DOI: 10.5061/dryad.djh9w0w66
title: The effect of neighbor species’ phylogenetic and trait difference on tree growth in subtropical forests

description: To comprehensively understand ecological dynamics within a forest
 ecosystem, it is vital to explore how surrounding trees influence the
 growth of individual trees in a community. Biotic interactions have a
 significant potential impacts on individual tree growth and their effects
 can be evaluated through trait and phylogenetic-based approaches. This
 study investigates the relative importance of biotic interactions on tree
 growth by examining several metrics and considering three classes of
 intrinsic growth rates among the focal individuals: slower, intermediate
 and faster-growing trees. The metrics include hierarchical and absolute
 trait differences of focal trees to neighbors, neighborhood crowding
 index, phylogenetic distance, and trait community metrics. Our results
 indicated that the phylogenetic distance between the focal tree and its
 neighbors positively impacted the growth of all classes, whereas different
 traits have distinct effects on slower and faster-growing trees. Specific
 leaf area (SLA) and leaf area (LA) showed hierarchical importance to tree
 growth. Trees surrounded by neighbors with higher SLA and LA than
 themselves grow better, particularly for slower-growing trees. Higher
 levels of wood density difference between the focal trees and their
 neighbors positively impacts slower and faster-growing trees, while height
 difference negatively impacts faster-growing trees. We conclude that the
 interactions between trees are mediated by their ecological differences,
 but the performance and responses to surrounding competitors vary along
 with their growth class within a community. This study has revealed that
 the tree's intrinsic growth rate mediates the effect of traits and
 phylogeny of surrounding trees on individual tree growth.
description: To assess the effects of neighborhood interactions and community
 structure on tree growth, we performed quantile regression models (QR)
 with AGR logarithmic as the response variable and non-correlated
 neighborhood variables as predictor, using the <em>‘rq’
 </em>function in the R package quantreg.
description: # Manuscript effect of neighbor on individual tree growth
 This study aimed to
 investigate the relative importance of biotic interactions on tree growth
 by examining several metrics, including hierarchical and absolute trait
 differences of focal trees to neighbors, neighborhood crowding index,
 functional community structure, and phylogenetic distance. ## Description
 of the data and file structure The dataset includes information related to
 the **site** and the **plot** where the tree individuals were collected,
 as well as their **code** in the permanent plots. Additionally,
 the **species'** individual trees were identified, as well as their
 growth **class** and annual growth rate (**AGR**). We utilized plant
 functional traits, which are indicators of plant functional strategies and
 are expected to be related to individual tree growth and performance.
 These traits included height (**H**, m), leaf area (**LA**, cm²), specific
 leaf area (**SLA**, cm².g-1), leaf dry matter content (**LDMC**, mg.g-1),
 and wood density (**WD**, g.cm³). The neighborhood variables considered in
 the study were: a) Neighborhood crowding index (**NCI**): based on the
 steam size and spatial distance of neighboring trees within a fixed radius
 of 5 m; b) neighborhood hierarchical mean trait difference (**LAh, SLAh,
 LDMCh, WDh, Hh**) and neighborhood absolute mean trait difference (**LAs,
 LDMCs, WDs, Hs**) : dissimilarity of functional traits between focal trees
 and their neighbors. These indices are associated with competitive
 abilities' trait-mediated ranks and niche differentiation,
 respectively; c) community weighted mean (**CWM; CWM_LA, CWM_SLA,
 CWM_LDMC, CWM_WD, CWM_H**): mean trait values of each community of tree
 neighbors accounting for species relative abundance in each community; d)
 functional diversity (**FD**): Rao weighted by species relative abundance
 in each community; e) mean phylogenetic difference (**mean_PD**): the mean
 phylogenetic distance between the focal individual to all neighbor trees
 within the radius To assess the effects of neighborhood interactions and
 community structure on tree growth, we performed quantile regression
 models (QR) with AGR logarithmic as the response variable and
 non-correlated neighborhood variables as predictors, using the
 'rq' function in the R package quantreg. We ran the QR using the
 equation log AGR~ mean_PD+ SLAh+ WDs+ LAh+ LDMCh+ LDMCs+ Hs+ NCI+ CWM_LA+
 CWM_SLA+ CWM_LDMC+ CWM_H+ FD and using three quantiles in line with our
 sampling design: the 25th percentile (QR 25%) for focal trees with slower
 growth, the 50th percentile (QR 50%) for trees with intermediary growth,
 and the 75th percentile (QR 75%) for focal trees with faster growth. The
 analysis is described in the script. ## Sharing/Access information none ##
 Code/Software