Cost-benefit analysis of industrial and homemade dendrometer bands

Abstract

Cost-benefi t analysis of industrial and homemade dendrometer bands 1 RESUMO (Análise do custo-benefício de dendrômetros industriais e artesanais). Os dendrômetros são utilizados para realizar medidas repetidas de crescimento radial arbóreo. Dois tipos de dendrômetros são mundialmente utilizados, o industrial e o artesanal. Os dendrômetros artesanais predominam nos estudos fl orestais no Brasil, mas os pesquisadores têm o trabalho de construí-los e instalá-los. Uma solução mais fácil é o uso de dendrômetros industriais, mas eles não são produzidos no Brasil e, portanto, são mais caros e podem não ser adequados às condições ambientais locais. Foram analisadas as medidas pareadas mensais de crescimento do tronco (de fevereiro de 2008 a janeiro de 2009) de dendrômetros industriais (importados) e artesanais (feitos com componentes nacionais), instalados em 20 árvores de Acacia tenuifolia numa fl oresta estacional decidual sobre afl oramentos calcários no Brasil Central. A análise de custo-benefício entre das medidas e dos preços dos dois instrumentos indicou que os dendrômetros artesanais possuem todos os benefícios e nenhum dos problemas dos industriais importados: (1) precisão semelhante nas medidas (análise de correlação: r ≥ 0,930, P < 0,01; teste t permutado: P ≥ 0,55), (2) custos bem menores (10 a 15 vezes mais baratos), (3) facilidade na manipulação e instalação no campo, e (4) ausência de alguns danos nos troncos que foram provocados pelos dendrômetros industriais. Palavras-chave: ABSTRACT(Cost-benefi t analysis of industrial and homemade dendrometer bands). Dendrometer bands are used to make repeated measurements of tree radial growth. Two types of dendrometers are used worldwide, the industrial and the homemade. Homemade dendrometers prevail in Brazilian forestry studies, but researchers have trouble constructing and installing them. An easier solution is to use industrial dendrometer bands, but they are not produced in Brazil and, therefore, are expensive and might not be appropriate for local environmental conditions. We analyzed trunk growth measurements each month (from February 2008 to January 2009) using both industrial (imported) and homemade (national components) dendrometer bands installed on 20 trees of Acacia tenuifolia in a seasonally dry forest on limestone outcrops in central Brazil. Cost-benefi t comparative analysis of measurements and prices indicates that homemade dendrometer bands have all benefi ts, and none of the problems, of the imported industrial dendrometer bands, such as the following: (1) similar precision of measurements (correlation analysis: r ≥ 0.930, P < 0.01; permutation t-test: P ≥ 0.55), (2) much lower costs (10 to 15 times cheaper), (3) easily manipulated and installated in the fi eld, and (4) absence of some damage to tree trunks that are caused by industrial dendrometers.

Using homemade stainless steel dendrometer band for long term tree growth measurements

“…To the best of our knowledge, our 10-year dendrometer band measurement period is the longest published tree diameter measurement period (Keeland and Shariz 1993; Carvalho and Felfili 2011 ). The long service life of the dendrometer bands can be attributed to the use of stainless steel.…”

“…Moreover, the long extension length of the spring provides ample space for long-term monitoring in the field. For examples, two or three years measurement periods and maximum extension length of the spring at around 60 mm were commonly conducted (Keeland and Shariz 1993; Pelissier and Pascal 2000 ; Pesonen et al 2004 ; Drew and Downes 2009 ; Carvalho and Felfili 2011 ). In this study, the maximum diameter increments were measured at 115.6 mm and 135.4 mm for coniferous and broadleaf trees, respectively, equaling 363 mm and 425 mm extensions in band circumference.…”

Growth strategies of the arborescent palmIriartea deltoideain a western Amazonian forest

“…To determine the diameter increment between 2011 and 2014, we measured the diameter of all I. deltoidea individuals ( N = 554), using dendrometer bands rather than tape or calipers as much as possible ( N = 382; Clark, Wynne & Schmoldt, ), because measurement error is often significant in relation to the expected growth over short‐term studies (Carvalho & Felfili, ). Following the protocol of Muller‐Landau & Larjavaara (), plastic dendrometer bands were constructed using a 1‐cm‐wide plastic banding (length: equal to tree circumference plus 35 cm) with both ends folded over the band (leaving one free, mobile end) and attached with metallic seals (length < 25 mm).…”