Carbon Cycling in Teak Plantations in Comparison with Seasonally Dry Tropical Forests in Thailand

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Forest Dynamics and Tree Distribution Patterns in Dry Evergreen Forest, Northeastern, Thailand

Deforestation based on anthropogenic activities is the main cause of biological diversity loss. This study clarified forest dynamics after intermediate disturbances and detected the tree distribution pattern in a dry evergreen forest (DEF). A 1 hectare (ha) permanent plot was set up in a lowland DEF in 2002 and all trees with a diameter at breast height (DBH) larger than 4.5 cm were tagged, measured and identified. Tree monitoring was done in 2009 and 2016. In addition, the permanent plot was expanded to 3 ha, for studying the tree distribution pattern and all trees with DBH greater than 2 cm were included and their coordinates also recorded during 2016. The forest dynamics during 2002 to 2016 showed the net recruitment rate was higher than the mortality rate (2.58 and 2.35 %/year, respectively); however, it varied among periods. The mortality rate in the second period (2009-2016) was greater than in the first period (2002-2009), with rates of 4.71 and 2.64 %/year, respectively, due to disastrous flooding in 2003. A clumped distribution pattern based on the Morisita index was detected for all selected species, indicating habitat heterogeneity in which the physical environments were patched and induced the clumped distribution

Species Composition and Spatial Distribution of Dominant Trees in the Forest Ecotone of a Mountain Ecosystem, Northern Thailand

Plants’ ecological niches are important to study, particularly for applying the knowledge to restoration programs. This study clarified the relationships of tree species composition and spatial distribution to environmental factors in a mountain ecosystem. A 3 ha permanent plot was established across the forest ecotone at Doi Suthep-Pui National Park, Chiang Mai Province, Thailand. The spatial distributions of the 20 dominant tree species were analyzed using a generalized linear model (GLM) combined with geographic information system (GIS) techniques. High species diversity was found, including 165 species representing 118 genera and 59 families. Elevation strongly influenced tree distribution, which could be divided into three groups: low-altitude species in deciduous dipterocarp forest (DDF), high-altitude species in lower montane forest (LMF) and coexisting DDF and LMF species. The GLM analysis revealed that soil texture, which ranged from sandy to clayey, influenced tree distribution. The results suggest that restoration programs should select suitable species based on their niches

Termitaria enhance soil and forest diversity in Deciduous Dipterocarp Forest, Northern Thailand

We characterised the soils and vegetation in 15 sets of four quadrats on and around mounds of Macrotermes annandalei (Isoptera, Macrotermitinae) on a plain of deep dystric clay over limestone in Deciduous Dipterocarp Forest in Northern Thailand. Termites have excavated the mounds from the deep calcareous substrate. The mound soils have darker subsoils, larger contents of clays and exchangeable cations, and higher pH values than the surrounding dystric clay loams. The thickets on the mounds are visually different from the surrounding Deciduous Dipterocarp Forest. They have few dipterocarps and are floristically similar to the regionally important Mixed Deciduous Forest. The clear visual differences are confirmed by floristic similarity, cluster, and canonical correspondence analyses for each of the tree, sapling and seedling size classes. The differences between the mound clays and surrounding red clay loams and the associations between soil and forest types are confirmed by ‘t tests’ and the significant correlations of the soil base status with the main floristic axis of the canonical correspondence analyses. Soil variability due to termites and other agents of pedoturbation can significantly contribute to short-range floristic and structural diversity in some dry tropical forests

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京都大学0048新制・課程博士博士(理学)甲第8776号理博第2348号新制||理||1224(附属図書館)UT51-2001-F106京都大学大学院理学研究科生物科学専攻(主査)教授 浅野 透, 助教授 湯本 貴和, 教授 戸部 博学位規則第4条第1項該当Doctor of ScienceKyoto UniversityDA

Maximum entropy modeling for the conservation of Hopea odorata in riparian forests, central Thailand

Abstract. Asanok L, Kamyo T, Marod D. 2020. Maximum entropy modeling for the conservation of Hopea odorata in riparian forests, central Thailand. Biodiversitas 21: 4663-4670. Hopea odorata plays a dominant role in both ecologically and economically in Thailand. We analyzed potentially suitable areas for H. odorata in the riparian zone of the Chao Phraya River using the software MaxEnt. Modeling included 164 occurrence records along with 19 climate-related variables, slope, aspect, and elevation. Precipitation was the key climatic variable influencing the distribution of H. odorata. Riparian areas along the Chao Phraya that were predicted to be highly suitable for this species were located in the provinces of Nakhon Sawan, Ang Thong, Phra Nakhon Si Ayutthaya, Pathum Thani, Nonthaburi, and Bangkok. The ROC AUC score was 0.891, indicating that MaxEnt is an excellent tool for predicting suitable regions for the restoration or cultivation of commercially and ecologically valuable species such as H. odorata. Models such as what we have presented here can facilitate habitat conservation and sustainable resource use for rare and important plants.</jats:p