Effects of canopy gap size on the regeneration of Scots pine (Pinus sylvestris L.) in Eskişehir-Çatacık region of Turkey (original) (raw)
Related papers
Gap characteristics and their effects on regeneration, dominance and early growth of woody species
Journal of Plant Ecology, 2009
Aims We aim to examine the canopy gap characteristics and evaluate their influence on regeneration, dominance and the early growth of woody species in seasonally dry Shorea robusta forests (Sal forests). Methods Sixty canopy gaps were surveyed in six randomly located transects belts in seasonally dry subtropical Sal forests of central Nepal. Each transect belt was followed until 10 gap sites were encountered. The equation for the area of an ellipse was used to calculate the size of canopy gap, measuring the longest axis and its perpendicular shorter axis. Number, sizes, ages and causes of tree falls creating canopy gaps along with number and sizes of border trees were identified and recorded. Detailed gap inventories were carried out using square 25-m 2 quadrats placed in the middle of each gap. All individuals >2 m in height within the quadrat were identified at the species level and their diameter at breast height was measured. We assigned a nested 4-m 2 quadrat to the corner of each 25-m 2 quadrat, within which all woody individuals >10 cm tall were identified at the species level, and counted them and their regeneration mechanisms were identified. The height and collar diameter of the tallest individuals were measured. Descriptive statistics was calculated for the variables of interests and Pearson correlation, linear regression, independent-sample t-test and chi-square test were used to relate them and to test for their associations. Important Findings The study found mean gap size of 283 m 2 and ;50% gaps of 10-15 years old. Gaps created by natural single-tree falls were significantly more numerous, and their mean size was significantly smaller than those resulting from artificial causes or multiple-tree falls. Gap size correlated with the basal area of felled trees, but it did not correlate with the number of tree falls. While tree fall basal area was significantly positively correlated to the seed-originated seedling to resprout ratio, it was negatively correlated, along with gap area and the basal size of retained trees, to seedling growth. The relative seedling density of Terminalia alata increased with increases in gap areas, while that of S.robusta decreased with increases in tree fall basal area, thereby lowering the plot-level dominance. However, the relative seedling densities of Eugenia operculata and Syzigium cumini were negatively and positively correlated, respectively, with tree fall basal area. Keywords: canopy gap d seedling density d seedling growth d basal area d Sal forests d Nepal
Plant Ecology, 2010
We examined the influence of small-scale gap disturbances on stand development and tree species coexistence in an old-growth Fagus sylvatica–Abies alba forest in the Dinaric Mountains of Bosnia–Herzegovina. The structure and composition of tree regeneration in gaps were compared to the forest as a whole, and the influence of gap size on the density and composition of regeneration was assessed. Transition probabilities were also calculated from gapfillers in different life stages to examine canopy replacement patterns. The structure and composition of tree regeneration were similar between gaps and the forest as a whole, and there was no relationship between overall regeneration density and gap size, indicating most individuals established prior to gap formation. Likewise, there was no strong evidence of gap-size partitioning for shade tolerant F. sylvatica and A. alba, although less tolerant Acer pseudoplatanus only recruited to taller life stages in larger gaps. Transition probabilities calculated from the seedling and sapling data suggest that most gaps will be captured by F. sylvatica, while probabilities based on pole-sized gapmakers indicate both A. alba and F. sylvatica will be maintained in the canopy. We suggest that gaps primarily play a role in reorganizing advance regeneration, and that coexistence of shade tolerant F. sylvatica and A. alba is more likely related to their differential ability to tolerate shaded understory conditions, particularly during larger life stages, rather than gap-size partitioning.
Forest Systems, 2013
Aim of the study: The aim of the research is to analyse the role of Quercus ilex advance regeneration in the stand regeneration of pine plantations after small-sized canopy openings, and to assess the influence of the forest stand and the canopy opening. The performance of the advance regeneration under the pine plantation is also examined. Area of study: A Pinus nigra plantation in dry Continental Mediterranean climate in eastern Spain. Materials and Methods: The tree regeneration of ten canopy openings of 0.17-0.43 ha was monitored during five years after treatment. It was also sampled in 0.12 ha-plots in the non-treated pine plantation surrounding the openings. Main results: An important increase in the height of Q. ilex regeneration was observed in the openings, unlike what was found in the intact pine plantation. In the pine plantation, stand density showed a moderate positive influence on the density of Q. ilex regeneration, whereas in the canopy gaps Q. ilex height was negatively influenced by stand density before the opening. Research highlights: The canopy opening triggered a response in Q. ilex advance regeneration, although height growth rates seemed to reduce over time. The results support the view that promoting Q. ilex in pine plantations may require different management strategies depending on the characteristics of the pine overstorey and on the density and size of the advance regeneration.
Journal of Forest Science, 2020
Forest gaps remain the optimal forest management practice in modern forestry. Upon all the physical properties of forest gaps, the ‘gap size’ feature stands out as an essential property. The effect of gap size on tree species composition and diversity of natural regeneration in forest gaps of different sizes was investigated. Eight research forest gaps were selected from the Training Forest School Enterprise, also called Masaryk Forest in Křtiny, a temperate mixed forest in the Czech Republic. By given gap sizes, small (< 700 m2) and large gaps (≥ 700 m2) were defined. Forty-one (41) regeneration microsites (RSs) of 1 m2 circular area at 2 m intervals were demarcated within each forest gap. These RSs served as data collection points. From the total of eleven (11) species enumerated, large gaps obtained higher species composition (10) and diversity (Simpson = 0.5 1-D; Shannon = 1.0 H and Pielou’s evenness = 0.5 J indices) records, yet, small gaps presented favourable conditions fo...
Annals of Forest Science
• Key message The browsing level of oak (Quercus petraea and Quercus robur) and fir (Abies alba) provided only a rough estimate of the expected regeneration success. Thus, it cannot be recommended as a standard measurement to predict forest development, unless the number of saplings and the height of those saplings are considered. • Context Browsing by large herbivores may affect regeneration success and forest development, with an impact that lasts for decades. • Aims Whether the browsing level of a tree species can be used in forestry as a standard measure to assess whether the target values (for instance regeneration success) of highly selected tree species, such as oak (Quercus petraea (Mattuschka) Liebl., Quercus robur (L.)) and fir (Abies alba (Mill.)), will be reached is unclear and need specification. • Methods In this study, 985 sampling plots (10 m 2) in Southern Germany (Baden-Württemberg) containing browsed and unbrowsed oak and fir-saplings were analysed. Both the browsing level and a measure of the expected regeneration success that considered not only the sapling density but also different height classes (≤ 20 cm; 21-50 cm; 51-130 cm) were calculated. • Results The use of the browsing level as a proxy for the expected regeneration success was statistically only partly justified. For fir the relationship between browsing level and expected regeneration success became even weaker for a new indicator variable which considers two height classes rather than one class for saplings exceeding 50 cm (51-80 cm and 81-130 cm). • Conclusion According to these results, the browsing level cannot be recommended as a standard measurement and/or predictor of damage, unless the number of saplings and the height of those saplings are considered. Thus, in efforts to mitigate conflicts between foresters and hunters, a measurement is needed that addresses the successful establishment of a sufficient number of trees despite browsing, rather than the browsing of trees alone.
Forestry, 2007
Gap regeneration in two old-growth forest reserves in Slovenia (Rajhenavski Rog) and Croatia ( Č orkova Uvala) was analysed in relation to within gap light heterogeneity. Both reserves were located in the Dinaric mountain range in south-central Europe and were dominated by beech ( Fagus sylvatica L.) -silver fi r ( Abies alba Mill.) forest communities with similar growing conditions. In total, the two largest gaps (700 -2000 m 2 ) in each reserve were included in the study ( n = 4), plus a further four gaps in Rajhenavski Rog and three in Č orkova Uvala (200 -500 m 2 ). All the gaps were ~ 10 years old and originated from one or two successive events, mostly due to a combination of fungi attack and windthrow. Consequently, all gaps had complex geometry and were covered by a well-developed regeneration layer. Each gap was mapped, followed by establishment of a N -S oriented 5 × 5 m grid within and around the area of the canopy opening. At the grid intersections 773, 1.5 × 1.5 m plots were established. On each plot, the coverage of tree regeneration and ground vegetation, seedling density in different height classes and browsing damage were recorded. In addition, the total stretched length and last growing season increment of the leading stem was measured on selected seedlings in each plot. Relative diffuse and direct radiation were estimated using digital hemispherical photographs. All plots were classifi ed into four microsites according to direct and diffuse radiation levels, and microsites were tested for differences in regeneration height and density. While there was more woody regeneration and an almost fi vefold higher (6.2 vs 1.3 m − 2 ) average total regeneration density in Rajhenavski Rog, mainly due to a high (5.5 vs 0.6 m − 2 ) density of beech, there was more ground vegetation and a higher density of silver fi r seedlings in Č orkova Uvala. The within-gap regeneration patterns proved to be similar in both forest reserves and showed that 1-year-old seedlings of beech and silver fi r and small beech seedlings preferably recruit on microsites under closed canopy or close to gap edges with lower levels of direct and diffuse radiation. There was no signifi cant difference in density of large-beech seedlings among the microsites, yet height and height increment were higher on microsites receiving the highest levels of direct and diffuse radiation. Within-gap heterogeneity in light conditions appears to signifi cantly
Fuel and Energy Abstracts, 2011
Virgin beech Fagus orientalis forests in northern Iran provide a unique opportunity to study the disturbance regimes of forest ecosystems without human influence. The aim of this research was to describe characteristics of natural canopy gaps and gap area fraction as an environmental influence on the success of beech seedling establishment in mature beech stands. All canopy gaps and related forest parameters were measured within three 25 ha areas within the Gorazbon compartment of the University of Tehran's Kheyrud Experimental Forest. An average of 3 gaps/ha occurred in the forest and gap sizes ranged from 19 to 1250 m 2 in size. The most frequent (58%) canopy gaps were <200 m 2 . In total, canopy gaps covered 9.3% of the forest area. Gaps <400 m 2 in size were irregular in shape, but larger gaps did not differ significantly in shape from a circle. Most gaps (41%) were formed by a single tree-fall event and beech made up 63% of gap makers and 93% of gap fillers. Frequency and diversity of tree seedlings were not significantly correlated with gap size. The minimum gap size that contained at least one beech gap-filling sapling (<1.3 m tall) was 23.7 m 2 . The median gap size containing at least one beech gap-filling sapling was 206 m 2 and the maximum size was 1808 m 2 . The management implications from our study suggest that the creation of small and medium sized gaps in mixed beech forest should mimic natural disturbance regimes and provide suitable conditions for successful beech regeneration.
Forest Ecology and Management, 2014
Quercus-Pinus forests of the eastern USA cover millions of hectares and span a variety of ecoregions. Understanding the influence of natural disturbance on developmental and successional pathways is important for managers that wish to sustain Pinus spp. in these mixtures. Quantifying developmental and successional patterns in this forest type can help assess the need to actively manage natural processes and inform silvicultural prescriptions to achieve management goals. Little research has been conducted on natural, gap-scale disturbance processes in Quercus stands with strong components of Pinus taeda, Pinus virginiana, and Pinus echinata. We examined 60 canopy gaps in a Quercus-Pinus forest on the southern Cumberland Plateau in Alabama to document gap formation, closure, and other characteristics and to analyze the influence of localized disturbance on development and succession. The majority of gapmaker trees (56%) were Pinus individuals and 44% were hardwoods. Most gaps (58%) closed by height growth of subcanopy trees. The majority of these gap filler taxa were hardwoods: Quercus (39%), Carya (14%), Nyssa sylvatica (12%), and other hardwoods (15%), with Pinus representing 14%. The number of Pinus gapmakers and the number of gaps projected to fill by subcanopy recruitment of hardwoods indicated the forest was in the latter stages of a composition shift from Pinus to a much stronger Quercus component. Significant positive relationships existed between gap size and sapling diversity (r 2 = 0.15, P = 0.002), tree diversity (r 2 = 0.21, P = 0.0002), and total stem diversity (r 2 = 0.29, P < 0.0001) indicating a positive relationship may exist between gap size and diversity on xeric ridge tops where shade-tolerant species are less competitive. We speculated the ridge top positions contributed to the relatively high gap formation rates noted in this study. Pinus composition was found to be patchy, indicating a gap-based approach may be used to manage for Pinus recruitment in hardwood dominated systems.