Can the structure of dormant cambium and the widths of phloem and xylem increments be used as indicators for tree vitality?

Abstract

We investigated the structure and width of the dormant cambium and of the increments of phloem and xylem of Quercus robur to estimate their potential as indicators for tree vitality. The samples were taken from three woodlands, two in Slovenia (KRA and MUS) and one in Croatia (KOB), with reported tree decline. The number of dormant cells seems to reflect the initial capacity of the cambium to accomplish cell division. With the exception of two trees at KRA, cell production was always higher on the xylem side than on the phloem side. The annual phloem increments were narrower, less variable among trees and with clear lower and upper limits. With increased cambial cell productivity, the share of the xylem in the total annual radial increment increased following a curvilinear function. In trees with an annual radial increment > 3.5 mm, the xylem size represented more than 90 % of the total radial growth. The anatomical variables analyzed show that the most limiting environmental conditions seem to prevail at KRA, whereas the conditions at MUS seem to be most favorable in terms of radial growth. Analysis of the width and structure of xylem and phloem increments, the number of dormant cambial cells and their interrelationships can provide additional information on the vitality of oaks.

Environmental conditions and vascular cambium regulate carbon allocation to xylem growth in deciduous oaks

“…This result verifies our second hypothesis, pointing out the crucial role played by dormant cambium size in the adjustment of xylem production to tree vigour (Gričar, Krže & Čufar ; Gričar et al . ). The association between stem diameter and the number of cambial cell layers is likely mediated by auxin fluxes transported through the cambial zone, which are involved in both cambial identity and xylem growth regulation (Schrader et al .…”

“…Trees having more dividing initials would be able to offset the long period required to complete mitosis (low mitotic index) in the cambial zone (Vaganov, Hughes & Shashkin ), hence increasing xylem production (Gričar, Krže & Čufar ; Gričar et al . ). In accordance with previous findings for P. mariana (Lupi et al .…”

“…Similarly, vigorous trees are assumed to have wider xylem rings, as well as more cambial cell layers during dormancy (Vaganov, Hughes & Shashkin ; Gričar, Krže & Čufar ; Gričar et al . ). In turn, the timing of xylem growth cessation is related to the amount of cells produced earlier in the season (Lupi et al .…”

Chronological Sequence of Leaf Phenology, Xylem and Phloem Formation and Sap Flow of Quercus pubescens from Abandoned Karst Grasslands

“…Earlywood with, on the other hand, is more stable resulting in its smaller proportion in the case of wider xylem rings (Gričar et al, 2014). In addition, decreasing conduit size under drought, leading to a reduction in water-conducting capacity and a lower risk of cavitation, is a stress avoidance strategy of Q. pubescens (Eilmann et al, 2006; Zweifel et al, 2006).…”

Seasonal dynamics in cambial activity and the formation of xylem and phloem in the branches of Cinnamomum camphora

“…The cambium activity and cell differentiation provide not only information about the age of trees (Callado et al, 2003;Worbes et al, 2003), but also clues about the possible factors controlling tree growth, the yield and quality of wood (Dave & Rao, 1982;Ohashi et al, 2001;Venugopal & Liangkuwang, 2007;Fonti et al, 2010;Krepkowski et al, 2011;Gričar & Jagodic, 2014), which are helpful in knowing wood formation, predicting timber and biomass yield, and in determining forest dynamics. In recent years, a series of studies have dealt with the seasonal cambial activity and wood formation in various tree species.…”