Verification of our empirical understanding of the physiology and ecology of two contrasting plantation species using a trait database

Abstract

The effects of climate change on forest ecosystems take on increasing importance more than ever. Information on plant traits is a powerful predictor of ecosystem dynamics and functioning. We reviewed the major ecological traits, such as foliar gas exchange and nutrients, xylem morphology and drought tolerance, of Cryptomeria japonica and Chamaecyparis obtusa, which are major timber species in East Asia, especially in Japan, by using a recently developed functional trait database for both species (SugiHinokiDB). Empirically, C. obtusa has been planted under drier conditions, whereas C. japonica, which grows faster but thought to be less drought tolerant, has been planted under wetter conditions. Our analysis generally support the empirical knowledge: The maximum photosynthetic rate, stomatal conductance, foliar nutrient content and soil-to-foliage hydraulic conductance were higher in C. japonica than in C. obtusa. In contrast, the foliar turgor loss point and xylem pressure corresponding to 50% conductivity, which indicate drought tolerance, were lower in C. obtusa and are consistent with the drier habitat of C. obtusa. Ontogenetic shifts were also observed; as the age and height of the trees increased, foliar nutrient concentrations, foliar minimum midday water potential and specific leaf area decreased in C. japonica, suggesting that nutrient and water limitation occurs with the growth. In C. obtusa, the ontogenetic shits of these foliar traits were less pronounced. Among the Cupressaceae worldwide, the drought tolerance of C. obtusa, as well as C. japonica, was not as high. This may be related to the fact that the Japanese archipelago has historically not been subjected to strong dryness. The maximum photosynthetic rate showed intermediate values within the family, indicating that C. japonica and C. obtusa exhibit relatively high growth rates in the Cupressaceae family, and this is thought to be the reason why they have been selected as economically suitable timber species in Japanese forestry. This study clearly demonstrated that the plant trait database provides us a promising opportunity to verify out empirical knowledge of plantation management and helps us to understand effect of climate change on plantation forests by using trait-based modelling.

Intraspecific variation in growth‐related traits—from leaf to whole‐tree—in three provenances of Cryptomeria japonica canopy trees grown in a common garden

“…In C. japonica, photosynthetic parameters such as P max , V cmax , and nitrogen content in the second-year (former current year) shoots decrease after summer and primary photosynthetic sites shift to current-year shoots as the seasons changed (Inoue et al, 2018;Kobayashi et al, 2010;Tobita et al, 2014). Considering that the P max in the present study was measured on the second-year shoots, it would be reasonable that P max was lower than that measured on the current year shoots of C. japonica in general (Osone et al, 2021). P max was similar among provenances, but the leaf wateruse efficiency (estimated by δ 13 C) tended to be higher in Yaku with lower growth rate (Tables 1 and 2).…”

“…Considering that the P max in the present study was measured on the second‐year shoots, it would be reasonable that P max was lower than that measured on the current year shoots of C . japonica in general (Osone et al, 2021). P max was similar among provenances, but the leaf water‐use efficiency (estimated by δ 13 C) tended to be higher in Yaku with lower growth rate (Tables 1 and 2).…”

“…We examined the intraspecific variations in leaf and whole-tree traits associated with NAR and LAR in relation to their growth rate in a common garden. C. japonica is widely distributed in the Japanese archipelago (from 30 15 0 N to 40 42 0 N) and comprises genetically differentiated provenances (Tsumura et al, 2012(Tsumura et al, , 2014 that differ in morphology, growth rate, allometries, and other functional traits (Hiura et al, 2021;Nishizono et al, 2014;Osone et al, 2021). Thus, this species is ideal for testing trait-growth relationships at the intraspecific level.…”

Preface: Functional biogeography in Japanese cedar

“…Furthermore, although BVOC and LMMOA emissions are a small proportion of the carbon cycling used by the entire population, they play an important role in interactions and communication (Hagiwara et al, 2021) with other organisms above and below ground, but the accumulation of information is very limited. Future analyses of the relationships among traits (e.g., Osone et al, 2021) using trait databases (e.g., Osone et al, 2020) are desirable, and studies on functional traits such as BVOC and LMMOA that have cascading effects on other trophic levels and other ecosystem functions in various regions are also warranted.…”