baumzaehlen - Primeval Forests & Their Trees

The reserve is a part of Rila National Park and also a UNESCO biosphere reserve. The core area is 15 km ² but only 2.5 km ² at the lowest elevations (1450–1950 m) ¹ are covered by exceedingly beautiful coniferous and mixed virgin forest. The highest part was used as pasture in the past and forest established there as pasturing was abandoned at the beginning of the 20th century ¹ . The reserve was created in the 1930s, but already before that the locality was a protected forest in which human activities were limited to hunting and pasturing on the alpine grassland above the forest ¹ . Foresters considered the locality as a very good example of pristine forest already in the 1920s ¹ . The oldest tree ( Pinus sylvestris (Scots pine)) established shortly before 1520 ¹ .

Picea abies (Norway spruce) is the most abundant tree species, followed by Abies alba (European silver fir), Fagus sylvatica (European beech) and P. sylvestris ¹ . Altogether, there are not much more than 10 tree species in the reserve; these are easy to identify. Wind has historically been the most important disturbance agent ¹ . Recently European spruce bark beetle ( Ips typographus ) has killed patches of P. abies ² like almost everywhere in temperate Europe. These gaps are mostly being filled by F. sylvatica . A. alba regenerates, too – a sign of not-too-dense populations of large herbivores. The reserve is located on a relatively gentle north-facing slope. The average annual temperature is 2–4.6°C and the annual precipitation about 950 mm, with a maximum in late spring and early summer ³ . Base rock is granite ⁴ .

The tallest tree of Bulgaria ( P. abies ) is located in this reserve ⁵ . Using TruPulse 200X laser instrument, Don Welsh and I measured it to 55.4 m in 2016. It is said that a now fallen tree (also P. abies ) nearby was still taller but it was not measured with a reliable method ² .

As of 2016, entry to the reserve was only allowed by special permit, but a short trail to the tallest tree was planned to open in the near future ⁵ . Rila National Park is adjacent to Rila Monastery Nature Park (see Rila Monastery Forest Reserve ).

References:

1 Panayotov, M. et al. (2011): Wind disturbances shape old Norway spruce-dominated forest in Bulgaria . Forest Ecology and Management , Vol. 262 , Issue 3, 470–481.

2 Nikolov, G., Rila National Park, pers. comm. (2016)

3 Panayotov, M. et al. (2016): Climate extremes during high competition contribute to mortality in unmanaged self-thinning Norway spruce stands in Bulgaria. Forest Ecology and Management 369 , 74–88.

4 Dountchev, A. et al. (2016): Consequences of Non-intervention Management for the Development of Subalpine Spruce Forests in Bulgaria . In Sustainable Mountain Regions: Challenges and Perspectives in Southeastern Europe . Springer. /c7074deeb774cebd720fe92e91510a65/publication/299134776_Consequences_of_Non-intervention_Management_for_the_Development_of_Subalpine_Spruce_Forests_in_Bulgaria

5 Kirilov, S., Rila National Park , pers. comm. (2016)

Official site:

http://rilanationalpark.bg/en/