担当区分：筆頭著者   掲載種別：研究論文（学術雑誌）   国際・国内誌：国際誌  

DOI： 10.1111/jvs.70129

担当区分：筆頭著者   掲載種別：研究論文（学術雑誌）   国際・国内誌：国際誌  

Abstract

Diseases are major natural disturbances to forest ecosystems that cause changes to overstory tree structure and influence seedling dynamics by altering environmental conditions via functional traits. Thus, identifying factors affecting seedling dynamics would improve broader understanding of the seedling regeneration process after disease disturbance.

We investigated 13,010 current year seedlings from 59 woody species, 44 genera, and 21 families in a Japanese warm‐temperate secondary forest, following Japanese oak wilt disease (JOW) in 2009–2013 and in 2018–2020. We also quantified temporal changes in canopy openness and soil moisture. Structural equation model (SEM) was used to explore the effects of environmental conditions and seedling functional traits on current year seedling density in autumn for 13 dominant species.

Canopy openness gradually increased, whereas soil water content decreased throughout the study site. After disruption by JOW, recruitment of current year seedlings increased through improvements in light conditions. The functional traits of current year seedlings were likely affected by soil nutrients in the late JOW period (2011–2013), whereas litterfall production influenced functional traits of current year seedlings in the post‐JOW period (2018–2020). Factors affecting seedling density varied as environmental conditions changed across the JOW periods. Seedling establishment was enhanced by increased canopy openness in the late JOW period and by low litterfall, high soil nutrient content, and high soil moisture in the post‐JOW period.

Our study provides evidence that temporal changes in environmental conditions and seedling densities occurring after disruption by JOW differ from the changes in forests impacted by other natural disturbances.

DOI： 10.1111/plb.70051

掲載種別：研究論文（学術雑誌）   国際・国内誌：国際誌  

Understanding water uptake depth and its relationship with functional traits offers valuable insights into resource-use partitioning among coexisting tree species as well as forest responses to drought. However, knowledge about water uptake patterns in vertical soil layers, especially among increasingly widespread secondary forest tree species, remains limited. In this study, we investigated interspecific and seasonal variations in water uptake depth among seven coexisting tree species over a 2-year period in a warm-temperate secondary forest in central Japan. We also analyzed the relationships of water uptake depth with tree height and functional traits, including specific leaf area (SLA), leaf dry matter content (LDMC), leaf nitrogen (N) content, and wood density (WD), to discern resource-use and -acquisition strategies. Results revealed that taller trees, especially when soil water is scarce, tend to access deeper soil water sources, indicating that water source partitioning is correlated with tree height. This interspecific and temporal variation in water sources likely stratifies trees to facilitate coexistence within the forest. Water uptake depth was primarily associated with WD and LDMC: trees absorbing more water from shallow soils during dry conditions exhibited lower WD and LDMC, indicating a proactive resource-use strategy. Conversely, SLA and leaf N content were orthogonal to water uptake depth, suggesting that strategies for acquiring belowground and aboveground resources may differ. Considering the alternation of tree species composition during secondary forest succession, our study highlights the importance of further data collection regarding root water uptake depth along successional stages to understand dynamic shifts in water uptake sources.

DOI： 10.30564/jees.v7i3.8019

担当区分：筆頭著者,　責任著者   掲載種別：研究論文（学術雑誌）   国際・国内誌：国際誌  

DOI： 10.1080/13416979.2023.2246755

掲載種別：研究論文（学術雑誌）   国際・国内誌：国際誌  

DOI： 10.1111/plb.13528

会議種別：ポスター発表  

開催地：京都  

会議種別：口頭発表（一般）  

開催地：京都  

会議種別：ポスター発表  

会議種別：ポスター発表  

会議種別：ポスター発表