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Diradamenti di cedui castanili invecchiati - risultati di due parcelle sperimentali (1975–1997) a Novaggio, Ticino | Study of the Problem of Thinning Ageing Chestnut Coppice Forest over 25-Years-Old: Findings from Two Study Areas near Novaggio, in the Canton of Ticino (1975–1997)

2000; Swiss Forestry Society; Volume: 151; Issue: 2 Linguagem: Inglês

10.3188/szf.2000.0043

2235-1469

Ernst Ott, Fabrizio Conceprio, Andrea Pedrini,

Forest Insect Ecology and Management

A study was undertaken to determine the extent to which practical and scientific results of a study in the Swiss Central plateau can be applied to the chestnut coppice to the south of the Alps in Switzerland. The Central plateau study was carried out using selective thinning in former coppice with standards and seedling forests. The neglect of the chestnut coppices which occurred during the early 1970s made this a topical issue at the time. With this in mind, our experiment was primarily aimed at answering the following question: Can selective thinning contribute to the long-term transformation of these chestnut coppices, and eventually bring about natural regeneration through seedlings? Particular interest was paid to the effect it has on improving timber production,timber quality, vitality, and species mixture. Two stands were selected for the study: these were sufficiently large to produce valid results, and had as homogeneous a structure as possible. One was a typical stand of chestnut coppice forest; the other contained chestnut coppice but also had a high proportion of Turkey oak and pedunculate oak. Two sub-plots of 50 ares were marked out on each stand; selective thinning was carried out on one sub-plot, the other was left untouched. In 1975, the condition of the four sub-plots was surveyed in great detail. All trees with a DBH of over 8 cm were permanently numbered, measured with calipers, and classified on the basis of the IUFRO system. The trees selected for culling in the two relevant sub-plots were then marked. In 1976, these trees were felled as planned. A second survey was conducted in 1980 and a final one carried out in 1996/97. Our findings largely match and confirm the practical experience gained over the last 20 years when thinning ageing chestnut coppice on dry sites, including those with an intermixture of Turkey and pedunculate oak. Coppice forests over the age of 25 were unable to replenish the loss of timber reserves by thinning. Both their growth and ability to react diminish greatly with age. As strongly light-demanding trees, the chestnuts and oaks in the saw-timber stage are unable to sufficiently regenerate their crowns once these are reduced by too great an extent through pressure from competing trees. Altogether, these findings match our practical observations and experiences. Thinning techniques used on sites to the north of the Alps cannot be applied to the chestnut coppice forests in dry sites to the south. We can conclude that the technique used in this study will not significantly improve the condition of chestnut coppice forests in dry sites to the south of the Alps.