Поширеність природних дубових деревостанів у різних типах лісорослинних умов Лівобережного Лісостепу

Abstract

Наведено результати аналізу розподілу природних дубових деревостанів Лівобережного Лісостепу за типами лісорослинних умов. Установлено, що в лісовому фонді проаналізованих державних лісогосподарських підприємств регіону на свіжі й вологі сугруди та сухі, свіжі й вологі груди припадає в середньому 98,8 % площі природних насіннєвих дубових насаджень, серед яких 83,3 % площі розташовано у свіжому груді.

Приведены результаты анализа распределения естественных дубовых древостоев Левобережной Лесостепи по типам лесорастительных условий. Установлено, что в лесном фонде проанализированных государственных лесохозяйственных предприятий региона на свежие и влажные сугруды, сухие, свежие и влажные груды приходится в среднем 98,8 % площади естественных семенных дубовых насаждений, из которых 83,3 % расположено в свежем груде.

Oak stands in the Left-bank Forest-Steppe are represented by natural stands of seed origin, by coppices and by plantations of seed origin. Numerous studies in the permanent plots prove the highest stability of natural oak stands, and the longest life-span of the stands of seed origin. However the productivity of oak forests considerably depends on forest site conditions and naturally increases in such sequence: C2 – C3 – D1 – D2 – D3 (fresh relatively fertile – humid relatively fertile – dry fertile – fresh fertile – humid fertile site conditions. Analysis of publications shows that fresh fertile site conditions and the forest type fresh maple and lime oak stand are the most spread in the Left bank Forest Steppe. However the part of different forest site conditions varies in the frame of the region. It was shown, that oak stands in the northern part of the Left-bank Forest Steppe have the longest life-span, than in the southern part. It was assumed that the mentioned fact is connected with higher part of the most fertile and humid forest site conditions in the northern part of the region. The aim of our research was to reveal the peculiarities of distribution of natural oak stands of the Left-bank Forest-Steppe by the types of forest site conditions. The database of Production Association "Ukrderzhlisproekt" was analyzed concerning forest fund of twelve Forest State Enterprises, located in the Left-bank Forest Steppe. There were five Forest State Enterprises from Kharkiv region, four Forest State Enterprises from Poltava region and three Forest State Enterprises from Sumy region. The forest plots with European oak (Quercus robur L.) as the main forest forming species were selected from database for each Forest Enterprise. These data were grouped by origin and the type of forest type conditions. Oak stand area distribution by forest site conditions was evaluated by statistical methods using software MS Excel. It is shown, that fresh and humid relatively fertile forest site conditions as well as dry, fresh and humid fertile forest site conditions are represented in average on 98.8 % of the area of natural oak stands of seed origin, and 83.3 % from this area is located in the fresh fertile forest site conditions. Oak stands in fresh and humid fertile forest site conditions occupy 80.1 and 2.4 % of area, in dry forest site conditions – 7.6 %, on fresh and humid relatively fertile forest site conditions – 6.9 and 1.4 %, in total 98.5 %. The highest diversity of oak stands by forest site conditions was assessed in Poltava region, particularly 13 types of forest site conditions were determined in the State Enterprise "Myrgorodsky Forest Economy", where 78.93 % of forest area is located in fresh fertile forest site conditions. Natural oak stands of seed origin grow in the same forest site conditions as do all oak stands except dry and wet relatively fertile forest site conditions. Oak stands of vegetative origin (coppices) also mainly grow in fresh fertile forest site conditions; the mean value is 79.7 % (from 45.3 to 90.7 % in different forest enterprises of the region). The novelty of research consists in revealing the peculiarities of modern oak stand distribution for each of twelve analyzed State Forest Enterprises of the Left-bank Forest Steppe. Obtained data must be taken into account for improvement the approaches to growing the natural oak forests of natural origin.