baumzaehlen - Primeval Forests & Their Trees

©2018copyright christoph hase

Dobra Primeval Forest, Austria

 

Dobra, protected since 1910, is despite its small area (12.3 ha) an important and interesting reserve, for its low elevation, optimal growth conditions and untouchedness1. The forest was saved because transporting timber from the deep valley was very difficult until about 1970 1. No direct human traces can be seen in the forest.

 

The reserve consists of a northeast–southwest orientated ridge and the adjoining slopes. The northwest-facing slope is very steep, the southeast-facing one less so. Opens internal link in current windowFagus sylvatica (European beech) dominates. Opens internal link in current windowUlmus glabra (wych elm) was until 1974 the second-most abundant tree. At that time, Dutch elm disease (Ophiostoma spp.) reached the locality and the last larger U. glabra trees were infected in 1977 1. Even today, young U. glabra can still be found but all the larger trees are gone. Particularly on the ridge there are also Opens internal link in current windowTilia platyphyllos (large-leaved linden). Opens internal link in current windowSambucus nigra (black elder) is abundant as shrubs or small trees. The other, much less common trees are Opens internal link in current windowAcer pseudoplatanus (sycamore maple), Opens internal link in current windowAcer platanoides (Norway maple), Opens internal link in current windowCarpinus betulus (European hornbeam), Opens internal link in current windowFraxinus excelsior (European ash), Opens internal link in current windowPicea abies (Norway spruce), Opens internal link in current windowAbies alba (European silver fir) and Opens internal link in current windowSorbus aucuparia (European rowan) 1 2. These are easy to distinguish from each other. Conifers P. abies and A. alba are not competitive here2. In addition, air pollution has killed the larger A. alba trees3. The lack of large predators has led to roe deer overpopulation, which has a strong effect on tree regeneration and prevents A. pseudoplatanus from replacing U. glabra as a pioneer tree1. F. sylvatica, instead, regenerates effectively.

 

On the wind-protected, microclimatically favourable1 and less steep southeast-facing slope, there are very large F. sylvatica individuals. On the footslope at the eastern end of the reserve, there are also a few very tall F. sylvatica: the tallest tree I measured in 2017 (with TruPulse 200X laser) was 47.4 m, only 1.9 m lower than the tallest reliably measured F. sylvatica 4. The tallest tree of Dobra had a girth of only 212 cm. Before the Dutch elm disease, U. glabra reached 154 cm girth 2. The high fertility of the soil can be seen, besides the impressive tree growth, from the luxuriant herb layer. On the steep northwest-facing slope the wood volumes and the growth rates are much lower 3. Elevation is 390–550 m, annual precipitation 650 mm and average annual temperature 7°C 1. The base rock is Gneiss2.

 

References:

 

1       Mayer, H. & Reimoser, F. (1978): Die Auswirkungen des Ulmensterbens im Buchen-Naturwaldreservat Dobra (Niederösterreichisches Waldviertel). Forstwissenschaftliches Centralblatt 97, 31421.

2       Mayer, H. (1971): Das Buchen-Naturwaldreservat Dobra/Kampleiten im niederösterreichischen Waldviertel. In Mayer. H. (ed.) 1987: Urwaldreste, Naturwaldreservate und schützenswerte Naturwälder in Österreich. Institut für Waldbau, BOKU.

3       Augustin, B.: Aufbau und waldbauliche Beurteilung des Buchen-Urwaldreservates Dobra II im Kamptal. Diploma thesis, BOKU.

4       http://www.ents-bbs.org/viewtopic.php?f=198&t=5400&p=23625


Fagus sylvatica (European beech) forest.
Fagus sylvatica (European beech) forest with Allium ursinum (ramsons) on forest floor. Also Sambucus nigra (black elder, left).
Fagus sylvatica (European beech) forest. Also one Acer pseudoplatanus (sycamore maple, large tree, right centre, leaning slightly to the right).
Fagus sylvatica (European beech) - Tilia platyphyllos (large-leaved linden, with furrowed bark) forest on stony ridge.
Acer platanoides (Norway maple) on ridgetop. Girth 342 cm. Other trees Fagus sylvatica (European beech). Bottom foreground Sambucus nigra (black elder) foliage.
Fagus sylvatica (European beech). Girth 456 cm. Other trees are F. sylvatica , too.
Fagus sylvatica (European beech). Height 47.4 m, girth 212 cm. Other trees are F. sylvatica , too.
The top of the same 47.4-metre Fagus sylvatica (European beech), top centre. Other trees are F. sylvatica , too.
Tilia platyphyllos (large-leaved linden). Behind it several small Sambucus nigra (black elder). Other trees: Fagus sylvatica (European beech).
40.4-metre Tilia platyphyllos (large-leaved linden, left centre) in Fagus sylvatica (European beech) forest.