Allometric models for leaf area estimation across different leaf-age groups of evergreen broadleaved trees in a subtropical forest

Abstract

The accurate and nondestructive determination of individual leaf area (LA) of plants, by using leaf length (L) and width (W) measurement or combinations of them, is important for many experimental comparisons. Here, we propose reliable and simple regressions for estimating LA across different leaf-age groups of eight common evergreen broadleaved trees in a subtropical forest in Gutianshan Natural Reserve, eastern China. During July 2007, the L, W, and LA of 2,923 leaves (202 to 476 leaves for each species) were measured for model construction and the respective measurements on 1,299 leaves were used for model validation. Mean L, W, LA and leaf shape (L:W ratio) differed significantly between current and older leaves in four out of the eight species. The coefficients of one-dimension LA models were affected by leaf age for most species while those incorporating both leaf dimensions (L and W) were independent of leaf age for all the species. Therefore, the regressions encompassing both L and W (LA = a L W + b), which were independent of leaf age and also allowed reliable LA estimations, were developed. Comparison between observed and predicted LA using these equations in another dataset, conducted for model validation, exhibited a high degree of correlation (R 2 = 0.96-0.99). Accordingly, these models can accurately estimate the LA of different age groups for the eight evergreen tree species without using instruments.Additional key words: evergreen broadleaved trees; leaf age; leaf area; leaf length and width; subtropical forest.

Non-destructive models to estimate leaf area on bell pepper crop

“…These non-destructively methods are increasingly used, since they are an economical, quick, reliable way on the leaf area estimation (ZHANG & PAN, 2011). The leaf area index is a dimensionless quantity, which presents the area of the sheet (top side only) per unit area of ground below it.…”

Regression models for estimating leaf area of seedlings and adult individuals of Neotropical rainforest tree species

“…Individual leaf area (LA) is a key variable in forest ecophysiological studies, because it directly influences light interception, photosynthesis and evapotranspiration of adult trees, saplings and seedlings (Niinemets, 2010;Zhang and Pan, 2011). Furthermore, LA is an important variable for seedling establishment and for sun/shade acclimation of tropical rainforest tree species (Varone and Gratani, 2009;Coste et al, 2011;Houter and Pons, 2012;Laurans et al, 2012).…”

“…Destructive methods involve leaf harvesting, which can be done using automated leaf area meters, photocopies, planimeters (Tsuda, 1999) and softwares that calculate LA based on scanned images and digital photos (O'Neal et al, 2002;Godoy et al, 2007;Toebe et al, 2010). Nondestructive methods do not require leaf destruction and are based on regression models to estimate LA from leaf linear dimensions, as length (L) and width (W) (Kandiannan et al, 2002;Antunes et al, 2008;Rouphael et al, 2010;Zhang and Pan, 2011;Pompelli et al, 2012;Souza and Habermann, 2014).…”

Number of leaves needed to model leaf area in jack bean plants using leaf dimensions

“…However, Williams andMartinson (2003), Cargnelutti Filho et al (2012b) and Toebe et al (2012) all recommend using models based on a single linear leaf dimension (width) due to the ease of measurement and the high level of accuracy. According to Williams and Martinson (2003) and Zhang and Pan (2011), using a single linear leaf dimension also prevents potential problems of colinearity between the independent variables in the model.…”

“…Zhang and Pan (2011) used samples of between 202 and 476 leaves to generate leaf area estimation models for a tree species. Pompelli et al (2012) used 1,200 leaves from Barbados nut plants to generate leaf area models and used two independent samples of 300 leaves for the validation of the generated models.…”