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Effect of Tree Shelters and Regeneration Method on Survival and Growth of Cork Oak Plantations in the Maamora Forest, Morocco

El Alami Sanae Lahlimi, El Aboudi Ahmed, El Antry Salwa, El Mnouar El Ayyachi, Dallahi Youssef, Rabhi Ameur

Journal of Ecological Engineering

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2023

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Vol. 24, nr 7

360--374

EN

Forests are under intense human pressure, hindering their restoration. A potential solution to regeneration problems is the adoption of tree shelters, which have demonstrated protective benefits in the early establishment of forest plantations. A 9-year study was conducted in the Maamora forest (Morocco) to evaluate the effects of tube shelters and regeneration methods (direct seeding and seedling) on the growth and survival of cork oak (Quercus suber) plantations. A split-plot design was developed with three replicates of 36 plants for each of the four shelter treatments, including T0 (control), T1 (Tubex 1.20 m), T2 (Tubex 1.50 m), and T3 (Tubex 1.80 m) for a total of 964 plants, where periodic inventories were conducted to assess plant survival and growth. Our results show regeneration methods and shelters significantly influenced the survival of cork oak. Direct-seeded plants were more successful than those from seedlings, presenting survival rates of up to 97%. Despite a minimal shelter effect at the beginning, their positive influence was strong later on. Only plants installed with the 1.20 m shelter had an overall success rate of over 50%. Regeneration method had a strong influence on height and diameter growth, with seedling units showing taller plants initially, which shifted to direct-seeded plants in subsequent years. Conversely, the effect of shelters on growth parameters was generally non-significant. Nonetheless, sheltered trees exhibited greater height and diameter than unsheltered trees, particularly in the latter years. Sheltered plants showed an overall faster rate of vertical growth, while unsheltered plants showed faster radial growth.

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Variation Between Voivodships in Terms of Forest Area and Silviculture Activities in Polish Forests in 2015-2019

Grużewska Agata, Rymuza Katarzyna, Niewęgłowski Marek

Rocznik Ochrona Środowiska

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2021

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Tom 23

524--538

EN

The objective of the study reported here was to compare voivodships in terms of forest area, forest regeneration area, afforested area, thinned forest area and natural forest regeneration area Main Statistical Office data for Polish voivodships was analysed. It included forest area, natural forest regeneration and silviculture activities (forest regeneration, afforestations and thinning) in all forests, state-owned forests and privately-owned forests. Voivodships were compared using the arithmetic mean, the indicator of structure, the average rate of change, principal component analysis and cluster analysis. Principal Component Analysis, revealed that state-owned forest area, forest regeneration in state forests, total forest regeneration, and thinning in state-owned forests had the greatest share in the multivariate variation among voivodships analysed in terms of forestry. Cluster analysis yielded two groups of voivodships. The voivodships in the first group had a higher average total forest area, area of state-owned forests, total area of forest regeneration and forest regeneration in state-owned forests, area of natural forest regeneration and thinning in state-owned forests. On average, forests of voivodships which formed group 2 included less privately-owned forests in which fewer forest regeneration and afforestation activities had been conducted. Opolskie and Śląskie Voivodships as well as Łódzkie and Świętokrzyskie Voivodships were the most similar in terms of all the analysed characteristics.

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Regeneration of Ostrya carpinifolia Scop. forest after coppicing : modelling of changes in species diversity and composition

Catorci A., Vitanzi A., Tardella F., Hrsak V.

Polish Journal of Ecology

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2011

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Vol. 59, nr 3

483-494

EN

In temperate forest ecosystems, management is one of the most relevant factors that can drive the temporal pattern of species. As species in an ecosystem show susceptibility to stress and disturbance, it is useful to take into account the plant community .compositional dimension., which derives from species behaviour and ecological attributes and provides information on the mechanisms underlying species assemblages. Taking into account the influence of environmental factors on species diversity and composition, in order to determine the most suitable ecological behaviour type of each species, the research aim was to generate a model for Ostrya carpinifolia coppiced woods (central Italy) that describes forest ecosystem regeneration after coppicing by the assessment of change in the composition of ecological behaviour types. Vascular species cover percentage, field data, soil data, light intensity at the undergrowth, dominant tree layer cover and time since last logging were recorded for 63 plots covering 400 m2 each (20 x 20 m), randomly selected within a set of homogeneous macro-environmental conditions. Low species richness is related to stressing factors (acid soil, high soil skeleton percentage), while high species richness is linked to high light intensity at the undergrowth level due to scarce canopy cover soon after coppicing. The driving forces affecting floristic composition, highlighted through multi-response permutation procedures (MRPP) were light intensity at the undergrowth, regenerative phase, dominant tree layer cover, acidity, presence/absence of outcropping rock or rock fragments and total nitrogen content. Six species groups, each one characterized by homogeneous ecological behaviour, were defined by indicator species analysis (ISA) and tested using bioindication values analysis. Floristic successional change, related to time since last coppicing, turned out to follow an ecological cycling process characterized by cyclical occurrence/disappearance of species belonging to the six groups.

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Przyczyny deforestacji w Sudetach Zachodnich

Sporek K.

Zeszyty Naukowe. Inżynieria Środowiska / Politechnika Opolska

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2002

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Vol. 274, z. 3

59-67

PL

Lasy sudeckie obejmują 213 tys. ha, co daje 38% lesistości obszaru geograficznego VII Sudeckiej Krainy Przyrodniczoleśnej. Teren Sudetów należy do obszarów Polski najbardziej dotkniętych klęską ekologiczną. Około 70% borów górnoreglowych w tym regionie jest poważnie uszkodzonych. Destabilizacja ekologiczna zagraża w największym stopniu świerkowi pospolitemu, który lokalnie osiąga do 90% udziału w drzewostanach, a charakteryzuje się wysoką wrażliwością na skażenia. Konflikt środowiskowy może być rozwiązany poprzez odtworzenie naruszonej równowagi ekologicznej. Wylesione zbocza górskie wymagają długiego czasu i trudu przy odbudowie i przebudowie lasów, zarówno pod względem składu gatunkowego, jak i struktury pionowej drzewostanów. Zamieranie lasów przyspieszają gradacje szkodników owadzich, a zakładane uprawy leśne niszczy nadmiar grubej zwierzyny łownej przez zgryzanie. W latach 1980-1988 w ośmiu nadleśnictwach sudeckich dotkniętych klęską ekologiczną pozyskano 4,6 min m3 grubizny, z czego 87% stanowiło drewno posuszowe. Wskutek klęski ekologicznej wylesieniu uległo około 14 000 ha, z czego odnowiono do roku 1993 około 13 800 ha. Duży wpływ na stan upraw miały szkody spowodowane przez gryzonie i zwierzynę łowną oraz nadal istniejące oddziaływanie na sadzonki i glebę substancji fitotoksycznych zawartych w powietrzu i opadach atmosferycznych. Pomimo licznych prób odtwarzania lasu, dotychczasowe efekty są niezadowalające w stosunku do nakładów pracy i środków finansowych.

EN

Forest decline persists in the southwestern part of the country on areas situated higher than 600 m a.s.l. Regeneration of the forest in deforested areas, although repeated many times, proved to be inefficient. Environmental alterations in an area of about 20 000 ha in the western Sudety (especially in the Izerskie Mountains) have a character of sudden ecological transformations: the forest ecosystems disappear and grassy formations arise instead. This phenomenon is characteristic especially for coniferous mountain forests on the slopes where west and southwest winds prevail. The forest decline in the Sudety Mountains is not a simple increase of tree mortality. This phenomenon seems to be a result of the simultaneous occurence of damaging agents, stimulating each other (a synergism feature). There are three groups of them by nature: abiotic (climate, site), anthropogenic (emissions, historical and economic factors) and biotic (insects, fungi, game animals, rodents, weeds). The main threat concerns conifers (fir, spruce, pine). The comeback of tree species on deforested areas is a condition for restoration and persistence of forest ecosystems in artificially barren areas. This primarily means the recultivation of dead and declining forests by means of introducing a regeneration of full value, i.e., forest plantations. Microclimatic changes, regressive succession, chemical and biological changes in the soil subsystem, altered water conditions and erosion make reintroduction of forest plantations impossible in the zone of mountain conifers, if current methods are applied. Main problems: Composition of the atmosphere, soil, and vegetation in the forest decline gradient in the Sudety Mountains (Problem I). The influence of continental and local emissions has very clearly appeared in the Sudety mountain forests (Świeradów and Szklarska Poręba forest inspectorates) and is spreading estwards. The beginning of the subalpine forest decline was observed in 1981, and in 1992 the deforestation area reached 14000 ha. In general we can state that pollution in the natural environment of the Sudeten Mountains still exists and the situation is deteriorating. Symptomatology of stress: reaction of trees, biocenotic and ecosystem changes (Problem II). The monitoring of changes in the behaviour of vegetation in the Sudety ecosystems, reactions of trees and other phenomena form a base for many fields of science and economic activity in the Sudety Mountains. The influence of the forest and economy on hydrographic agents of mountain watersheds and the influence of the forest on circulation of pollution in mountain watersheds (Problem III). Hydrological investigations are closely connected with problems of restitution of deforested areas. They are also one of the elements of ecological bases for recultivation in the regions of deforestation included in Problem IV. Forest restoration and silviculture in deforestated regions in the Sudety Mountains (Problem IV). Problem IV contains issues of forest restitution and silviculture, mainly in subalpine forests of western Sudety Mountains on ecological bases, i.e. based on hydrological, microclimatic and phytosociological investigations.