In Val di Sole, Trentino, dendrochronology, historical records and stand monitoring were used to determine the history, structure and dynamics of mixed woodlands of European larch (Larix decidua), Cembran pine (Pinus cembra) and Norway spruce (Picea abies) at different altitudes (1,900m - 2,300m) at the alpine upper timberline. Structure and dynamics of timberline woodlands are a result of past land-use: charcoal was made to fuel the smelting furnaces of the local iron industry from at least the 12th century (archives), leading to the depletion and, in some cases, complete destruction of upper Val di Sole woodlands in the early to mid-15th century (archives and dendrochronological evidence); woods were cleared for summer grazing at least from the 13th century, and disputes over the scarcity of grazing land are reported from the 14th century (archives). This land-use lowered the upper timberline independently of the prevailing climatic conditions. In sample plots covering 5.5ha, more than 3,100 trees and 1,700 saplings were monitored over four years: for all individuals, exact location, species and health condition were recorded, as well as girth at breast height, and age and height ( of a sub-sample) for trees, and absolute height and annual height increment for saplings. The oldest trees were 14th century larches, found above 2,100m altitude, but most trees were young, indicating re-colonization of the timberline predominantly by larch, from the second half.of the 19th century throughout the 20th century. At 2,200m to 2,300m, 60% to 90% of the trees had been recruited during the last century. This large-scale re-colonization was favoured by decreased grazing pressure in the 20th century (archives), coinciding with a period of climatic warming which had started in the 1850s
(dendrochronological evidence). The state of health of trees and saplings is good. For the first time, small charcoal pieces (average 1.78cm, +/-0.65cm; with up to 149 tree rings) from charcoal kilns were dated dendrochronologically, indicating that the Val Comasine woods had been clear-felled in the 1460s. The 14th century advance regeneration spared by the charcoal-makers, and the seedlings established soon afterwards, make up today's relict larch stand (dendrochronological evidence) of 124 ancient larches (mean diameter at breast height 80cm, maximum 140cm). From 160 charcoal pieces and 82 larches, a dendrochronological master curve was constructed, dating from 993 AD to 1995 AD, which was validated on the basis of comparisons with two older Swiss and Italian chronologies. The Comasine chronology consists of samples derived from one square km at 2, 1 OOm to 2,250m altitude and, therefore, reflects the climatic conditions at the upper timberline where larch is very sensitive to climatic influence. This master curve has indicated favourable and detrimental climatic conditions for tree growth during the last millennium. The dendrochronological dating of charcoal (dendroanthracology) is more accurate than 14C-dating and has great potential as a new dating method for the study of woodland and land-use history, as well as ecological development.