How old are the largest Southern Swedish oaks: a dendrochronological analysis

• In the southern Scandinavian landscape, large oaks Quercus robur provide habitat for a wide range of species, including a large number species on the national Red list and the EU habitat directive. Since most of these trees are hollow and have likely been growing in conditions different from the ones of an “average” oak in today’s more forested landscape, direct inference of their age from diameter may be biased. To provide support for the management of these trees, we estimate their age by combining inventory data on diameter distribution of the largest oaks (n = 236) in the Swedish province of Scania and ring width distribution for large (> 1 m in stem diameter) oaks collected in seven oak-dominated stands (both woodland-type and denser closed-canopy forests) in southern Sweden (ntrees = 69, nrings = 12399). The mode of ring-width distribution was 1.26 mm /year. The central 90% of ring width distribution was within 0.54 and 3.38 mm, demonstrating the high growth plasticity of the species. Both ring width distribution in large oaks, divided into 16 width classes, and cumulative 20-yr diameter increments (19 classes) were well approximated by the log-normal function. The largest oaks in Scania are unlikely to exceed 1000 yr, the most probable age estimates of the majority of the inventoried oaks were centered around 500-700 yr. The age distribution of 18 large (69.4 - 178 cm dbh) non-hollow oaks suggesting the maximum age being around 400-600 yr. Conservation-oriented management of oak populations should address the need for preservation of such old trees

Subject headings

LANTBRUKSVETENSKAPER  -- Lantbruksvetenskap, skogsbruk och fiske -- Trädgårdsvetenskap/hortikultur (hsv//swe)

AGRICULTURAL SCIENCES  -- Agriculture, Forestry and Fisheries -- Horticulture (hsv//eng)

LANTBRUKSVETENSKAPER  -- Annan lantbruksvetenskap -- Miljö- och naturvårdsvetenskap (hsv//swe)

AGRICULTURAL SCIENCES  -- Other Agricultural Sciences -- Environmental Sciences related to Agriculture and Land-use (hsv//eng)

LANTBRUKSVETENSKAPER  -- Lantbruksvetenskap, skogsbruk och fiske -- Skogsvetenskap (hsv//swe)

AGRICULTURAL SCIENCES  -- Agriculture, Forestry and Fisheries -- Forest Science (hsv//eng)

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