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Prime valutazioni sull'introduzione della rinnovazione naturale nel bosco ceduo di castagno misto a faggio nella foresta sperimentale e didattica della SPF di Zurigo a Novaggio, Cantone Ticino | Preliminary evaluation of the introduction of natural regeneration into a chestnut-beech coppice in Novaggio, Tessin, Switzerland

2003; Swiss Forestry Society; Volume: 154; Issue: 2 Linguagem: Inglês

10.3188/szf.2003.0051

2235-1469

Ernst Ott, Fabrizio Conceprio, Andrea Pedrini,

Mediterranean and Iberian flora and fauna

To date there has been very little information on the dry deciduous forests on the southern side of the alps. To redress this imbalance we carried out an intensive and detailed survey of the natural regeneration processes in chestnut-beech-coppice stands in a deciduous forest over a period of 6 years. On a steep sunless slope with easterly exposure we clear cut four narrow aisles, each about 15 metres wide and 100 metres long. On numerous transsections within these aisles, all the way up to the borders where trees were left standing, we installed 119 test sample areas of 1m2, systematically and objectively distributed. The regular examination and taking stock of initial rich natural seeding shows very clearly that this abundance was made possible, above all, by the roughening up of the top soil during clearing. In the following years nearly all test sample areas were covered with increasingly thick layers of leaf-mould which appears to have made subsequent seeding amazingly difficult. In fact, numerous specialist publications and surveys confirm that thick organic cover (the accumulation of leaves over many years with the subsequent formation of leaf-mould)on locations with frequent and severe risk of dehydration is especially unfavourable to germination substrate. However,once the seedlings have successfully put down roots the risk of mortality is strongly diminished in the presence of adequate light. In order to foster natural regeneration in these dry deciduous forest stands we recommend that following procedures be implemented. Using a uniform shelterwood compartment system,the very first light felling (opening up of the stand) should be carried out in winter immediately after effective seeding and the top soil should be roughened up, at least in some places, down to the level of mineral earth layers. Felling carried out in the traditional manner is usually enough to ensure that the top soil is roughened up and, in addition, that seeds and mineral earth are mixed. The increase in the amount of light should optimised in such a way as to allow, on the one hand, regeneration seedlings to survive and grow, but that does not heighten competition from the development of vegetation and possible shoots on the other. Our examination produced further results: growth and survival of the regeneration depends on the amount of light, regeneration reserve under the previous old stand, as well as on the strong throttling of development of the vegetation and shoots in the narrow aisles with little sunlight.