Pilot experiment: tree sapling biomass allocation to constituents

Usage Rights

This data is Free for public.

Permission is granted to anybody to access, use and publish all open for public data freely. The commercial use of any data is prohibited. The quality and completeness of data cannot be guaranteed. Users employ these data at their own risk. In order to make attribution of use for owners of the data possible, the identifier of ownership of data must be retained with every data record. Users must publicly acknowledge, in conjunction with the use of the data, the data owners. Cite the data as follows: Lang, A., von Oheimb, G. and Härdtle, W. (2013):Competition of tree saplings -Pilot- Biomass of target saplings - biomass allocation to constituents. BEF-China data portal (Accessed through URL http://china.befdata.biow.uni-leipzig.de/datasets/143)

Dataset Abstract

Questions: One tenet of biodiversity and ecosystem functioning research is the dependence of ecosystem functions on species-specific differences in traits. Community assembly theory predicts niche differentiation among the constituent species, for which there is as yet no empirical evidence for subtropical forest ecosystems.We thus ask:
(1) Which mechanisms promote sapling coexistence in the four abundant early-successional subtropical species Schima superba, Elaeocarpus decipiens, Quercus serrata and Castanea henryi?
(2) Do species richness, species composition, species identity and stand density have an impact on growth patterns and crown architecture of tree saplings?
This dataset represents only one part of the analyses for the mentioned manuscript

Dataset Design

In a field experiment, we manipulated the local neighbourhood of saplings with regard to species richness (1, 2 and 4 species), species composition (monocultures, six two-species combinations and one four-species combination) and stand density (low, intermediate and high). Saplings were planted in low, medium and high density. The low density treatment was one individual per plot. The medium and high density treatment comprised 16 individuals, planted with 25 cm and 15 cm planting distance respectively.

Spatial Extent

To analyse biomass allocation patterns with regard to stratification (i.e. height layers) and to different constitutents (stem, branches and leaves), the four central individuals per plot were harvested in September 2010 in 50 cm strata starting from ground. Saplings were divided into stem, branches and leaves for each stratum. Biomass was dried at 70° C for 48 h and weighed to 0.01 g precision. Biomass data were logarithmically transformed prior to analyses.To analyse the vertical above-ground biomass distribution, we calculated the cumulative biomass fraction C, i.e. the proportion of cumulative above-ground biomass, summed up from the ground to the height strata hs (50, 100, 150, 200, 250 cm).

Published

Mechanisms promoting tree species coexistence:
Experimental evidence with saplings of subtropical forest ecosystems of China
;onlinelibrary.wiley.com/doi/10.1111/j.1654-1103.2012.01403.x/pdf

Temporal Extent

Sapling have been planted in 2009 and harvested in autumn of 2010.

Taxonomic Extent

4 Species: Schima superba, Elaeocarpus decipiens, Quercus serrata, Castanea henrii

Data Analysis

The overall aim of this study was to disentangle neighbourhood effects on growth, biomass allocation, crown architecture and branch demography of saplings. Firstly, the complete dataset was used to test for diversity effects by fitting mixed effects models (Model 1) including species richness and density as factorial variables and the initial diameter as fixed effect. The initial diameter was used to account for differences in size at the beginning of the experiment. Secondly, all two species combinations were analysed for species composition. Mixed effects models (Model 2a) were fitted using species composition, density and initial diameter as fixed effect. The analyses with Model 2b were performed for the high density treatment data divided by species to exclude density effects and to test for composition effects on the individual-level of each species. Model 2b contained species composition and initial diameter as fixed effects. Thirdly, mixed effects models (Model 3) for all monocultures were calculated to test for species identity. They were fitted by the predictor variables species identity, density and initial diameter as fixed effects. Random effects for all models were plot nested in block. Model simplification was performed by stepwise backward selection of fixed factors, removing the least significant variables until only significant predictory variables remained (p < 0.05). The significant categorical variables were further examined by a Tukey post-hoc test.

Freeformat files (1)

  • sp2 pilot.zip (252 KB)
    Original data in both wide and long format for the different strata. Plus r script to reshape the files from wide to long. This data is not described with metadata.

Data columns available in the raw data part of this dataset

plot_id
Individual complex ID for identifying exactly each plot; it connects with underline character the block number and the community code, i. e. the block number with the plots treatment. The plot identifier contains the information, which block the plot is in and which community is is comprised of.; Datagroup description: Reasearch 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. Main Experiment plots have a size of 1 mu, which is about 25x25m^2 in horizontal projection. Pilot Study Plots have a size of 1x1 m^2. Research plots on the main experiment have a "p" in front of their IDs and then a 6 digit code: Plots in the main sites A and B are named according to their position in the original spreadsheet, in which they were designed. They consist of 6 digits: _1st digit_: Site (1:A, 2:B), _digit 2and3_: southwards row: as in spreadsheets the rows are named from the top to the bottom; _digit 4 and 5_: westward column: as in the original spreadsheet, but the letters are converted to numbers (A=01, B=02); _6th digit_: indicator, if the plot has been shifted a quarter mu. Example: "p205260": "p" means that this is a plot that is specified. "2" means, that we are at site B. Now the coordinates of the south - west corner: "0526". Since "e" is the fifth letter of the alphabet, this is Plot E26. The last digit "0" means that this plot was not moved by a quarter of a Mu, as some sites in Site A. The 6th digit can also indicate the subplot within the plot. "5", "6", "7", "8" indicate the northwest, northeast, southeast, and southwest quarter plot respectively.
Data group: BEF research plot name
Keywords: Pilot experiment
Values
2_AE01
2_AE03
2_AE02
2_AE05
2_AE04
Ind_pos
number of individual, Individuals were consecutively numbered starting from the SW corner of the plot
Data group: Individual position within Pilot experiment
Values
6
7
10
1
11
Code
individual related unique code
Data group: Individual related unique code for the Pilot experiment
Keywords: tree individual
Values
1AE02_07
1AE02_06
1AE01_07
1AE01_11
1AE01_10
density
density of planted saplings. Saplings were planted in low, medium and high density. The low density treatment was one individual per plot. The medium and high density treatment comprised 16 individuals, planted with 25 cm and 15 cm planting distance respectively.
Data group: Density class
Keywords: competition, abundance
Values
25
50
15
Spp
species identity of individual
Data group: Scientific plant species name
Keywords: species
Values
Quercus serrata
Schima superba
Elaeocarpus decipiens
Castanea henryi
L.fresh
Leaf biomass fresh weight
Unit: g
Data group: Above and below ground biomass measurement
Keywords: fresh weight, aboveground biomass
Values
0.5
0.26
0.52
0.53
0
L.dry
Leaf biomass dry weight
Unit: g
Data group: Above and below ground biomass measurement
Keywords: biomass, leaf, dry weight
Values
0.19
0
0.12
0.18
0.24
W.fresh
Wood (stem) biomass fresh
Unit: g
Data group: Above and below ground biomass measurement
Keywords: fresh weight, aboveground biomass
Values
10.08
100.35
101.86
10.06
100.98
W.dry
Wood(stem) biomass dry
Unit: g
Data group: Above and below ground biomass measurement
Keywords: dry weight, aboveground biomass
Values
103.47
10.1
10.35
100.2
0.82
B.fresh
Branch biomass fresh weight
Unit: g
Data group: Above and below ground biomass measurement
Keywords: fresh weight, aboveground biomass
Values
0.19
0.66
0.75
0.4
0.57
B.dry
Branch biomass dry weight
Unit: g
Data group: Above and below ground biomass measurement
Keywords: biomass, branch, dry weight
Values
0.23
0.35
0.22
0.09
0.27
Tot.bio.fresh
Total biomass fresh weight
Unit: g
Data group: Above and below ground biomass measurement
Keywords: fresh weight, aboveground biomass
Values
102.88
100.76
101.05
102.68
1049.6
Tot.bio.dry
Total biomass dry weight
Unit: g
Data group: Above and below ground biomass measurement
Keywords: biomass, tree individual, dry weight
Values
100.38
101.32
100.9
101.12
101.61
Bio.rat
ratio of total dry biomass to total fresh biomass
Data group: Dry weight - fresh weight ratio
Keywords: ratio dry/fresh weight
Values
0.23
0.37
0.36
0.34
0.35