| Abstract | Razredbe terena neophodne su za planiranje radova pridobivanja drva, odnosno za daljnje planiranje otvaranja šuma. Za formiranje razredbe terena provedeno je istraživanje značajki terena (nagib terena, indeks neravnosti terena, stjenovitost tla, načini vlaženja tla te rizik od erozije tla vodom) kao i sastojinskih značajki. Upravo su sastojinske značajke, odnosno bioklimati, kao prostorno definirano područje s klimatskim tipom i određenim, toj klimi prilagođenim vegetacijskim tipom – biljnom zajednicom, temelj nove razredbe terena za potrebe pridobivanja drva. Istraživanje bioklimata provedeno je na razini privatnih idržavnih šuma RH, začije potrebe je uspostavljena GIS baza podataka.
Provedene analize ukazuju kako je šumsko područje Republike Hrvatske moguće, sa udjelima pridolaska podijeliti na: 1. Pretplaninske šume klekovine (0,01%), 2. Pretplaninske bukove i smrekove šume (2,52 %), 3. Jelove, bukovo-jelove te smrekove šume (13,70%), 4. Brdske bukove šume (24,42%), 5. Brežuljkaste šume hrasta kitnjaka (22,99%), 6. Nizinske šume hrasta lužnjaka i poplavne šume (21,26%), 7. Submediteranske šume bukve i crnog bora (4,89%), 8. Submediteranske šume medunca i crnog graba (1,85%), 9. Submediteranske šume medunca i bijelog graba (5,91%) i 10. Mediteranske šume i makije alepskog bora i hrasta crnike (2,44%).
Sukladno definiranim područjima pridolaska bioklimata te formiranom GIS bazom podataka istraživanog područja, jednostavnim slučajnim uzorkovanjem odabrano je 20 gospodarskih jedinica, jednoliko raspoređenih u sljedeća četiri gospodarski najznačajnija bioklimata (udjelom najzastupljenija i drvnom zalihom najbogatija) Republike Hrvatske: 1. Nizinske šume hrasta lužnjaka i poplavne šume, 2. Brežuljkaste šume hrasta kitnjaka, 3. Brdske bukove šume i 4. Jelove, bukovo-jelove te smrekove šume.Unutar četiri odabrana bioklimata prvotno je provedena analizira stupnja korekcije šumskih cesta (ŠC). U tu svrhu proučavano je bočno odstupanje svakog izraženog horizontalnog loma šumskih cesta od pravocrtnih linija kao i čimbenika korekcije šumskih cesta (odnos duljine pravocrtne linije i stvarne duljine šumske ceste između njenih točaka početka i završetka). Provedene analize potvrđuju kako se
šumskeceste nizinskih šuma hrasta lužnjakaipoplavnih šuma značajno razlikuju od ŠC-a ostala 3 bioklimatapo bočnomodstupanju segmenata ŠC-a i po čimbenicima korekcije ŠC-a.
Za 20 reprezentativnih gospodarskih jedinica provedene su kvantitativne i kvalitativne analize postojećeg stanja otvorenosti. Budući da su analize ukazale na lošiju relativnu otvorenost gotovo svih gospodarskih jedinica, proveden je postupak unaprjeđenja primarne šumske prometne infrastrukture – planiranjem, odnosno postavljanjem nul linijskih poligona do razine vrlo dobre ili izvrsne otvorenosti. U svrhu unaprjeđenja mreže primarnih šumskih prometnica konstruiran je i model primarnog otvaranja šuma, provjeren na primjeru dvije gospodarske jedinice koje su sukladno sustavu procjene primarne relativne otvorenosti nedovoljno otvorene.
Analize pogodnih sustava pridobivanja drva provedene su pomoću novodefiniranih modela, za 20 reprezentativnih gospodarskih jedinica u državnom vlasništvu (Hrvatske šume d.o.o.), temeljem njihovih terenskih i sastojinskih značajki. Iste su provedene u dva navrata: 1. Za postojeće stanje otvorenosti i 2. Za unaprijeđeno stanje otvorenosti. U tu svrhu odabrano je sljedećih 7 sustava pridobivanja drva: 1. Harvester – forvarder, 2. Harvester sa sidrenim vitlom – forvarder sa sidrenim vitlom, 3. Motorna pila – Forvarder, 4. Motorna pila – forvarder sa sidrenim vitlom, 5. Motorna pila – skider s vitlom, 6. Motorna pila – vučena šumska žičara i 7. Motorna pila – stupna kamionska žičara.
Rezultati modela pridolaska sustava pridobivanja drva ukazuju na mogućnost primjenestrojnesječeiizradeu gospodarskimšumama RH, kao i važnost tradicionalnog sustava pridobivanja drva, motorna pila – skider sa vitlom čiji udio pridolaska je osobito izražen u gospodarskim jedinicama bioklimata jelovih, bukovo-jelovih te smrekovih šuma. Osim toga, evidentan je pozitivan utjecaj otvaranja šuma na pridolazak visokomehaniziranih sustava pridobivanja drva. |
| Abstract (english) | Terrain classification is necessary for the planning of timber harvesting and planning of forest accessibility. For the formation of the terrain classes, the research of terrain characteristics (terrain slope, terrain roughness index, stoniness, the risk of soil erosion by water) and stand characteristics has been used. Stand characteristics as bioclimates are spatially defined areas with a climatic type and a specific vegetation type adapted to these climates - phytocenosis and form the basis of the new terrain classification for the purpose of timber harvesting. Research of bioclimates has been proven at the level of state and private forests in the Republic of Croatia and a GIS database has been established.
The conducted analyses indicate that the forest area of the Republic of Croatia can be divided into: 1. Subalpine dwarf pine forests (0.01%), 2. Subalpine spruce and beech forests (2.52%), 3. Mountainous fir, beech-fir and spruce forests (13.70%), 4. Submountainous beech forests (24.42%), 5. Sessile oak forests of hilly terrain (22.99%), 6. Common oak and floodplain forests (21.26%), 7. Sub Mediterranean mountainous beech and black pine forests (4.89%), 8. Sub-Mediterranean pubescent oak forests with hop-hornbeam (1.85%), 9. Sub-Mediterranean pubescent oak forests with oriental hornbeam (5.91%) and 10. Mediterranean Aleppo pine and holm oak forests and maquis (2.44%).
Following the defined areas of bioclimate arrival and the formed GIS database of the researched area, 20 management units were selected by simple random sampling, evenly distributed in the following four economically most important bioclimates of the Republic of Croatia: 1. Common oak and floodplain forests, 2. Sessile oak forests of hilly terrain, 3. Submountainous beech forests and 4. Mountainous fir, beech-fir and spruce forests.
Within the four selected bioclimates, an analysis of the degree of correction of forest roads was initially conducted. For thispurpose, the lateral deviation of each pronounced horizontal fracture of forest roads fromstraight lines and the correction factor of forest roads (ratio of straight-line length and actual length of forestroad between its startand endpoints) were studied. Research has shown that common oak and floodplain forests significantly differ from the forest roads of the other three bioclimates in the lateral deviation of the forest roads segments and the forest road correction factors.
Quantity and quality analyses of the current state of forest accessibility were conducted for 20 representative management units. Since the analysis indicated poorer relative openness of almost all management units, improving the primary forest transport infrastructure was carried out by planning and designing zero line polygons to the level of very good or excellent relative openness of management units. To improve the network of primary forest roads, a model of primary forest planning was constructed and tested on the example of two management units that were insufficiently accessible.
Analyses of suitable timber harvesting systems were performed using newly defined models for 20 representative state-owned management units based on their terrain and stand characteristics. Harvesting system analysis were carried out for two scenarios: 1. For the existing primary forest road network and 2. For the improved condition of forest accessibility i.e. enhanced primary forest road network. For this purpose, the following seven timber harvesting systems were selected: 1. Harvester - Forwarder, 2. Tethered harvester-Tethered forwarder, 3. Chainsaw-Forwarder, 4. Chainsaw - Tethered forwarder, 5. Chainsaw - Cable skidder, 6. Chainsaw - Small-scale cable yarder and 7. Chainsaw - Tower yarder.
The results showed the possibility of using fully mechanised harvesting systems in the commercial forests of the Republic of Croatia, as well as the importance of the traditional harvesting system, Chainsaw - Cable skidder which share is particularly important in mountainous fir, beech-fir and spruce forests. In addition, the positive impact of greater forest accessibility on the share of fully mechanized timber harvesting systems is evident. |
