DOI: 10.5061/dryad.q573n5tfx
title: Data from: Including tree spatial extension in the evaluation of neighbourhood competition effects in Bornean rain forest

description: Classical tree neighbourhood models use size variables acting at point
 distances. In a new approach here, trees were spatially extended as a
 function of their crown sizes, represented impressionistically as points
 within crown areas. Extension was accompanied by plasticity in the form of
 crown removal or relocation under the overlap of taller trees. Root
 systems were supposedly extended in a similar manner. For the 38 most
 abundant species in the focal size class (10 - &lt;100 cm stem girth)
 in two 4-ha plots at Danum (Sabah), for periods P1 (1986-1996) and P2
 (1996-2007), stem growth rate and tree survival were individually
 regressed against stem size, and neighbourhood conspecific (CON) and
 heterospecific (HET) basal areas within incremented steps in radius. Model
 parameters were critically assessed, and statistical robustness in the
 modelling set by randomization testing. Classical and extended models
 differed importantly in their outcomes. Crown extension weakened the
 relationship of CON effect on growth versus plot species’ abundance,
 showing that models without plasticity over-estimated negative density
 dependence. A significant negative trend of difference in CON effects on
 growth (P2 − P1) versus CON or HET effect on survival in P1 was strongest
 with crown extension. Model outcomes did not then support an explanation
 of CON and HET effects being due to (asymmetric) competition for light
 alone. An alternative hypothesis is that changes in CON effects on small
 trees, largely incurred by a drought phase (relaxing light limitation) in
 P2, and following the more shaded (suppressing) conditions in P1, were
 likely due to species-specific (symmetric) root competition and
 mycorrhizal processes. The very high variation in neighbourhood
 composition and abundances led to a strong ‘neighbourhood stochasticity’,
 and hence to largely idiosyncratic species’ responses. A need to much
 better understand the roles of rooting structure and processes at the
 individual tree level was highlighted.
description: 1. Plot data for
 the tree neighbour modeling The data presented here come from
 the two 4-ha permanent plots in lowland dipterocarp forest within the
 Danum Valley Conservation Area, Sabah, East Malaysian (NE Borneo), close
 to the Ulu Segama, set up and maintained for a study of long-term forest
 dynamics. Full details of the plots’ set-up, coordinates, site background,
 methods of enumeration, taxonomy, etc. are to be found in previous papers
 [1-3]. 1]
 Lingenfelder, M. & Newbery, D. M. 2009 On the detection of dynamic
 responses in a drought-perturbed tropical rainforest in Borneo.
 <i>Plant Ecology</i> <b>201</b>,
 267-290. [2]
 Newbery, D. M., Campbell, E. J. F., Lee, Y. F., Ridsdale, C. E. &
 Still, M. J. 1992 Primary lowland dipterocarp forest at Danum Valley,
 Sabah, Malaysia: structure, relative abundance and family composition.
 <i>Philosophical Transactions of the Royal Society of London Series
 B-Biological Sciences</i> <b>335</b>, 341-356.
 [3] Newbery, D. M., Campbell, E. J. F., Proctor, J.
 & Still, M. J. 1996 Primary lowland dipterocarp forest at Danum
 Valley, Sabah, Malaysia. Species composition and patterns in the
 understorey. <i>Vegetatio</i> <b>122</b>,
 193-220. 2. 
 Output results from the regression
 modeling These data
 tables are referenced, and linked to here, in Appendix S4 of the main
 paper. In the paper a complete explanation is found of the statistical
 data analysis. It is intended that these tables will be consulted in
 conjunction with reading the main paper.
description: 1. Plot data for
 the tree neighbour modeling The archived text file
 (nncrexm.inputData.csv) consists of comma-separated values for the
 following variables: ‘Plot’ – main plots 1 and 2 (MP1, MP2); ‘Tag’ – tree
 identification number (unique to plot); ‘X, Y’ – tree coordinate positions
 within each plot; ‘Code07’ – 8-character taxonomic code; ‘GBH86, GBH96,
 GBH01, GBH07’ – stem girths (in cm) at breast height [normally 1.3 m above
 ground] of trees ≥ 10 cm GBH, for the censuses of 1986, 1996, 2001 and
 2007. Where the GBH is recorded as ‘0.0’ the tree had died in the
 preceding interval. Cells lacking values are indicated by ‘NA’s: they
 appear either at censuses before the one in which the tree was recruited,
 the census after which the tree died, or at the census ending the interval
 in which the tree regressed (its GBH became &lt; 10 cm). In ‘Code07’
 only those necessary are shown, namely the 48 selected focal tree species
 used in the present modelling work (they are listed with their full
 nomenclature in Appendix 1: Table S1 of the paper), otherwise coded as
 ‘NONFOCAL’. The data-table has 23382 rows (= trees). These data form the
 input to the crown extension programs stored at GitHub (see Appendix 2 of
 the paper for details) and the related neighbourhood regression
 modeling. On
 tabulation here, the counts of focal trees (10 - &lt; 100 cm gbh) per
 species at the start of each period, i.e. P1 or P2 (from GBH86 or GBH96
 respectively), are the sums of counts of trees potentially usable for
 growth estimates (i.e. the survivors to end of the period) plus the counts
 of number of trees dying by the end of the period, as shown in Appendix
 S1: Table S1 of the paper. 2.
 Output results from the regression
 modeling Four tables of the estimated coefficients, measures of statistical fit and significances, and best fitting radii, of the regression outcomes, for 48 species, non-spatial and two (‘removed’ and ‘relocated’) spatial models, and growth and survival responses in periods P<sub>1</sub> and P<sub>2</sub> (.xls files). Table of the effect sizes for CON and HET terms in the non-spatial and all eight combinations of spatial models, for 48 species, and growth and survival responses in periods P<sub>1</sub> and P<sub>2</sub> (.xls file). In these files, collected in 'nncrexm.modEsts.zip', fitted estimates and effect sizes for the CON and HET terms are given for all 48 species first considered. Of them, the first 38 (name codes in black) were selected and they formed the basis for the summaries, tables and graphs, at the species level, in the main paper. The last 10 species (name codes in red) were dropped. The eight-letter species codes in column 1 are explained in AppendixS1: Table S1.