Reproduction-related variation in carbon allocation to woody tissues inFagus crenatausing a natural¹³C approach

Abstract

The contribution of new photo-assimilates and stored carbon (C) to plant growth remains poorly understood, especially during reproduction. In order to elucidate how mast seeding affects C allocation to both reproductive and vegetative tissues, we measured biomass increase in each tissue, branch starch concentration and stable C isotope composition (δC) in bulk leaves, current-year shoots, 3-year branches and tree rings in fruiting and non-fruiting trees for 2 years, as well as in fruits. We isolated the effect of reproduction on C allocation to vegetative growth by comparing C enrichment in woody tissues in fruiting and non-fruiting specimens. Compared with 2‰C enrichment in shoots relative to leaves from non-fruiting trees, fruiting reduced the enrichment to 1‰ and this reduction disappeared in the following year with no fruiting, indicating that new photo-assimilates are preferentially used for woody tissues even with fruiting burden. In contrast, fruits had up to 2.5‰ C enrichment at mid-summer, which dropped thereafter, indicating that fruit production relies on C storage early in the growing season then shifts to current photo-assimilates. At this tipping point, growth of shoots and cupules had almost finished and nuts had a second rapid growth period thereafter. Together with shorter shoots but higher biomass increment per length in fruiting trees than non-fruiting trees, these results indicate that the C limitation due to fruit burden is minimized by fine-tuning of allocation of old C stores and new photo-assimilates, along with the growth pattern in various tissues. Furthermore, fruiting had no significant effect on starch concentration in 3-year-old branches, which became fully depleted during leaf and flower flushing but were quickly replenished. These results indicate that reproduction affects C allocation to branches but not its source or storage. These reproduction-related variations in the fate of C have implications for evaluating forest ecosystem C cycles during climate change.

Inter-annual and decadal changes in teleconnections drive continental-scale synchronization of tree reproduction

“…Negative summer-NAO is associated with cool-wet summers in Central-Northern Europe (Fig. 4 , see also Folland et al 11 and Bladé et al 12 ), a weather pattern strongly correlated with beech masting when occurring 2 years before fruiting 3 , and commonly interpreted as increasing available resources by enhancing litter mass loss and nutrient uptake due to high soil moisture 20 , 23 – 25 . In contrast, positive summer-NAO is associated with warm-dry summers in Central-Northern Europe (Fig.…”

Stand basal area and solar radiation amplify white spruce climate sensitivity in interior Alaska: Evidence from carbon isotopes and tree rings

“…A novel and noteworthy result of our work is that mast years are recorded as particularly low Δ 13 C and high iWUE values in white spruce tree rings in DNPP. Similarly, current year shoots in Fagus crenata showed 13 C enrichment during fruiting (Han, Kagawa, Kabeya, & Inagaki, ). Reduced radial growth during mast years is likely due to a shift toward reproduction at the expense of stem growth.…”

Temperature and masting control Norway spruce growth, but with high individual tree variability

“…However, other tree ring parameters may also provide information on masting. For example, Han et al (2016) reported small differences in δ 13 C in tree rings associated with mast years in Fagus crenata, and Rodríguez-Ramírez et al (2018) showed potential for mast year reconstruction based on wood anatomical traits. Additionally, our results indicate that the individualist responses of trees to masting may also prove useful in identifying mast years using individual tree ring data.…”