Journal articles on the topic 'Stand structure'
To see the other types of publications on this topic, follow the link: Stand structure.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Stand structure.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Muir, Patricia S. "Disturbance effects on structure and tree species composition of Pinuscontorta forests in western Montana." Canadian Journal of Forest Research 23, no. 8 (August 1, 1993): 1617–25. http://dx.doi.org/10.1139/x93-201.
Full textAbstract:
To what extent are stand structure and tree species composition affected by the nature of stand-initiating disturbances and other disturbances that cause significant tree mortality? I documented recent disturbance history and tree species composition, density, spatial pattern, and age structure in 48 stands dominated by Pinuscontorta Dougl. ex Loud. ssp. latifolia (Engelm.) Critchfield in western Montana. Stand modal ages ranged from 8 to 267 years, and sites were sampled across a range of elevations and aspects. Disturbance histories included stand-replacing fires (N = 25), partial burns (N = 8), clear-cutting (N = 7), and other disturbances (N = 8). All young stands (modal tree age < 23 years) had unimodal age structures; however, within-stand ranges in tree ages were greater following cutting than burning. Young fire-origin stands were more strongly dominated by P. contorta than young clearcut-origin stands. For older stands, within-stand variability in tree ages was greatest after nonfire disturbances and lowest after stand-replacing burns, while tree density was highest after such bums, and tree species diversity did not differ among disturbance types. The primary axis of variation in age structures across all stands, as revealed by principal components analysis, related to within-stand variability in tree ages. Compositional and structural stand features were not correlated with this axis.
2
Deal, Robert L. "The effects of partial cutting on forest plant communities of western hemlock Sitka spruce stands in southeast Alaska." Canadian Journal of Forest Research 31, no. 12 (December 1, 2001): 2067–79. http://dx.doi.org/10.1139/x01-143.
Full textAbstract:
The effects of partial cutting on plant species richness, community structure, and several understory species that are important for deer forage were evaluated on 73 plots in 18 stands throughout southeast Alaska. These partially cut stands were harvested 1296 years ago when 1696% of the former stand basal area was removed. The species richness and community structure of understory plants were similar in uncut and partially cut plots. However, plots where more than 50% of the basal area was cut had a significantly different plant community structure. Species composition and abundance also appeared to be distinctly different between hemlock-dominated and spruce-dominated stands. Partial cutting did not significantly change abundance for most of the important forage species for deer. The similarity in plant community structure between partially cut and uncut old-growth stands may be related to forest stand structures. The heterogeneous stand structures that develop after partial cutting are more similar to old-growth stands than to the uniform young-growth stands that develop after stand replacing disturbances such as clear-cutting.
3
Špulák, Ondřej, Jiří Souček, and Jakub Černý. "Do stand structure and admixture of tree species affect Scots pine aboveground biomass production and stability on its natural site?" Journal of Forest Science 64, No. 11 (December 3, 2018): 486–95. http://dx.doi.org/10.17221/117/2018-jfs.
Full textAbstract:
The paper analyses stand structure and production on two experimental forest stand series of mature pure and mixed Scots pine stands, growing on natural Scots pine sites in the Czech Republic. Sessile oak was the main admixed species. In mixed stands, Scots pine constituted the dominant level of the stand, admixed species grew mostly as subdominants. Admixture increased stand densities and aboveground biomass production compared to pure stands. Sessile oak with the 20–30% number share within the Scots pine stand led to an increase of the Scots pine tree dimensions and mean stem merchantable wood (DBH ≥ 7 cm) volume compared to the pure Scots pine stand of similar density. The Scots pine and sessile oak slenderness ratios increased in mixed stands compared to monocultures, however, the stand mechanical stability was not threatened.
4
Jaworski, A., and Z. Kołodziej. "Beech (Fagus sylvatica L.) forests of a selection structure in the Bieszczady Mountains (southeastern Poland)." Journal of Forest Science 50, No. 7 (January 11, 2012): 301–12. http://dx.doi.org/10.17221/4627-jfs.
Full textAbstract:
The characteristics of two beech (Fagus sylvatica L.) stands are presented in this paper. One, the Tarnicki stand, situated in the Bieszczadzki National Park, represents the growing up stage and selection phase of a forest of primeval character. The other one, the Otryt stand, is situated in managed forests of the Lutowiska Forest District. In each stand two sample plots were established. The distribution of the number of trees in each sample plot agreed with de Liocourt sequence and Meyer curve. Both stands were characterized by the structure of many generations. The Otryt stand, with respective volumes of 238 and 324 m<sup>3</sup>/hain two sample plots, was characterized by a lack of large diameter trees and a high percent of trees of the smallest diameters, while the Tarnicki stand, with volumes of 442 and 517 m<sup>3</sup>/ha, was characterized by the presence of large diameter trees (d<sub>1.3</sub> ≥ 72 cm). The phase of the selection forest in the Tarnicki stand is of temporary character because, due to natural processes, a two-storied structure may develop there, and with time, a one-storied structure in the optimal stage. In the Otryt stand, representing a managed forest, the maintenance of the selection structure may be expected due to selection cuttings. It has to be acknowledged that managed stands of characteristics similar to those presented in this paper makes it possible to carry out selection cutting, especially in the protection zone surrounding the Bieszczadzki National Park.
5
Stajic, Branko. "Definition of optimal structure of white ash juvenile stands." Bulletin of the Faculty of Forestry, no. 89 (2004): 213–22. http://dx.doi.org/10.2298/gsf0489213s.
Full textAbstract:
Optimal structure of young white ash stands was studied in the region of Majdanpecka Domena. The stands are characterized by poor crown development and a high number of trees. The definition of the optimal stand structure was based on the analysis of causal relationships between crown structure and tree and stand increment. It was concluded that the optimal number of trees on the sample plots should be considerably lower compared to the actual number of trees. This would enable an economic utilization of growth space, forming of more efficient crown assimilation, faster growth and more effective tree and stand dimensions, as well as the greater stand vigor and stability.
6
Rahman, Ataur, Nasrullah Khan, Rafi Ullah, and Kishwar Ali. "Stand Structure and Dynamics of the Naturally Managed Oak-Dominated Forests and Their Relation to Environmental Variables in Swat Hindu Kush Range of Pakistan." Sustainability 15, no. 5 (February 22, 2023): 4002. http://dx.doi.org/10.3390/su15054002.
Full textAbstract:
Although oak woodlands are a characteristic landscape component in the Swat Hindukush Mountain ranges, little is known about their current or historical stand population structure and regeneration dynamics related to environmental variables. Therefore, the present study assessed the stand structure, regeneration status, and relationship of oak communities with environmental variables. The study assessed 30 oak-dominated forest sites using the quadrates method, sampling 300 quadrates for evaluating the phytosociological and environmental variables. The stand structures of forests were dominated by four oak species, i.e., Quercus incana, Quercus baloot, Quercus dilatata, and Quercus semecarpifolia, distributed along with the elevation. The lower elevation stand structures were most diverse and dominated by Q. incana, having higher stand parameters, i.e., importance value index, basal area, and density. In contrast, the higher-elevation stand structures were dominated by Q. semecarpifolia, having stand parameters in moderate measures, while those at intermediate elevations have lower stand parameters. The environmental variables were negatively correlated with the stand structures, i.e., elevation (r = −0.51), precipitation (r = −0.47), and relative humidity (r = −0.77), whereas soil nutrients such as Potassium concentration have a significant negative relation with stands structure (r = −0.66) indicating their vital role in sustaining the oak communities. The communities were fairly regenerated, with an age structure between 12–36 years, indicating young communities. These results concluded that the observed wide range of variability in stand characteristics reflects the mechanisms that have shaped them. The recent anthropogenic factors, i.e., military operations and natural hazards such as the flood of 2010, have deliberately affected the communities under natural restoration.
7
Rudnicki, Mark, Victor J. Lieffers, and Uldis Silins. "Stand structure governs the crown collisions of lodgepole pine." Canadian Journal of Forest Research 33, no. 7 (July 1, 2003): 1238–44. http://dx.doi.org/10.1139/x03-055.
Full textAbstract:
We investigated tree sway and crown collision behavior of even-aged lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) stands of different structure in Alberta, Canada, to examine how these factors might affect loss of leaf area as stands mature. The Two Creeks stand (TC) had high density and slender trees, while the Chickadee stand (CH) had stout trees. The TC stand was then thinned (TCT) to reduce the stand density. For each stand, simultaneous tree sways of a group of 10 trees were monitored with biaxial clinometers during wind speed of 5 m/s (canopy top). Crown collisions were reconstructed by combining sway displacement of individual trees with their respective crown dimensions. Comparing the sway statistics between stands with contrasting mean bole slenderness (TC and CH) indicated that more slender trees have greater sway displacements, faster sway speeds, and a greater depth of collision. Disturbance by thinning increased sway displacements, sway speeds, and depth of collisions at TCT. Tree sway patterns were circular in shape and not aligned with wind direction, but patterns were elongated after thinning. This demonstrates the high frequency of crown collision experienced by stands with slender trees and supports the notion that crown collisions result in empty space between crowns of trees.
8
Jaworski, A., Zb Kołodziej, and K. Porada. "Structure and dynamics of stands of primeval character in selected areas of the Bieszczady National Park." Journal of Forest Science 48, No. 5 (May 17, 2019): 185–201. http://dx.doi.org/10.17221/11874-jfs.
Full textAbstract:
The investigations carried out in 1988 and 1998 on three permanent sample plots in stands of the East Carpathian beech forest (Dentario glandulosae-Fagetum) showed that in the growing up stage, the storeyed structure phase (Jawornik I stand), the stand volume increased from 547 m<sup>3</sup>/ha to 578 m<sup>3</sup>/ha while in the optimum stage, the ageing and regeneration phases (Jawornik II), it decreased from 631 m<sup>3</sup>/ha to 600 m<sup>3</sup>/ha, and in the growing up stage, the storeyed structure phase (Tworylczyk), from 611 m<sup>3</sup>/ha to 610 m<sup>3</sup>/ha. In all three stands beech dominated in the upgrowth. During the 10-year period the volume of dead trees (standing and lying ones) increased in Jawornik II and Tworylczyk stands while in Jawornik I stand it decreased. The beech stands of the Bieszczady Mountains have a largely differentiated structure, from one-storey structure in the optimum stage, the ageing phase to many-storeyed structure in the growing up stage. This creates an opportunity for forming the complex stand structure, also the selection forest structure, in managed beech forests of the Carpathians.
9
Janowiak, Maria, Linda M. Nagel, and Christopher Webster. "Minimum Tree Size and Interpretation of Stand Structure in Uneven-Aged Northern Hardwoods." Northern Journal of Applied Forestry 27, no. 1 (March 1, 2010): 34–37. http://dx.doi.org/10.1093/njaf/27.1.34.
Full textAbstract:
Abstract Uneven-aged management of northern hardwoods frequently relies on diameter distributions in evaluating and controlling stand structure. However, the minimum tree diameter used to analyze diameter distributions varies among studies and may affect the interpretation of distribution shapes and, subsequently, stand structure. It has been suggested that the use of larger minimum diameters in the construction of these distributions would cause rotated sigmoid stand structures to exhibit a negative exponential distribution shape. To test this hypothesis, we constructed diameter distributions using minimum diameters of 3.0 and 13.0 cm for seven northern hardwood stands. Differences in distribution shape were observed only in unmanaged stands, in which three distribution shapes classified as rotated sigmoid using a 3.0-cm minimum diameter were classified as increasing-q when the 13.0-cm minimum diameter was used.
10
Stimm, Kilian, Michael Heym, Ralf-Volker Nagel, Enno Uhl, and Hans Pretzsch. "Long-Term Productivity of Monospecific and Mixed Oak (Quercus petraea [Matt.] Liebl. and Quercus robur L.) Stands in Germany: Growth Dynamics and the Effect of Stand Structure." Forests 13, no. 5 (May 5, 2022): 724. http://dx.doi.org/10.3390/f13050724.
Full textAbstract:
Wood production is one of the most important ecosystem service that forests provide to society. However, under changing climatic conditions, this appears to be subject to increasing uncertainties. In the present study we analyzed how long-term productivity of oak (Quercus petraea [Matt.] Liebl. and Quercus robur L.) stands has developed, how oak behaved on tree and stand level depending on the stand structure and which trade-offs can be observed. For the analyses, data from 147 long-term monospecific and mixed stands were investigated, which have been regularly recorded since 1898. Firstly, long-term stand productivity has increased up to 21% until 2020 as compared to 1960. This trend was observed for both, monospecific as well as mixed oak stands. Secondly, stand productivity was on average 19% higher in mixed compared to monospecific oak stands. This superiority can be explained by higher stand densities, a vigorous understory and the admixture of beech in particular. With increasing age, the observed positive effect of stand density was higher. Thirdly, individual oak productivity slowed down under interspecific competition, especially in young to mid-aged stands. In this context, the productivity of individual oaks depended strongly on their social position within the stand. Fourthly, in terms of growth partitioning larger trees contributed most in young oak stands, regardless of mixture. In order to preserve oak as a productive component of future mixed forests, the results suggest a silvicultural promotion of oak. Consistent management of dominant and vital oaks can achieve high productive trees while maintaining the positive characteristics of highly structured and mixed forests. A vigorous secondary stand can increase overall stand productivity at lower densities and allows silvicultural flexibility at the stand level. Creating vertical stand structure to reduce competition has only a limited positive effect on productivity of individual oaks that is highly related to its social status. Special attention should still be paid to beech as admixed tree species, which can continue to crowd oak even at higher stand ages.
11
Moussaoui, Louiza, Alain Leduc, Miguel Montoro Girona, Annie Claude Bélisle, Benoit Lafleur, Nicole J. Fenton, and Yves Bergeron. "Success Factors for Experimental Partial Harvesting in Unmanaged Boreal Forest: 10-Year Stand Yield Results." Forests 11, no. 11 (November 13, 2020): 1199. http://dx.doi.org/10.3390/f11111199.
Full textAbstract:
Over the past two decades, partial harvesting has been increasingly used in boreal forests as an alternative to clearcutting to promote irregular stand structures and maintain a balance between biodiversity preservation and continued timber production. However, relatively little is still known about the silvicultural potential of partial harvesting in Canada’s boreal forest, especially in areas prone to organic matter accumulation (paludification), and most prior research has focused on biodiversity responses. In this study, we assess the effects of partial harvesting on stand development (recruitment, growth, and mortality) ten years after harvesting in previously unmanaged black spruce stands and quantify its effectiveness in reducing the impacts on ecosystem structures. Our analyses revealed that pre-harvest stand structure and site characteristics, especially initial basal area, sapling density, tree diameter, and organic layer thickness (OLT) were major factors involved in stand development ten years following these partial harvesting treatments. Depending on pre-harvest structure and site characteristics, partial harvesting can result in either an increase in post-harvest tree recruitment and growth or a loss of stand volume because of standing tree mortality. To increase the chances of partial harvesting success in ensuring an increase in decennial stand yield after harvest in black spruce forest stands, sites prone to paludification (i.e., where OLT >17 cm) should be left unharvested. This study illustrates the importance of taking into account pre-existing structure and site characteristics in the selection of management strategies to maximize the potential of partial harvesting to achieve sustainable forest management in black spruce stands.
12
Nagel, Linda M., and Kevin L. O'Hara. "The influence of stand structure on ecophysiological leaf characteristics of Pinus ponderosa in western Montana." Canadian Journal of Forest Research 31, no. 12 (December 1, 2001): 2173–82. http://dx.doi.org/10.1139/x01-156.
Full textAbstract:
The effects of vertical arrangement of foliage in even-aged and multiaged stand structures of ponderosa pine (Pinus ponderosa Dougl. ex P. Laws. & C. Laws.) on overall stand growth, light interception, and physiological leaf properties were tested on five plot pairs in western Montana. The primary structural difference between stand structures involves greater canopy depth and stratification of foliage in the multiaged stands. Both area- and mass-based maximum photosynthetic rates (Aarea and Amass) were relatively constant with canopy depth in both stand structures. Area- and mass-based leaf nitrogen (Narea and Nmass) decreased with increasing canopy depth in the even-aged stand structures but not in the multiaged. Specific leaf area (SLA) tended to increase with increasing canopy depth, although this relationship was only significant in the multiaged stand structures. The typical linear relationship observed for many species between photosynthetic rate and leaf nitrogen was not present in either stand structure; however, Narea was highly correlated to SLA in both even-aged and multiaged stand structures (R2 = 0.66 and R2 = 0.52, respectively). There were no differences in the light extinction coefficient (k), basal area growth or efficiency, or stand-level leaf area index between even-aged and multiaged plot pairs. Relative constancy in leaf physiology combined with similarities in site occupancy and growth rates help explain how different stand structures of ponderosa pine maintain similar rates of woody biomass productivity.
13
Návar, José. "Modeling tree diversity, stand structure and productivity of northern temperate coniferous forests of Mexico." PeerJ 7 (August 14, 2019): e7051. http://dx.doi.org/10.7717/peerj.7051.
Full textAbstract:
There is increasing evidence complex forest structure and tree diversity correlates positively with the productivity of forest ecosystems. However, there is little quantitative information regarding the effect of these factors on stand productivity of northern temperate coniferous forests of Mexico. This study aimed to test the hypothesis tree diversity and canopy structure positively associates with forest productivity. Parameterization of tree diversity, stand structure and productivity were carried out on dasometric data from 36 permanent sampling plots re-measured in 1982, 1993, and 2004. Statistical analysis of stand parameters tested the null hypothesis. Statistical relationships revealed well-balanced canopy strata and imbalanced diameter structures positively correlated with stand productivity. Tree diversity was also positively linked with stand productivity, but the effect appeared to be most important in the early to intermediate stages of succession. Further research is required to understand the long-term effects of tree diversity and canopy structure on stand productivity. These preliminary observations stress the importance of prescribing silvicultural practices that maintain the three-dimensional structure of stands and diversity of forest canopies that aim to preserve ecosystem function, diversity, and productivity.
14
Gonçalves, Ana Cristina. "Stand Structure Impacts on Forest Modelling." Applied Sciences 12, no. 14 (July 9, 2022): 6963. http://dx.doi.org/10.3390/app12146963.
Full textAbstract:
Modelling is essential in forest management as it enables the prediction of productions and yields, and to develop and test alternative models of silviculture. The allometry of trees depends on a set of factors, which include species, stand structure, density and site. Several mathematical methods and techniques can be used to model the individual tree allometry. The variability of tree allometry results in a wide range of functions to predict diameter at breast height, total height and volume. The first functions were developed for pure even-aged stands from crown closure up to the end of the production cycle. However, those models originated biased predictions when used in mixed, uneven-aged, young or older stands and in different sites. Additionally, some modelling methods attain better performances than others. This review highlights the importance of species, stand structure and modelling methods and techniques in the accuracy and precision of the predictions of diameter at breast height, total height and volume.
15
Siipilehto, J. "Modelling stand structure in young Scots pine dominated stands." Forest Ecology and Management 257, no. 1 (January 2009): 223–32. http://dx.doi.org/10.1016/j.foreco.2008.09.001.
Full text
16
O'Hara, K. L. "Stand structure and growing space efficiency following thinning in an even-aged Douglas-fir stand." Canadian Journal of Forest Research 18, no. 7 (July 1, 1988): 859–66. http://dx.doi.org/10.1139/x88-132.
Full textAbstract:
The growth of individual trees from four thinning treatments in a 64-year-old Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) stand was analyzed to determine desirable residual stand structures after thinning. Dominant and codominant trees had the highest individual tree stem volume growth rates over the previous 5 years, and accounted for most stand volume growth in thinned and unthinned stands. Two measures of growing space, crown projection area and sapwood basal area (a surrogate for leaf area), were used to measure how efficiently individual trees used their growing space. Crown classes were useful in characterizing growing space efficiency (volume growth per unit of growing space) only in the unthinned treatment. In thinned treatments, tall trees with medium-sized crowns were most efficient, while in the unthinned treatment, tall trees with relatively large crowns were most efficient. A large crown in an unthinned stand was comparable in size to a medium-sized crown in a thinned stand. Results suggest growing space is not limiting individual tree growth in thinned stands and that thinning to a particular stand structure is more appropriate than thinning to a particular level of stand density.
17
Vacek, Stanislav, Rostislav Linda, Ivo Králíček, Karel Vančura, Anna Prokůpková, and Romana Prausová. "Effect of structure and dynamics of forests on the occurrence of Erythronium dens-canis." Journal of Forest Science 66, No. 9 (September 29, 2020): 349–60. http://dx.doi.org/10.17221/96/2020-jfs.
Full textAbstract:
The paper presents the results of a study on the impact of forest stand structure and development in 1998 to 2018 on the occurrence of dog’s tooth violets (Erythronium dens-canis L.) in the Medník National Nature Monument, Czech Republic. The research was carried out in mixed European hornbeam and sessile oak stands, herb-rich European beech stands and the Sázava-river Norway spruce ecotype stands. The site and stand characteristics of the following three forest stand types were compared: 1) oak-hornbeam forests, 2) herb-rich beech forests and 3) secondary spruce forests. The results showed that the ratio of sterile and fertile plants was 2.9 to 1. The occurrence of E. dens-canis was higher in older stands with differentiated structure. On the contrary, stands characterized by a higher number of trees and basal area negatively affected the population size of E. dens‑canis. Significantly, the density of E. dens-canis decreased with increasing stand density index (SDI) and increased with increasing diameter differentiation index in relation to tree neighbours (TM<sub>d</sub>). During the period of 20 years, the E. dens-canis population increased by 40.4% on permanent research plots, while the highest changes were observed on spruce plots (+92.1%) and the lowest increase was in oak-hornbeam forests (+18.0%). The highest numbers of E. dens-canis plants were found in herb-rich beech forests (1 774 plants·ha<sup>–1</sup>), lower numbers occurred in oak-hornbeam forests (784 plants·ha<sup>–1</sup>) and minimal in secondary spruce forests (51 plants·ha<sup>–1</sup>). <br /><br />
18
Matsala, Maksym, Andrii Bilous, Roman Feshchenko, Raisa Matiashuk, Svitlana Bilous, and Yaroslav Kovbasa. "Spatial and compositional structure of European oak urban forests in Kyiv city, Ukraine." Journal of Forest Science 67, No. 3 (March 5, 2021): 143–53. http://dx.doi.org/10.17221/173/2020-jfs.
Full textAbstract:
Forest dimensional structure and tree species composition strictly define ecosystem resilience, success of its functioning and development. Spatial structure of forest compartments provides an additional information on the forest stand heterogeneity. The aim of this study is to examine structural patterns (both spatial and nonspatial ones) in European oak (Quercus robur L.) urban forests located in Kyiv city, Ukraine. We compared two middle-aged (~ 80 years) and two mature (~ 180 years) oak stands in terms of structural metrics collecting a data from geo-referenced trees on the established permanent sample plots. Younger stands reached similar tree diameter diversity (9.07 and 10.45 vs. 11.42 and 14.05 of Shannon indices), while the compositional diversity was driven by the dominance of either oak or European hornbeam (Carpinus betulus L.). We have not found any differences in the species mingling and deadwood distribution indices except a clear occurrence pattern for the stand located near roads. Herewith, the largest distance between the plot and park pathways was an indicator of changed spatial variation and tree dimensional differentiation within one middle-aged stand. We hypothesize that human impacts can alter structural development in urban deciduous forests providing both positive (gap formation, deadwood occurrence and ecosystem complexity) and negative (shifts in compositional and successional trajectories) effects on such forest stands.
19
KENNARD, DEBORAH K. "Secondary forest succession in a tropical dry forest: patterns of development across a 50-year chronosequence in lowland Bolivia." Journal of Tropical Ecology 18, no. 1 (January 2002): 53–66. http://dx.doi.org/10.1017/s0266467402002031.
Full textAbstract:
Stand structure, species richness and population structures of tree species were characterized in 12 stands representing 50 y of succession following slash-and-burn agriculture in a tropical dry forest in lowland Bolivia. Estimates of tree species richness, canopy cover and basal area reached or surpassed 75% of mature forest levels in the 5-, 8-, and 23-y-old stands respectively. Total stem density of the 50-y-old stand was almost twice that of the mature forest stand. This rapid recovery may be due to a high percentage of sprouting tree species, potentially high seed fall into abandoned fields, or the disturbance history of the mature stand. The even-aged size-class structures, dominance of long-lived pioneers, and presence of charcoal and pottery shards in soils of the mature forest stand suggest it formed after a severe disturbance, possibly fire of anthropogenic origin.
20
Boucher, D., L. De Grandpré, and S. Gauthier. "Développement dun outil de classification de la structure des peuplements et comparaison de deux territoires de la pessière à mousses du Québec." Forestry Chronicle 79, no. 2 (April 1, 2003): 318–28. http://dx.doi.org/10.5558/tfc79318-2.
Full textAbstract:
Forest stand structure is an important element for biodiversity and, from a sustainable forest management perspective, uneven-sized stands should be managed in order to maintain the structural diversity over the landscape. The first objective of this study is to develop a statistical tool to characterize stand structure that can be used in forest management planning. The second objective is to classify the stand structure of two regions to illustrate a possible use for the tool. The statistical tool for characterizing stand structure has been developed from forest inventory data gathered by the ministère des Ressources naturelles du Québec, using discriminant analysis. The analysis makes it possible to classify the stands into three types of structure, even-sized, uneven-sized and inverse J-shaped, with an error rate estimated at only 7%. Proportions of different structure types in Quebecs eastern black spruce forest region have been compared with those found in the western black spruce forest region. Nearly 90% of the western black spruce forest region is composed of pure black spruce stands, contrary to the eastern black spruce region, where there are more pure fir and mixed spruce-fir stands. Most of the western black spruce forest stands are even-sized (62%), while almost 70% of the eastern black spruce forest stands are uneven-sized or inverse J-shaped. Pure black spruce stands are more even-sized than pure fir stands, but regional differences are also found within pure black spruce stands. Our results show that it is possible to develop a robust tool that makes it possible to classify thousands of stands rapidly. Such tools are required if we want to consider stand structure for appropriate management prescriptions in the boreal forest. Key words: Even- and uneven-sized structure, fire regime, Picea mariana, Abies balsamea, boreal forest, structural diversity
21
Ahtikoski, Anssi, Jouni Siipilehto, Hannu Salminen, Mika Lehtonen, and Jari Hynynen. "Effect of Stand Structure and Number of Sample Trees on Optimal Management for Scots Pine: a Model-Based Study." Forests 9, no. 12 (November 30, 2018): 750. http://dx.doi.org/10.3390/f9120750.
Full textAbstract:
This study presents an attempt to discover the effect of sample size on the financial outcome derived by stand-level optimization with individual tree modeling. The initial stand structure was altered to reflect sparse, average, and dense Scots pine (Pinus sylvestris L.) stands. The stands had varying numbers of stems but identical weighted median diameters and stand basal areas. The hypothetical Weibull diameter distributions were solved according to the parameter recovery method. The trees were systematically sampled with respect to the tree basal area corresponding to sample sizes of 10, 20, or 40 trees. We optimized the stand management with varying numbers of sample trees and with varying stand structures and compared the optimal solutions with respect to the objective function value (maximum net present value) and underlying management schedule. The results for the pine stands in southern and central Finland indicated that the variations in the objective function value relating to sample size were minor (<2.6%) in the sparse and average stand densities but exceeded 3% in the dense stands. Generally, the stand density is not always known, and thus, we may need to generalize the average density for all cases in question. This assumption, however, resulted in overestimations with respect to the optimal rotation period and financial performance in this study. The overestimations in the net present value decreased along with the increasing sample size, from 22% to 14% in the sample sizes of 10 and 40 trees, respectively.
22
Novotny, Vladimir, Ivan Balenović, Tomislav Dubravac, Dijana Vuletić, and Stjepan Dekanić. "First Results of Monitoring of Stand Structure Changes in Unmanaged Beech Stands in NP Plitvice Lakes." South-east European forestry 1, no. 2 (December 31, 2010): 91–98. http://dx.doi.org/10.15177/seefor.10-10.
Full text
23
Berrill, John-Pascal, and Kevin L. O'Hara. "Simulating Multiaged Coast Redwood Stand Development: Interactions between Regeneration, Structure, and Productivity." Western Journal of Applied Forestry 24, no. 1 (January 1, 2009): 24–32. http://dx.doi.org/10.1093/wjaf/24.1.24.
Full textAbstract:
Abstract Multiaged management regimes and harvesting scenarios were simulated in coast redwood (Sequoia sempervirens [D. Don.] Endl.) stands using models of stand growth and yield (CRYPTOS) and stocking assessment (redwood MASAM). Various stocking and age-class combinations were modeled on site index 100 and 130 ft (50 years). Results demonstrated how the number of cohorts, upper limit of stocking, and cohort densities affected growth and yield. Board foot volume increment reached a plateau in stands with a prescribed upper limit of stocking above leaf area index 7.2 to 8.6. Productivity did not differ between stands with two to five cohorts producing the same tree size at harvest. It was affected by stand structure when a cutting cycle of 20 years was prescribed in stands with three to five cohorts. Stands with the same density returned to the upper limit of stocking much sooner on better sites. Prolonging the cutting cycle by reducing stand density resulted in larger tree sizes at harvest and greater productivity. The growth of trees remaining after cutting 10–50% of stand basal area and growth of new stump sprouts were also simulated. Stands quickly returned to preharvest stocking after light cutting, implying that heavy or frequent light cutting is needed to sustain growth and vigor of regeneration in multiaged coast redwood stands.
24
Torquato, Luciane Paes, David Auty, Roger E. Hernández, Isabelle Duchesne, David Pothier, and Alexis Achim. "Black spruce trees from fire-origin stands have higher wood mechanical properties than those from older, irregular stands." Canadian Journal of Forest Research 44, no. 2 (February 2014): 118–27. http://dx.doi.org/10.1139/cjfr-2013-0164.
Full textAbstract:
In the eastern Canadian boreal forest, long fire return intervals lead to over 60% of stands having an irregular, uneven-aged structure, which is associated with slower growth. The aim of this study was to examine the effect of stand structure on the clear wood mechanical properties of black spruce (Picea mariana (Mill.) B.S.P.). A total of 128 trees were destructively sampled from stands of regular and irregular structure across Quebec, Canada. Nonlinear mixed-effects models were developed for each stand type to describe the variation in modulus of elasticity (MOE) and modulus of rupture (MOR) in small defect-free samples as functions of cambial age and annual ring width. Mechanical properties were strongly related to cambial age, with a smaller influence of ring width. After accounting for these variables, both MOE and MOR were higher in samples from stands of regular structure, although differences were less pronounced in the upper stem compared with breast height. The fixed effects of the models explained between 34% and 53% of the variation in mechanical properties. A higher incidence of mild compression wood in trees of layer origin may explain the observed differences between stand structures.
25
Ex, Seth A., R. Justin DeRose, and James N. Long. "Stand Development and Population Dynamics of Curlleaf Mountain Mahogany (Cercocarpus ledifolius Nutt.) Woodlands in Utah's Bear River Mountains." Western Journal of Applied Forestry 26, no. 4 (October 1, 2011): 183–88. http://dx.doi.org/10.1093/wjaf/26.4.183.
Full textAbstract:
Abstract Curlleaf mountain mahogany (Cercocarpus ledifolius Nutt.) is a little-studied woodland tree that occurs in pure stands throughout the Intermountain West. Stand development and population dynamics of this species are poorly understood, despite their relevance to management. We describe here the development of stand age structures and population dynamics of mahogany woodlands in northern Utah using tree ages and measurements representing five structurally diverse stands. Establishment periods in all stands lasted decades, and regeneration continued intermittently in the absence of stand-replacing disturbance, eventually creating multiaged structure. Height, crown size, and basal area varied among older mahogany, which may reflect more intense intraspecific competition or increased likelihood of crown damage in older stands. Mahogany woodland managers face significant challenges. It is difficult to characterize historic stand conditions using current age structures because aging mature trees is generally unfeasible. Furthermore, there is little precedent for regenerating mahogany using silvicultural methods. Results suggest that the biggest risk in regenerating mahogany woodlands is low seedling survival, leading to the prolonged absence of mature trees. Consequently, multiaged methods that retain mature trees are recommended.
26
Novák, J., and M. Slodičák. "Structure and accumulation of litterfall under Norway spruce stands in connection with thinnings." Journal of Forest Science 50, No. 3 (January 11, 2012): 101–8. http://dx.doi.org/10.17221/4605-jfs.
Full textAbstract:
The effect of thinning on the structure and accumulation of litterfall and holorganic horizons (L, F, H) in young Norway spruce stands was investigated. The research was conducted on a Norway spruce thinning experiment Polom (established in 1980) in the Orlické hory Mts. (north-eastern part of the Czech Republic). In 1992, the monitoring of litterfall started on an unthinned control stand (plot 1) and on a comparative stand with very heavy thinning from below (plot 3). During the period of observation (age of the stand 27–37 years), the total weight of litterfall ranged between 1,800 and 4,800 kg/ha. The amount of litterfall was partly influenced by climatic factors (precipitation and temperature), growth processes (basal area increment) and thinning regimes in individual years. The results of the investigations showed that dry biomass accumulated under a 36 years old Norway spruce stand ranged from 9,200 to 11,300 kg/ha in horizon L, from 37,000 to 38,200 kg/ha in horizon F and from 138,300 to 146,400 kg/ha in horizon H. The quality (content of basic nutrients) of litterfall and material from holorganic horizons are discussed.
27
Stašiov, Slavomír, and Marek Svitok. "The influence of stand density on the structure of harvestmen communities (Opiliones) in a submountain beech forest." Folia Oecologica 46, no. 1 (May 1, 2019): 10–15. http://dx.doi.org/10.2478/foecol-2019-0002.
Full textAbstract:
AbstractModification of forest stand density by thinning is a common silvicultural practice implemented in management of production forests. However, changes in the stand density can entail considerable changes to the present forest environment and communities. The current knowledge about the effect of stand density modification on the local animal communities is based mainly on the flagship groups such as carabid beetles or birds. We focused our study on harvestmen. We explored how the stand density influences species composition of this species communities in submountain beech forests. The study was conducted in the Kováčovská dolina valley (Kremnické vrchy Mts, Central Slovakia) in 1997 and 1998, the method used was pitfall trapping. In total, 9 harvestmen species from 5 families were recorded. Prior to our research, the forest stands at the study locality were subject to thinning interventions the intensity of which influenced the structure of the local harvestmen communities. The most pronounced was the effect of very intensive thinning with stand density reduced below 0.5. From the recorded species, four preferred forest stands with lower stand density (Lophopilio palpinalis, Oligolophus tridens, Nemastoma lugubre, Trogulus nepaeformis), two species (Platybunus bucephalus, Dicranolasma scabrum) preferred forest stands with higher stand density. Generalization of the observed pattern requires to explore a wider spectrum of beech forests.
28
Shibuya, Masato, and Satoshi Ishibashi. "Stand-level windthrow patterns and long-term dynamics of surviving trees in natural secondary stands after a stand-replacing windthrow event." Forestry: An International Journal of Forest Research 92, no. 4 (March 29, 2019): 473–80. http://dx.doi.org/10.1093/forestry/cpz015.
Full textAbstract:
Abstract We examined typhoon windthrow patterns in stand-scale permanent plots within three natural forests and the long-term dynamics of surviving trees in two of these plots. The aim was to verify whether pre-disturbance composition and structure affected windthrow damage and stand recovery. The stands, which were in Hokkaido, the northernmost main island of Japan, differed in pre-disturbance composition (coniferous, mixed and broadleaved stands) and structure, and the basal area losses by the windthrow event were 81–93 per cent. Tree mortality was significantly related to tree size (diameter at breast height) and species. The windthrow patterns differed among the three stands; and, windthrow severity was affected by the pre-disturbance composition and structure. The mortality of trees that survived the windthrow event was ~60 per cent in the two plots. The surviving trees comprised a majority of the canopy layer in the secondary stands. The relative basal area of surviving trees decreased rapidly with increasing tree density in the stand initiation stage but differed between plots. Consequently, the pre-disturbance composition and structure influenced windthrow severity, stand recovery and secondary succession in the recovered stands.
29
Kollenberg, Cassandra L., and Kevin L. O'Hara. "Leaf area and tree increment dynamics of even-aged and multiaged lodgepole pine stands in Montana." Canadian Journal of Forest Research 29, no. 6 (June 1, 1999): 687–95. http://dx.doi.org/10.1139/x99-039.
Full textAbstract:
Age structure and distribution of leaf area index (LAI) of even and multiaged lodgepole pine (Pinus contorta var. latifolia Engelm.) stands were examined on three study areas in western and central Montana. Projected leaf area was determined based on a relationship with sapwood cross-sectional area at breast height. Stand structure and LAI varied considerably between individual plots. LAI and stand stem volume increment were significantly higher in multiaged than even-aged stands with the exception of one study area, which had higher volume increment in even-aged stands. Older cohorts and higher canopy strata generally had greater LAI than younger cohorts and lower strata. Ratios of stem volume increment to leaf area were used to assess stand, cohort, and individual tree vigor or growing space efficiency (GSE). Even-aged stands had significantly higher GSEs in individual study areas and overall than multiaged stands. Cohort GSE generally increased with increasing age of the cohort. Stand increment was weakly associated with stand LAI. Individual tree volume increment was strongly related to projected leaf area when stands were divided by age-classes or canopy strata. These results suggest separating these stands into components, such as age classes or canopy strata, and summing predicted increment for each component may provide more accurate prediction of stand increment than using whole-stand LAI.
30
Schneider, Robert, Jean Bégin, Alain Danet, and René Doucet. "Effect of selective precommercial thinning on balsam fir stand yield and structure." Forestry Chronicle 89, no. 06 (December 2013): 759–68. http://dx.doi.org/10.5558/tfc2013-138.
Full textAbstract:
Silvicultural tools such as green retention harvesting and multiple variations of partial cut systems are being developed to implement ecosystem-based forest management. However, very little effort has been expended in developing silvicultural treatments for young stands. Results for a selective precommercial thinning (three thinning intensities and control) covering a 28-year period in a balsam fir-dominated stand are presented. Thinning did not significantly increase stand yield, nor change stand diameter diversity or distribution. Furthermore, diameter distributions and diversity of dead stems also did not differ significantly (P > 0.05) among thinning intensity. More important than intensity effects, statistical differences were found between initial stand densities. Low initial densities had greater yields and more diverse diameter distributions. Nevertheless, for low initial stand densities, light to moderate thinning seemed to increase yield, whereas moderate to heavy thinnings would be appropriate for high initial stand densities. Although selective precommercial thinning does not result in significant changes in stand structure, it could be used as a first step in increasing stand complexity within the context of ecosystem-based management.
31
Li, Yuanyuan, Han Chen, Qianyun Song, Jiahui Liao, Ziqian Xu, Shide Huang, and Honghua Ruan. "Changes in Soil Arthropod Abundance and Community Structure across a Poplar Plantation Chronosequence in Reclaimed Coastal Saline Soil." Forests 9, no. 10 (October 15, 2018): 644. http://dx.doi.org/10.3390/f9100644.
Full textAbstract:
Poplar plantations have the capacity to improve the properties of soils in muddy coastal areas; however, our understanding of the impacts of plantation development on soil arthropods remains limited. For this study, we determined the community dynamics of soil dwelling arthropods across poplar plantations of different ages (5-, 10-, and 21-years) over the course of one year in Eastern Coastal China. The total abundance of soil arthropods differed with stand development. Further, there were some interactions that involved the sampling date. On average, total abundance was highest in the 10-year-old stands and lowest in the 5-year-old stands. Total abundance exhibited strong age-dependent trends in June and September, but not in March or December. The abundance of Prostigmata and Oribatida increased in the 5- to 21-year-old stands, with the highest levels being in the 10-year-old stands. The abundance of Collembola increased with stand development; however, the stand age had no significant impact on the abundance of epedapic, hemiedaphic, and euedaphic Collembola. Order richness (Hill number q = 0) curve confidence intervals overlapped among three stand ages. Shannon and Simpson diversity (Hill numbers q = 1 and q = 2) differed between 10- and 21-year-old stand age. They showed almost similar trends, and the highest and lowest values were recorded in the 21- and 10-year-old stand ages, respectively. Permutational multivariate analysis of variance demonstrated that composition also varied significantly with the sampling date and stand age, and the 10-year-old stands that were sampled in June stood well-separated from the others. Indicator analysis revealed that Scolopendromorpha and Prostigmata were indicators in June for the 10-year-old stands, while Collembola were indicators for the 21-year-old stands sampled in September. Our results highlight that both stand development and climate seasonality can significantly impact soil arthropod community dynamics in the reclaimed coastal saline soils of managed poplar plantations.
32
Przybylski, Jan, Andrzej Majcher, and Mirosław Neska. "A Reconfigurable Control System for a PA-PVD Technology Test Stand." Solid State Phenomena 220-221 (January 2015): 504–9. http://dx.doi.org/10.4028/www.scientific.net/ssp.220-221.504.
Full textAbstract:
The construction of technological test stands is connected with the problem of a proper determination of the structure of the stands enabling the execution of technological processes with different types of instruments and devices. The article presents the test stand for Plasma–Assisted Physical Vapour Deposition (PA-PVD) technological processes. The configurability of the stand was achieved thanks to the modular structure of the stand and the use of appropriate software and hardware solutions. The authors describe the developed solution facilitating the execution of plasma processes applied for surface engineering.
33
Kuttner, Ben, Jay R. Malcolm, and Sandy M. Smith. "Multi-cohort stand structure in boreal forests of northeastern Ontario: Relationships with forest age, disturbance history, and deadwood features." Forestry Chronicle 89, no. 03 (June 2013): 290–303. http://dx.doi.org/10.5558/tfc2013-060.
Full textAbstract:
Multi-cohort forest management (MFM) is a natural disturbance emulation strategy for boreal forests that recommends a diversification of silvicultural techniques to emulate three broad successive phases of post-fire development, termed “cohort classes”. Here, for boreal mixedwood (n = 308) and black spruce (n = 108) stands of northeastern Ontario, we: 1) present a multivariate approach to classify the three cohort classes based on a broad set of stand structural variables related to live-tree diameters, densities, and measures of canopy stratification and 2) investigate variation in stand age, mode of stand origin (including horse- and mechanically logged and natural-origin stands), and deadwood features among the cohort classes. In both forest types, average stem diameter distributions in cohort class 1 were normally distributed, those in class 2 showed broader normal distributions, and those in class 3 showed inverse-J distributions. Mean stand age increased with cohort class, and was positively correlated with cohort class in both forest types. Overall, variation in age and deadwood features as a function of cohort class in both forest types provided strong support for developmental aspects of our cohort classifications. Previously logged stands were primarily associated with lower cohort classes, whereas natural-origin stands were strongly associated with complex cohort class 3 stand structures, especially in mixedwoods. As it is primarily the silvicultural manipulation of stand structure that has been proposed to emulate age-related multi-cohort development, our structural cohort classification approach is particularly relevant to the application of MFM in Ontario.
34
Šimerda, L., and J. Souček. "Long-term silvicultural experiment with transformation of the mixed stand structure." Journal of Forest Science 57, No. 6 (July 7, 2011): 259–65. http://dx.doi.org/10.17221/2/2011-jfs.
Full textAbstract:
The paper summarizes the main characteristics of a mixed stand during 80-year transformation to the mixed stand with permanent selective structure. The initial main stand was mostly composed of conifers with group arrangement, broadleaves as the reserved trees created the upper storey. Partial opening by thinnings prepared the stand for regeneration. Heavy thinning in 1959 (22% of the growing stock) opened the main stand and released the advance growth of broadleaves. Subsequent stand development was negatively affected by air pollution. Mainly fir and spruce responded to air pollution by deteriorated health condition and increment reduction. Beech and other broadleaves gradually increased their proportion in the stand (64% of the growing stock in 2008). Initial diameter distribution was sinistral, reserved trees affected the frequency of thick trees. Final diameter distribution resembled the model curve for selective forests, the number of thin trees was below the model curve for broadleaved forests with selective structure in these types of localities. Mean increments of individual species changed according to their stand position. Low fecundity of trees, weed infestation and game damage limited natural regeneration, artificial regeneration dominated for the whole time. The complicated structure corresponding to selective forest occurred rarely during the monitored period, the stand was differentiated mainly by spatial arrangement.
35
Krstic, Milun. "The proposition of optimal silvicultural-reclamation operations in untended beech stands of mixed origin." Bulletin of the Faculty of Forestry, no. 89 (2004): 155–70. http://dx.doi.org/10.2298/gsf0489155k.
Full textAbstract:
The state, quality, spontaneous development and silvicultural demands of untended beech stands of mixed origin were studied, the age of trees in the dominant layer is about 75 years. The analysis of stand development through a 17-year period (1986-2003) included the monitoring of the elements of stand structure: Number of trees, basal area, volume, diameter and volume increment, mean stand diameter, structure, mortality and tree removal from the stand, morphological, biological and technical characteristics of trees and biological differentiation of trees. The adequate silvicultural-reclamation measures are proposed based on the identified stand state.
36
Zeller, Laura, Astor Toraño Caicoya, and Hans Pretzsch. "Analyzing the effect of silvicultural management on the trade-off between stand structural heterogeneity and productivity over time." European Journal of Forest Research 140, no. 3 (February 1, 2021): 615–34. http://dx.doi.org/10.1007/s10342-020-01350-z.
Full textAbstract:
AbstractThis study combined an empirically based simulation with an analysis of the trade-off between structural heterogeneity and stand productivity depending on time, spatial scale, and silvicultural management, whereas volume growth and tree species diversity have been examined in detail, the role of forest structure and its interdependencies with stand productivity has only lately become a stronger research focus. We used the growth simulator SILVA to examine the development of stand structural heterogeneity and its trade-off with stand productivity in age-class versus uneven-aged pure and mixed spruce and beech stands at different spatial scales over 100 years. Those stands were based on typical forest types in Bavaria and were representative of forests in Central Europe. We examined how stand structure and its trade-off with productivity were modified by a multifunctional, a production-oriented, and a set-aside management scenario. The production-oriented management scenario applied to uneven-aged stands led to a reduction in structural heterogeneity per unit of productivity over time. In age-class stands, the production-oriented scenario was able to maintain the initial structural heterogeneity. The structural heterogeneity per unit of productivity increased more strongly with increasing spatial scale in age-class stands compared to uneven-aged stands. Combining forest stand simulation with scenario analyses is an exemplary method for testing the effect of silvicultural management alternatives on forest structure. This approach can later be connected to climate models considering long-term changes in growing conditions and support the planning of multifunctional forests.
37
Gass, Tobah M., and Andrew P. Robinson. "A hierarchical analysis of stand structure, composition, and burn patterns as indicators of stand age in an Engelmann spruce – subalpine fir forest." Canadian Journal of Forest Research 37, no. 5 (May 2007): 884–94. http://dx.doi.org/10.1139/x06-301.
Full textAbstract:
We studied the relationship between observed fire effects and stand age in a recently burned subalpine Engelmann spruce ( Picea engelmannii Parry ex. Engelm.) – subalpine fir ( Abies lasiocarpa (Hook.) Nutt.) forest in New Mexico. We installed a network of variable-radius plots to assess stand structure, and cored 379 trees to measure the spatial patterns of the stand ages with respect to fire boundaries. We found that pre-fire stand age and stand mortality were not significantly related at either of two spatial scales (p ≤ 0.33 and p ≤ 0.26). We also found that stand structure and stand composition were poor indicators of stand age. The random effects terms of a linear mixed-effects model revealed substantial heterogeneity in stand structure and composition with respect to age at fine spatial scales. Discussions of the factors contributing to stand-replacing fires in subalpine Engelmann spruce – subalpine fir forests might be improved by focusing on traits that are more reliably linked to fuel characteristics, rather than on the age of the stands.
38
Permata, Fitriana Wulansari, Budi Kuncahyo, Haruni Krisnawati, and Relawan Kuswandi. "Stand Structure Dynamic of Logged Over Forest after Selective Timber Harvesting in Boven Digoel, Papua." Jurnal Sylva Lestari 11, no. 1 (January 28, 2023): 177–91. http://dx.doi.org/10.23960/jsl.v11i1.610.
Full textAbstract:
Logged-over natural forest has a different stand structure and composition from primary natural forest due to logging activities. This study aimed to examine forest dynamics (upgrowth, ingrowth, and mortality) of the logged-over forest in PT. Tunas Timber Lestari (TTL) Papua in both stands with and without treatments. The data used in this study were based on the measurement in the Permanent Measurement Plots (PUP) for ten years. This study grouped data into five diameter classes of 10 cm intervals and three wood species groups (meranti timber, mixed timber, and non-commercial timber). Data analysis was carried out by forming a stand structure model and calculating the rate of ingrowth, upgrowth, and mortality. The stand structure model for each species group in stands with treatment had a significant R² value compared to those without treatment. The average ingrowth rate in the stands with treatment was smaller than without treatment. The values of upgrowth varied with the increase in diameter classes for both stands with and without treatments. The mortality rate in stands without treatment tended to be higher, especially in mixed timber and non-commercial timber groups. In contrast, in the meranti timber group, the mortality rate mostly occurred in the stands with treatment. The stand structure models resulting in this study can be used as important information in determining appropriate silvicultural options for forest stands. Keywords: Forest dynamics, logged-over forest, meranti, selective logging
39
Remeš, J. "Transformation of even-aged spruce stands at the School Forest Enterprise Kostelec nad Černými lesy: Structure and final cutting of mature stand." Journal of Forest Science 52, No. 4 (January 9, 2012): 158–71. http://dx.doi.org/10.17221/4498-jfs.
Full textAbstract:
This paper deals with the transformation of pure even-aged forest stands to mixed and more uneven-aged stands on an example of selected even-aged Norway spruce stands in the School Forest Enterprise (SFE) in Kostelec nad Černými lesy. A forest stand where individual tree felling was used as the main method of forest stand regeneration was chosen as a conversion example. The main criterion of tree maturity is the culmination of mean volume increment of a single tree. The analyses confirmed a very high variability in the growth potential of individual trees. The potential and actual increment was strongly influenced by the stand position of tree and by crown release. These results show a high potential level of tree growth even at the age of 120 years. From 30% to 9% of all trees on particular experimental plots achieved felling maturity.
40
Petráš, R., J. Mecko, and V. Nociar. "Diameter structure of the stands of poplar clones." Journal of Forest Science 56, No. 4 (May 3, 2010): 165–70. http://dx.doi.org/10.17221/65/2009-jfs.
Full textAbstract:
The construction of a continuous mathematical model of frequency distributions of the diameters of trees of poplar clones Robusta and I-214 in dependence on tree diameter and mean diameter of stand is presented. Empirical material consists of diameter measurements on research plots from poplar regions in Slovakia. There were 90 plots for I-214 clone and 142 plots for Robusta clone. There were about 10–250 trees with mean diameter 2–70 cm on the research plots. The model was derived according to the three-parameter Weibull function. Its parameters were estimated by maximum likelihood method of the logarithm of the probability density function. Smoothed sample probability densities were processed in continuous mathematical models where the probability density of trees in stands is a function of their diameters and mean diameter of the stand. The method of regression smoothing of the parameters of Weibull function from sample sets in dependence on their mean diameter was used. In the whole range of mean diameters both clones have slightly left-skewed distribution with a relatively small variation range.
41
Rossi, Sergio, Marie-Josée Tremblay, Hubert Morin, and Valérie Levasseur. "Stand structure and dynamics of Picea mariana on the northern border of the natural closed boreal forest in Quebec, Canada." Canadian Journal of Forest Research 39, no. 12 (December 2009): 2307–18. http://dx.doi.org/10.1139/x09-152.
Full textAbstract:
The boreal forest of higher latitudes constitutes a reservoir of trees of great ecological importance and unknown economic potential, but the stand dynamics in these regions still remain essentially unexplored. This paper examines the change in age and size structures during stand development on the northern border of the natural closed boreal forest in Quebec, Canada. Height, diameter, and age of trees were measured in 18 plots with stand ages between 77 and 340 years. The occurrence, size, and origin (layer or seed) of seedlings and saplings were assessed in subplots. Tree density ranged from 600 to 3750 trees·ha–1. Picea mariana (Mill.) BSP was the dominant species, mainly originating by layering. A cluster analysis segregated plots into even-aged and uneven-aged stands according to tree age, but size distribution of trees, saplings, and seedlings did not differ statistically between the two groups. Even-aged stands exhibited a 60% probability of assuming an uneven-aged structure between 120 and 200 years after stand initiation. At high latitudes, the closed boreal forest of P. mariana appears homogeneously sized, with similar distributions of diameter and height across all stages of stand development.
42
Klinka, K., G. J. Kayahara, and R. E. Carter. "Forest reproduction methods for coastal British Columbia: Principles, criteria, and a stand selection guide." Forestry Chronicle 70, no. 5 (October 1, 1994): 569–77. http://dx.doi.org/10.5558/tfc70569-5.
Full textAbstract:
Once a decision to regenerate a particular stand is made at the forest level, a forester has to make critical decisions at the stand level as to the choice of cutting method for existing stands to regenerate the desired species and develop a stand of the desired structure. Two related critical decisions in stand-level forest management are (1) selecting the best tree species to regenerate on a given site, and (2) selecting the appropriate method of cutting existing stands for both the regeneration of the desired species within a certain time and for maintaining or developing the desired stand structure. This paper discusses the management factors and principles and criteria for choosing a cutting method to meet decision (2) (i.e., the reproduction method). The four criteria used to guide the appropriate reproduction method are (1) maximum sustainable forest productivity, (2) stand reliability, (3) silvicultural feasibility, and (4) harvesting feasibility. With these criteria in mind, a stand-level guide devised for coastal British Columbia is proposed. This guide is in the form of a dichotomous key and is based on 13 selected ecological, stand, and management factors. Combining this approach with principles, criteria and guidelines for tree species selection already practiced, regeneration and management objectives can be achieved both on a species-and site-specific basis. Key words: forest reproduction methods, decision support systems, silvicultural prescriptions, harvesting methods, stand regeneration, stand structure
43
Dostálek, Jiří, Tomáš Frantík, and Miroslava Lukášová. "Genetic differences within natural and planted stands of Quercus petraea." Open Life Sciences 6, no. 4 (August 1, 2011): 597–605. http://dx.doi.org/10.2478/s11535-011-0034-8.
Full textAbstract:
AbstractFive sessile oak [Quercus petraea (Matt.) Liebl.] stands from the Czech Republic were studied to learn about the impact of different types of forest management regimes on the genetic differences among tree populations and on population structures. One population had not been markedly affected by human activity, two populations represented unplanted stands that were extensively managed for a long period of time using the coppice system, and two populations were planted stands. Approximately 100 trees from each stand were mapped and subsequently genotyped using 10 nuclear microsatellite loci. We determined the spatial genetic structure of each population and the genetic differentiation among the populations. We found that: (i) the populations were genetically differentiated, but the differences between the unplanted and planted stands were not markedly significant; (ii) the genetic differentiation among the populations depended on the geographical distribution of the populations; (iii) within unplanted stands, a strong spatial genetic structure was seen; and (iv) within planted stands, no spatial genetic structure was observed. Our findings implies that the analysis of spatial genetic structure of the sessile oak forest stand can help reveal and determine its origin.
44
Rabelo, Guilherme Rodrigues, Denise Espellet Klein, and Maura Da Cunha. "Does selective logging affect the leaf structure of a late successional species?" Rodriguésia 63, no. 2 (June 2012): 419–27. http://dx.doi.org/10.1590/s2175-78602012000200014.
Full textAbstract:
The anatomical characteristics of both sun and shade leaves of Alseis pickelii were investigated in order to evaluate the consequences of selective logging (in seasonally dry Atlantic Forest) on the leaf structure of this species. Fully expanded sun and shade leaves were collected in two distinct stands of tabuleiro forest; a stand of recently logged forest and an unlogged stand. Only leaves from the unlogged stand revealed significantly different magnitudes of response to light regimes, producing leaves with structural characteristics associated with different levels of irradiance. The sun leaves from this stand had a thicker adaxial surface, mesophyll, palisade and spongy parenchyma, a secondary cell wall of fibers and a lower leaf area compared with the shade leaves. However, in the logged stand, the leaf cuticles of sun and shade leaves showed no significant differences, although the leaf area of the sun leaves was higher than the shade leaves. According to these data, we concluded that the unlogged stand produced typical "sun" and "shade" leaves. In contrast, leaves from the logged stand showed a lower variation of types, where neither typical "sun" nor typical "shade" leaves were produced, suggesting lower leaf plasticity of this late successional tree in this area.
45
Berrill, John-Pascal, and Kevin L. O’Hara. "Estimating site productivity in irregular stand structures by indexing the basal area or volume increment of the dominant species." Canadian Journal of Forest Research 44, no. 1 (January 2014): 92–100. http://dx.doi.org/10.1139/cjfr-2013-0230.
Full textAbstract:
Estimating site productivity in irregular structures is complicated by variations in stand density, structure, composition in mixed stands, and suppression experienced by subordinate trees. Our objective was to develop an alternate to site index (SI) and demonstrate its application in models of individual-tree and stand growth. We analyzed coast redwood (Sequoia sempervirens (Lamb. ex D. Don) Endl.) tree and stand growth in a grid of 234 permanent sample plots covering a 110 ha study area in north coastal California. Partial harvesting created a mosaic of densities and openings throughout the 60-year-old redwood-dominated forest. Redwood SI was a poor predictor of volume increment (VI) per hectare among redwood in each plot over two decades after harvest. A new index of redwood basal area increment (BAI) productivity, calculated using inventory data for all stems in even-aged stands and the oldest cohort of multiaged stands, was a stronger predictor of VI. Diameter increment of individual redwood trees correlated strongly with stand density and the new BAI index. Forest managers should expect widely divergent responses following partial harvesting in crowded even-aged stands, with the greatest response coming from dominant redwoods with long crowns retained in areas with low residual stand density and high BAI index.
46
Gheorghe, Iuliana F., Iovu A. Biriş, and Cristina M. Valcu. "Efficiency of different forest types in carbon storage depends on their internal structure." Acta Societatis Botanicorum Poloniae 79, no. 4 (2011): 325–32. http://dx.doi.org/10.5586/asbp.2010.040.
Full textAbstract:
Forest vegetation is a key factor in the maintenance of global carbon cycle balance under the present climate change conditions. Forest ecosystems are both buffers against extreme climatic events accompanying climate change and carbon sinks diminishing the environmental impact of anthropogenic greenhouse gas emissions. We investigated the influence of stand structure and site characteristics on the productivity and carbon storage capacity of temperate forest types. Predictors of species productivity were parameters such as stand density, age, height, average diameter and wood density. <em>Morus alba</em> (L.) was more productive than average both in terms of annual volume increment and annual biomass gain, while <em>Quercus sessiliflora</em> (Matt.) Lieb. and <em>Quercus frainetto</em> (Ten.) were significantly less productive than average. Differences in stand productivity were explained by stand density, age, height, altitude, type of regeneration and species composition. Statistically significant differences were measured between the productivity of stands dominated by different woody species, with low productive stands dominated by slow growing species with high wood density like <em>Quercus</em> or <em>Fagus</em>, and highly productive stands rich in fast growing species with low wood density like <em>Populus</em> or <em>Salix</em>. Stands with different plant communities in the underlying herbaceous layer also tended to have different levels of productivity.
47
Singh, Vikaspal, Dhanpal Singh Chauhan, and Sabyasachi Dasgupta. "Effect of stand structure and aspect on the regeneration of banj oak (Quercus leucotrichophora A. Camus) forest along disturbance in Garhwal Himalaya, Uttarakhand, India." Forestry Studies 68, no. 1 (June 1, 2018): 33–39. http://dx.doi.org/10.2478/fsmu-2018-0003.
Full textAbstract:
Abstract A study was conducted in an oak forest, to find out the relationship of stand structure, aspect and regeneration of species. Among all disturbance stands the density of banj oak Quercus leucotrichophora A. Camus individuals was peaked at 40–50 cm and 50–60 cm diameter at breast height (DBH) classes and low tree density was observed with the increasing DBH classes. North aspect showed higher density for most of girth classes as compared to south facing aspect. Among all the stands, low seedling density was recorded in undisturbed stand at south facing aspect as compared to the moderately and highly disturbed stands. The tree density of Q. leucotrichophora was higher in the undisturbed stand followed by moderately disturbed and highly disturbed stand. But in case of seedling density the higher density were observed at undisturbed and highly disturbed stand in both of the aspects.
48
Verwijst, Theo. "Clonal differences in the structure of a mixed stand of Salixviminalis in response to Melampsora and frost." Canadian Journal of Forest Research 20, no. 5 (May 1, 1990): 602–5. http://dx.doi.org/10.1139/x90-079.
Full textAbstract:
This study presents results from a stand structure analysis of an energy forest plantation of Salixviminalis L., clone 77-683. The stand, which was expected to contain only one clone, was shown to be composed of at least one male and one female clone. The male clone was susceptible to Melampsoraepitea Thüm. and displayed a larger proportion of frost damage after infection and lower mean size and weight than the uninfected clone. Regression analysis showed that the infected and uninfected shoots differed significantly in their size-weight relationships. Relative differences in size and damage between infected and uninfected stools were larger within the stand than along the border rows. The results illustrate how genetic differences in response to a pathogen can result in unevenly structured stands.
49
Remeš, J., and J. Kozel. "Structure, growth and increment of the stands in the course of stand transformation in the Klokočná Forest Range." Journal of Forest Science 52, No. 12 (January 9, 2012): 537–46. http://dx.doi.org/10.17221/4534-jfs.
Full textAbstract:
This paper deals with transformation of pure even-aged forest stands to uneven-aged irregular stands on an example of the Klokočná Forest Range. The fully operational management system according to principles of shelterwood or selection systems has been executed here since 1993. An investigation of this transformation process started in 1999 and it is focused on the places with more distinct structural differences. On the basis of research analysis, it is possible to consider about the permanent uneven-aged forest stands in future here. But for successful achievement of this goal it is necessary to continue this transformation step by step for a long time. The transformation is still at the beginning and its result depends on the effort and the forest management goal and the priority of the particular forest functions.
50
Gilbert, Brian A., and Wade Pierce. "Predicting the Availability of Understory Structural Features Important for Canadian Lynx Denning Habitat on Managed Lands in Northeastern Washington Lynx Ranges." Western Journal of Applied Forestry 20, no. 4 (October 1, 2005): 224–27. http://dx.doi.org/10.1093/wjaf/20.4.224.
Full textAbstract:
Abstract Stands identified as potential Canadian lynx denning habitat by a habitat suitability model were sampled in northeastern Washington for stand structure and understory structural features identified as important for denning lynx. Potential den structures were quantified by use of strip transects, and stand structure was quantified through an enhanced forest inventory approach focused on assessing understory and downed wood conditions. Information theoretic model selection methods indicated that the best model to predict potential denning understory structure availability included downed wood abundance, total basal area, and average stand diameter. The strong predictive ability of our models suggest that understory features important to denning lynx can be predicted using traditional inventory data with the addition of a downed wood line intercept methodology. In general, our study supports the suggestion that assessing downed wood availability will effectively address concerns over quantifying the availability of understory structural features identified as being important at lynx den sites. West. J. Appl. For. 20(4):224–227.