CSPs: Tree neighbour competitive traits in the comparative study plots - tree individuals

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Dataset Abstract

This research is done to quantifiy individual tree growth and mortality within and among different species in the comparative study plots. Local neighbourhood interactions are analysed by the means of competition indices. Questions are: (a) does diversity reduce competition? (b) does competition change with successional stage? The data might provide valuable information to be compared with data from the main experiment. We chose 20 target trees each of the two most abundant evergreen species (Castanopsis eyrei FAGACEAE and Schima superba THEACEAE ) and of the two most abundant decidious species (Quercus serrata and Castanea henryi FAGACEAE). Competitors were defined as all trees with a dbh> 10 cm in middle and old successional forests and >3 cm in early successional forests and within a radius that is 1/2 of the height of the target tree. The positions of the competitors in relation to the respective target tree were evaluated (distance and azimuth). Following parameters were measured of all trees: total height, heigth of bifurcatin point, dbh and the crown width in 8 directions.

Dataset Design

Selection of target species: the two most abundant evergreen and decidious species were selected. Selection of target trees: prerequisites for target trees: (a) the crown is part of the upper most canopy layer (b) the tree is single stemmed (c) the crown does not suffer a crown loss of more than 30% of the original crown caused by snow break (2008) (d) there are no completely broken trees in the closest neighbourhood (we assume that the effect of open space would influence the growth of the target tree more than the competitors) (e) the tree's position is within the CSP or in the nearby (not more than 30m away, and only in comparable environment (slope direction, species composition)) If there were several potential target trees they were chosen randomly. Selection of competitors: all neighbours within a radius of 1/2 the height of the target tree were said to be competitors. Additionally, the dbh limit was >10cm in middle and late successional and >3cm in early successional plots. Measurements:(a) Position: the position of the target tree is noted in relation to one corner of the CSP (distance and angle). The positions of the competitors in relation to the middle of the stemfoot of the target tree are assessed (distance and angle) (b) total height was measured by the means of a Vertex Forester hypsometer in cases this was not yet done by SP1 (c) diameter at breast heigth (dbh) was measured by the means of a diameter tape (dbh>10cm) and with a callipper (dbh<10cm) in the direction of the slope and perpendicular to it. In the case of multistemmed trees the average of all stems was calculated. (d) height of bifurcation point was measured by the means of a Vertex Forester hypsometer. The bifurcation point was measured at the lowest real branch with leaves. If the crown was broken it was determined to be at the first branch (including more than one year old Wasserreißer) that was of importance for the crown. In the case that the whole crown was broken the height where the Wasserreißer got very dense creating a secondary crown was measured. (e) crown width Each crown was measured in eight directions (N, NE, E, SE, S, SW,W,NW). The widest extension of the respective direction (as the distance from the middle of the stem foot to the last leaf) was determined by the means of a crown mirror and measured with the Vertex Forester hypsometer. In the case that there was only a one direction measurement, the distance to the crown starting (first leaf) was taken additionally, the middle of the crown claculated and from that point the crown extension in the two perpendicular directions was measured (one point measurement). If there could not be measured any leaf in any of the directions a one point measurement in the direction of the overall widest crown extension was made. The direction was noted (angle in gon). Additional parameters: (a) % coverage:estimation of how much percent of the projected crown area (surroundes by the measured points) are covered by leaves and branches (I-V, in 20% steps) (b) % crown loss: estimation of the percentage of crown loss of the original crown volume because of breaking induced by the heavy snow load in February 2008 (1-4 in 25% steps, 5 complete crownloss)

Spatial Extent

CSPs
29°08'-29°17'N
118°02'-118°11'E
Measurements and calculated variables Crown radii in the eight subcardinal directions were determined by means of a crown mirror. The crown projection area (hereafter crown area) was calculated using the formula for a polygon. In cases of extraordinary crown displacement – the crown projection did not include the stem base – the distances to the proximal and distal edge of the crown were measured in all possible directions (if
this was only possible for one direction, four crown radii were measured as follows: the distances to the proximal and distal edge of the crown were determined and, starting at the centre of this crown diameter, on the axis perpendicular to it. In this case, crown area was approximated as a quadrangle). Relative crown displacement (rd) was considered to be the distance of the centre of gravity of the crown area from the stem base, divided by the mean crown radius (Longuetaud et al., 2008). In cases where the centre of gravity perfectly matches the stem base, rd is equal
to 0. Main tree stems may deviate from vertical stature in two different ways: stem inclination and stem bendiness, with the former
involving straight but leaning stems and the latter bent or curved stems (Schamp et al., 2007). In the forest interior of Gutianshan NNR bent growth forms are confined to a relatively small number of trees. To obtain the degree of stem inclination, we first measured the height of the bifurcation point (height at which the lowest living crown branch of the tree branches off, excluding epicormics or springs), and then the horizontal distance of the bifurcation point from the stem in the direction of the slope. The angle of inclination was calculated as tan alpha of these two distances. If the stem was inclined towards the slope, stem inclination was considered to be negative. This method is similar to that used by Matsuzaki et al. (2006), where stem inclination was defined by referring to a straight line between the stem base and the top of the tree. However, in our study we used the bifurcation point as a reference point in order to separate the effect of crown asymmetry from that of stem inclination.The dbh (measured with a diameter measurement tape) and total height were recorded for all trees. The relative position of the neighbours to the target tree was measured as the horizontal distance from stem base to stem base. All height and distance measurements were conducted using a Forester Vertex Hypsometer (Haglöf, Sweden). All neighbours were determined to species. Local species richness (i.e. the species richness of the group) was estimated using the rarefaction method (Hurlbert’s formula, 1971) of the vegan package in R (subsample size: two trees). We applied the
same method to obtain ameasure for local functional diversity. For this purpose we classified the species into seven functional groups. Since our hypotheses are based on growth characteristics of crown and stem, the trees were allocated to the functional groups according to adult tree height (canopy tree vs. sub-canopy tree) (Poorter et al., 2006), leaf longevity (evergreen vs. deciduous) (Deng et al., 2008) and leaf morphology (simple leaves, compound leaves, needles). We decided to establish an additional functional group for Fabaceae, because of their well known ability to fix nitrogen and the resulting differential preconditions for growth.To characterise the competitive power of the target trees competition indices have been calculated. Upper canopy heightwasdefined as themeanheight of the highest 20% trees in the respective group.For each tree group, data for slope inclination and aspect were collected and transformed after Beers et al. (1966).

Published

Lang et al. 2010, FORECO 260, 1708-1715; http://dx.doi.org/10.1016/j.foreco.2010.08.015

Taxonomic Extent

Tree species in the Comparative study plots

Measurement Circumstances

There were different periods, in wich data was measured. This might cause differences in the crown measurements. In December some of the decidious had no leaves any more. If so the tip of the longest twigg was measured (if possible to see). It causes some problems to look through a crown of a competitor with a cover of V. The great steepness caused some problems to the crown measurements since it was sometimes very diffcult to walk in the explicit direction. Also the trees were growing in such strange angles that the crown could only be measures with "one point" measurements which causes some problems to the comparability of the data.

Data Analysis

We tested speciesspecific differences of crown area, relative crown displacement and stem inclination using a mixed effects model with species as fixed effect and plot as random effect. We refined our models by testing for main effects of abiotic and biotic environmental variables in order to verify their effects on crown and stem parameters. Biotic variables included species richness, functional diversity, competition index, the dbh of the target tree and mean upper canopy height, while the abiotic variables were slope inclination, slope aspect and soil depth. Target species identity was also included as a categorical predictor variable. Similar to the previous models, plot was included as random effect.

Paper proposal submissions

Published

2011

2010

Data columns available in the raw data part of this dataset

CSP
name of the CSP in the Nature ReserveBEF research plot nameReasearch plots of the Biodiversity - Ecosystem functioning experiment (BEF-China). There are three main sites for research plots in the BEF Experiment: Comparative Study Plots (CSP) in the Gutianshan Nature Reserve, having a size of 30x30m^2, measured on the ground.
Data group: BEF research plot name
Keywords: CSP, location
Values
CSP03
CSP02
CSP04
CSP01
CSP05
date
date of fieldwork
Data group: Date time information
Keywords: date
Values
2008-07-21
2008-07-11
2008-07-03
2008-07-18
2008-07-28
target_group
focal plot around the target tree including tree neighbours
Data group: Group of competitors around a target tree for tree tree interaction.
Keywords: competitive neighbourhood, location
Values
CSP_02Ss
CSP_02Ch
CSP_02Qs
CSP_01Qs
CSP_02Ce
tree_status
target tree or competitor. The name consists of the CSP name and an acronym for the target tree species. CSP_*Ss CSP number Schima superba, CSP_*Ce CSP number Castanopsis eyrei, CSP_*Qs CSP number Quercus serrata, CSP_*Ch CSP number Castanea henrii
Data group: Helper
Keywords: competition
Values
CSP_01QsC01
CSP_01QsC04
CSP_01QsC03
CSP_01Qs
CSP_01QsC02
species
name of the tree species
Data group: Scientific plant species name
Keywords: species, explanatory
Values
Acer cordatum
Albizia kalkora
Adinandra millettii
Alangium kurzii
Castanea henryi
species_comment
species_comment
Data group: Helper
Values
species unsure, species name added from dataset "CSP_tree_stem_reference_list" (Dataset nr 238 on the protal) according to silverID/stem_tag. Should be treated with care.
secies not quite sure, may be a different one and should be treated with care
silverID
number on silver tag attached to the tree. Trees with "BRIM" in front of the common 6 digits ID have been added to the present investigation by taging trees in an extra permanent plot near the CSP12 (responsible person for questions: Minjiang Yu)
Data group: CSP metal tag number (trees, woody debris)
Keywords: tree
Values
363055
275831
363512
363553
363502
silverID_comment
silverID_comment
Data group: Helper
Values
Stefan: 379758
pos_azimuth
angle seen from "relative point", compass
Unit: gon (0-400)
Data group: Azimuth
Keywords: tree position
Values
10
0
100
101
1
pos_dist
ground distance to relative point, Vertex Forester
Unit: m
Data group: Helper
Values
0.6
0.3
0.5
0
0.4
pos_hdist
horizontal distance to relative point, Vertex Forester
Unit: m
Data group: Helper
Values
0.4
0.5
0.2
0
0.6
rel_point
relative point to which individual trees are measured. NE north eastern corner of CSP, NW north western corner of CSP, SE south eastern corner of CSP, SW south western corner of CSP, T target tree
Data group: Helper
Values
Mittel NE
NE inner
NE
NE/ 40 NW
NO
dbh
diameter at breast hight
Unit: cm
Data group: Diameter at breast height
Keywords: biomass, dbh, tree performance, explanatory
Values
10
10.1
10.03
10.13
10.12
tot_hi
total height
Unit: m
Data group: Plant height
Keywords: height, tree performance, explanatory
Values
10.4
10.3
10.1
10
10.2
bifurcat
height of bifurcation point
Unit: m
Data group: Bifurcation point
Keywords: bifurcation point, crown architecture
Values
0.6
0
10
0.3
1
cr_length
cr_length
Data group: Crown architecture
Values
0.2
0.4
0
0.1
0.3
cr_ratio
cr_ratio
Data group: Crown architecture
Values
0.01
0.03
0
0.04
0.02
stem_slend
stem_slend
Data group: Stem morphology
Values
0.2
0.13
0.15
0.14
0.17
nndist
widest extension of the crown in northern direction (ground distance)
Unit: m
Data group: Crown architecture
Keywords: crown architecture
Values
0.1
0.2
0
0.3
0.4
nnhdist
widest extension of the crown in northern direction (horizontal distance)
Unit: m
Data group: Crown architecture
Values
0
0.1
0.3
0.4
0.2
nedist
widest extension of the crown in northeastern direction (ground distance)
Unit: m
Data group: Crown architecture
Values
0.3
0.1
0
0.4
0.2
nehdist
widest extension of the crown in northeastern direction (horizontal distance)
Unit: m
Data group: Crown architecture
Values
0.3
0
0.1
0.2
0.4
eedist
widest extension of the crown in eastern direction (ground distance)
Unit: m
Data group: Crown architecture
Keywords: crown architecture
Values
0
0.3
0.2
0.1
0.4
eehdist
widest extension of the crown in eastern direction (horizontal distance)
Unit: m
Data group: Crown architecture
Values
0.1
0.4
0.2
0.3
0
sedist
widest extension of the crown in southeastern direction (ground distance)
Unit: m
Data group: Crown architecture
Values
0.2
0.1
0
0.4
0.3
sehdist
widest extension of the crown in southeastern direction (horizontal distance)
Unit: m
Data group: Crown architecture
Values
0.2
0
0.3
0.4
0.1
ssdist
widest extension of the crown in southern direction (ground distance)
Unit: m
Data group: Crown architecture
Keywords: crown architecture
Values
0.4
0.3
0.1
0
0.2
sshdist
widest extension of the crown in southern direction (horizontal distance)
Unit: m
Data group: Crown architecture
Values
0.1
0.4
0
0.3
0.2
swdist
widest extension of the crown in southwestern direction (ground distance)
Unit: m
Data group: Crown architecture
Values
0.3
0.4
0.1
0
0.2
swhdist
widest extension of the crown in southwestern direction (horizontal distance)
Unit: m
Data group: Crown architecture
Values
0
0.1
0.4
0.3
0.2
wwdist
widest extension of the crown in western direction (western distance)
Unit: m
Data group: Crown architecture
Keywords: crown architecture
Values
0.1
0.2
0
0.3
0.4
wwhdist
widest extension of the crown in western direction (horizontal distance)
Unit: m
Data group: Crown architecture
Values
0.3
0.4
0
0.1
0.2
nwdist
widest extension of the crown in northwestern direction (ground distance)
Unit: m
Data group: Crown architecture
Values
0.2
0.4
0.1
0
0.3
nwhdist
widest extension of the crown in northwestern direction (horizontal distance)
Unit: m
Data group: Crown architecture
Values
0.1
0
0.2
0.3
0.4
st_nnhdist
shortest extension of the crown in nn direction, if not zero (stem); only possible for crowns whose crown does not overtop the stem in one or more directions
Unit: m
Data group: Crown architecture
Values
0.3
0.5
0.4
0.7
0.6
st_nndist
shortest extension of the crown in nn direction, if not zero (stem); only possible for crowns whose crown does not overtop the stem in one or more directions.
Unit: m
Data group: Crown architecture
Values
0.3
0.7
0.5
0.4
0.6
st_nehdist
shortest extension of the crown in nn direction, if not zero (stem); only possible for crowns whose crown does not overtop the stem in one or more directions
Unit: m
Data group: Crown architecture
Values
0.1
0.4
0.7
0.5
0.8
st_nedist
shortest extension of the crown in nn direction, if not zero (stem); only possible for crowns whose crown does not overtop the stem in one or more directions
Unit: m
Data group: Crown architecture
Values
0.3
0.7
0.1
0.5
0.4
st_eehdist
shortest extension of the crown in nn direction, if not zero (stem); only possible for crowns whose crown does not overtop the stem in one or more directions
Unit: m
Data group: Crown architecture
Values
0.5
0.7
0.4
0.6
0.3
st_eedist
shortest extension of the crown in nn direction, if not zero (stem); only possible for crowns whose crown does not overtop the stem in one or more directions
Unit: m
Data group: Crown architecture
Values
0.6
0.3
0.5
0.7
0.4
st_sehdist
shortest extension of the crown in nn direction, if not zero (stem); only possible for crowns whose crown does not overtop the stem in one or more directions
Unit: m
Data group: Crown architecture
Values
0.3
0.4
0.7
0.5
0.6
st_sedist
shortest extension of the crown in nn direction, if not zero (stem); only possible for crowns whose crown does not overtop the stem in one or more directions
Unit: m
Data group: Crown architecture
Values
0.3
0.4
0.5
0.9
0.6
st_sshdist
shortest extension of the crown in nn direction, if not zero (stem); only possible for crowns whose crown does not overtop the stem in one or more directions
Unit: m
Data group: Crown architecture
Values
0.5
0.3
0.7
0.2
0.6
st_ssdist
shortest extension of the crown in nn direction, if not zero (stem); only possible for crowns whose crown does not overtop the stem in one or more directions
Unit: m
Data group: Crown architecture
Values
0.5
0.6
0.2
0.8
0.7
st_swdist
shortest extension of the crown in nn direction, if not zero (stem); only possible for crowns whose crown does not overtop the stem in one or more directions
Unit: m
Data group: Crown architecture
Values
0.3
0.4
0.1
0.5
0.2
st_swhdist
shortest extension of the crown in nn direction, if not zero (stem); only possible for crowns whose crown does not overtop the stem in one or more directions
Unit: m
Data group: Crown architecture
Values
0.2
0.3
0.1
0.5
0.4
st_wwhdist
shortest extension of the crown in nn direction, if not zero (stem); only possible for crowns whose crown does not overtop the stem in one or more directions
Unit: m
Data group: Crown architecture
Values
0.5
0.1
0.2
0.3
0.4
st_wwdist
shortest extension of the crown in nn direction, if not zero (stem); only possible for crowns whose crown does not overtop the stem in one or more directions
Unit: m
Data group: Crown architecture
Values
0.4
0.2
0.5
0.1
0.3
st_nwhdist
shortest extension of the crown in nn direction, if not zero (stem); only possible for crowns whose crown does not overtop the stem in one or more directions
Unit: m
Data group: Crown architecture
Values
0.1
0.3
0.2
0.4
0.5
st_nwdist
shortest extension of the crown in nn direction, if not zero (stem); only possible for crowns whose crown does not overtop the stem in one or more directions
Unit: m
Data group: Crown architecture
Values
0.4
0.2
0.3
0.1
0.5
crownstartdist
ground distance to starting of crown, for crowns extending only in one direction
Unit: m
Data group: Crown architecture
Values
0.1
0.4
0.5
0.6
0
crownstarthdist
horizontal distance to starting of crown, for crowns extending only in one direction
Unit: m
Data group: Crown architecture
Values
0.5
0
0.1
0.4
0.6
crownenddist
ground distance to the end of the crown, for crowns extending only in one direction
Unit: m
Data group: Crown architecture
Values
1.7
10
12.7
11.4
10.5
crownendhdist
horizontal distance to the end of the crown, for crowns extending only in one direction
Unit: m
Data group: Crown architecture
Values
10.5
10.4
1.3
10
2.2
crowndirect
direction of the crownspine
Unit: subcardinale directions
Data group: Crown architecture
Values
190
115
188
215
158
perp1dir
1st perpendicular direction to the crown spine direction
Unit: subcardinale directions
Data group: Crown architecture
Values
177
160
122
112
115
perp1dist
widest extension of the crown in the 1st perpendicular direction (ground distance), from the middle of the distance (crownend -crownstart)
Unit: m
Data group: Crown architecture
Values
0
0.3
0.25
0.2
0.1
perp1hdist
widest extension of the crown in the 1st perpendicular direction (horizontal distance), from the middle of the distance (crownend -crownstart)
Unit: m
Data group: Crown architecture
Values
0.2
0.3
0.1
0
0.25
perp2dir
second perpendicular direction to the crown spine direction
Unit: subcardinale directions
Data group: Crown architecture
Values
120
290
258
288
176
perp2dist
widest extension of the crown in the second perpendicular direction (ground distance), from the middle of the distance (crownend -crownstart)
Unit: m
Data group: Crown architecture
Keywords: crown architecture
Values
0
0.25
0.3
0.1
0.2
perp2hdist
widest extension of the crown in the second perpendicular direction (horizontal distance), from the middle of the distance (crownend -crownstart)
Unit: m
Data group: Crown architecture
Values
0.3
0.2
0
0.1
0.25
cover
percentage coverage of the projected crown; estimation of how much percent of the projected crown area (surroundes by the measured points) are covered by leaves and branches (I-V, in 20% steps)
Data group: Vegetation layer cover
Keywords: crown architecture, explanatory
Values
sp2 IV
sp2 II
sp2 V
sp2 I
sp2 III
loss
percentage of loss due to the snow break event in Feb 2008
Data group: Percentage of crown loss due to disturbance
Keywords: disturbance, ice storm
Values
d4
d2
d0
d1
d3
st_incl_dist
ground distance of the bifurcation point from the stem base in the direction of slope aspect
Unit: m
Data group: Stem morphology
Values
0
0.2
-0.1
0.1
-0.2
st_incl_hdist
horizontal distance of the bifurcation point from the stem base in the direction of slope aspect
Unit: m
Data group: Stem morphology
Keywords: tree performance, stem morphology
Values
0.1
-0.2
0.2
-0.1
0
st_incl_rad
calculated stem inclination in rad
Unit: rad
Data group: Stem morphology
Values
-0.008849789
0.010638699
0.00909116
-0.009709043
0
st_incl_degree
calculated stem inclination in degree
Unit: °
Data group: Stem morphology
Values
-0.507055533
0
0.609552565
0.520885072
-0.556287183
stem_azi
azimuth of the stem
Unit: gon (0-400)
Data group: Stem morphology
Values
110
120
0
10
100
m_cr_dia
mean crown diameter
Unit: m
Data group: Crown architecture
Keywords: explanatory
Values
0
0.2125
0.1375
0.2
0.1875
cr_a_t
crown area calculated from triangles
Unit: squaremeter
Data group: Crown architecture
Keywords: crown architecture, explanatory
Values
0.117809725
0.063817764
0
0.09424778
0.031415927
cr_a_p
corwn area calculated from polygons
Unit: squaremeter
Data group: Crown architecture
Keywords: explanatory
Values
0.053033009
0.09424778
0
0.031415927
0.117809725