The Impact of Phenological Gaps on Leaf Characteristics and Foliage Dynamics of an Understory Dwarf Bamboo, Sasa kurilensis

Phenological gaps exert a significant influence on the growth of dwarf bamboos. However, how dwarf bamboos respond to and exploit these phenological gaps remain enigmatic. The light environment, soil nutrients, leaf morphology, maximum photosynthetic rate, foliage dynamics, and branching characteristics of Sasa kurilensis were examined under the canopies of Fagus crenata and Magnolia obovata. The goal was to elucidate the adaptive responses of S. kurilensis to phenological gaps in the forest understory. The findings suggest that phenological gaps under an M. obovata canopy augment the available biomass of S. kurilensis, enhancing leaf area, leaf thickness, and carbon content per unit area. However, these gaps do not appreciably influence the maximum photosynthetic rate, total leaf number, leaf lifespan, branch number, and average branch length. These findings underscore the significant impact of annually recurring phenological gaps on various aspects of S. kurilensis growth, such as its aboveground biomass, leaf morphology, and leaf biochemical characteristics. It appears that leaf morphology is a pivotal trait in the response of S. kurilensis to phenological gaps. Given the potential ubiquity of the influence of phenological gaps on dwarf bamboos across most deciduous broadleaf forests, this canopy phenomenon should not be overlooked

The Impact of Phenological Gaps on Leaf Characteristics and Foliage Dynamics of an Understory Dwarf Bamboo, <i>Sasa kurilensis</i>

Phenological gaps exert a significant influence on the growth of dwarf bamboos. However, how dwarf bamboos respond to and exploit these phenological gaps remain enigmatic. The light environment, soil nutrients, leaf morphology, maximum photosynthetic rate, foliage dynamics, and branching characteristics of Sasa kurilensis were examined under the canopies of Fagus crenata and Magnolia obovata. The goal was to elucidate the adaptive responses of S. kurilensis to phenological gaps in the forest understory. The findings suggest that phenological gaps under an M. obovata canopy augment the available biomass of S. kurilensis, enhancing leaf area, leaf thickness, and carbon content per unit area. However, these gaps do not appreciably influence the maximum photosynthetic rate, total leaf number, leaf lifespan, branch number, and average branch length. These findings underscore the significant impact of annually recurring phenological gaps on various aspects of S. kurilensis growth, such as its aboveground biomass, leaf morphology, and leaf biochemical characteristics. It appears that leaf morphology is a pivotal trait in the response of S. kurilensis to phenological gaps. Given the potential ubiquity of the influence of phenological gaps on dwarf bamboos across most deciduous broadleaf forests, this canopy phenomenon should not be overlooked

Effects of large-scale forest fire followed by illegal logging on the regeneration of boreal forests in Mongolia

We aimed to test the hypothesis that large-scale forest fire followed by illegal logging inhibits the regeneration of boreal forests in Mongolia. For this purpose, we compared regeneration of the forest between five stands in a large-scale post-fire site, i.e., (1) undisturbed stand in the unburnt and remaining forest, (2) stand disturbed by illegal logging in the unburnt and remaining forest, (3) stand disturbed by forest fire, (4) stand disturbed by forest fire followed by illegal logging and located in proximity to the remaining forest, which acts as a seed source, and (5) stand disturbed by forest fire followed by illegal logging and located far from the remaining forest, which acts as a seed source. The stand disturbed by logging showed similar species composition of regenerated individuals as the undisturbed stand. In the stand disturbed by logging, Picea obovata and Pinus sibirica were abundant because of advance regeneration on the intact forest floor. In the stand disturbed by forest fire and that disturbed by forest fire followed by illegal logging, Larix sibirica and Betula platyphylla were abundant, and the regenerated individuals of these two species were new individuals after the disturbances. L. sibirica was abundant in the stand disturbed by forest fire because the mother trees survived the forest fire because of their thick bark. B. platyphylla was abundant in the stand disturbed by forest fire followed by illegal logging because the mother trees of L. sibirica were logged and the seeds of B. platyphylla are able to disperse further than that of L. sibirica. However, in the stand disturbed by forest fire followed by illegal logging that was located far from the remaining forest, the regeneration was much reduced because only few seeds, including that of B. platyphylla, were dispersed into this stand and sprouts of B. platyphylla were damaged by the logging operation. In addition, the regeneration of L. sibirica and B. platyphylla was likely to have been reduced for several years after the forest fire because of the loss of safe sites for their invasion by the changes of the forest floor conditions. Therefore, it is likely that large-scale forest fires that are followed by illegal logging inhibit the regeneration in many parts of the post-fire site and those parts will change into open forests of B. platyphylla or grassland

Survival and growth of <i>Fagus crenata</i> seedlings in relation to biological and microtopographical factors in a cool temperate broadleaf forest

<p>The seedling stage is critical in the life cycle of trees, and performance is controlled by both abiotic and biotic factors, which are spatially heterogeneous. We investigated the relationships between the seedling survival or growth of <i>Fagus crenata</i> and seven potentially influencing factors (culm density of dwarf bamboo, slope angle, topographic convexity, distance from the nearest conspecific adult, and local density of <i>F. crenata</i> seedlings, and seedling size and age), under consideration of the changes in direction and strength of the microtopographic effects across space. In 2011, we identified all <i>F. crenata</i> seedlings (maximum stem length <50 cm) within a 90 × 30-m plot in a cool-temperate forest in western Japan and then recorded their survival and growth of stem length in 2012. The best model based on Akaike’s information criterion indicated that the size, age, and distance had positive effects on the survival while slope and convexity had negative effects, and that the strength of the negative effect of convexity varied spatially even within our plot. Meanwhile, the size and culm density had positive and negative effects on the growth, respectively. These results suggest that <i>F. crenata</i> seedlings have more chance to survive at the site on a gentle slope with planar or relatively concave undulations, where the conspecific adults stood apart, and that the seedlings show higher growth rate at the sites without dense dwarf bamboo. Furthermore, we demonstrate that the spatially nonstationary effect of microtopography controls the spatial pattern of seedling survival.</p