Effects of climatic warming on spring phenology in subtropical trees:
process-based modelling with experiments designed for model development
Abstract
We developed process-based tree phenology models for four subtropical
tree species, and for the first time for these trees, we based the model
development on explicit experimental work particularly designed to
address the processes being modelled. For all the four species, a model
of seedling leafout was developed, and for Torreya grandis, a
model for female flowering in adult trees was additionally developed.
The models generally showed reasonable accuracy when tested against two
sources of independent data. In scenario simulations, the models
projected an advanced spring phenology under climatic warming for 2020
– 2100. For the leafout of seedlings, the advancing rates varied
between 4.7 and 5.9 days per one oC warming, with no
major differences found between the climatic scenarios RCP4.5 and
RCP8.5. For Torreya flowering, less advancing was projected, and
the projected advancing per one oC warming was less
for RCP8.5 (0.9 days / oC) than for RCP4.5 (2.3 days /
oC). The low advancing rates of Torreya
flowering were caused by reduced chilling under the warming climate and
by the particular temperature responses found for Torreya
flowering. These findings highlight the need to base the model
development on explicit experiments particularly designed to address the
process modelled.