Growth and anatomical traits of indigenous pinus species in the mountain ranges of south central vietnam

Ho, Le Tuan Vom Fachbereich VI (Raum- und Umweltwissenschaften) der Universität Trier zur Erlangung des akademischen Grades Doktor der Naturwissenschaften (Dr rer nat.) angenommene Dissertation Growth and anatomical traits of indigenous Pinus species in the mountain ranges of South-Central Vietnam Betreuer: Prof Dr Frank Thomas Berichterstattende: Prof Dr Gebhard Schüler, Prof Dr Sören Thiele-Bruhn Tag der mündlichen Prüfung: 27 August 2021 Trier, September 2021 ABSTRACT Pines are known for their adaptability and fast-growing nature, thriving in the most temperate regions However, they are mostly absent from native forests in the tropics, and for some that manage to populate in tropical mountain ranges, they are often discussed as ill-equipped to compete with highly productive tropical angiosperms This research aims at investigating the reasons behind this phenomenon Tree ring samples were taken from Pinus kesiya across elevational gradients and P dalatensis and Pinus krempfii at intermediate elevations in the mountain ranges of South-Central Vietnam We analysed the stem diameter increment, the isotope discrimination against 13C (13C), anatomical traits, and Blue Intensity (BI) P kesiya, a widely distributed pine species of southern and south-eastern Asia, is found to significantly decrease in height and basal area increment (BAI) along an elevational gradient of ~900 to ~2000 m a.s.l Lower temperature at higher elevations curbs the process of nitrogen and phosphorus mineralisation, which in turn, has an indirect negative effect on tree development This may be further hampered by lower concentrations of "base" cations (upon enhanced leaching by precipitation) and negative feedback from the low availability of mineralised N and P at higher elevations Using a dendrochronological approach, we examined the resistance, recovery, and resilience of radial stem increment towards episodes of growth deterioration, as well as the accompanying variation of 13 C discrimination against atmospheric CO2 (13C) in tree rings of two palaeotropical pine species P dalatensis and P kesiya We found that P kesiya undergoes growth at a similar rate as P dalatensis, even at the margin of its distribution area and under below-optimum edaphic conditions This result suggests that between the two species, P kesiya is more resistant to environmental stress, whereas P dalatensis can be heavily influenced by external elements, even at the "core" region of its occurrence We compared the recently developed blue intensity (BI) method for determining wood density with anatomical analyses in studying three rarely investigated palaeotropical Pinus species with greatly differing distribution areas Results of the BI and the anatomical method were closely correlated, especially for the sapwood P kesiya exhibited strong drought response strategies and hydraulic traits e.g.: higher wood density and cell wall: lumen ratios of its smaller xylem conduits; lower calculated hydraulic conductance, and more negative 50 values; allowing it to respond well to a low-water stressful environment As an effective and cost-efficient method for wood density examination, BI may also be a suitable preliminary screening approach to assess water transport capacity and drought resistance for other species  ... phenomenon Tree ring samples were taken from Pinus kesiya across elevational gradients and P dalatensis and Pinus krempfii at intermediate elevations in the mountain ranges of South-Central Vietnam We... analysed the stem diameter increment, the isotope discrimination against 13C (13C), anatomical traits, and Blue Intensity (BI) P kesiya, a widely distributed pine species of southern and south-eastern... episodes of growth deterioration, as well as the accompanying variation of 13 C discrimination against atmospheric CO2 (13C) in tree rings of two palaeotropical pine species P dalatensis and P