DOI: 10.5061/dryad.wpzgmsbk5
title: Application of leaf size and leafing intensity scaling across subtropical trees

description: Understanding the scaling between leaf size and leafing intensity (leaf
 number per stem size) is crucial for comprehending theories about the leaf
 costs and benefits in the leaf size–twig size spectrum. However, the
 scaling scope of leaf size vs. leafing intensity changes along the twig
 leaf size variation in different leaf habit species remains elusive. Here,
 we hypothesize that the numerical value of scaling exponent for leaf mass
 versus leafing intensity in twig is governed by the minimum leaf mass
 versus maximum leaf mass (Mmin vs. Mmax) and constrained to be ≤ -1.0. We
 tested this hypothesis by analyzing the twigs of 123 species datasets
 complied in the subtropical mountain forest. The standardized major axis
 regression (SMA) analyses showed the Mmin scaled as the 1.19 power of Mmax
 and the -a (-1.19) was not statistically different from the exponents of
 Mmin vs. leafing intensity in whole data. Across leaf habit groups, the
 Mmax scaled negatively and isometrically with respect to leafing
 intensity. The pooled data's scaling exponents ranged from -1.14 to
 -0.96 for Mmin and Mmax vs. the leafing intensity based on stem volume
 (LIV). In the case of Mmin and Mmax vs. the leafing intensity based on
 stem mass (LIM), the scaling exponents ranged from -1.24 to -1.04. Our
 hypothesis successfully predicts that the scaling relationship between
 leaf mass and leafing intensity is constrained to be ≤ -1.0. More
 importantly, the lower limit to scaling of leaf mass and leafing intensity
 maybe closely correlate with Mmin vs. Mmax. Besides, constrained by the
 maximum leaf mass expand, the broad scope range between leaf size and
 number may be insensitive to leaf habit groups in subtropical mountain
 forest.
description: A total of 68 and 75
 species were sampled from the two sites (Table 1). The total number of
 sampled species was 123 (including 20 overlapping species) belonging to 92
 genera of 53 families. In August 2016 and 2017, three to five current-year
 undamaged, healthy twigs from three individuals of each species were
 randomly selected. All of the leaves (with petioles) on each twig were
 removed and counted (<i>N</i><sub>L</sub>). Twig
 diameter (<i>D</i>) and length (<i>L</i>) were
 measured using a vernier caliper, with an accuracy of 0.1 mm (Milla,
 2009). The stem volume of each twig
 (<i>V</i><sub>stem</sub>,
 mm<sup>3</sup>) was estimated using <i>L</i> and
 <i>D</i> assuming stems are cylindrical. Stems and leaves were
 brought to the laboratory where they were oven-dried at 75 ºC to determine
 total leaf mass (<i>M</i><sub>leaf</sub>) and stem
 mass (<i>M</i><sub>stem</sub>). Each leaf of each
 twig was subsequently scanned and its area was calculated using the Image
 J software (Image J 1.2v; National Institutes of Health, USA). Then, we
 multiplied the area of the largest and smallest leaf per twig by leaf mass
 per area (LMA, total leaf mass divided by total leaf area) to estimate the
 maximum and minimum leaf mass per twig, respectively. The volume-based
 leafing intensity (LIV) is here defined as
 <i>N</i><sub>L </sub>/
 <i>V</i><sub>stem</sub>; the mass-based leafing
 intensity (LIM) is here defined as <i>N</i><sub>L
 </sub>/ <i>M</i><sub>stem</sub>.
description: This dataset contains the leaf traits of 123 woody species.