Winter-spring temperature pattern is closely related to the onset of cambial reactivation in stems of the evergreen conifer Chamaecyparis pisifera

Abstract

Temperature is an important factor for the cambial growth in temperate trees. We investigated the way daily temperatures patterns (maximum, average and minimum) from late winter to early spring affected the timing of cambial reactivation and xylem differentiation in stems of the conifer Chamaecyparis pisifera. When the daily temperatures started to increase earlier from late winter to early spring, cambial reactivation occurred earlier. Cambium became active when it achieves the desired accumulated temperature above the threshold (cambial reactivation index; CRI) of 13 °C in 11 days in 2013 whereas 18 days in 2014. This difference in duration required for achieving accumulated temperature can be explained with the variations in the daily temperature patterns in 2013 and 2014. Our formula for calculation of CRI predicted the cambial reactivation in 2015. A hypothetical increase of 1-4 °C to the actual daily maximum temperatures of 2013 and 2014 shifted the timing of cambial reactivation and had different effects on cambial reactivation in the two consecutive years because of variations in the actual daily temperatures patterns. Thus, the specific annual pattern of accumulation of temperature from late winter to early spring is a critical factor in determining the timing of cambial reactivation in trees. Wood is used as raw material for timber, furniture, pulp and paper, chemicals and fuel 1,2. On global scale, the biological process of wood formation is important for mitigation of climate change via carbon sequestration. Cambium is the meristematic tissue in trees that is responsible for production of xylem and phloem and thus for radial growth of trees 3. Cambium in trees from temperate environments undergoes alternating annual cycles/ periods of dormancy and activity, controlled by internal and environmental factors 4-8. The timing of cambial reactivation from late winter to early spring influences both the quantity and the quality of wood. Earlier reactivation of cambium might potentially increase the duration of cambial activity in Picea mariana 9,10 and resulted in wider xylem increments in Picea mariana 10,11 and in Populus sieboldii × P. grandidentata 12. In addition, the duration of the growing season depends on the cessation of cambial activity 10. Environmental temperature is closely associated with the radial growth of trees 10,13-22 which is the result of the active growth of cambium during annual vegetation periods. The active period of cambium continues from a few weeks to several months, according to species and, local climates and growth conditions in trees 23-26. Moreover,

Climate change and tree growth in the Khakass-Minusinsk Depression (South Siberia) impacted by large water reservoirs

“…The relationship of the shift to advanced phenology in spring is also supported by the abrupt nature of this shift and its greater severity in the areas near the reservoirs, where changes in the dates of temperature transition in the range of T thr = 0–5 °C were also abrupt. It is known that bud burst and activation of photosynthesis in trees can depend not only on a certain threshold of air temperature, but also on the sum of active temperatures, photoperiod, soil temperature, the duration of the chilling requirements and the timing of snow melting 58 – 61 . A better understanding of the phenological triggers for larch and pine could be advanced by more physiological research using the study area as a testing ground for its uniquely high rate of climatic changes and diverse forest settings.…”

Tree-Ring Oxygen Isotope Variations in Subalpine Firs from the Western Himalaya Capture Spring Season Temperature Signals

“…According to Figures 5 and 6, the years with high spring (FMA) temperature led to an early initiation of springwood (earlywood) formation by increasing the rate of stomatal conductance, allowing more uptake of soilmoisture by the roots. There are records of winter-spring temperature warming inducing early initiation of springwood in conifer [73] and phonological changes [74] from different regions. The transpiration process modulates the isotopic composition of leaf water by preferential loss of the lighter isotope ( 16 O) through the stomata, enriching the 18 O in leaf water [35].…”

Photoperiod drives cessation of wood formation in northern conifers

“…Most studies on the responses of xylem phenology to climate change have concentrated on spring phenology (i.e., the onset of wood formation or differentiation). It is well known that the onset of wood formation is driven primarily by the variability of winter and spring temperatures and photoperiods (Delpierre et al, 2016(Delpierre et al, , 2019Guada et al, 2020;Huang et al, 2020;Koerner & Basler, 2010b;Rahman et al, 2020;Yang et al, 2017). The most common constraint to the onset of wood formation is low temperature, which limits the initiation of new cambium cells.…”