Does tree-ring formation follow leaf phenology in Pedunculate oak (Quercus robur L.)?

Abstract

We monitored leaf phenology and xylogenesis of 12 Pedunculate oaks in northern Poland in 2014. We hypothesized that the individual trees, which differed in size, age and habitat (tree stand or gap), also diverged in terms of the seasonal patterns of leaf phenology and xylogenesis. The samples used for wood formation observations were collected most frequently during the early leaf phenophases (from March to end of June). The transverse sections of the cambial region were cut with a sledge microtome. We counted the number of cambial cells, measured the width of xylem increment and assessed the timing of xylogenesis and earlywood-vessel formation. We found significant differences in leaf phenology and timing of xylogenesis among individual trees. The smallest differences in wood formation among the trees were observed at the beginning of the vegetation season when the first earlywood vessels were detected (9 days). The dates of completion of the first tangential row of earlywood vessels varied by up to 30 days, while for the completion of the entire earlywood dates varied by up to 32 days. The highest productivity of cambial cells (13 cell layers) was observed around the time of bud swelling at mid-April. In the last days of April, the number of cambial cell layers decreased and subsequently increased again when the leaves were nearly fully expanded at the end of May. To summarize, we observed a high seasonal variability in the number of cambial cell layers. Differences in the time of cessation of cambial activity and xylogenesis amounted to 1 month. We conclude that: (1) oak tree-ring widths and earlywoodvessel sizes and numbers may not be sensitive indicators for early spring temperature and spring defoliation; (2) the missing association between leaf phenophases and xylogenesis as well as the phenological variability may be the reasons for the lack of a clear climatic effect on the abovementioned parameters.

Phenology and growth of Fagus sylvatica and Quercus robur seedlings in response to temperature variation in the parental versus offspring generation

“…; Puchałka et al . ). In general, the diameter growth in oak seedlings is favoured by early cambium growth irrespective of the leaf flush receiving an additional advantage in terms of growth, while in beech both cambial growth and leaf flushing occur simultaneously (Čufar et al .…”

“…; Puchałka et al . ). In general, we expect increased plant growth with warming, which may, however, be limited by water availability during the growing season (Martinez‐Sancho et al .…”

The Dynamics of the Phenological Development of Four Woody Species in South-West and Central Slovakia

“…The earlier development of trees can affect the number and size of early wood vessels due to the early spring temperature [42,43]. The authors [13] observed damage after the sudden frost in May in some individuals of the Pedunculate oak, but they did not validate the hypothesis that the springtime ground frost had a negative effect on either tree-ring width or the number and size of earlywood vessels. The authors [44,45] said that species with late leaf development responded to climate change on average less than species with earlier leaf development.…”

“…We used data from the database of the Climatological and Meteorological Information System of the Slovak Hydrometeorological Institute in Bratislava to study the phenological conditions in Slovakia. In order to capture the variability of vegetation during the year, we processed the phenophases of flowering BBCH scale 60, leaves unfolding-BBCH 11 and ripe of fruit-BBCH 86 [13]. We focused on native species: C. avellana (european hazel-COA), C. oxyacantha (hawthorn-CO), P. spinosa L. (blackthorn-PS) and T. cordata (small-leaved lime-TC).…”

“…The occurrence of drought associated with warming can affect production through a change in plant nutrient resorption in the following year, as well as shortening the vegetation period through earlier senescence [11]. The early wood formation can be influenced by the length of the previous vegetation period due to the assimilates produced [12,13]. As in the whole of Europe, Slovakia has experienced significant warming, the occurrence of long waves of heat and drought, and warmer winter temperatures [14][15][16] since the 1990s.…”