Kenichi Yazaki

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Nitrogen fixation in Alnus species in response to elevated CO 2 may depend on the presence of non-N 2 -fixing tree species in addition to soil conditions. Alnus is a major genus of actinorhizal plants. Symbiosis with Frankia allows the Alnus species to fix nitrogen (N) at the rate of several to 320 kg N ha−1 year−1 with a nodule biomass of 16–480 kg ha−1.(More)
Invasive species are frequently found in recently disturbed sites. To examine how these disturbance-dependent invasive species exploit resource pulses resulting from disturbance, twelve physiological and morphological traits, including age-dependent responsiveness in leaf traits to nitrogen pulse, were compared between Bischofia javanica, an invasive tree(More)
To estimate the N2 fixation ability of the alder (Alnus hirsuta (Turcz.) var. sibirica), we examined the seasonal variation in nitrogenase activity of nodules using the acetylene reduction method in an 18-year-old stand naturally regenerated after disturbance by road construction in Japan. To evaluate the contribution of N2 fixation to the nitrogen (N)(More)
Ground-level ozone (O3) concentrations are expected to increase over the 21(st) century, especially in East Asia. However, the impact of O3 has not been directly assessed at the forest level in this region. We performed O3 flux-based risk assessments of carbon sequestration capacity in an old cool temperate deciduous forest, consisting of O3-sensitive(More)
Climate-induced forest die-off is widespread in multiple biomes, strongly affecting the species composition, function and primary production in forest ecosystems. Hydraulic failure and carbon starvation in xylem sapwood are major hypotheses to explain drought-induced tree mortality. Because it is difficult to obtain enough field observations on(More)
Partial leaf shedding induced by hydraulic failure under prolonged drought can prevent excess water consumption, resulting in delayed recovery of carbon productivity following rainfall. To understand the manner of water use of invasive species in oceanic island forests under a fluctuating water regime, leaf shedding, multiple physiological traits, and the(More)
Regeneration of planted forests of Cryptomeria japonica (sugi) and Chamaecyparis obtuse (hinoki) is the pressing importance to the forest administration in Japan. Low seed germination rate of these species, however, has hampered low-cost production of their seedlings for reforestation. The primary cause of the low germinability has been attributed to highly(More)
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