Stem wood properties of Populus tremuloides, Betula papyrifera and Acer saccharum saplings after 3 years of treatments to elevated carbon dioxide and ozone

Abstract

The aim of this study was to examine the effects of elevated carbon dioxide [CO 2 ] and ozone [O 3 ] and their interaction on wood chemistry and anatomy of five clones of 3-yearold trembling aspen (Populus tremuloides Michx.). Wood chemistry was studied also on paper birch (Betula papyrifera Marsh.) and sugar maple (Acer saccharum Marsh.) seedling-origin saplings of the same age. Material for the study was collected from the Aspen Free-Air CO 2 Enrichment (FACE) experiment in Rhinelander, WI, USA, where the saplings had been exposed to four treatments: control (C; ambient CO 2 , ambient O 3 ), elevated CO 2 (560 ppm during daylight hours), elevated O 3 (1.5 Â ambient during daylight hours) and their combination (CO 2 1 O 3 ) for three growing seasons (1998)(1999)(2000). Wood chemistry responses to the elevated CO 2 and O 3 treatments differed between species. Aspen was most responsive, while maple was the least responsive of the three tree species. Aspen genotype affected the responses of wood chemistry and, to some extent, wood structure to the treatments. The lignin concentration increased under elevated O 3 in four clones of aspen and in birch. However, elevated CO 2 ameliorated the effect. In two aspen clones, nitrogen in wood samples decreased under combined exposure to CO 2 and O 3 . Soluble sugar concentration in one aspen clone and starch concentration in two clones were increased by elevated CO 2 . In aspen wood, a-cellulose concentration changed under elevated CO 2 , decreasing under ambient O 3 and slightly increasing under elevated O 3 . Hemicellulose concentration in birch was decreased by elevated CO 2 and increased by elevated O 3 . In aspen, elevated O 3 induced statistically significant reductions in distance from the pith to the bark and vessel lumen diameter, as well as increased wall thickness and wall percentage, and in one clone, decreased fibre lumen diameter. Our results show that juvenile wood properties of broadleaves, depending on species and genotype, were altered by atmospheric gas concentrations predicted for the year 2050 and that CO 2 ameliorates some adverse effects of elevated O 3 on wood chemistry.

Elevated CO2 concentration and temperature effects on the partitioning of chemical components along juvenile Scots pine stems (Pinus sylvestris L.)

“…Barton and Jarvis (1999) state that the surplus of assimilates, composed in branches of Picea sitchensis at elevated [CO 2 ], did not lead to an increase in non-structural carbohydrate contents or stimulate growth or meristematic activity in branches. However, in the stem wood of deciduous trees (Populus tremuloides, Betula papyrifera and Acer saccharum) relative contents of soluble sugar and starch increased at elevated [CO 2 ] (Kaakinen et al 2004). Our results support the hypothesis that the accumulation of non-structural carbohydrates is only marginally enhanced in the lower stem parts by elevated [CO 2 ].…”

“…Therefore, this study has focused on these effects of elevated [CO 2 ] and temperature. The interaction of [CO 2 ] and temperature increase is complex, and the combined effects on trees have been far less studied than the impact of [CO 2 ] increase alone (Kaakinen et al 2004). …”

The Impact of SO₂ and NO₂ Industrial Emissions on Anatomical Stem of <i>Salix </i><i>alba</i>

“…and Acer saccharum Marsh., when they were exposed to elevated O 3 concentration. In our work, industrial emissions of SO 2 and NO 2 do not change the pith diameter of the stem [23]. However, due to the increase of primary cortex and secondary cortex indices the stem diameter in the studied S. alba plant affected by phytotoxic pollutant increases substantially.…”

“…Several authors marked a decrease of stem diameter growth under the influence of sulfur (IV) and nitrogen (IV) oxides in a number of tree species: Betula pendula Roth., Populus nigra L., B. pubescens Ehrh., Robinia pseudoacacia L. [21,22] and T. cordata [10,22]. Kaakinen et al (2004) found a statistically significant reduction of the distance between the core and the cortex in Populus tremuloides Michx., Betula papyrifera Marsh. and Acer saccharum Marsh., when they were exposed to elevated O 3 concentration.…”

Deciphering the ozone-induced changes in cellular processes: a prerequisite for ozone risk assessment at the tree and forest levels

“…This is understandable since leaves show clear O 3 -induced damage and a fast response while stems react much later ). An increase in lignin content was observed in stems of poplar and birch fumigated for 3 years in a free-air fumigation experiment (Kaakinen et al 2004), but this observation was not maintained after 5 years (Kostiainen et al 2008). In a recent study, O 3 was observed to repress the phenylpropanoid pathway in poplar wood (Richet et al 2011), probably as a result of reduced cambial growth.…”