A Comparison of Tree Volume Estimation Models for Forest Inventory

Kelly, John F.; Beltz, Roy C.

doi:10.2737/so-rp-233

Cited by 9 publications

(2 citation statements)

References 5 publications

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“…The 15 modeIs studied in a comparison of their performance comprised the 3 volume models (equations 1-3) combined with each of 5 error models. These latter included the 4 weighting functions used by and the following additional exponential weighting function: which has been studied by Cunia (1964), McClure et al (1983), Meng and Tsai (1986), Kelly and Beltz (1987), and Gregoire and Dyer (1989). Model: which was suggested by Scott et al (1978).…”

Section: Methodsmentioning

confidence: 99%

Weighted linear regression using D2H and D2 as the independent variables

Schreuder¹,

Williams²

1998

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Section: Methodsmentioning

confidence: 99%

Weighted linear regression using D2H and D2 as the independent variables

Schreuder¹,

Williams²

1998

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“…However, some basic requirements such as normal distribution and errors independence, constant variance and non-collinearity among the independent variables should be considered [19]. When some of those requirements are violated, the use of transformations of the data is required [14,20].…”

Section: Mathematical Modeling Of the Biochemical Oxygen Demand (Bod)mentioning

confidence: 99%

Mathematical Modeling of the Biochemical Oxygen Demand (BOD) from Water Table in Sugar Cane Plantation Fertirrigated with Vinasse in Brazil

Silva¹,

Castro²,

Florêncio³

2016

MESE

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The uses of the vinasse as fertilizer through fertirrigation for sugar cane plantations constitute a potential high source pollutant of soils and underground waters. Thus, it is necessary to monitor areas fertirrigated with vinasse to evaluate the quality conditions of those waters in order to conduct inferences and or diagnoses of the environmental quality. The decomposition of the vinasse organic matter, represented by the biochemical oxygen demand (BOD) is the most important parameter in terms of pollution indicators. The BOD laboratory analysis is not a direct measurement and can last some days to determine it. The adjustment of mathematical models can generate equations to estimate BOD as a function of independent variables that can be determined directly in short time. The data set for this study came from an area of 12 hectares planted with sugar cane, fertirrigated with vinasse. Thirty observation wells were installed with depths of 3 m, distributed in parallel transects 100 m from one to another. Eleven water quality parameters from three collect along the time (three, six and nine months) were analyzed. Simple and multiple linear and non-linear models, the Chapman-Richards and Silva-Bailey models were used to estimate the BOD. The Adjusted Fit Index in percent (AFI%) obtained presented values of adjustments superior to 95%. The Silva-Bailey model adjusted with two independent variables COD (chemical demand of oxygen) and T (age of the plantation) showed the higher AFI% = 98.78%. In the experimental conditions, the results showed that BOD could be estimated mathematically through its relationship with other chemical variables of simplified analytical procedures. The chemical oxygen demand (COD) stood out among the selected variables.

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Modelling and quantifying tree biometric properties of dry Afromontane forests of south-central Ethiopia

Asrat

Eid

Gobakken

et al. 2020

Trees

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Key message Models for quantifying tree biometric properties, imperative for forest management decision-making, including height, diameter, bark thickness and volume were developed, and wood basic density was documented for dry Afromontane forests of south-central Ethiopia. Abstract Tree biometric properties such as height (ht), diameter at breast height (dbh), bark thickness (bt), volume and wood basic density (wbd) are imperative for forest management decision-making. For dry Afromontane forests in south-central Ethiopia, models for quantifying such tree properties are totally lacking. This study, therefore, aimed at developing models for ht based on dbh, for dbh based on stump height diameter (dsh), for bt based on dbh, for volume based on dbh, ht and crown width (crw), as well as documenting wbd data. Comprehensive and representative datasets were collected from Degaga–Gambo and Wondo Genet forests. The ht, dbh and bt modelling were based on 1345 sampled trees during forest inventories, while the volume modelling and wbd documentation were based on 63 destructively sampled trees from 30 species covering 87% of the total basal area in the study sites. Weighted least squares regression was applied for modelling and leave one out cross-validation was used for evaluation. The ht–dbh and dbh–dsh models performed well (pseudo-R2 = 0.72 and 0.98), while bt–dbh performed poorer (pseudo-R2 = 0.42). Models for the total tree, merchantable stem and branches volume were developed with different options for independent variables, where pseudo-R2 varied from 0.74 to 0.98, with smallest values for the branches models The models may be applied to forests outside the present study sites provided that the growing conditions are carefully evaluated. The species-wise wbd was ranging from 0.426 to 0.979 g cm−3, with the overall mean of 0.588 g cm−3. The wbd data will be useful for building up a national wbd database and may also be included in the Global Wood Density database. The study represents a significant step towards sustainable forest management including REDD + MRV practices in the dry Afromontane forests of south-central Ethiopia.

show abstract

A Comparison of Tree Volume Estimation Models for Forest Inventory

Cited by 9 publications

References 5 publications

Weighted linear regression using D2H and D2 as the independent variables

Weighted linear regression using D2H and D2 as the independent variables

Mathematical Modeling of the Biochemical Oxygen Demand (BOD) from Water Table in Sugar Cane Plantation Fertirrigated with Vinasse in Brazil

Modelling and quantifying tree biometric properties of dry Afromontane forests of south-central Ethiopia

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