Root system development in Douglas fir (Pseudotsuga menziesii [Mirb.] Franco) on fertile sites

Abstract

ABSTRACT:The paper analyses the root system development in the artificially established stands of Douglas fir aged 10, 20, 30, 60 and 80 years on aerated soils (Cambisols) without skeleton. On these sites, the Douglas fir develops a uniform root system of substitute taproots and anchors, which has great predispositions to assure the good mechanical stability of trees as well as its resistance to sudden changes in upper soil horizons. Several anchors growing in positive geotropic direction shoot from the stem base, several slant anchors shooting from the side of the stem base turn into the positive geotropic direction of growth. In humus horizons, horizontal skeletal roots shoot from the stem base, which turn into lower soil horizons in an "elbow-pipe" manner and from which shoot positively geotropically growing anchors. Trees of Douglas fir develop this type of root system already at an age of twenty years.

Soil-forming effect of Douglas fir at lower altitudes - a case study

“…Douglas fir can exhibit a very favourable soilforming role compared with prevailing domestic coniferous species, especially in mixtures with broadleaved tree species, which is recommended also for the good growth of forest stands (Hofman 1964;Kenk, Ehring 1995;Beran, Šindelář 1996;Burgbacher, Greve 1996;Huss 1996). Replacing partly the Norway spruce at lower altitudes, it can contribute not only to improvement and revitalisation of forest soils but also to the higher static stability of forest stands (Mauer, Palátová 2012) and to better use of shortening soil water resources. Douglas fir so represents a promising tree species among other introduced taxa, replacing site non-corresponding Norway spruce in these conditions partly, supposing to select responding provenances.…”

Ectomycorrhizas and tree seedling establishment are strongly influenced by forest edge proximity but not soil inoculum

“…There are several, non‐mutually exclusive factors that could explain the EMF limitation away from edges. The lateral roots of Douglas‐fir generally extend less than 1 m past the canopy edge (Mauer and Palátová ), and because EMF require carbon from a host plant to be metabolically active, seedlings planted beyond the canopy may be unable to access mycorrhizal networks associated with the mature edge trees. Additionally, mycorrhizal fungi cannot reproduce without host plants, and 95% of basidiospores disperse less than 1 m from the fruiting body (Galante et al.…”

Root architecture might account for contrasting establishment success of Pseudotsuga menziesii var. menziesii and Pinus sylvestris in Central Europe under dry conditions

“…3). The accumulation of fine roots in the upper soil layers seems to allow the species to efficiently exploit soil nutrients (Mauer and Palatova 2012) and might be the reason why Pseudotsuga menziesii, once established, is able to maintain high radial growth rates also under drier conditions (Eilmann and Rigling 2012;Lévesque et al 2014). Plant available water in the upper soil layers is, on the other hand, strongly tied to single precipitation events (Rennenberg et al 2006), which may put seedlings at risk of desiccation during long dry periods.…”

“…Like most pines species, Pinus sylvestris produces a taproot already during the earliest seedling stages (Wilcox 1968), reaching up to 40-cm soil depth within 6 months after germination (Moser et al 2015) and allowing it to acquire water from deeper soil layers that are less rapidly depleted during drought events (Ryel et al 2008). By contrast, little is known about the root architecture of Pseudotsuga menziesii seedlings during early establishment (but see Preisig et al 1979 for 5-8-year-old seedlings), while 10-80-year-old Pseudotsuga menziesii were shown to have a superficial root system (Mauer and Palatova 2012), which only slowly advances to deeper soil layers (Domec et al 2004).…”