The Pattern of Influence of Individual Forest Trees on Soil Properties

Soil response to canopy position and feral pig disturbance beneath Quercus agrifolia on Santa Cruz Island, California

“…Similar effects have been studied for other tree species (Mergen and Malcolm, 1955;Zinke, 1962;Challinor, 1968;Garcia-Moya and McKell, 1970;Holland, 1973;Tiedemann and Klemmedson, 1973;Callaway and Nadkarni, 1991). For example, increasing soil moisture with proximity to the trunk has been attributed to increased stemflow (Gersper and Holowaychuk, 1970), suppressed evaporation due to canopy shadowing and insulation by leaf litter (Birkeland, 1984), and the influence of greater organic matter content on soil structure under the canopy (Brady, 1984).…”

“…For example, increasing soil moisture with proximity to the trunk has been attributed to increased stemflow (Gersper and Holowaychuk, 1970), suppressed evaporation due to canopy shadowing and insulation by leaf litter (Birkeland, 1984), and the influence of greater organic matter content on soil structure under the canopy (Brady, 1984). Variations in soil pH may relate to the influence of the canopy on leaching processes (Birkeland, 1984), primarily through spatial patterns in the acidity of litter underneath the canopy (Zinke, 1962), or through stemflow processes (Gersper and Holowaychuk, 1970). Similarly, subcanopy patterns in soil nitrogen (Harradine, 1954) have been ascribed to litter characteristics (Zinke, 1962;Callaway and Nadkarni, 1991) or facilitation by the tree canopy of subcanopy species which contribute organic matter (Garcia-Moya and McKell, 1970).…”

Changes in the composition of humus profiles near the trunk base of an oak tree (Quercus petraea (Mattus.) Liebl.)

“…Soil acidification and litter accumulation in the vicinity of tree trunk bases have been recorded frequently since the pioneer work of Zinke [50]. Unfortunately, some controversy still exists about the possible causes of this widely observed phenomenon.…”

“…water running down along branches and stem, has been often considered to explain acidification of the stemflow area under beech [17,18,19,15,8,16], more especially in polluted countries [49,48,24,21,43]. Changes in litter quantity and quality under the canopy of trees have been also evoked, more especially the role of bark deposition [50,26,19]. Compared to Beech, Sessile Oak [Quercus petraea (Mattus.)…”

The heterogeneity of humus components in a virgin beech forest

“…In virgin forests, an important component of horizontal heterogeneity, the eco-unit, can be interpreted as a stage in a successional process starting from the so-called zero-event [28]. Other well-known patterns in woodlands are the acidification of the soil which occurs near trunk bases [5,45].…”