Sampling Alternatives for Eucalyptus Trees in Integrated Crop-Livestock-Forest System

Tonini, Helio; Wink, Charlote; Silva, Andrey Gregory da Mota Ferreira e

doi:10.1590/2179-8087.089317

Original Article, Forest Management • Floresta Ambient. 26 (3) • 2019 • https://doi.org/10.1590/2179-8087.089317 linkcopy

Sampling Alternatives for Eucalyptus Trees in Integrated Crop-Livestock-Forest System

Authorship SCIMAGO INSTITUTIONS RANKINGS

The aim of this paper was to compare methods and sampling procedures applied to eucalyptus grown under different spatial arrangements in an integrated crop-livestock-forest system (ICLF). The study was carried out in Sinop county, Mato Grosso state, Brazil. Arrangements combining fixed and variable area methods to simple random and systematic sampling were tested. Precision, accuracy, efficiency, and diameter-distribution measurements were used for selection of the best sampling arrangement. The sampling intensity, sample unit optimal size and the relative efficiency have been changed depending on the spatial arrangement for 10% sampling error and 95% probability level. The fixed area method based on systematic sampling, as well as smaller sample units with eight to nine plants (48 m² to 54 m²) were the most accurate; however, larger plots (192 m² to 216 m²) were more efficient. All sample units size provided good estimates on the number of trees by diameter classes.

Keywords:
forest inventory; Eucalyptus grandis × Eucalyptus urophylla; agroforestry systems

Double rows
Random sampling
SS	N.T	N.pu		I%	N.su			S_x	CV		Er	CIT					Sample Estimates								Row Parameters
SS	N.T	N.pu		I%	N.su			S_x	CV		Er	LCL		UCL			d			h		V_wb			d		h		V_wb
1	6	80		23	18			2.5	26.1		1.72	20.13		21.46			9.68			9.7		20.25(6.08)			9.4		9.5		19.86(5.42*)
2	8	60		23	14			1.8	22.2		4.73	18.86		20.35			9.14			9.1		19.00(5.71)
3	16	30		20	6			2.3	13.8		4.02	19.02		20.44			9.26			9.0		19.13(5.74)
4	32	15		27	4			3.0	7.6		1.53	20.56		23.09			9.61			9.8		20.21(6.07)
Systematic sampling
5	6	80		23	18			2.3	25.6		0.05	19.84		21.18			9.56			9.6		19.91(5.98)
6	8	60		23	14			1.8	22.1		0.40	19.71		21.08			9.39			9.4		19.82(5.95)
7	16	30		20	6			2.3	17.7		3.00	19.78		21.82			9.43			9.5		19.32(5.79)
8	32	15		27	4			2.2	14.1		1.06	20.21		28.12			9.48			9.4		19.69(5.91)
Triple rows
Random sampling
SS	N.T	N.pu	I%		N.su		S_x	CV	Er	CIT			Sample Estimate										Row Parameters
SS	N.T	N.pu	I%		N.su		S_x	CV	Er	LCL		UCL	d		h			V					d	h			V_wb
1	6	120		18		22		6.6	26.1	2.51		33.77	35.56			9.81			11.0		33.92(42.64)			9.5		10.6		33.09(41.60*)
2	9	80		21		17		6.5	22.2	0.03		32.93	34.76			9.55			10.7		33.10(41.62)
3	18	40		18		7		6.6	13.8	2.09		33.65	35.59			9.66			10.9		33.78(42.47)
4	36	20		15		3		6.6	7.6	3.35		34.11	39.47			9.77			10.9		34.20(42.99)
Systematic sampling
5	6	120		18		22		5.1	26.6	1.78		33.69	35.49			9.61			10.8		33.68(42.34)
6	9	80		21		17		4.3	22.6	0.06		33.03	35.09			9.46			10.6		33.11(41.62)
7	18	40		18		7		5.7	16.3	1.51		33.38	35.30			9.67			10.8		33.59(42.23)
8	36	20		15		3		3.9	10.8	0.24		32.80	37.71			9.52			10.8		33.01(41.50)

T1 (double line rows)
SS	S_x	EA_Vcc	CIT_Vcc	EA_dap	EA_h	Total (m)
2	1	5	4	4	3	17
3	2	4	3	5	4	18
5	2	1	1	3	2	9
6	1	2	2	1	2	8
7	2	3	5	2	1	13
T2 (triple line rows)
2	3	1	2	3	2	11
6	2	2	1	2	1	8
8	1	3	3	1	3	11

T1
Area (m²)	Unit time (min)				Total time (min)				CV (%)	RE
Area (m²)	Displ.	Inst.	Meas.	Total	Displ.	Inst.	Meas.	Total	CV (%)	RE
48	0.42	0.55	2.38	3.38	5.97	8.00	33.30	47.27	25.92	0.031
96	0.74	0.64	4.75	6.13	5.21	4.53	33.19	42.93	23.23	0.043
192	1.03	0.85	9.86	11.73	4.11	3.40	39.43	46.94	17.54	0.069
T2
Area (m²)	Unit time (min)				Total time (min)				CV (%)	RE
Area (m²)	Desl.	Inst.	Med.	Total	Desl.	Inst.	Med.	Total	CV (%)	RE
54	0.29	0.62	2.83	3.77	5.83	11.1	51.01	67.90	24.37	0.024
108	0.55	0.75	5.43	6.75	5.00	6.82	48.92	60.70	13.31	0.093
216	1.28	0.88	10.1	12.26	5.1	3.52	40.4	49.03	9.11	0.002

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[1] SS is sampling system; N.T is number of trees; N.pu is number of potential units; I% is sample intensity; N.su is number of sampled units; S_x is standard error of the mean; CV is coefficient of variation; Er is absolute error (m³); CIT is confidence interval of the total (m³ha^–1); LCL is lower confidence limit; UCL is upper confidence limit; d is diameter at breast height (cm); h is total height (m); V_wb is total volume with bark in trees rows (m³);

[TFN1] ^*
volume of wood produced in one hectare in ICLF system.