Biogradska Gora’s (54 km²) virgin forest reserve (16 km²) consists of a mountain valley. The most famous feature of Biogradska Gora, a strikingly beautiful small lake Biogradsko Jezero, lies in the valley bottom (elev. 1093 m). However, the old-growth forest continues below the lake almost to the valley bottom of Tara River at approx. 900 m elevation. The average annual temperature in Tara Valley is 9°C ³, and 5°C at Biogradsko Jezero¹. Annual precipitation is high at 1962 mm; spring and autumn are the rainiest periods, July the driest^{1 3}. The base rocks are volcanic in the valley³; however, numerous white boulders can be seen in the valley, too: the base rocks at high elevations include limestone, which has rolled into the valley over the years, thus influencing the soils in the valley, too – a common phenomenon in the Dinaric Alps.

According to the national park information³, 86 tree species have been found there but this is a translation error: they mean woody species including shrubs. The most important forest types are almost pure European beech (Fagus sylvatica) forest and mixed forest composed mainly of beech and European silver fir (Abies alba), and to a lesser extent Norway spruce (Picea abies). Other species grow here and there, e.g. sycamore maple (Acer pseudoplatanus), Norway maple (A. platanoides), European ash (Fraxinus excelsior) and wych elm (Ulmus glabra). At higher altitudes, Heldreich’s maple (A. heldreichii) gradually replaces sycamore maple. On the valley bottom and around the lake the forest is mainly composed of beech, fir, spruce and sycamore maple but also many other species can be found, in addition to all the above-mentioned (except Heldreich’s maple), e.g. large-leaved lime (Tilia platyphyllos), European wild pear (Pyrus communis subsp. pyraster) and grey alder (Alnus incana). At the end of the lake around the delta of the inflowing Biogradska Rijeka (creek) there is lush moist forest composed mainly of ash and grey alder, with the giant leaves of butterbur (Petasites hybridus) filling much of the forest floor. Between this moist forest and the lake there is a still wetter area, seasonally flooded each year, with stands of white willow (Salix alba). The level of the lake has been raised slightly by building a small dam across the outflowing creek. Nevertheless, the lake becomes half-dry after long rainless periods, as in the autumn 2019.

South of the lake, secluded on a gently sloping terrace at 1350 m elevation in the middle of an otherwise steep northeast-facing slope, grew an exceptional fir tree, found and named “Doria” by an Italian group in 2018 ⁴ (photo right). With a height of 59.7 m and a girth of 713 cm it was not only the tallest and the thickest known European silver fir, but also the tallest known tree in European old-growth forests (outside Russia) and possibly the largest European forest tree by volume (volume estimate by MB, based on circumferences of the fallen trunk: 60–65 m³). But was Doria a new find? Some old (unreliable) European record lists mention a Biogradska Gora fir with height 60 m and diameter 2.02 m ^{5 6} – the same tree? Doria fell in 2019 or 2020. From the breaking point, it can be seen that the base was completely rotten. Not far away, there are other unusually tall and large trees: the tallest known (59.0 m) Norway spruce in old-growth forests (the very tallest Norway spruce is 62.7 m but grows in an otherwise managed forest), the thickest known single-trunked Norway spruce (671 cm with a height of 56.2 m) and one of the tallest known wych elms (40.6 m) ⁷. Around the lake giant sycamore maples are amazing, as are two gigantic ashes close to the moist ash–alder forest; one of these now lies on the forest floor. The maximum tree ages are more than 400 years for fir and spruce and more than 300 years for beech¹.

Due to the wide variability of its different habitats, Biogradska Gora is a very aesthetic area: lake, river, mountains, different forest types, large trees, cathedral groves and forests with dense herb layers of butterbur, wild garlic (Allium ursinum) or sanicle (Sanicula europaea) – all can be found in a relatively small area.

Right at the lake there is a rather noisy campsite. For light sleepers the site also has a few cabins. From the campsite, where the parking place, a visitor centre and a good restaurant are also located, starts a trail around the lake. Behind the lake the trail crosses the above-mentioned moist ash – alder forest via a boardwalk built a metre above the forest floor. Almost all the visitors hike only this trail. Additionally there are trails to the northern and southern ridges. A trail along Biogradska Rijeka up in the mountains has also been marked in maps. The beginning of this trail has also been marked on the field but it ends very soon – the rest has overgrown and disappeared under fallen trees and landslides.

KR, TM & MB