Light responses of shade-tolerant tropical tree species in north-east Queensland: a comparison of forest- and shadehouse-grown seedlings

Shadehouse design may have a significant influence on the results of shadehouse studies investigating the light responses of tropical seedlings. Shadehouse effects were investigated by examining the seedling growth and morphological properties of four shade-tolerant tree species from north-east Queensland in the forest and in neutral-density shadehouses for up to 1 y. Understorey plots were compared with 0.8% shadehouses, and single-treefall gaps were compared with 10% shadehouses. Seedlings of all species showed higher growth rates in the shadehouses compared with the equivalent forest treatments. Nonetheless, trends found between high- and low-light growth rates in the shadehouse seedlings were mirrored in forest-grown seedlings. Specific leaf area (SLA) values in the shadehouses provided a good approximation of SLA in the forest for species in both light treatments. In contrast, biomass allocation and leaf area ratios were only comparable for forest and shadehouse seedlings grown in the high-light treatment. Furthermore, seedlings grown in shadehouses differed significantly from forest-grown seedlings in terms of their root morphology. Despite the differences in absolute values of plant characters in the shadehouse and forest seedlings, 65% of significant differences detected between high- and low-light plant characters in shadehouse-grown seedlings were also found in the forest-grown plants.

[1]  K. Kitajima.  Relative importance of photosynthetic traits and allocation patterns as correlates of seedling shade tolerance of 13 tropical trees , 1994, Oecologia.

[2]  M. Turnbull.  The effect of light quantity and quality during development on the photosynthetic characteristics of six Australian rainforest tree species , 1991, Oecologia.

[3]  D. Metcalfe,et al.  Soil dilution as a surrogate for root competition: effects on growth of seedlings of Australian tropical rainforest trees , 2002 .

[4]  In situ field measurements of photosynthetic rates of tropical tree species: a test of the functional group hypothesis , 2000 .

[5]  S. Lewis,et al.  Effects of above- and belowground competition on growth and survival of rain forest tree seedlings. , 2000 .

[6]  S. Hubbell,et al.  Growth responses of seedlings of two neotropical pioneer species to simulated forest gap environments , 1999, Journal of Tropical Ecology.

[7]  Yanhong Tang,et al.  Heterogeneity of Light Availability and its Effects on Simulated Carbon Gain of Tree Leaves in a Small Gap and the Understory in a Tropical Rain Forest 1 , 1999 .

[8]  Stephen J. Wright,et al.  Light-Gap disturbances, recruitment limitation, and tree diversity in a neotropical forest , 1999, Science.

[9]  R. Kobe.  LIGHT GRADIENT PARTITIONING AMONG TROPICAL TREE SPECIES THROUGH DIFFERENTIAL SEEDLING MORTALITY AND GROWTH , 1999 .

[10]  E. Rincón,et al.  Responses to light changes in tropical deciduous woody seedlings with contrasting growth rates , 1997, Oecologia.

[11]  Robert W. Pearcy,et al.  Photosynthetic responses to dynamic light under field conditions in six tropical rainforest shrubs occuring along a light gradient , 1997, Oecologia.

[12]  Adaptation and inertia in the Australian tropical lowland rain-forest flora: Contradictory trends in intergeneric and intrageneric comparisons of seed size in relation to light demand , 1996 .

[13]  Swaine.  Ecology of forest trees in Ghana , 1996 .

[14]  A. Stokes,et al.  Responses of young trees to wind and shading: effects on root architecture , 1995 .

[15]  David W. Lee,et al.  Irradiance and Spectral Quality Affect Asian Tropical Rain Forest Tree Seedling Development , 1995 .

[16]  O. O. Osunkoya,et al.  Influence of seed size and seedling ecological attributes on shade-tolerance of rain-forest tree species in northern Queensland , 1994 .

[17]  Queensland Herbarium.  Queensland vascular plants : names and distribution , 1994 .

[18]  D. Sims,et al.  Sunfleck frequency and duration affects growth rate of the understorey plant, Alocasia macrorrhiza , 1993 .

[19]  F. Bongers,et al.  Gaps and forest zones in tropical moist forest in Ivory Coast. , 1993 .

[20]  A. Ellison,et al.  SEED AND SEEDLING ECOLOGY OF NEOTROPICAL MELASTOMATACEAE , 1993 .

[21]  F. Bazzaz,et al.  BIRCH SEEDLING RESPONSES TO DAILY TIME COURSES OF LIGHT IN EXPERIMENTAL FOREST GAPS AND SHADEHOUSES , 1993 .

[22]  J. Molofsky,et al.  Habitat and Predation Effects on Seedling Survival and Growth in Shade‐Tolerant Tropical Trees , 1993 .

[23]  R. Latham.  Co‐Occurring Tree Species Change Rank in Seedling Performance with Resources Varied Experimentally , 1992 .

[24]  P. Reich,et al.  Leaf mass per area, nitrogen content and photosynthetic carbon gain in Acer saccharum seedlings in contrasting forest light environments , 1992 .

[25]  M. Ducrey.  Variation in leaf morphology and branching pattern of some tropical rain forest species from Guadeloupe (French West Indies) under semi-controlled light conditions , 1992 .

[26]  F. Bazzaz,et al.  IS PHYSICAL SPACE A SOIL RESOURCE , 1991 .

[27]  I. Turner.  The seedling survivorship and growth of three Shorea species in a Malaysian tropical rain forest , 1990, Journal of Tropical Ecology.

[28]  The size and composition of soil seed-banks in remnant patches of three structural rainforest types in North Queensland , 1990 .

[29]  Robin L. Chazdon,et al.  Sunflecks and Their Importance to Forest Understorey Plants , 1988 .

[30]  J. Piper.  GERMINATION AND GROWTH OF BIRD‐DISPERSED PLANTS: EFFECTS OF SEED SIZE AND LIGHT ON SEEDLING VIGOR AND BIOMASS ALLOCATION , 1986 .

[31]  J. Grace,et al.  The Role of the Red/Far-Red Ratio in the Response of Tropical Tree Seedlings to Shade , 1986 .

[32]  J. Tracey.  The Vegetation of the Humid Tropical Region of North Queensland. , 1983 .

[33]  R. Hunt.  Plant Growth Curves: The Functional Approach to Plant Growth Analysis , 1983 .

[34]  T. Ingestad.  Relative addition rate and external concentration; Driving variables used in plant nutrition research , 1982 .

[35]  F. James Rohlf,et al.  Biometry: The Principles and Practice of Statistics in Biological Research , 1969 .