<p>Removal of litter and humus layers and herb vegetation dominated by the grass <em>Deschampsia flexuosa</em> ("sod-cutting") in Scots pine <em>(Pinus sylvestris)</em> stands enhanced numbers of species and sporocarps of ectomycorrhizal fungi, particularly in middle-aged and old stands. Three and a half years after sod-cutting soil conditions and the ectomycorrhizal flora in a middle-aged secondary stand on non-podzolic sandy soil came to closely resemble the nutrient-poor soil conditions and rich ectomycorrhizal flora in a spontaneously established Scots pine stand in a drift sand area. Sporocarps of ectomycorrhizal species, among which <em>Cantharellus cibarius, CoItricia perennis, Rhizopogon luteolus, Suillus bovinus</em> and <em>Tricholoma albobrunneum</em> were observed in the sod-cut plots, and not in the control plots. Sod-cutting on a podzolic soil was less effective due to higher nutrient concentrations and lower pH in the mineral soil compared to non-podzolic soil. After sod- cutting on podsolic and non-podsolic sandy soil, the tree roots recovered in the mineral soil up to a depth of 60 cm. The ectomycorrhizal colonization potential also increased after the treatment.<p>Addition of litter and humus layers to existing ectorganic layers ("sod-adding") in young and middle-aged stands did not affect numbers of species and sporocarps of ectomycorrhizal fungi and ectomycorrhizal development in the mineral soil up to a soil depth of 60 cm, but reduced ectomycorrhizal colonization potential.<p>Ectomycorrhizal succession during stand development is mainly driven by soil processes, whereas tree ageing plays a less important role.<p>Laboratory experiments were carried out to provide a lower-level explanation for the results of the field experiments. Development of <em>Laccaria bicolor, R. luteolus</em> and <em>S</em> . <em>bovinus</em> on Scots pine seedlings on forest soils in growth chambers was largely in accordance with field observations. Extracts of Scots pine needles and shoots and roots of the grass <em>D. flexuosa</em> containing considerable amounts of nitrogen and phenolic compounds reduced development of <em>Laccaria proxima</em> and <em>R</em> . <em>luteolus</em> in pure culture. Sporocarps of these fungi were mainly found in young Scots pine stands or in sod-cut plots. <em>Paxillus involutus</em> and <em>Xerocomus badius</em> were less sensitive to needle and grass extracts, although sporocarps of those species were observed in older stands. <em>Laccaria bicolor,</em> which was insensitive to needle and grass extracts, could persist as mycelium in grassy Scots pine stands, but tremendously increased sporocarp production after sod-cutting.<p>The results of the field and laboratory experiments show that sod-cutting in Scots pine stands with thick nitrogen-rich litter and humus layers leads to a (partial) restoration of the ectomycorrhizal flora.
|Qualification||Doctor of Philosophy|
|Award date||9 Jun 1995|
|Place of Publication||S.l.|
|Publication status||Published - 1995|
- litter (plant)
- pinus sylvestris