Localized cooling of stems induces latewood formation and cambial dormancy during seasons of active cambium in conifers

Abstract

Artificial cooling of stems induced latewood formation and cessation of cambial activity, indicating that cambium and its derivatives can respond directly to changes in temperature. A decrease in the temperature of the stem is a critical factor in the control of cambial activity and xylem differentiation in trees.

Photoperiod cues and patterns of genetic variation limit phenological responses to climate change in warm parts of species’ range: Modeling diameter‐growth cessation in coast Douglas‐fir

“…Diameter growth in trees is primarily a function of wood production (xylogenesis), which ceases with the end of cell division and expansion in the cambium and xylem. Declining temperatures have been shown to correspond with the cessation of both cell division and expansion in these tissues (Begum et al, 2016).…”

“…Declining temperatures have been shown to correspond with the cessation of both cell division and expansion in these tissues (Begum et al, 2016). Diameter growth in trees is primarily a function of wood production (xylogenesis), which ceases with the end of cell division and expansion in the cambium and xylem.…”

“…Although the literature suggests that temperature and photoperiod are the primary environmental determinants of diameter-growth cessation in autumn (Begum et al, 2016;Delpierre et al, 2016;Peltola et al, 2002;Rossi et al, 2011), other environmental factors could also play a role. For example, studies of autumn leaf phenology have found that precipitation, insolation (independent of photoperiod), and growth-initiation timing can affect the timing of autumn events (Fu et al, 2014;Liu et al, 2016).…”

“…(2) How does genetic variation influence this event? Low temperatures (Begum et al, 2016;Peltola, Kilpelainen, & Kellomaki, 2002;Rossi, Morin, Deslauriers, & Plourde, 2011) and short photoperiods (Delpierre et al, 2016) have both been posited as cues for diametergrowth cessation, but results from observational studies along elevational gradients are equivocal as to which mechanism predominates (Moser et al, 2010;Oladi, Pourtahmasi, Eckstein, & Braeuning, 2011;Prislan, Gricar, De Luis, Smith, & Cufar, 2013;Takahashi & Koike, 2014). Question 1: Knowing the extent to which diameter-growth cessation is determined by temperature versus photoperiod is critical in determining how this phenological event will shift in the future, because temperatures will likely change drastically while photoperiod will not.…”

“…Budburst in temperate and boreal trees is generally more strongly influenced by temperature (both cool temperatures to satisfy chilling requirements and warm temperatures to trigger budburst) than photoperiod, but these sensitivities vary among species and photoperiod effects sometimes become stronger under warmer conditions (i.e., photoperiod may have little effect under cool winter/spring conditions, but under warm conditions, long photoperiods can promote budburst and compensate for low chilling) (H€ anninen, 2016;Laube et al, 2014). Low temperatures (Begum et al, 2016;Peltola, Kilpelainen, & Kellomaki, 2002;Rossi, Morin, Deslauriers, & Plourde, 2011) and short photoperiods (Delpierre et al, 2016) have both been posited as cues for diametergrowth cessation, but results from observational studies along elevational gradients are equivocal as to which mechanism predominates (Moser et al, 2010;Oladi, Pourtahmasi, Eckstein, & Braeuning, 2011;Prislan, Gricar, De Luis, Smith, & Cufar, 2013;Takahashi & Koike, 2014). Modeling the joint effects of temperature and photoperiod could help clarify the apparent confusion in the literature, as this interaction is known to be important in determining the timing of bud set and cessation of shoot elongation (Tanino, Kalcsits, Silim, Kendall, & Gray, 2010), and could provide more realistic projections of climate change impacts than approaches focused on one cue or the other.…”