BIRCH FORESTS
(Betula platyphylla, B. mandshurica, B. costata, B. dahurica, B. schmidtii)

Birch forests    Forests formed by B. mandshurica and B. platyphylla are normally combined under the name white birch groves. Native white birch groves form small disconnected forest massifs among meadows and bogs in the wide lower parts of valleys of right-bank tributaries of Ussuri River and on ancient lake terraces of Hanka plain.
    Most alpine white birch groves are secondary forests that formed in lieu of burnt or felled conifer and broad-leafconifer forests. Herbaceous types of white birch trees, grade III-IV, form in the high-altitude belt of spruce-fur forests on slopes of various exposure and steepness. White birch groves with grade I-II Corylus sppl, underbrush prevail on relatively gently sloping southerly exposures in the belt of broad-leafconifer forests. On northerly slopes, white birch groves with participation of conifer and broad-leaf species form more frequently to indicate that their existence was much more short-lived compared with other white birch trees.
    Betula costata is a component of numerous types of spruce-fur and broad-leaf cedar forests. When older Picea ajanensis and Pinus koraiensis generations die off in tree stocks of different age, B. costata becomes temporarily prevalent. Said prevalence may last 25-30 and more years. Such yellow birch groves, as they are often called, are an age-development stage of fur and cedar trees. But in most cases, yellow birch trees are secondary forests that form after felling, less often after fires, in mixed forests with prevalence of conifer species. Over the last decades, yellow birch areas had substantially increased for this very reason.
    Forests with prevalent B. dahurica (black birch) occur in the form of disconnected sites over low mountains and ridges of the Hanka-Ussuri plain and the surrounding foothills. They occupy slopes of varying steepness and exposure, being as they are secondary forests of different types of oak groves after oak felling.
    The iron birchB. schmidtiiis the most unique representative of the genus Betula in Primorye. It has hard, dark, brown-black bark and very dense and heavy timber, which sinks in water in freshly felled state. Single specimens and small groves with prevalence of B. schmidtii occur only in the very south of Primorye, and most of them had formed after oak and other species with participation of oak were felled. Felling of B. schmidtii is banned in Primorye.
 
 
  
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