Dendrogeomorphology review and new techniques of tree ring dating
In this study the same methods used by estimated an average period of 8 yr before the first trees germinate.
Our own findings covering the period 1650 to 1655 indicate that the forest may have begun to regenerate within about 5 yr of each event.
Swiss Federal Institute for Forest, Snow and Landscape Research, CH-8903 Birmensdorf nd Department of Geography, University of Zurich, CH-8057 Zurich, Switzerland.
Towards the end of the 16th century there was a slight aggradation, indicated only by a few adventitious roots on tree no. The date of the event is probably related to a large scar dated 1573. In the middle of the 17th century a large debris flow buried the stand, and all the trees affected formed adventitious roots at the corresponding level. The debris flow must have occurred in 1655 or shortly earlier.
During the first half of the 17th century, tree growth increments were very regular. The analysis of these roots was difficult, since the tree rings were sometimes extremely narrow and their point of origin could not be determined. 2 the ring count showed 1655 as the year of origin, while tree no. It is quite possible that adventitious roots originating in 1669 may be related to this event.
Injuries also occurred repeatedly during the following period until the massive debris flow of 1784 buried the trees even deeper. Only one large scar, formed in 1907, was observed for the first half of the 20th century. Nevertheless the development of the 8-cm-thick soil layer, buried in 1958, must almost certainly have begun before 1907.Individual scars such as occur on the lower buried sections of trees in the study area can be dated, but not definitely associated with a particular event.Dating becomes more problematic the lower and more deeply buried the injury is, because the tree rings may be so narrow or so decomposed as to be indistinguishable.Six of the trees were already growing when the flow occurred. 7 displayed a particularly thick adventitious root sprouting in 1669, which is considerably later than that of other roots. The year of each event may therefore be roughly estimated from the age of the oldest adventitious root in each cohort.For two of them the date of sprouting of the adventitious roots could only be roughly estimated (tree no. Many mountain pines germinated on the debris deposited by the flow of 1655. Such wounds could only have been inflicted by a subsequent exposure of the roots.