Białowieża Forest is an ancient woodland straddling the border between Belarus and Poland, located 70 km (43 mi) north of Brest (BE). It is one of the last and largest remaining parts of the immense primaeval forest which once spread across the North European Plain.
The whole forest is around 125,000 hectares, of which 67,000 ha in Belarus and 58,000 ha in Poland.
On the Polish side, part of the Białowieża Forest is protected as the Białowieża National Park (Białowieski Park Narodowy). An area of 4700 ha has been a National Park and strict reserve since around 1921, but in 1994 the National Park was enlarged to 10,500 ha (40 square miles).
The whole forest area originally was a hunting area for the Polish kings and Russian Tsars. Because of this, for centuries the forest was protected against intensive woodcutting and grazing by domestic cattle. Nevertheless in some periods the density of game was artificially very high, which has had an influence on the developement of the forest.
Nowadays every year about 100,000 tourists visit the Polish part of the forest. In the village Białowieża there are several research stations for forestry, forest ecology and zoological research.
In the National Park several forest types can be found, related to different soils and dryer and wetter locations.
On fertile, loamy soils mixed forests grow, with Hornbeam, Small-leaved Lime, Norway Maple, Pedunculate Oak, Wych Elm, Norway Spruce, Silver Birch and Aspen. This forest type is called lime-oak-hornbeam forest.
Near rivers more European Ash grows, and at locations with higher water tables the forest is dominated by Ash and Black Alder.
On poorer, more acid soils coniferous forests of Scots Pine and Norway Spruce grow, sometimes mixed with Pedunculate Oak. On wet, acid sandy soils Sphagnum moss grows in forests of spruce and pine.
The tallest trees in the forest are Norway Spruce, often reaching 40 to 45 m with maxima of 48 to over 50 m.
Pedunculate Oak and Ash on the loam soils grow into large trees with heights of 33 to 40 m, with record specimens of 43 - 44 m. Scots Pine reaches comparable heights. Small-leaved Lime, Norway Maple (and formerly Wych Elm) form a second layer of 28 - 35, sometimes 38 m height. The Small-leaved Lime is not as tall as given in literature, where it was given a height up to 42 m, but in fact it rarely surpasses 35 m. Below this layer grow the Hornbeams, normally 20 - 30 m tall with maximum of 34 m.
At open places created by fallen trees, Silver Birch and Aspen often grow. Lime and Hornbeam regenerate in great numbers. Also many young trees of Wych Elm can be found, but we saw no trees of 10 - 50 years old. Many large elms have died from Dutch elm desease during recent decades.
It is not clear how the oak rejuvenates. In the forest on richer loam soils the oaks are mostly over 150 years; young oaks are missing. Rejuventation of oak can be seen mostly in open forests of Scots Pine. Scots Pine itself according to recent research regenerates only after forest fires have taken place and in very open areas.
There is hardly a shrub layer, species such as Hazel, Wych Elm, Rowan and Spindle are kept small by grazing Bison, Red Deer and Roe Deer. Daphne (Daphne mezereum), a shrub of a metre high, is fairly general.
In the spring there is a rich flowering with carpets of Wood Anemone, Yellow Anemone, Hepatica, Wild Garlic and many other herbs.
The absence of trees like Beech, Wild Cherry, Sycamore Maple and Field Maple is striking. Beech does not grow in northeastern Poland because of the low rainfall during the growing season. Sycamore is a species of hills and mountains, perhaps the precipitation is also too low for this species. For Wild Cherry and Field Maple the severe winters might be the cause of their absence.
The Polish tree hunter Tomasz Niechoda has made an inventory of the largest and tallest trees of the Bialowieza Forest for several years now, inside as well as outside the National Park. For height measurements he uses a Nikon Forestry laser rangefinder.
In April 2011 Leo Goudzwaard and Jeroen Philippona visited many parts of the National Park guided by Tomasz and saw and measured a lot of the champion trees Tomasz had found before. In these three days they found several new height record trees for several species.