Juvenile tree growth in relation to light availability in second-growth tropical rain forests

2006 ◽  
Vol 22 (2) ◽  
pp. 223-226 ◽  
Author(s):  
Mary Beth Palomaki ◽  
Robin L. Chazdon ◽  
J. Pablo Arroyo ◽  
Susan G. Letcher
Keyword(s):  
Tropical Forests ◽  
Light Availability ◽  
Tree Seedlings ◽  
Tropical Rain Forests ◽  
Annual Increment ◽  
Growth And Survival ◽  
Second Growth ◽  
Direct Measurements ◽  
Crown Shape ◽  
Made In

Light is a key environmental factor limiting growth and survival of trees in the subcanopy of wet tropical forests (Davies 2001, Thomas 1996). Light availability varies both vertically and horizontally and affects tree height, crown shape and tree architecture (Bongers & Sterck 1998, Sterck & Bongers 2001, Sterck et al. 1999) in addition to growth and survival (Clark & Clark 1992, 2001). Although many studies of tree seedlings and saplings have shown that growth varies significantly with light availability in tropical wet forests (Clark et al. 1993, Iriarte & Chazdon 2005, King 1991, Kohyama 1991, Montgomery & Chazdon 2002, Oberbauer et al. 1988, 1993; Poorter & Werger 1999, Sterck et al. 1999, Welden et al. 1991), few studies have examined these relationships in size classes above 5 cm dbh (Sterck 1999). King et al. (2005) found that annual increment growth of trees in the 8–20-cm dbh size class in two Asian forests was positively dependent on an index of crown light interception, but no direct measurements of light availability were taken in this study. Due to logistical challenges, few direct measurements of light environments above tree crowns have been made in tropical forests (Sterck & Bongers 2001). To our knowledge, no measurements have been made in second-growth forests.

Functional ecology of advance regeneration in relation to light in boreal forests

1999 ◽  
Vol 29 (6) ◽  
pp. 812-823 ◽  
Author(s):  
Christian Messier ◽  
René Doucet ◽  
Jean-Claude Ruel ◽  
Yves Claveau ◽  
Colin Kelly ◽  
...  
Keyword(s):  
Boreal Forests ◽  
Light Availability ◽  
Growth Patterns ◽  
Functional Ecology ◽  
Tree Seedlings ◽  
Maximum Height ◽  
Surface Area Ratio ◽  
Growth And Survival ◽  
Advance Regeneration ◽  
Leaf Level

This paper reviews aspects of the functional ecology of naturally established tree seedlings in the boreal forests of North America with an emphasis on the relationship between light availability and the growth and survival of shade tolerant conifers up to pole size. Shade tolerant conifer species such as firs and spruces tend to have a lower specific leaf mass, photosynthetic rate at saturation, live crown ratio, STAR (shoot silhouette area to total needle surface area ratio), and root to shoot ratio than the shade intolerant pines. The inability of intolerant species such as the pines and aspen to survive in shade appears to be mainly the result of characteristics at the shoot, crown, and whole-tree levels and not at the leaf level. Although firs and spruces frequently coexist in shaded understories, they do not have identical growth patterns and crown architectures. We propose a simple framework based on the maximum height that different tree species can sustain in shade, which may help managers determine the timing of partial or complete harvests. Consideration of these functional aspects of regeneration is important to the understanding of boreal forest dynamics and can be useful to forest managers seeking to develop or assess novel silvicultural systems.

Trenching increased growth, and irrigation increased survival of tree seedlings in the understorey of a semi-evergreen rain forest in Panama

2007 ◽  
Vol 23 (3) ◽  
pp. 257-268 ◽  
Author(s):  
Edmund V. J. Tanner ◽  
Ignacio M. Barberis
Keyword(s):  
Tropical Forests ◽  
Rain Forest ◽  
Common Species ◽  
Nutrient Supply ◽  
Tree Seedlings ◽  
Tropical Rain Forests ◽  
Seedling Mortality ◽  
Canopy Trees ◽  
Below Ground ◽  
Dry Seasons

Seedlings in tropical forests are ultimately the source of canopy trees, thus factors controlling their composition and growth potentially influence the composition of the forest. Seedlings are primarily limited by above-ground competition with trees, but below-ground competition is potentially also important. Over 4 y we experimentally reduced below-ground competition by trenching to 50 cm and reduced drought stress by irrigating in the dry seasons (6 cm every 2 d) in the understorey of a semi-evergreen rain forest in Panama. There were four irrigated plots and four unirrigated, in each plot there were eight subplots (four trenched, four untrenched); 32 seedlings (two per subplot) of each of four tree species were equally allocated to the four treaments; the four species were: Aspidosperma cruenta; Gustavia superba; Simarouba amara and Tachigali versicolor. Over all species together, trenching increased seedling height by 41% and leaf area by 140% over 4 y. The cause was likely to be increased nutrient supply, because the amounts of N, K and Ca were higher in trenched plants, though concentrations were not higher. Irrigation had no significant effect on growth. Irrigation, but not trenching, reduced seedling mortality. We conclude that below-ground competition was a major limitation for seedling growth for at least some common species (Gustavia and Tachigali in this experiment). More experiments are necessary to determine whether below-ground competition is also important in other tropical rain forests on fairly fertile soils.

Female courtship calls of the litter frog (Rana curtipes) in the tropical forests of Western Ghats, South India

2005 ◽  
Vol 26 (4) ◽  
pp. 431-435 ◽  
Author(s):  
Savitha Krishna ◽  
Sharath Krishna
Keyword(s):  
Tropical Forests ◽  
Western Ghats ◽  
South India ◽  
Forest Litter ◽  
Calling Behavior ◽  
Tropical Rain Forests ◽  
Low Volume ◽  
Gravid Females ◽  
Female Call ◽  
The Western Ghats

AbstractWe noticed an uncommon phenomenon of female vocalization in the forest litter frog, Rana curtipes during the breeding season. We digitally recorded the male and female vocalization of the litter frogs in the tropical rain forests of the Western Ghats of South India and analyzed the call characteristics. The female call varied from the male call by being single note in composition. In contrast, the male calls were composed of seven to eight notes and longer in duration. We observed that gravid females, occupying the same location every day, emitted low volume calls when numerous males were found calling at that time. Some females arrived asynchronously and called even in the absence of males possibly to declare their receptive condition. Calling females responded agonistically to receptive conspecifics of the same sex. In addition to declaring receptivity, this calling behavior may be a response to adjacent competing females when the males are few.

Light-dependent seedling survival and growth of four tree species in Costa Rican second-growth rain forests

2005 ◽  
Vol 21 (4) ◽  
pp. 383-395 ◽  
Author(s):  
Silvia Iriarte Vivar Balderrama ◽  
Robin L. Chazdon
Keyword(s):  
Tree Species ◽  
Seedling Survival ◽  
Light Availability ◽  
Light Transmittance ◽  
Growth Responses ◽  
Low Light ◽  
Growth Increments ◽  
Light Gradient ◽  
Second Growth ◽  
Survival And Growth

The dependence of tree seedling survival and growth on light availability was evaluated over 15 mo in three second-growth, wet forest stands (15–18 y old) in north-eastern Costa Rica. Seedlings of four canopy tree species (Dipteryx panamensis, Hyeronima alchorneoides, Virola koschnyi and Vochysia guatemalensis) were planted into four canopy treatments in three replicated stands and in a pasture site, spanning a nearly complete gradient of light availability. Survival and growth of all species increased in response to increasing light availability, but species differed in survival in shaded microsites (6–20% light transmittance) and in growth increments per light increase. Hyeronima showed the highest mortality at low light levels and the highest relative height growth increase per light increase. In contrast, Virola showed high survival at low and moderate light, but showed the lowest leaf area and above-ground biomass per light increase among all species. Dipteryx and Vochysia maintained relatively high rates of survival and growth across the entire light gradient. Hyeronima and Virola showed trade-offs between growth and survival responses to light, unlike Dipteryx and Vochysia. Differences among species in seedling survival at low light may be determined by a variety of physiological and morphological traits that may or may not be mechanistically linked to growth responses.

Profiles of CO2 concentration and δ13C values in tropical rain forests of the upper Rio Negro Basin, Venezuela

1986 ◽  
Vol 2 (3) ◽  
pp. 207-217 ◽  
Author(s):  
Ernesto Medina ◽  
Gustavo Montes ◽  
Elvira Cuevas ◽  
Zarko Rokzandic
Keyword(s):  
Organic Matter ◽  
Soil Surface ◽  
Co2 Concentration ◽  
Plant Tissues ◽  
Tree Seedlings ◽  
Tropical Rain Forests ◽  
Physiological Factors ◽  
Canopy Trees ◽  
Rio Negro ◽  
Rio Negro Basin

ABSTRACTConcentration of CO2, above and below the soil surface and δ13C values of plant tissues, soil litter and organic matter were measured in a caatinga forest of the upper Rio Negro basin in southern Venezuela. CO2, concentrations near the forest floor were consistently higher than in the atmosphere. CO2, gradient in the soil was very steep probably because of the poor aeration in this flood-prone forest. δ13C values of plant tissues showed a clear pattern with lower values in the ground herbaceous plants and under-canopy trees. Tree seedlings showed δ13C values similar to the upper-canopy trees indicating their dependence on reserves carried in the seed from the mother tree. Decomposing litter and soil organic matter also showed δ13C values similar to the upper-canopy trees. It is suggested that lower δ13C values of the shade flora result primarily from the assimilation of CO2, depleted in δ13C originating from soil respiration. Probable effects of low light intensity and physiological factors are discussed.

EFFECT OF HYPOPHYSECTOMY AND A LOW SODIUM DIET ON THE VOLUMES OF THE GLOMERULAR ZONE, FASCICULAR AND RETICULAR ZONES AND MEDULLA OF RATS

1965 ◽  
Vol 50 (3) ◽  
pp. 486-492 ◽  
Author(s):  
Richard A. Miller
Keyword(s):  
Body Weight ◽  
Pars Distalis ◽  
Deficient Diet ◽  
Sodium Deficiency ◽  
Mean Values ◽  
Low Sodium Diet ◽  
Low Sodium ◽  
Direct Measurements ◽  
Hypophysectomized Rats ◽  
Made In

ABSTRACT Direct measurements of volume of the glomerular zone, fascicular and reticular zones and medulla were made in normal and hypophysectomized rats. All zones of the cortex and the medulla atrophied after hypophysectomy. However, while medullary and glomerular atrophy was proportional to the decrease in body weight, fascicular atrophy exceeded the loss in body weight. Hypertrophy of the glomerular zone occurred in rats fed a sodium deficient diet for 5 to 28 days beginning 14 days after hypophysectomy. Hence the volume of the glomerular zone is probably independent of the pars distalis, since the glomerular zone does not atrophy after hypophysectomy and can be stimulated to hypertrophy after it and the infundibular process are removed. Calculation of mass from areas in a mid-section by the Bahn formula and from direct measurements of volume yielded similar values for the mass of the fascicular zone. However, mean values for glomerular mass and for medullary mass were each significantly different. None the less, there was a high correlation between values, and the percent changes in mass of the glomerular zone resulting from the sodium deficiency were similar. Hence, the Bahn formula seems to be a useful shortcut procedure for detecting changes in the mass of the several regions of the cortex.

Selective feeding of pine voles on roots of tree seedlings

2009 ◽  
Vol 87 (2) ◽  
pp. 183-187 ◽  
Author(s):  
L. A. Schreiber ◽  
R. K. Swihart
Keyword(s):  
Field Studies ◽  
Tree Seedlings ◽  
Quercus Alba ◽  
White Oak ◽  
Yellow Poplar ◽  
Growth And Survival ◽  
Field Evidence ◽  
Microtus Pinetorum ◽  
Belowground Herbivory ◽  
Oak Seedlings

Previous studies have implicated numerous physical and biotic factors as contributing to the failure of oak to regenerate successfully throughout substantial portions of eastern North America. Recent field evidence in southern Indiana implicated belowground herbivory by pine voles ( Microtus pinetorum (LeConte, 1830)) as a potentially important but overlooked mortality agent for oak seedlings. We used cafeteria-style feeding trials to determine whether selection of hardwood seedlings by captive pine voles differed according to species or age. White oak ( Quercus alba L.) was selected more frequently and experienced a greater proportion of root removal by pine voles than same-age seedlings of the other four species tested. Yellow poplar ( Liriodendron tulipifera L.) was never eaten. White oak seedlings 3 and 6 weeks of age suffered proportionately greater root removal than conspecific seedlings 12 and 15 weeks of age; pine voles removed roughly constant levels of root biomass irrespective of seedling age. Our results confirm that pine voles selectively feed on oak seedlings. In areas where pine voles are abundant, belowground herbivory could limit regeneration of oak by reducing seedling growth and survival. The importance of pine voles as factors influencing the success of oak regeneration warrants closer scrutiny in future field studies.

Effects of antitranspirants on seed germination, growth, and survival of tree seedlings

1974 ◽  
Vol 40 (1) ◽  
pp. 225-229
Author(s):  
William R. Chaney ◽  
Theodore T. Kozlowski
Keyword(s):  
Seed Germination ◽  
Tree Seedlings ◽  
Growth And Survival
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