Sterck2001

Report for study: Sterck2001

Contact Information

Data contributor: Frank Sterck

Email: Frank.Sterck@wur.nl

Address:

• Centre for Ecosystem Studies, Forest Ecology and Forest Management Group, Wageningen University and Research Centre, P.O. Box 47, 6700 AA, Wageningen, The Netherlands

Data source

Citation: Sterck FJ and Bongers F (2001). 'Crown development in tropical rain forest trees: patterns with tree height and light availability.' Journal of Ecology, 89(1), pp. 1-13.

DOI: 10.1046/j.1365-2745.2001.00525.x

Abstract: 1 Monitoring of two canopy species Dicorynia guianensis and Vouacapoua americana (Caesalpiniaceae) in a tropical rain forest in French Guiana was used to investigate vegetative crown development at five organizational levels: leaf, metamer, extension unit, sympodial unit and whole crown. The effects of light availability and tree height on different traits were evaluated in trees < 25 m in height and compared with taller individuals (25-37 m). Path-analysis is used to illustrate the consequences of trait changes at multiple levels of organization for the whole crown level. 2 Tree height and canopy openness influenced crown development at each organizational level. Crowns in higher light levels had lower specific leaf area, greater leaf spacing, greater extension of all branches, and greater extension of the leader shoot. With increasing tree height, crowns had a lower specific leaf area, greater leaf area index and greater relative crown depth. 3 Vouacapoua showed some responses to light not seen in Dicorynia. In particular, Vouacapoua increased meristem activity with light, but the lack of response in Dicorynia may be due to moderate light levels rather than inability to respond. 4 Low leaf-display costs at low light availability may enable trees to survive light suppression. 5 Light availability cannot explain trait changes with tree height. Alternative explanations for trait changes with tree height are discussed. 6 Several of the relationships between plant traits and tree height or canopy openness became non-linear when taller trees (25-37 m) were included. In these taller trees, vegetative growth was reduced at all organizational levels, particularly in Vouacapoua, which does not grow as tall as Dicorynia. 7 Qualitatively, plant responses to light did not differ between trees of different height, and were similar to seedling and sapling data in the literature. Responses were, however, quantitatively different, suggesting that small saplings cannot serve as model organisms for crown development in taller trees.

Overview of data provided

The dataset includes records for 66 individuals from 2 species belonging to 1 family(ies), presenting 1 functional type(s), growing in 1 condition(s) within 1 major type(s) of habitat, with data included for the following variables:

Variable	Label	Units	N	Min	Median	Max
latitude	Latitude	deg	66	4.1	4.1	4.1
longitude	Longitude	deg	66	-53	-53	-53
a.lf	Leaf area	m2	63	0.032	0.83	199
a.stbh	Stem area at breast height	m2	36	0.000064	0.0027	0.71
a.cp	Crown area	m2	63	0.059	1.4	79
h.t	Height	m	65	0.59	4.5	38
h.c	Height to crown base	m	61	0.35	3.3	26
d.bh	Dbh	m	36	0.009	0.058	0.95
h.bh	Height of d.bh measurement	m	66	1.3	1.3	1.3
d.cr	Crown width	m	63	0.27	1.3	10
c.d	Crown depth	m	60	0.03	1.6	14
m.lf	Leaf mass	kg	40	0.0031	0.061	18
a.ilf	Area of individual leaf	m2	65	0.0046	0.04	0.19
ma.ilf	Leaf mass per area	kg m-2	40	0.034	0.055	0.09

And locally within the country:

The sites sampled are:

Location	Longitude	Latitude	Vegetation
les Nouragues Biological Field Station, French Guiana	-52.66	4.08	Tropical rainforest

The growing conditions of sampled plants was:

Location	growingCondition
les Nouragues Biological Field Station, French Guiana	field wild

Species sampled

Species	Family	Pft
Dicorynia guianensis Amshoff.	Caesalpiniaceae	evergreen angiosperm
Vouacapoua americana Aubl.	Caesalpiniaceae	evergreen angiosperm

Methods used

Sampling strategy: In a natural tropical forest site, a 12-ha plot was mapped for trees with a stem diameter 3 10 cm at 1.30 m above ground level (d.b.h.), and a central 1.5-ha plot was mapped for trees with a stem diameter < 10 cm, but with a height greater than 0.50 m. For each species, we selected 20 of the inventoried individuals that were less than 4 m tall, ensuring that the full range of light levels within the site was represented. The crowns of taller individuals could only be studied from neighbouring trees (climbed using spikes or alpinist ropes). Because only a few of the inventoried individuals were accessible in this way, we included a selection of the accessible > 25 m trees (Vouacapoua, 25, 35 and 37 m, and Dicorynia, 26 and 37 m) from the adjacent area outside the plots.

Leaf area: Leaves were counted on all individuals, and for the bigger trees we did this by climbing carefully along the length of these individuals. Leaf area was determined (Delta Image Analysis System, Eijkelkamp 1991) as the mean value for 20 leaves taken from random positions in the crown. Total leaf area per trees was then calculated as the product of the number of leave and the average leaf area.

Stem cross sectional area: The stem diameter at 1.3 was used to calculate the stem cross section area assuming a circular area.

Height: Height was measured by keeping a centimeter from the top of the crown down to the ground, at equal height as the stem base.

Crown area: Crown widths were measured in two perpendicular directions using a centimeter for small plant (up to 4 meters), and a Suunto clinometer for taller trees. Assuming a elliptoid crown surface area, we estimated the crown surface area.

Biomass: Total leaf biomass was measured as the product of the total number of leaves and the average leaf dry weight.

Traits: Leaf traits were sampled for a subsample of 20 leaves per tree.

Other variables: Hemispherical photographs were made to estimate the light condition as the canopy openness percentrage per tree.

Plots of data

This is how the study Sterck2001 fits in the entire dataset (grey). each colour represents a species. A legend of species names with colours is included at the end for reports with 1 < n < 20 species.