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Beech (Fagus orientalis L.) trees at the edge of canopy gaps (A) and adjacent closed stand (B) in site.
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Silvicultural operations, including single-tree selection create gaps in forest canopies and these gaps impact on the forests structure. This study examines the influences of different harvest-created gap sizes on the oriental beech (Fagus orientalis L.) trees traits in temperate Hyrcanian forest, northern Iran. We selected three gap sizes (small,...
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... sampling was conducted in summer 2017 on 15 artificial forest gaps within beech stand which were created in 2011. Beech tree in overstory was the gap maker species accounting for 15 gaps which selected randomly ( Fig. 1). At the time of sampling, age of forest gaps was 6 years. The area of expanded gaps (hereafter gaps), was calculated (A = πLW 4 ) by measuring its long (L) and short (W) axes as ellipse shape (Runkle, 1981). Gap length was divided by gap width to calculate eccentricity, where values > 1 indicate elliptical gaps (Alexander and Mack, ...
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One of the most important issues indicating the quality and quantity of forest ecosystems is the distribution of natural disturbances resulting in canopy gaps (CGs). The present study was conducted in one of the Hyrcanian beech forests in northern Iran in summer 2018. The gap areas were classified into small (< 200 m<sup>2</sup>), medium (200‒500 m...
Citations
... The expansion of monoculture plantation forests led to severe issues such as a decline in biodiversity and soil nutrients (Firn et al., 2007;Liu et al., 2018;Wang et al., 2019a). To counteract these effects and establish mixed species stands forest gaps are increasingly adopted as management option (Muscolo et al., 2014;Yang et al., 2017;Wang et al., 2018;Amolikondori et al., 2021;). However, we still lack understanding of the consequences of forest gaps on soil biodiversity, which is critical to the development of strategies for forest management and biodiversity conservation. ...
Soil biodiversity and the structure of soil animal communities are important foundations for forest ecosystem functions. Forest gap formation is an important forest management practice used to transform monocultures into mixed forests. However, whether and how gap size and age affect soil biodiversity and modify nematode communities remains limited. We manipulated gap size (100, 200, and 400 m 2) in Pinus massoniana plantations and studied the communities of soil nematodes, bacteria, fungi, and understory plants two and four years after gap formation. Compared to the no-gap treatment, soil nematode abundance across forest gaps increased by a factor of 1.40, which was largely attributed to the increase in herbivorous nematodes as the abundance and diversity of understory plants increased. The increased abundance of soil nematodes in forest gaps was also associated with increased soil pH presumably related to reduced input of pine needles. Furthermore, the abundance (− 5.3 %) and diversity (− 25.1 %) of soil nematodes decreased with gap age, presumably because of increased soil temperature and decreased soil moisture in the four-compared to the two-year-old gaps. In contrast to nematodes, the abundance and diversity of soil bacteria (21.8 % and 7.1 %) and fungi (10.5 % and 10.0 %) increased significantly with gap age. Overall, forest gaps increased the diversity of understory plants and soil biota, and changed the community and functional group structure of soil nematodes. These results provide guidelines for fostering soil biodiversity and maintaining soil functioning when transforming coniferous forests into mixed forests.
... These conditions allow edge beech, pine and oak trees to achieve higher growth rates than the trees in the stand and benefit from the gap. However, these conditions also depend on the size of the gap, as found by Abd Latif and Blackburn (2010) or Amolikondori et al. (2021). Larger gaps increase light availability and can enhance the microclimatic conditions in the gap. ...
... Високият процент за Парангалица се дължи на засилени процеси на отпад, предимно на едроразмерни дървета от обикновена ела и обикновен смърч и съответно формиране на множество прозорци и котли през последните 2-3 десетилетия . Данните за размера и гъстотата на прозорците в букови гори във фаза на старост са сходни с проучвания на други подобни гори в Европа (Drössler and von Lupke, 2005;Nagel and Svoboda, 2008;Kenderes et al., 2008;Kucbel et al., 2010;Garbarino et al., 2012) и Каспийския район на Иран (Amolikondori et al., 2021). Специфичен момент, който е наблюдаван в участъци на резерватите Стенето и Северен Джендем е формирането и на линейни котли с дължина до няколкостотин метра по посока на наклона на склона след ледоломи и снеговали (Глава 3). ...
We collected and analyzed structural and tree-ring data in Steneto and Boatin Natural Reserves and studied tree response after disturbances (ice and wind damages and fires) in North Dzhendem, Steneto and Sokolna reserves in the Central Balkan National Park, Bulgaria. Our aim was to contribute to the understanding of the structural variability of unmanaged old-growth Fagus sylvatica forests on different spatial scales. A grid permanent circular plots (1500 m2) were established in Steneto and Boatin forest reserves, in total, 14 and 28 plots respectively. This work was done within the framework of project REMOTE-Primary forest (https://www.remoteforests.org/ )
The total number of live trees with the DBH>6 cm for the whole studied forest patches ranged between 269 (patch Steneto 1) and 367 trees/ha (Boatin). The volume of alive trees was about 400 m3/ha, of the dead standing trees 6-20 m3/ha, of the dead lying wood about 50-70 m3/ha. The forests were dominated by European Beech with few other species. The DBH structure resembled Reverse-J in all forests. The age varied strongly, between 100 and 500+ years. The highest concentration of old trees was found in Steneto 1 forest patch, where there were many trees over 300 years. In Steneto 2 patch dominated trees below 250 years. In Boatin reserve there was a peak of trees between 200 and 250 years with oldest ones above 500 years. After disturbances the tree reactions were varying strongly, but were not only releases. There were also suppressions and especially after the fires the post-disturbance mortality was very high.
... However, gap closure depends on different drivers, such as the density of seedlings, sapling diameter and the height of gap-filling trees in each layer [45]. Similar to our findings, species of the genus Fagus have been reported as the main species for gap closure in other research [45,46,48,85,86]. This situation is mainly due to the fact that beech is a shade-tolerant tree species, with highly developed and interconnected root systems and advanced growth, which overwhelm other species [51]. ...
The interest to assess the relationship between forest gap characteristics and topography features has been growing in the last decades. However, such an approach has not been studied in undisturbed mixed sessile oak-beech old-growth forests. Therefore, the present study carried out in one of the best-preserved sessile oak-beech old-growth forests in Europe, aims to assess the influence of topographic features (slope, altitude and aspect) on (i) some characteristics of canopies and expanded gaps (surface, diameter and perimeter) and (ii) the proportion of beech and sessile oak as bordering trees, gap fillers and gap makers. Through a complete gap survey on an area of 32 ha, 321 gaps were identified and mapped. The largest gaps and also the highest gap frequency (140) was found in the slope class (15.1-20°), while the gap frequency increased with altitude, with 99 gaps being recorded at 601-650 m a.s.l. The size and perimeter of the canopy and expanded gaps, as well as the number of gap makers, were negatively related to the slope and altitude. The expanded gap to canopy gap size ratio decreased with the slope and was positively related to the altitude, while a significant negative decrease in gap filler density with altitude was encountered. The sessile oak participation ratio as bordering trees forming the gap increased not only with the altitude but also with the slope. The topography plays an important role in the formation of gaps as well as in the characteristics of the future stand. This study provides valuable insights into the relationship between canopy gap characteristics and topography, which is useful information for forest owners that pursue the design of forest management toward nature-based solutions.
Soil biodiversity and the structure of soil animal communities are important foundations for forest ecosystem functions. Forest gap formation is an important forest management practice used to transform monocultures into mixed forests. However, whether and how gap size and age affect soil biodiversity and modify nematode communities remains limited. We manipulated gap size (100, 200, and 400 m2 ) in Pinus massoniana plantations
and studied the communities of soil nematodes, bacteria, fungi, and understory plants two and four years after gap formation. Compared to the no-gap treatment, soil nematode abundance across forest gaps increased by a factor of 1.40, which was largely attributed to the increase in herbivorous nematodes as the abundance and diversity of understory plants increased. The increased abundance of soil nematodes in forest gaps was also
associated with increased soil pH presumably related to reduced input of pine needles. Furthermore, the abundance ( 5.3 %) and diversity ( 25.1 %) of soil nematodes decreased with gap age, presumably because of increased soil temperature and decreased soil moisture in the four- compared to the two-year-old gaps. In
contrast to nematodes, the abundance and diversity of soil bacteria (21.8 % and 7.1 %) and fungi (10.5 % and 10.0 %) increased significantly with gap age. Overall, forest gaps increased the diversity of understory plants and soil biota, and changed the community and functional group structure of soil nematodes. These results provide guidelines for fostering soil biodiversity and maintaining soil functioning when transforming coniferous forests into mixed forests.
Allometric relationships between crown width (CW) and stem diameter at breast height (DBH) contribute in understanding forest dynamics and estimating forest biomass and carbon stocks. Nevertheless, the response of tree crown allometry to gap management and climate interactions remain unclear. We used 934 paired CW and DBH of Robinia pseudoacacia trees from 38 man-made gap forest sites (GPFs) of different sizes and 40 unmanaged forest sites (UMFs) in three counties with different climatic conditions in the Loess Plateau to (1) evaluate potential deviations in CW estimation from existing crown allometry models for R. pseudoacacia; (2) compare the predictive ability of nine common theoretical functions for crown allometry; (3) analyze scaling exponents variations of crown allometry, and test their fit to theoretical predictions; and (4) examine the influence of stand-level and climatic variables on crown allometric relationships. The existing CW-DBH equations provided better fit for GPFs than for UMFs, although substantial deviations were observed. The power function outperformed other theoretical forms for crown allometry in both GPFs and UMFs. The scaling exponents of the allometric relationships were lower in UMFs than in GPFs, which was closer to the metabolic-scaling theory predictions. Distance-independent competition considering average DBH accounted for major variations in crown allometric relationships in both gap-managed and unmanaged forests. Variations in scaling exponents in GPFs were also explained by diffuse light availability and climatic (annual precipitation and wind speed) variables. Our results highlight the significant role of climatic variables in affecting crown allometric relationships in forest gaps. These results have implications for developing vegetation models and long-term forest management in the context of climate change.
