Epicormic ontogeny on Quercus petraea trunks and thinning effects quantified with the epicormic composition

Abstract

Abstract• Effects of thinning on epicormics have rarely been demonstrated especially due to inaccurate surveying methods.• Our objective was to assess the effect of contrasted thinnings on the ontogeny of epicormics on sessile oak. We used the epicormic composition defined as the arrangement of epicormics in different classes (isolated bud, clustered buds, short and long shoots and "picots") and quantified by the total frequency of epicormics and the proportion of each class.• Epicormic composition was recorded in a silvicultural experiment testing highly contrasted thinnings, at 3 different stand stages and on lower (0.5-3 m) and upper (3-6 m) boles. Ageing provoked an accumulation of bud clusters and of picots. After thinning, epicormic shoots emerged mainly from (1) still present short epicormic shoots, (2) buds either isolated or in clusters depending on the stand stage. Upper boles bore epicormic compositions close to those observed on lower boles in the few preceding years. Upper logs were more reactive than lower boles.• To conclude, the epicormic composition was a relevant tool to follow the dynamics of the epicormic ontogeny and to demonstrate the effects of thinning on it.

Tracking rameal traces in sessile oak trunks with X-ray computer tomography: biological bases, preliminary results and perspectives

“…However, the results of this study were a valuable confirmation of previous results obtained (Fontaine et al 2001;Colin et al 2010b), thanks to external observations. More important, by providing a consistent framework for measuring and encoding rameal traces, they pave the way for an exhaustive retrospective analysis of the rameal traces found in oak stems.…”

“…Epicormic buds have different fates (Spiecker 1991;Fontaine et al 2001Fontaine et al , 2004Colin et al 2010b). They may (1) remain in the same state; (2) die and be engulfed in the wood; (3) develop into epicormic shoots of various sizes ( Fig.…”

“…On oaks stems aged around 20 years, epicormics are mainly composed of short epicormic shoots (32%), isolated buds (29%) and bud clusters (27.5%) (Colin et al 2010b). Ten years later, bud clusters are the most frequent type (57.5%) due to the continuous branching of buds (Colin et al 2010b).…”

“…1, 18). When stands are heavily thinned (Colin et al 2010b), buds of all types (isolated, within bud clusters, burls or even on picots) may develop into short or long epicormic shoots (Fig. 1,(19)(20), sometimes leading to particularly thick epicormic knots ( Fig.…”

Does past emergence of epicormic shoots control current composition of epicormic types?

“…In addition to branches, bud clusters, burls and picots may also originate from suppressed buds (Colin et al 2010a). All of these are named epicormic structures, including suppressed buds, epicormic being in this case an adjective.…”