DIGITALNA ARHIVA ŠUMARSKOG LISTA
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| ŠUMARSKI LIST 1-2/1971 str. 14 <-- 14 --> PDF |
pijeska i šljunka. Nakon sječe ili odumiranja topola, druge trajnije vrste drveća bit će toliko razvijene da će i bez topola smanjiti štetne utjecaje voda, vjetrova i gravitacije. POPLARS ON THE SEABOARD REGION Distribution, ecological and economic significance There are almost no data in the domestic and foreign forest literature about the distribution of Poplars in the Mediterranean region. In the Croatian part of the Yugoslav seabord we recordet about 100.000 grown-up Poplar trees whose maximum diameters b. h. range up to 40—80 cm., and even to 150 cm. They are mostly spread on coastal grounds and on low elevation sites. Found were the following species of the genus Populus: P. nigra, P. canescens, P. alba, P. tremula, P. euramericana. No special investigation were performed concerning the ecological adaptability according to the individula Poplar species and clones. Ecological characters. Poplars inhabit soils of different composition; they thrive best on alluvial and diluvial soils, along watercourses and seas and also on skeletal soils. They stand elevated temperatures rather well; if temperatures did not affect badly the humidity of the air, warmth would not be a critical factor. The critical factor for a good growth and increment is lack of water and strong insolation, and sometimes Poplars shed a part of their foliage. On the sea-shores Poplars benefit from filtrated sea ater. Older Poplars stand well the adverse mechanical influences of the winds, in some places even better than Austrian Pine (Fig. 1). They also stand well the salinity of the soil and air. On drier soils Poplars lengthen much their roots. Probably the most important problem of the development and growth rate of Poplars is the summer drought when the Mediterranean tree species pass through a relatively long period of rest. Expansion of area. On the basis of the ecological and vegetational relationships of the recorded Poplars habitats it may be assumed that if adequate clones are chosen, these broadleaved species can successfully be propagated in the Mediterranean region: a) by geographical zones — in the Submediterranean area and on better sites of the Eumediterranean area, b) according to the pedosphere — primarily in deeper alluvial and deluvial soils, in skeletoidal soils along the shores of watercourses and seas, exceptionally also elsewhere. Economic significance. U:p to a certain age Poplars display also on the seaboard a much higher growth rate than any of the native and foreign coniferous or broad- leaved species, and they survive relatively well. When there occurs the need for a rapid establishment of the stands, groups and alleys of forest tree species, Poplars are irreplaceable, especiallv on fresh sites and deeper soils. This task can be solved more completely by raising two-storeyed stands of Poplar overstory and Pine understory. Such a consociation of Poplars and Pines is sometimes very rational and economically justified. On the best soils of fields Poplar growing can be used for wood production, and on less good sites for the »production of shade«, for windbreaks, soil stabilization and protection of harbours. The Poplar planting stock can successfully be raised also in seaboard nurseries. When establishing the tourist forests, wide-spread crowns of Poplars (Which also can be expanded by cutting off the tree tops) and of Pinus brutia make it possible to produce a sufficiently dense shade with about 500 plants per ha. after 7—10 years of age. Already in the first year of tourist exploitation camping forests can pay off their cost price. Such a yield is many times higher than the annual yield given by the forest exploitation of a grown-up forest. |