Response of water-bound fluxes of potassium, calcium, magnesium and sodium to nutrient additions in an Ecuadorian tropical montane forest

Abstract:Not much is known about the nitrogen (N) uptake capacity and N-form preference of tropical trees. In a replicated labelling experiment with15N-ammonium,15N-nitrate and dual-labelled glycine applied to saplings of six tree species from southern Ecuadorian montane forests, we tested the hypotheses that (1) the saplings of tropical trees are capable of using organic N even though they are forming arbuscular mycorrhizas, and (2) with increasing altitude, tree saplings increasingly prefer ammonium and glycine over nitrate due to reduced nitrification and growing humus accumulation. Three- to 5-y-old saplings of two species each from 1000, 2000 and 3000 m asl were grown in pots inside the forest at their origin and labelled with non-fertilizing amounts of the three N forms;15N enrichment was detected 5 days after labelling in fine roots, coarse roots, shoots and leaves. The six species differed with respect to their N-form preference, but neither the abundance of ammonium and nitrate in the soil nor altitude (1000–3000 m asl) seemed to influence the preference. Two species (those with highest growth rate) preferred NH4+over NO3−, while the other four species took up NO3−and NH4+at similar rates when both N forms were equally available. After13C-glycine addition,13C was significantly accumulated in the biomass of three species (all species with exclusively AM symbionts) but a convincing proof of the uptake of intact glycine molecules by these tropical montane forest trees was not obtained.

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Vertical patterns and duration of surface wetness in an old-growth tropical montane forest, Indonesia

Flora ◽

10.1016/j.flora.2006.03.004 ◽

2007 ◽

Vol 202 (2) ◽

pp. 111-117 ◽

Cited By ~ 28

Author(s):

Johannes Dietz ◽

Christoph Leuschner ◽

Dirk Hölscher ◽

Heinrich Kreilein

Keyword(s):

Montane Forest ◽

Tropical Montane Forest ◽

Old Growth ◽

Surface Wetness

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Variation in longevity and traits of leaves among co-occurring understorey plants in a tropical montane forest

Journal of Tropical Ecology ◽

10.1017/s0266467407004725 ◽

2008 ◽

Vol 24 (2) ◽

pp. 121-133 ◽

Cited By ~ 14

Author(s):

Satomi Shiodera ◽

Joeni S. Rahajoe ◽

Takashi Kohyama

Keyword(s):

Life Form ◽

Census Data ◽

Condensed Tannin ◽

Leaf Traits ◽

Life Forms ◽

Montane Forest ◽

Cox Proportional Hazards ◽

Leaf Longevity ◽

Tropical Montane Forest ◽

Leaf Mass Per Area

Abstract:The relationship between leaf longevity and other leaf traits was compared among different life-form categories (trees, herbs, climbers and epiphytes) of 101 plant species in a tropical montane forest on Mt. Halimun, West Java, Indonesia. We applied the Cox proportional hazards regression to estimate the leaf longevity of each species from 30 mo of census data. We examined whether estimated longevity was explained by either species life-form categories, taxonomic groupings (eudicots, monocots, magnoliids and chloranthales, and ferns) or such leaf traits as leaf area, leaf mass per area (LMA), mass-based leaf nitrogen, penetrometer reading, condensed-tannin-free total phenolics and condensed tannin. There was a wide-ranged interspecific variation in leaf longevity, mostly 10–50 mo, similarly across life-form categories. LMA showed a strong positive influence on leaf longevity. We found that relationships between leaf longevity and some leaf traits were different among various life forms. Trees tended to have high LMA, while climbers tended to have low LMA at the same leaf longevity. We hypothesize that such difference among life forms reflects shoot architecture characteristics. Multi-shoot trees with branching architecture need to have self-supporting leaves, whereas semi-epiphytic climbers can maintain relatively low biomass investment to leaves hanging or relying upon the mechanical support from host plants.

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