Only few original communities of plants continue to exist today.

Between the two world wars there were considerable specimens of juniper in Masuria. Today these plants grow near Lipowietz and they reach a height of 14 m there.

Pines and spruces as well as oaks, red beeches, hornbeams, limes, maples, birches, alders, ashes and hazels can be found in the woodlands. The beech tree reaches its northern boundary of range at the level of Lake Spirding .

Bilberries grow in Johannisburg Heath and in the woods between Bialla and Arys and near Neidenburg, mushrooms in Johannisburg Heath, in the Lyck Lake District and in the woods between Bialla and Arys and near Neidenburg.

There are large stands of reed by Lake Spirding.

Sundew, Siberian iris, lady's slipper, common daphne, spotted orchis, Turk's-cap lily, European globeflower and club moss are amongst the rarities.

Borken Heath (230 km²) (in Polish: Puszcza Borecka) consists of primeval forest: In 1853 butterflies of nun, amounting to millions, entered the forests near Goldap, Lyck and Angerburg, resulting in complete defoliation through the caterpillars in the following years and also affecting Borken Heath. After reafforestation and decades of regeneration of the woods hurricans destroyed the stand again. From then on the woods were neglected and grew into today's primeval forest.

On 4 July 2002, a hurrican raged across Johannisburg Heath and destroyed a third of the stand of trees. It will take decades to reafforest those desolate wooded areas.