Assessing spatial structure in the beech and silver fir forest stands

V treh sestojih jelovo-bukovih gozdov na visokem krasu smo raziskali sestojno strukturo in njeno prostorsko zgradbo. Na treh raziskovalnih ploskvah, velikih2 ha, smo izmerili koordinate dreves ter njihove dendrometrijske znake.Raziskovalne ploskve v treh sestojih se med seboj razlikujejo po svoji zgradbi, gostotah in tudi po parametrih prostorske zgradbe, ki smo jih ocenilina podlagi metod za ocenjevanje prostorske razmestitve dreves. Za drevesa v I in II debelinskem razredu smo izračunali višje povprečne relativnerazlike v sestojnih gostotah kot za debelejša drevesa. Ko so vzorčne ploskve presegle velikost 6 a, so bile povprečne relativne razlike pri ocenjevanju števila dreves v III debelinskem razredu v vseh treh sestojih manjše od 30 % v vseh treh sestojih. Na podlagi teoretičnih modelov je bilo mogoče o šopasti rasti dreves sklepati le v sestoju s prevladujočo jelko. V dveh sestojih jelke in bukve smo določili tudi sestojne skupine, ki so jih oblikovala drevesa na površini do 0,5 ha. Za jelko, smreko in bukev smo ocenili (P10 cm in diameter at breast height (dbh) on 2 ha plots. The structure of the forest stands on three research plots varied in stand density and in the spatial distribution of stems, analysed using different methods for the characterisation of spatial distribution of trees. The mean relative differences for measuring tree density were substantially greater for trees 50 cm dbh class were less than 30 %. Based on theoretical models of spatial distribution, a tendency of clustering or clumping of trees was evident in the stand dominated by silver fir. In two beech and silver fir stands, stems were aggregated in large patches of up to 0.5 ha in size. The spatial distribution of silver fir, spruce and beech varied significantly (P<0,01) from a random distribution. Stems of these species aggregated in small and medium patches up to 0.25 ha. Dominant trees were regularly and randomly distributed in the three stands, indicating that after the period of silver fir decline the structure of stands did not deteriorate

Konsistentnost ocen sestojnih gostot in njihova variabilnost v gozdnih inventurah na slovenskem

The national estimates of forest resources in Slovenia are based on data aggregation from forest inventories conducted in forest management units of Slovenia Forest Service (SFS) and on the parallel forest inventory established within the Forest and Forest Ecosystem Condition Survey (FECS) as a continuation of international forest monitoring programme. Since the difference in sampling design and temporal dynamics of data collection is of key importance for inventories at the level of forest management units compared to large-area forest inventories, the consistency of stand densities was checked in both concepts. Comparing growing stock estimates in FECS on the systematic 4-km grid of sampling plots from SFS forest management planning, no overall significant differences in temporally comparable periods have been detected. We propose a basis enabling consistent estimates of structural forest characteristics at the national level for the process of forest inventory harmonization in Slovenia.V Sloveniji so ocene o gozdnih virih na ravni države sestavljene iz podatkov gozdnih inventur v gozdnogospodarskih enotah Zavoda za gozdove Slovenije (ZGS) in vzporedne gozdne inventure, ki je bila zasnovana v sklopu Monitoringa gozdov in gozdnih ekosistemov % popis MGGE Gozdarskega inštituta Slovenije. Ker je za inventure na ravni gozdnogospodarskih enot v primerjavi s konceptom nacionalnih gozdnih inventur ključna razlika v zasnovi vzorčenja in časovni dinamiki zbiranja podatkov, smo preverili konsistentnost sestojnih gostot, ki jih ocenjujemo v obeh sklopih gozdnih inventur. S primerjavo lesnih zalog, ocenjenih v popisu MGGE in na prilagojeni sistematični 4-km vzorčni mreži vzorčnih ploskev gozdnogospodarskega načrtovanja ZGS, nismo odkrili značilnih razlik v časovno primerljivih obdobjih. Za proces harmonizacije gozdnih inventur na Slovenskem predlagamo izhodišča, po katerih bo mogoče usklajeno ocenjevati strukturne značilnosti gozdov na ravni države

Forest habitat types on Natura 2000 sites in landscape structure of the Pohorje Mts range

In Slovenia, the natura 2000 network covers 3�.�% of its territory or 28� areas, encompassing 10 forest habitat types. The majority of indicators for the assessment of the conservation status and changes of forest habitat types are to be estimated within the forest management planning framework. In this paper, a hierarchical concept of forest habitat types monitoring in Pohorje Mts (810 km2 ) was examined and presented, based on landscape structure and position of habitat types in this structure. A spatial model was designed for the assessment of forests structure and spatial characteristics of forest habitat types and changes in the extension and spatial structure of habitat types based on data of forest management plans and line transect method for a quick assessment of changes in the landscape and stand structure. Based on spatial model and on the presented inceptions in terms of monitoring, significant changes in the area of habitat types in the Pohorje Mts may be expected. The spatial model that was used in order to estimate the landscape structure draws attention to its fragility in the event of potential abandonment of agricultural use in the areas with harsh farming conditions

Umetni energijski vnosi in ohranjenost primestnih gozdov na Slovenskem

Slovene forestry is concerned with nature conservation, but in the past, the species variety of forests has often been changed and, similarly as elsewhere in Europe, the share of forest with artificial dominance of Norway spruce increased. Based on the spatial model of landscape structure, we estimated the arrangement in conservation of suburban forests in eight Slovene macro regions. In the area of town Kočevje, we assessed artificial energy inputs in the forests lying within one kilometre large area used by inhabitants for daily recreation. In this area, 65 % of forests were categorized as forests with artificial dominance of Norway spruce.Slovensko gozdarstvo je naravovarstveno usmerjeno, toda v preteklosti je bila vrstna sestava gozdov pogosto spremenjena in podobno kot drugje v Evropi se je povečal delež zasmrečenih gozdov. Na podlagi prostorskega modela krajinske zgradbe smo ocenili razporeditev in ohranjenost primestnih gozdov v osmih slovenskih makroregijah. Na območju mesta Kočevje smo ocenili umetne energijske vnose v gozdovih, ki ležijo znotraj kilometrskega pasu mesta, na območju dnevne rekreacije prebivalcev. V tem pasu je kar 65 % gozdov sodilo v kategorijo zasmrečenih gozdov