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Hernandez, Jonathan Ogayon
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Agriculture, Biological Sciences & Forestry Earth & Planetary Sciences Energy Environmental Science Materials Science & Nanotechnology

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Aboveground Phenology of Tectona philippinensis Benth. & Hook.f.: Insights into Its Adaptive Mechanisms Hernandez, Jonathan Ogayon
Jurnal Sylva Lestari Vol. 12 No. 1 (2024): January
Publisher : Department of Forestry, Faculty of Agriculture, University of Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/jsl.v12i1.797

Abstract

The present study investigated the leaf flushing, leaf shedding, flowering, and fruiting cycles in Tectona philippinensis Benth. & Hook.f., shedding light on its adaptation mechanisms for reproductive success and survival. A plotless inventory of tree individuals was undertaken from pre-determined observation points from January 2022 to February 2023 in Lobo, Batangas. All 430 sampled trees exhibited leaf shedding and leaf flushing, while flowering and fruiting events were observed in only 201 and 133 trees, respectively. Major leaf flushing of trees was observed in mid-October, and they generally shed in summer (peak: March). Trees bloomed in early May and reached its peak in June. Fruiting occurred in the wet season (early July to September). There was a general pattern of leaf shedding, flushing, and varying flowering and fruiting cycles, indicating adaptability to environmental changes. The species also exhibited a significant time lag (7–8 months) between leaf flushing and shedding, potentially serving as adaptive features to promote reproductive success and survival in response to changing environmental conditions. Thus, the aboveground phenology of T. philippinensis may vary depending on environmental conditions. The findings are relevant for developing in-situ conservation strategies for the species. Keywords: flowering, flushing, Lamiaceae, phenological inventory, Shedding
Leaf Traits of Parashorea malaanonan Along Elevational Gradient in Mount Makiling Forest Reserve, Philippines Ebale, Marsh Reginald Bico; Hernandez, Jonathan Ogayon; Tinio, Crusty Estoque
Jurnal Sylva Lestari Vol. 12 No. 1 (2024): January
Publisher : Department of Forestry, Faculty of Agriculture, University of Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/jsl.v12i1.798

Abstract

Studying leaf trait variation and relationships along elevational gradients will enhance our understanding of how plants respond to changing environmental conditions. Thus, we analyzed the leaf traits variation in ecologically and economically important Parashorea malaanonan and the potential influence of environmental covariables (rainfall, relative humidity, and air temperature) on leaf traits along an elevational gradient in Mount Makiling Forest Reserve (MMFR). Three sampling sites were selected based on elevation, i.e., low (400–500 masl), mid (500–600 masl), and high (> 600 masl). The leaf samples were collected from seedlings, saplings, and adult trees of P. malaanonan. There was no significant variation in most of the measured leaf traits, leaf area (LA), specific leaf area (SLA), leaf thickness (LT), leaf length-to-width ratio (L:W) across sampling sites, except vein density (VD). The SLA and LT at high elevations are significantly and negatively correlated (r2 = 0.7396). The environmental covariables had a significant (p < 0.05) impact on the leaf traits of P. malaanonan. The observed variation in some leaf traits may have been influenced by the elevation gradient and its associated environmental conditions. Thus, P. malaanonan may have developed adaptive mechanisms to cope with the changing environment. Keywords: conservation, elevational gradients, environmental variables, leaf traits, Parashorea malaanonan
Effects of Decapitation, Water-Deficit Stress, and Pot Size on Morpho-Anatomy and Physiology of Pterocarpus indicus Hernandez, Jonathan Ogayon; Combalicer, Marilyn Sabalvaro; Umali, Arthur Glenn Agojo; Maldia, Lerma San Jose
Jurnal Sylva Lestari Vol. 12 No. 1 (2024): January
Publisher : Department of Forestry, Faculty of Agriculture, University of Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/jsl.v12i1.821

Abstract

The interacting effects of stem decapitation, water-deficit stress, and pot size on the growth, morpho-anatomical, and physiological traits of Pterocarpus indicus seedlings were analyzed in this study. Changes in root collar diameter (RCD), biomass allocation, number of leaflets (NL), mean leaf area, guard cell size, stomatal aperture size, phloem cap fiber (PCF) thickness, xylem vessel density (XVD), relative leaf water content (RWC), stomatal conductance (gsw), transpiration rate (E), fluorescence quantum yield, transpiration (E), photosynthesis (PN), and electron transport rate (ETR) of decapitated and undecapitated P. indicus seedlings in different pot sizes (small, medium, large) and watering regimes (every 2, 7, and 14 days) were analyzed. The decapitation × water-deficit stress × and pot size interaction did not affect growth and morpho-anatomical variables, but they did on most of the physiological traits. Decapitated seedlings watered every 14 days and planted in medium or large pots have lower gsw, PN, E, and RWC. While the RCD of large-potted and water-stressed (every 14 days) seedlings decreased, allocations to stem and fine roots increased. Moreover, the NL and PCF significantly decreased, while the ETR and XVD significantly increased in decapitated and water-stressed seedlings. Overall, the decapitation-watering interaction caused significant stress to P. indicus seedlings. Keywords: biomass allocations, decapitation, drought stress, multiple stress, xylem vessel density
Litter Decomposition of a Deciduous Tectona philippinensis and an Evergreen Parashorea malaanonan Across Contrasting Sites Hernandez, Jonathan Ogayon; Maldia, Lerma San Jose; Tinio, Crusty Estoque; Combalicer, Marilyn Sabalvaro
Jurnal Sylva Lestari Vol. 12 No. 2 (2024): May
Publisher : Department of Forestry, Faculty of Agriculture, University of Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/jsl.v12i2.909

Abstract

Litter traits and site conditions alter nutrient inputs from deciduous and evergreen forests by influencing litter decomposition processes. Here, we investigated the leaf and stem mass loss rate (MLR) of a deciduous (Tectona philippinensis) and an evergreen (Parashorea malaanonan) tree species and the factors influencing it through an intersite experiment and litterbag method in secondary forests in Lobo, Batangas and Mount Makiling Forest Reserve (MMFR). Variations in initial litter quality (leaf area, specific leaf area (SLA), leaf thickness, vein density), and site factors (light intensity and temperature) were assessed. P. malaanonan has a lower SLA and vein density than T. philippinensis. The leaf and stem MLR were significantly higher in the mixed litter (44.09–57.83%) than that of a single-species litter of either T. philippinensis (28.16–41.83%) or P. malaanonan (33.60–47.66%). The leaf MLR of T. philippinensis was greater when placed in Lobo (where the litter originated) than at a different site (i.e., MMFR). Moreover, leaf litter decomposition was faster in T. philippinensis than in P. malaanonan, particularly during the rainy season. Overall, the study showed that litter decomposition in deciduous and evergreen differed across sites due to variations in litter quality and environmental variables. Keywords: decomposability traits, home-field advantage (HFA), intersite experiment, litter quality, mass loss rate
Co-Authors Combalicer, Marilyn Sabalvaro Ebale, Marsh Reginald Bico Maldia, Lerma San Jose Tinio, Crusty Estoque Umali, Arthur Glenn Agojo