A classification proposal for coefficients of variation in <i>Eucalyptus</i> experiments involving survival, growth and wood quality variables

Mora, Freddy; Arriagada, Osvin

doi:10.1590/1678-4499.458

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Áreas Básicas • Bragantia 75 (3) • Jul-Sep 2016 • https://doi.org/10.1590/1678-4499.458 copy

A classification proposal for coefficients of variation in Eucalyptus experiments involving survival, growth and wood quality variables

Authorship SCIMAGO INSTITUTIONS RANKINGS

ABSTRACT

The objective of this study was to present a classification proposal for coefficients of variation (CV) in Eucalyptus experiments, aiming at providing a useful tool for experiments involving growth, survival and wood quality traits. Ninety-four studies were selected from a search for peer-reviewed journals yielding a total of 508 data. The CVs were classified as low, moderate, high and very high. The mean, standard deviation, maximum and minimum values, skewness and kurtosis were estimated to describe the distribution shape. The Shapiro-Wilk test confirmed that all variables satisfied the assumption of normality (p < 0.05). The results indicated that the growth traits had the highest variability, being variables strongly affected by the environment. In contrast, all variables related to wood quality (except extractives) had the lowest range of CVs. In summary, the classification proposed in this report provides a useful tool for researchers interested in estimating the accuracy of their experiments.

Key words
Eucalyptus spp.; experimental accuracy; experimental error; rank-ordering

	Traits	n	p (W)^* * p > 0.05 indicate that the data are normally distributed according to the Shapiro-Wilk test;	p (χ²)^ p > 0.05 indicate that the data do not differ significantly from the normal distribution according to the chi-square goodness-of-fit test. n = Number of CV values; DBH = Diameter at breast height; TH = Total height; SURV = Survival; S/G = Syringyl to guaiacyl ratio; KL = Klason lignin content; TL = Total lignin content; CC = Cellulose content; EXT = Extractives; KPY = Kraft pulp yield; DEN = Wood density.	Skewness	Kurtosis
Growth
	DBH	78	0.13	0.07	0.29	-0.16
	TH	45	0.05	0.53	-0.17	-1.11
	SURV	32	0.05	0.34	0.61	-0.65
Wood quality
	S/G	43	0.26	0.69	-0.20	-0.99
	KL	37	0.69	0.82	0.37	-0.25
	TL	57	0.24	0.58	0.29	-0.62
	CC	48	0.21	0.46	0.32	-0.54
	EXT	63	0.11	0.30	0.47	-0.34
	KPY	36	0.09	0.92	0.51	-0.51
	DEN	69	0.14	0.43	0.42	-0.55
Overall		508	< 0.001		1.43	2.03

Trait	Min	Max	Mean	SD	Classification
Trait	Min	Max	Mean	SD	Low	Moderate	High	Very high
DBH	5.0	31.2	18.2	6.0	CV < 12.2	12.2 ≤ CV < 24.2	24.2 ≤ CV < 30.2	CV ≥ 30.2
TH	4.2	21.0	12.4	4.4	CV < 8.0	8.0 ≤ CV < 16.8	16.8 ≤ CV < 21.2	CV ≥ 21.2
SURV	6.4	48.3	24.0	11.7	CV < 12.3	12.3 ≤ CV < 35.7	35.7 ≤ CV < 474	CV ≥ 47.4
S/G	0.5	5.2	2.9	1.3	CV < 1.6	1.6 ≤ CV < 4.2	4.2 ≤ CV < 5.5	CV ≥ 5.5
KL	0.4	7.3	3.3	1.5	CV < 1.8	1.8 ≤ CV < 4.8	4.8 ≤ CV < 6.3	CV ≥ 6.3
TL	0.7	9.7	4.2	2.1	CV < 2.1	2.1 ≤ CV < 6.3	6.3 ≤ CV < 8.4	CV ≥ 8.4
CC	0.1	6.5	2.8	1.6	CV < 1.2	1.2 ≤ CV < 4.4	4.4 ≤ CV < 6.0	CV ≥ 6.0
EXT	2.3	42.8	17.6	9.2	CV < 8.4	8.4 ≤ CV < 26.8	26.8 ≤ CV < 36.0	CV ≥ 36.0
KPY	1.4	6.3	3.0	1.2	CV < 1.8	1.8 ≤ CV < 4.2	4.2 ≤ CV < 5.4	CV ≥ 5.4
DEN	2.4	12.5	6.6	2.3	CV < 4.3	4.3 ≤ CV < 8.9	8.9 ≤ CV < 11.2	CV ≥ 11.2
Overall	0.1	48.3	9.9	8.9	CV < 1.0	1.0 ≤ CV < 18.8	18.8 ≤ CV < 27.7	CV ≥ 27.7

Trait	Mean	SD	Classification
Trait	Mean	SD	Low	Moderate	High	Very high
DBH	18.2	6.0	CV < 12.2	12.2 ≤ CV < 24.2	24.2 ≤ CV < 30.2	CV ≥ 30.2
Garcia (1989)Garcia, C. H. (1989). Tabelas para classificação do coeficiente de variação. Piracicaba: IPEF. Circular técnica, 171.	8.9	4.0	CV < 4.9	4.9 ≤ CV < 12.9	12.9 ≤ CV < 16.9	CV ≥ 16.9
TH	12.4	4.4	CV < 8.0	8.0 ≤ CV < 16.8	16.8 ≤ CV < 21.2	CV ≥ 21.2
Garcia (1989)Garcia, C. H. (1989). Tabelas para classificação do coeficiente de variação. Piracicaba: IPEF. Circular técnica, 171.	8.6	3.9	CV < 4.7	4.7 ≤ CV < 12.5	12.5 ≤ CV < 16.4	CV ≥ 16.4
SURV	24.0	11.7	CV < 12.3	12.3 ≤ CV < 35.7	35.7 ≤ CV < 474	CV ≥ 47.4
Garcia (1989)Garcia, C. H. (1989). Tabelas para classificação do coeficiente de variação. Piracicaba: IPEF. Circular técnica, 171.	11.8	7.1	CV < 4.7	4.7 ≤ CV < 18.9	18.9 ≤ CV < 26.0	CV ≥ 26.0

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[1] *Corresponding author: arriagada.lagos.o@gmail.com