Appendix 1
We collected pilot data in 2012 and 2013 from 914 1-m2 understory monitoring
quadrats placed within 1.2 km of the experiment. Data include all seedlings < 1.0 cm dbh,
but exclude new germinants. In these data from across a range of forest types, we
observed a mean of 11.4 individuals (range: 1-174) and 3.9 species (range: 1-15). Thus,
fifteen individuals is on par with mean natural seedling densities, and fifteen species is
the high end of observed species richness. The fifteen species employed also comprise
90% of the ~33,000 overstory stems (>1.0 cm DBH) in ~15 hectares of mapped forest
located within 0.5 km of the experiment (G. Parker, unpublished data), and represent 15
of the 23 most common tree species
Figure A1: Natural occurrence data for seedlings. Species are labeled with their
USDA symbol: Acer rubrum (ACRU), Carpinus caroliniana (CACA18), Carya alba
(CAAL27), Carya glabra (CAGL8), Cornus florida (COFL2), Fagus grandifolia
(FAGR) Fraxinus pennsylvanica (FRPE), Lindera benzoin (LIBE3), Liquidambar
styraciflua (LIST2), Liriodendron tulipifera (LITU), Nyssa sylvatica (NYSY), Platanus
occidentalis (PLOC), Quercus alba (QUAL), Quercus falcata (QUFA), and Quercus
rubra (QURU). Darker colors correspond to more frequent species pairings, and the gray
boxes on the diagonal indicate the number of quadrats in which each species occurred.
Given that all species co-occurred as adults in the 15-ha plot, and that uncommon
species-pairings are among the least common species in the understory, we infer that less
common pairings are due to species rarity rather than markedly different habitat
requirements.
Table A1: Species-specific replication and results
The “low-density” column refers to the number of low-density monocultures in
2011, 2012, and 2013 for each species, respectively in each year. The “high density”
indicates the number of high-density monocultures and polycultures in each year. For
example, we had two low density plots of Liriodendron tulipifera in 2011, but none in
2012 and 2013. For high density plots, exposed plots (“deer”) are listed first, followed by
caged plots (“no deer”). Diversity benefit refers to the percent change in 2013 biomass
between exposed monocultures and mixtures. Biomass / individual refers to the average
biomass of an individual growing in a caged plot, and species are ordered from largest to
smallest mean biomass. Rank order of deer preference is shown in the last column (1 =
most preferred, 12 = least preferred and ‘np’ indicates non-preferred species that did not
receive damage. Ranks are based on mean proportional damage across 2012 and 2013 for
uncaged monocultures. We never observed browsing on Liriodendron tulipifera due to
mortality, thus we could not assess browsing preference.
scientific name
Fraxinus pennsylvanica
Quercus alba
Fagus grandifolia
Cornus florida
Carpinus caroliniana
Quercus rubra
Platanus occidentalis
Liquidamber styraciflua
Quercus falcata
Nyssa sylvatica
Lindera benzoin
Carya alba
Acer rubrum
Carya glabra
Liriodendron tulipifera
15-spp polycultures
low
density
2, 1, 1
2, 2, 2
2, 2, 2
2, 2, 2
1, 1, 1
2, 2, 2
2, 2, 1
1, 0, 0
2, 2, 2
2, 2, 1
2, 2, 2
0, 0, 0
2, 2, 0
1, 1, 0
2, 0, 0
n/a
replication
high density
(deer / no deer)
3, 3, 3 / 3, 2, 2
3, 3, 3 / 3, 3, 3
3, 3, 3 / 3, 3, 3
3, 3, 3 / 3, 3, 3
3, 3, 3 / 3, 3, 3
3, 3, 3 / 3, 3, 3
3, 3, 3 / 3, 1, 2
3, 3, 3 / 3, 2, 2
3, 3, 3 / 3, 3, 3
3, 3, 3 / 3, 3, 3
3, 3, 3 / 3, 3, 3
3, 3, 3 / 3, 3, 3
3, 3, 3 / 3, 3, 3
3, 3, 3 / 3, 3, 3
2, 1, 1 / 3, 0, 0
25, 24, 24 / 25, 25, 25
diversity
benefit (%)
0
135
109
1
25
118
80
-12
-14
72
45
131
245
0
n/a
biomass /
individual (g)
16.1
9.1
6.9
5.1
5.1
4.6
4.6
4.5
3.8
3.1
2.0
1.9
1.4
0.9
n/a
deer
preference
1
5
6
3
8
4
9
np
7
11
np
12
2
10
n/a
Appendix 2
We used the harvested seedlings (N ~ 100 / species, ranging from 61 to 129) to
construct allometric relationships between height and the natural log of biomass (g) (Fig.
A2). We used these formulae (see Table A3) to estimate biomass in 2011 and 2012. In
addition, we lost biomass samples for 23 individuals harvested at the end of the
experiment, so we estimated their 2013 biomass from these allometric formulae as well.
After we converted height to biomass, we back-transformed the estimates to remove them
from the ln-scale. Note that we did not determine an allometric equation for Liriodendron
tulipifera because only one individual in the entire experiment lived and thus its biomass
in each plot was effectively zero.
Table A2: Allometric equations by species
scientific name
Acer rubrum
Carpinus caroliniana
Carya alba
Carya glabra
Cornus florida
Fagus grandifolia
Fraxinus pennsylvanica
Lindera benzoin
Liquidambar styraciflua
Liriodendron tulipifera
Nyssa sylvatica
Platanus occidentalis
Quercus alba
Quercus falcata
Quercus rubra
allometric equation
0.049x – 1.878
0.036x – 0.634
0.104x – 1.455
0.103x – 2.583
0.040x – 0.732
0.040x – 0.549
0.028x – 0.512
0.049x – 1.468
0.031x – 0.465
n/a
0.034x – 0.517
0.023x – 0.375
0.044x – 0.239
0.045x – 0.038
0.034x – 0.258
R2
0.69
0.75
0.56
0.74
0.67
0.76
0.66
0.78
0.78
n/a
0.68
0.83
0.71
0.62
0.82
Figure A2: Relationship between height (cm) and biomass (g) for each species
Appendix 3
The raw data for this experiment is included as a text file (Appendix 3.txt). Please contact
Dr. John Parker (parkerj@si.edu) for permission to use this data in a publication.
Table A3: Metadata for the raw data
column header
plot
tag
spp
dens
diversity
cage
liveF11
liveF12
liveS13
lf12
lf13
insect11
deer11
deer12
insect12
deer13
insect13
ht11
ht12
ht13
BM13
description
unique plot identifier
unique identifier for seedling
species designation using United States Department of Agriculture codes
(plants.gov)
intial planting density
monoculture = single species, mixture = 15 species
cage = protected from deer, no cage = exposed to deer
number of individuals alive in Fall 2011
number of individuals alive in Fall 2012
number of individuals alive in Summer 2013
number of leaves present in 2012
number of leaves present in 2013
number of leaves damaged by insects in 2011
number of leaves damaged by deer in 2011
number of leaves damaged by deer in 2012
number of leaves damaged by insects in 2012
number of leaves damaged by deer in 2013
number of leaves damaged by insects in 2013
height in 2011
height in 2012
height in 2013
biomass in 2013