounted for 3.0% of the variation. Interactions between clones in mixtures were not significant (p = 0.5676), but some cases of both over- and under-compensation appeared to be developing. Percentiles of the cumulative diameter distribution were predicted as functions of quadratic mean diameter, and therefore included indirect effects of both genetic and planting site differences. Only the minimum diameter (D0) was directly affected by proportions of clones planted. Most of the monocultures and mixtures of clones had smaller minimum diameters than expected for a given value of quadratic mean diameter. The predicted quadratic mean diameter and percentiles were used to recover parameters of the Weibull distribution such that the predicted diameter distribution has the same quadratic mean diameter as obtained from the stand basal area model. The predicted distributions indicated that a common stand-level model was not sufficient for accounting for variations in diameter distributions of eastern cottonwood clones. As a result of the differences in diameter distributions, monocultures and mixtures of the Texas clones appeared to have less volume and greater stand variance than the Mississippi clones.

scholarly journals Probability density functions for description of diameter distribution in thinned stands of Tectona grandis

CERNE ◽  
2012 ◽  
Vol 18 (2) ◽  
pp. 185-196 ◽  
Author(s):  
Daniel Henrique Breda Binoti ◽  
Mayra Luiza Marques da Silva Binoti ◽  
Helio Garcia Leite ◽  
Leonardo Fardin ◽  
Julianne de Castro Oliveira
Keyword(s):  
Fatigue Life ◽  
Goodness Of Fit ◽  
Basal Area ◽  
Tectona Grandis ◽  
Diameter Distribution ◽  
Permanent Plots ◽  
Weibull Function ◽  
Goodness Of Fit Test ◽  
Mato Grosso ◽  
Kolmogorov Smirnov

The objective of this study was to evaluate the effectiveness of fatigue life, Frechet, Gamma, Generalized Gamma, Generalized Logistic, Log-logistic, Nakagami, Beta, Burr, Dagum, Weibull and Hyperbolic distributions in describing diameter distribution in teak stands subjected to thinning at different ages. Data used in this study originated from 238 rectangular permanent plots 490 m² in size, installed in stands of Tectona grandis L. f. in Mato Grosso state, Brazil. The plots were measured at ages 34, 43, 55, 68, 81, 82, 92, 104, 105, 120, 134 and 145 months on average. Thinning was done in two occasions: the first was systematic at age 81months, with a basal area intensity of 36%, while the second was selective at age 104 months on average and removed poorer trees, reducing basal area by 30%. Fittings were assessed by the Kolmogorov-Smirnov goodness-of-fit test. The Log-logistic (3P), Burr (3P), Hyperbolic (3P), Burr (4P), Weibull (3P), Hyperbolic (2P), Fatigue Life (3P) and Nakagami functions provided more satisfactory values for the k-s test than the more commonly used Weibull function.

Predicting Crown Sizes and Diameter Distributions of Tanoak, Pacific Madrone, and Giant Chinkapin Sprout Clumps

1992 ◽  
Vol 7 (4) ◽  
pp. 103-108 ◽  
Author(s):  
Timothy B. Harrington ◽  
John C. Tappeiner ◽  
Ralph Warbington
Keyword(s):  
Goodness Of Fit ◽  
Basal Area ◽  
Diameter Distribution ◽  
Weibull Function ◽  
Regression Equations ◽  
Growing Seasons ◽  
Lithocarpus Densiflorus ◽  
Pacific Madrone ◽  
Crown Size ◽  
Diameter Distributions

Abstract Crown size and stem diameters were measured on a total of 908 sprout clumps of tanoak (Lithocarpus densiflorus), Pacific madrone (Arbutus menziesii), and giant chinkapin (Castanopsis chrysophylla). The clumps, age 1 to 16 years, were located at 23 sites in southwestern Oregon and 20 sites in northwestern California. Regression equations were developed for predicting individual-clump crown size and stem-diameter distributions of dominant sprouts from the total basal area (dm² at 1.37 m) in stems of the parent tree (PBA) and number of growing seasons since burning (AGE). Variables of PBA, AGE, and species in combination accounted for over 75% of the total variation in hardwood crown width and height and for 62% of the variation in sprout number. Variables describing site characteristics and competing vegetation abundance did not explain more than 2% of additional variation in hardwood crown size or sprout diameter distribution. On the basis of the Kolmogorov-Smirnoff test (α = 0.05), the Weibull function adequately described the reverse J-shaped distribution of stem diameters for individual sprout clumps. The goodness of fit for each of the predictive models for tanoak and madrone was verified with independent data. West. J. Appl. For. 7(4):103-108.

scholarly journals Deriving Tree Size Distributions of Tropical Forests from Lidar

2021 ◽  
Vol 13 (1) ◽  
pp. 131
Author(s):  
Franziska Taubert ◽  
Rico Fischer ◽  
Nikolai Knapp ◽  
Andreas Huth
Keyword(s):  
Size Distribution ◽  
Spatial Scales ◽  
Basal Area ◽  
Tree Height ◽  
Tree Size ◽  
Diameter Distribution ◽  
Forest Inventories ◽  
Allometric Relations ◽  
Lidar Measurements ◽  
Derived Data

Remote sensing is an important tool to monitor forests to rapidly detect changes due to global change and other threats. Here, we present a novel methodology to infer the tree size distribution from light detection and ranging (lidar) measurements. Our approach is based on a theoretical leaf–tree matrix derived from allometric relations of trees. Using the leaf–tree matrix, we compute the tree size distribution that fit to the observed leaf area density profile via lidar. To validate our approach, we analyzed the stem diameter distribution of a tropical forest in Panama and compared lidar-derived data with data from forest inventories at different spatial scales (0.04 ha to 50 ha). Our estimates had a high accuracy at scales above 1 ha (1 ha: root mean square error (RMSE) 67.6 trees ha−1/normalized RMSE 18.8%/R² 0.76; 50 ha: 22.8 trees ha−1/6.2%/0.89). Estimates for smaller scales (1-ha to 0.04-ha) were reliably for forests with low height, dense canopy or low tree height heterogeneity. Estimates for the basal area were accurate at the 1-ha scale (RMSE 4.7 tree ha−1, bias 0.8 m² ha−1) but less accurate at smaller scales. Our methodology, further tested at additional sites, provides a useful approach to determine the tree size distribution of forests by integrating information on tree allometries.

scholarly journals Modeling Diameter Distribution of Black Alder (Alnus glutinosa (L.) Gaertn.) Stands in Poland

Forests ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 412 ◽  
Author(s):  
Piotr Pogoda ◽  
Wojciech Ochał ◽  
Stanisław Orzeł
Keyword(s):  
Goodness Of Fit ◽  
Mean Squared Error ◽  
Alnus Glutinosa ◽  
Weibull Model ◽  
Diameter Distribution ◽  
Stand Age ◽  
Weibull Function ◽  
Black Alder ◽  
Kolmogorov Smirnov ◽  
Non Parametric

We present diameter distribution models for black alder (Alnus glutinosa (L.) Gaertn.) derived from diameter measurements made at breast height in 844 circular sample plots set in 163 managed stands located in south-eastern Poland. A total of 22,530 trees were measured. Stand age ranged from six to 89 years. The model formulation was based on the two-parameter Weibull function and a non-parametric percentile-based method. Weibull function parameters were recovered from the first raw and second central moments estimated using the stand quadratic mean diameter. The same stand characteristic was used to predict values of 12 percentiles in the percentile-based method. The model performance was assessed using the k-fold cross-validation method. The goodness-of-fit statistics include the Kolmogorov–Smirnov statistic, mean error, root mean squared error, and two variants of the error index introduced by Reynolds. The percentile model developed, accurately predicted diameter distributions in 88.4% of black alder stands, as compared to 81.9% for the Weibull model (Kolmogorov–Smirnov test). Alternative statistical metrics assessing goodness-of-fit to empirical distributions suggested that the non-parametric percentile model was superior to the parametric Weibull model, especially in stands older than 20 years. In younger stands, the two models were accurate only in 57% of the cases, and did not differ significantly with respect to goodness-of-fit measures.

A longitudinal height–diameter model for Norway spruce in Finland

2004 ◽  
Vol 34 (1) ◽  
pp. 131-140 ◽  
Author(s):  
Lauri Mehtätalo
Keyword(s):  
Norway Spruce ◽  
Mixed Model ◽  
Basal Area ◽  
Tree Height ◽  
Growth Patterns ◽  
Diameter Distribution ◽  
Stand Age ◽  
Canopy Layer ◽  
Mixed Model Approach ◽  
D Model

A height–diameter (H–D) model for Norway spruce (Picea abies (L.) Karst.) was estimated from longitudinal data. The Korf growth curve was used as the H–D curve. Firstly, H–D curves for each stand at each measurement time were fitted, and the trends in the parameters of the H–D curve were modeled. Secondly, the trends were included in the H–D model to estimate the whole model at once. To take the hierarchy of the data into account, a mixed-model approach was used. This makes it possible to calibrate the model for a new stand at a given point in time using sample tree height(s). The heights may be from different points in time and need not be from the point in time being predicted. The trends in the parameters of the H–D curve were not estimated as a function of stand age but as a function of the median diameter of basal area weighted diameter distribution (dGm). This approach was chosen because the stand ages may differ substantially among stands with similar current growth patterns. This is true especially with shade-tolerant tree species, which can regenerate and survive for several years beneath the dominant canopy layer and start rapid growth later. The growth patterns in stands with a given dGm, on the other hand, seem not to vary much. This finding indicates that the growth pattern of a stand does not depend on stand age but on mean tree size in the stand.

Structural stocking guides: a new look at an old friend

2004 ◽  
Vol 34 (5) ◽  
pp. 1044-1056 ◽  
Author(s):  
Jeffrey H Gove
Keyword(s):  
Basal Area ◽  
Primary Objective ◽  
Diameter Distribution ◽  
Minimal Amount ◽  
Forest Types ◽  
Quadratic Mean ◽  
Parameter Recovery ◽  
Distribution Shape ◽  
New Information ◽  
New Type

A parameter recovery-based model is developed that allows the incorporation of diameter distribution information directly into stocking guides. The method is completely general in applicability across different guides and forest types and could be adapted to other systems such as density management diagrams. It relies on a simple measure of diameter distribution shape, the basal area larger than quadratic mean stand diameter, to estimate the parameters of the unknown distribution. This latter quantity is shown to have high correlation with stocking guide variables in northeastern forest types. A primary objective of this new type of guide is that its use should require a minimal amount of new information from the user and that the underlying model should be as simple as possible.

Stand, species, and tree dynamics of an uneven-aged, mixed conifer forest type

1995 ◽  
Vol 25 (5) ◽  
pp. 803-812 ◽  
Author(s):  
John P. McTague ◽  
William F. Stansfield
Keyword(s):  
Tree Mortality ◽  
Forest Type ◽  
Species Abundance ◽  
Basal Area ◽  
Logistic Function ◽  
Conifer Forest ◽  
Individual Tree ◽  
Recovery Method ◽  
Parameter Recovery ◽  
Tree Survival

Stand-level equations are presented that project future merchantable tree survival, pole-tree basal area, and sawtimber basal area. Total basal area (excluding ingrowth) is the sum of the pole-tree and sawtimber components. Ratio equations are used for eight species (seven softwoods and one hardwood) to compute the change in species abundance and species basal area over time. Individual-tree mortality is predicted with a logistic function, while individual-tree diameter growth is predicted as a function of stand and individual-tree attributes. The individual-tree and species-level equations are adjusted so that tree frequency and basal area are consistent with the stand-level projection equations. Total ingrowth is computed with a stand-level projection equation and is distributed with a parameter recovery method using the uniform distribution. The presence or absence of ingrowth for a given species is determined with a discriminant function, while the proportion of total ingrowth allocated to a species is predicted with a logistic function.

scholarly journals Size and Charge Stability of Oil Bodies from Peanut

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Lihua Hao ◽  
Fusheng Chen ◽  
Yimiao Xia ◽  
Lifen Zhang ◽  
Ying Xin
Keyword(s):  
Salt Concentration ◽  
Aqueous Extraction ◽  
Diameter Distribution ◽  
Oil Bodies ◽  
Absolute Value ◽  
Mean Diameter ◽  
Median Diameter ◽  
Charge Stability ◽  
The Mean ◽  
The Absolute

In order to offer scientific bases for the application of oil bodies from peanut in food, this research was undertaken to study the size and charge stability of oil bodies from five peanut varieties. It showed that the mean diameter of oil bodies fromyuhua9719andyuhua9830is obviously larger thanyuhua23,yuhua27, andyuhua9502in the peanut cell. Moreover, the analysis of diameter distribution of oil bodies also showed that the median diameter of oil bodies increased dramatically in the order ofyuhua9719>yuhua9830>yuhua23>yuhua27>yuhua9502after aqueous extraction. The charge stability of oil bodies from peanut was observed with zeta (ζ) potential measurements, which indicated that charge properties and the absolute value of oil bodies from five peanut varieties were significantly affected by pH and salt concentration, but the degree of influence is different. Of the five peanut varieties,yuhua27andyuhua9830possessed excellent charge stability (ζ-potential>35 mV) in neutral microenvironment without salt concentration.

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