Effects of Tree Height and Light Availability on Plant Traits at Different Organisation Levels

Pinus radiata D. Don was grown on its own and with a range of densities of either buddleia (Buddleja davidii Franchet) or broom (Cytisus scoparius L.), two important forest weed species, in a field trial at Rotorua, New Zealand. Tree growth from the time of planting to age 3 was modelled as a function of tree size and a competition modifier. The competition modifier is, in effect, a multiplier that reduces tree growth according to the degree of competition defined by a competition index (CI). A range of CIs, with some sensitivity to both weed and tree growth and development over time, were individually incorporated into the modifier and evaluated. The "best" CI combined measures of weed height relative to tree height, proximity of the weed to the tree, and weed abundance, and was negatively correlated with an index of light availability. For a given value of CI, the effect on tree growth was independent of weed species. For diameter growth, the effect of CI was independent of tree age. However, for height growth the negative effect of a given CI value was much higher in year 3 than in years 1 and 2. This suggest that competition has an immediate effect on diameter but a delayed effect on height growth.

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Relationship between seed size and litter effects on early seedling establishment of 15 tropical tree species

Journal of Tropical Ecology ◽

10.1017/s0266467408005300 ◽

2008 ◽

Vol 24 (05) ◽

pp. 569-573 ◽

Cited By ~ 9

Author(s):

Fabiano Micheletto Scarpa ◽

I. F. M. Valio

Keyword(s):

Seed Size ◽

Shade Tolerance ◽

Carbon Fixation ◽

Plant Traits ◽

Seedling Survival ◽

Light Availability ◽

Low Light ◽

Relative Growth ◽

Close Relationship ◽

Early Seedling

A close relationship has been reported between seed size and many different plant traits such as seedling size, relative growth rate, seedling survival, distance of dispersion, colonization and density of seeds in the soil (Coomes & Grubb 2003, Jurado & Westoby 1992, Lahoreauet al. 2006, Saverimuttu & Westoby 1996, Souza & Valio 2001). Although the association of seed size and shade tolerance is unclear (Westobyet al. 1996) some authors have suggested that a larger-seeded species is better able to tolerate low light availability (Foster 1986, Foster & Janson 1985, Leishman & Westoby 1994) by producing a vigorous seedling with a higher ability to withstand predation (Armstrong & Westoby 1993, Foster 1986) and delaying the beginning of carbon fixation so as to increase survival under a canopy and under leaf litter.

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Reaktion von Weisstannen auf ein- bis mehrmaligen Verbiss entlang von Lichtgradienten

Schweizerische Zeitschrift fur Forstwesen ◽

10.3188/szf.2014.0198 ◽

2014 ◽

Vol 165 (7) ◽

pp. 198-207 ◽

Cited By ~ 2

Author(s):

Anna Camille Kolly ◽

Andrea Doris Kupferschmid

Keyword(s):

Light Availability ◽

Total Mortality ◽

Abies Alba ◽

Tree Height ◽

Canopy Openness ◽

Silver Fir ◽

Low Light ◽

Lateral Shoot ◽

Light Gradient ◽

Terminal Shoot

Response of Abies alba saplings to single and repeated browsing along light gradients Browsing of silver fir (Abies alba) saplings by ungulates is one of the most important issues concerning decreasing regeneration of this tree species. In addition to genetic drivers, environmental factors such as light availability play an important role for the response of a browsed tree. Using an experimental design with fences, we investigated the influence of natural browsing on tree growth along a light gradient. The few fir saplings that responded by flagging up a lateral shoot compensated the browsing induced height difference compared to unbrowsed trees within four vegetation periods. Most firs however reacted with new shoots and remained smaller than unbrowsed ones. The more often a fir sapling was damaged on its terminal shoot, the smaller the tree remained. A positive relation between tree height and light was found only up to a canopy openness of 11%. Mortality over the whole five years was high in low light (<10%) and in forest gaps (>15%), due to desiccation, competition with other plants or browsing (50% of total mortality). We recommend regenerating firs under moderately shaded conditions.

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The effect of tree height and light availability on photosynthetic leaf traits of four neotropical species differing in shade tolerance

Functional Ecology ◽

10.1046/j.1365-2435.2000.00395.x ◽

2000 ◽

Vol 14 (1) ◽

pp. 77-86 ◽

Cited By ~ 129

Author(s):

T. Rijkers ◽

T. L. Pons ◽

F. Bongers

Keyword(s):

Shade Tolerance ◽

Light Availability ◽

Tree Height ◽

Leaf Traits ◽

Neotropical Species

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Fast determination of light availability and leaf area index in tropical forests

Journal of Tropical Ecology ◽

10.1017/s0266467402002201 ◽

2002 ◽

Vol 18 (2) ◽

pp. 295-302 ◽

Cited By ~ 32

Author(s):

Laurent Cournac ◽

Marc-Antoine Dubois ◽

Jérôme Chave ◽

Bernard Riéra

Keyword(s):

Leaf Area Index ◽

Leaf Area ◽

Optical Sensors ◽

Light Availability ◽

Tree Height ◽

Light Transmittance ◽

Limiting Factor ◽

Area Index ◽

Gap Fraction ◽

Direct Measurements

An important property of plant communities is the Leaf Area Index (LAI), which is the vertically integrated surface of leaves per unit of ground area. Leaves are the primary sites of photosynthesis and transpiration, thus the LAI, which conditions the light interception by the canopy, is directly related to carbon and water exchange with the atmosphere at the stand scale (McNaughton & Jarvis 1983). LAI also has an impact on tree growth through the interception of light. Light availability below canopies is the principal limiting factor of tree recruitment and growth in forests (Denslow et al. 1990). Several methodologies have been used for measuring LAI in the field. These can be classiffed in four categories (Marshall & Waring 1986): (1) direct measurements by litterfall collection or destructive sampling, (2) allometric correlations with variables such as tree height or tree diameter, (3) gap-fraction assessment (e.g. with hemispherical photographs), (4) measurement of light transmittance with optical sensors.

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