CONICITY AND YIELD FOR LUMBER FROM COMMERCIAL SPECIES FROM THE AMAZON

Santos, Misael Freitas dos; Gama, João Ricardo Vasconcellos; Figueiredo, Afonso; Costa, Daniele Lima da; Retslaff, Fabiane Aparecida de Souza; Silva-Ribeiro, Renato Bezerra da; Rode, Rafael

doi:10.1590/01047760201925042648

ABSTRACT

Stem conicity and the sawing pattern, besides the presence of hollows and sapwood, are among the principal factors that are responsible for the low yield of lumber from harvested wood in the Amazon. Therefore, the objective of this study was to analyze of logs and stem conicity, and its effect on yield of sawn wood from the species Handroanthus impetiginosus (Mart. ex DC.) Mattos, Lecythis lurida (Miers) S. A. Mori, Manilkara huberi (Ducke) Chevalier, Astronium lecointei Ducke and Couratari sp., which are currently the most important commercial species in the study area. The data used were obtained from six production units in the Tapajós National Forest, Pará. The variables analyzed were conicity (obtained as a function of the difference between diameters at the base and top) between logs, DBH classes (diameter at breast height) and species, as well as yield (estimated using the Software MaxiTora) between logs and species. The majority of the species showed differences in conicity between logs, with the first log being the most conic, which was directly reflected by the lower yield for this log. There was a tendency of increase in conicity in the larger DBH classes, and differences in conicity and yield between species. The estimated yields were superior to the percent yields observed for Amazonian species in studies done using samples with similar characteristics. Therefore, it was concluded that conicity can vary between species, logs, and DBH classes, and is a characteristic that directly effects the yield of lumber. Furthermore, the incorporation of cutting templates represents an alternative for maximizing lumber yield.

Keywords:
Native Amazonian tree species; Stem form; Regional sawmill industry; Sawn patterns

[1] + misael02freitas@gmail.com

Species	Average diameter (DBH) and commercial height (Hc) of the selected sample trees by diameter class (cm)
	60-79.9		80-99.9		≥ 100.0
	DBH (cm)	Hc (m)	DBH (cm)	Hc (m)	DBH (cm)	Hc (m)
H. impetiginosus	75.0	25.1	89.1	25.0	114.5	25.3
L. lurida	72.2	23.9	88.0	23.7	111.1	23.3
M. huberi	72.8	23.9	89.2	23.8	109.9	23.9
A. lecointei	71.9	25.2	88.2	25.3	111.4	25.2
Couratari sp.	72.6	24.8	89.3	24.9	109.4	24.6

Logs	H. impetiginosus	L. lurida	M. huberi	A. lecointei	Couratari sp.
	Conicity (cm.m^-1)
1st	2.2535 a	2.2140 a	2.0775 a	1.6517 a	0.9514 a
2nd	0.9495 b	0.9374 b	0.8796 b	0.6444 bc	0.7773 a
3rd	0.8048 b	0.7879 b	0.6590 c	0.4893 c	0.7098 a
4th	0.7851 b	0.8129 b	0.6900 c	0.7516 b	0.9306 a
	Yield (%)
1st	55.12 b	55.52 c	54.58 b	57.34 b	61.83 a
2nd	60.52 a	60.97 a	60.48 a	62.63 a	61.89 a
3rd	60.10 a	60.30 ab	59.41 a	62.25 a	61.40 a
4th	58.74 a	58.39 b	58.66 a	59.42 a	58.36 b

DBH class (cm)	H. impetiginosus	L. lurida	M. huberi	A. lecointei	Couratari sp.
DBH class (cm)	Conicity (cm.m^-1)
60 - 79.9	1.1144 b	1.1061 a	1.0141 a	0.8494 a	0.7383 a
80 - 99.9	1.0863 ab	1.1314 a	1.0287 a	0.8807 a	0.9157 a
≥ 100	1.3479 a	1.2700 a	1.2043 a	0.9399 a	0.8523 a
		Artificial form factor
60 - 79.9	0.6638 a	0.6293 a	0.6425 a	0.6217 a	0.6085 a
80 - 99.9	0.6521 a	0.6152 a	0.5797 a	0.5980 a	0.5962 a
≥ 100	0.5806 a	0.6043 a	0.5939 a	0.5987 a	0.5540 a

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CONICITY AND YIELD FOR LUMBER FROM COMMERCIAL SPECIES FROM THE AMAZON

ABSTRACT