Root development across a chronosequence in a Japanese cedar (Cryptomeria japonicaD. Don) plantation

Abstract

We investigated the biomass, vertical distribution, and specifi c root length (SRL) of fi ne and small roots in a chronosequence of Japanese cedar (Cryptomeria japonica D. Don) plantations in Nara Prefecture, central Japan. Roots were collected from soil blocks up to 50 cm in depth in fi ve plantations of differing age: 4, 15, 30, 41, and 88 years old. Fine-root biomass reached a maximum (639 g m −2 ) in the 15-year-old stand before canopy closure, decreased in the 30-year-old stand (422 g m −2 ), and thereafter was stable. Except in the 30-year-old stand, fi ne-root biomass increased in deeper soil layers as stand age increased, and the depth at which the cumulative biomass of fi ne roots reached 90% exhibited a good allometric relationship with mean stem diameter. Both root-length density (root length per unit soil volume) and SRL decreased with soil depth in all stands, indicating that plants mainly acquire water and nutrients from shallow soils. The highest SRL was observed in the 4-year-old stand, but the relationship between SRL and stand age was unclear in older stands. The SRL in surface soils seemed to decrease with increases in root-length density, suggesting that branching of the fi neroot system during development is related to densitydependent processes rather than age.

Root distribution of Fagus sylvatica in a chronosequence in western France

“…This decline in fine root biomass with age was also observed by Claus and George (2005) in their time sequence of four Fagus sylvatica stands: total fine root biomass for 0-30 cm (plus the organic layers) was 5.3-6.4 Mg ha -1 for the 15-year-old and 30-year-old stands and fell to 2.4 Mg ha -1 and 3.3 Mg ha -1 for the 62-year-old and 111-year-old stands, respectively. Similar observations exist for coniferous forests (Vogt et al 1987;Vanninen and Mäkelä 1999;Fujimaki et al 2007) and deciduous forests (Idol et al 2000), where fine root biomass increased to a peak at canopy closure, after which it gradually declined in maturing stands. Small root biomass showed a different pattern, and no clear trend with stand age appeared.…”

“…The Fagus sylvatica stands differed in age from 9 years to 146 years and had limited understorey vegetation. We expected that root distributions would vary between these stands, as fine root biomass had previously been shown to decrease with stand age (Vogt et al 1987;Vanninen and Mäkelä 1999;Claus and George 2005;Fujimaki et al 2007). Our objective was to establish whether root distributions and total biomass of fine and small roots varied with stand age.…”

“…Vertical root distribution is commonly described as a simple one-dimensional depth function with the greatest density of fine roots in the top soil layers, which contain the highest levels of nutrients for most forests (Parker and van Lear 1996;Jackson et al 1996). The size of a root system depends on tree age (Vogt et al 1987;Vanninen and Mäkelä 1999;Claus and George 2005;Fujimaki et al 2007), and the relative proportion of fine roots to total biomass has been shown to decrease with increasing age (Ovington 1957;Helmisaari et al 2002) or size (Ritson and Sochacki 2003) of the trees. Whether general root distribution patterns and variability in such root distribution are affected by tree age is not evident from the literature.…”

Effet du stress hydrique sur l’architecture racinaire de jeunes plants <i>d’Acacia tortilis</i> (Forsk.), de <i>Balanites aegyptiaca</i> (L) Del., et de <i>Zizyphus mauritiana</i> Lam.

“…Chez ces espèces, différentes stratégies sont notées sur le plan qualitatif (topologie, diversité des types racinaires) et sur le plan quantitatif (géométrie, densité des types racinaires, distribution de longueur, de volume d'extension latérale des racines). l'efficacité de l'acquisition des ressources profondes dépend au plan qualitatif, de la forme, de la structure et de l'architecture du système racinaire (Fujimaki et al, 2007). L'évolution de celle des espèces xérophiles dépend des conditions du milieu (Logbo et al, 2006 (Noubissie Tchiagam et al, 2011) et d'A.…”

Special feature: development and function of roots of forest trees in Japan

“…They also argue that slope position exerts a major control over fi ne-root biomass in Japanese forests. Fujimaki et al (2007) present a chronosequence study using fi ve C. japonica plantations ranging from 4 to 88 years old. Fineroot biomass was highest in a young stand (15 years old),…”