scholarly journals Structural analysis of mixed stands coming from natural regeneration and plantations after fire

Web Ecology ◽  
2010 ◽  
Vol 10 (1) ◽  
pp. 32-37
Author(s):  
T. Tsitsoni ◽  
M. Tsakaldimi ◽  
E. Simeliadou ◽  
M. Fouska
Keyword(s):  
Stand Structure ◽  
Structural Characteristics ◽  
Basal Area ◽  
Stem Diameter ◽  
Diameter Distribution ◽  
Cupressus Sempervirens ◽  
Mixed Stands ◽  
Crown Length ◽  
Stem Quality ◽  
Naturally Regenerated Stands

Abstract. We analyzed the structure and growth of naturally regenerated stands of Pinus brutia that mixed with planted broad-leaved and conifer species, 12 years after wildfire and examined the degree of species mix. Field data on stand structure of P. brutia forest were taken in spring 2009 on northern and southern aspects differing in regeneration conditions. Sixteen sample plots were selected and all individuals and their attributes measured. The results showed that in northern aspects the forest is composed of P. brutia in the over-storey and Quercus pubescens and Cupressus sempervirens in the under-storey, while in southern aspects the forest was mainly composed by P. brutia (81%). Stem diameter distribution of P. brutia in both aspects followed almost a normal pattern. All P. brutia individuals were characterized by vigorous growth and good to normal stem quality. Aspect did not statistically affect structural characteristics of P. brutia trees and saplings. However, on the northern aspect stem diameter, height, crown length and basal area of P. brutia were greater than in the southern aspect. Aspect significantly affected structural characteristics of Q. pubescens.

scholarly journals Thinning Response and Potential Basal Area in a Mixed Sub-humid Low-elevation Oak-Hornbeam Forest

2021 ◽  
Author(s):  
Mathias Neumann ◽  
Hubert Hasenauer
Keyword(s):  
Stand Structure ◽  
Basal Area ◽  
Climatic Conditions ◽  
Diameter Distribution ◽  
Stem Density ◽  
Growing Stock ◽  
A Site ◽  
Water Nutrients ◽  
Related Mortality

Abstract Competition for resources (light, water, nutrients, etc.) limits the size and abundance of alive trees a site can support. This carrying capacity determines the potential carbon sequestration in alive trees as well as the maximum growing stock. Lower stocking through thinning can change growth and mortality. We were interested in the relations between stand structure, increment and mortality using a long-unmanaged oak-hornbeam forest near Vienna, Austria, as case study. We expected lower increment for heavy thinned compared to unmanaged stands. We tested the thinning response using three permanent growth plots, whereas two were thinned (50% and 70% basal area removed) and one remained unmanaged. We calculated stand structure (basal area, stem density, diameter distribution) and increment and mortality of single trees. The heavy thinned stand had over ten years similar increment as the moderate thinned and unthinned stands. Basal area of the unthinned stand remained constant and stem density decreased due to competition-related mortality. The studied oak-hornbeam stands responded well even to late and heavy thinning suggesting a broad “plateau” of stocking and increment for these forest types. Lower stem density for thinned stands lead to much larger tree increment of single trees, compared to the unthinned reference. The findings of this study need verification for other soil and climatic conditions.

scholarly journals The contribution of natural and artificial regeneration at the restoration of fire-affected peri-urban forest of Thessaloniki (Northern Greece)

2017 ◽  
Vol 19 (1) ◽  
pp. 29-36
Keyword(s):  
Natural Regeneration ◽  
Urban Forest ◽  
Burned Area ◽  
Cupressus Sempervirens ◽  
Northern Greece ◽  
Mixed Stands ◽  
Artificial Regeneration ◽  
Pinus Brutia ◽  
Stem Quality ◽  
Cupressus Arizonica

<p>In this study, the post-fire regeneration of three coniferous species (<em>Pinus brutia, Cupressus sempervirens </em>and<em> Cupressus arizonica)</em> was examined in the peri-urban forest of Thessaloniki, Northern Greece. The wildfire took place in July 1997 and burned almost 60% of the forest vegetation. During the autumn of 2010, 34 experimental plots were established in all aspects within the burned area. In each experimental plot the following measurements were carried out: height, diameter at breast height and crown projection in two perpendicular diameters. The results show that the <em>Pinus brutia </em>individuals, most of which came from natural regeneration, presented the best growth, in relation to the two other species in all aspects. As for <em>Cupressus sempervirens</em>, equal parts of which came from natural and artificial regeneration was characterized by remarkable growth especially in the Northeastern aspect. Finally, <em>Cupressus arizonica</em> existed in all aspects except the Northeastern. It also presented a satisfactory development, especially on the Southern aspect. Fourteen years after the fire pure or mixed stands of the above mentioned species show vigorous growth and good stem quality. Finally, the rates of participation of individual forest species indicate that the restoration has been achieved mainly by natural regeneration.</p>

scholarly journals A Structure Analysis for Ecological Management of Moist Tropical Forests

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Adrien Djomo Njepang
Keyword(s):  
Species Composition ◽  
Stand Structure ◽  
Human Impacts ◽  
Basal Area ◽  
Diameter Distribution ◽  
Ecological Management ◽  
Natural Forests ◽  
Forest Types ◽  
Moist Forest ◽  
Commercial Species

Human interventions alter stand structure, species composition, and regeneration capacity of the forest. There is no enough information on how different management systems affect the forest structure. The main objective of this study was to analyze the differences on stand structure and species composition caused by different logging intensities. The study was conducted in a lowland evergreen moist forest of 22 000 ha in Cameroon. The forest was subdivided into three forest types with different human impacts:2-Logged,1-Logged, andUnlogged. The diameter corresponding to mean basal area of stems of2-Logged(31.8 cm,N=369) was almost equal to that ofUnlogged(30.1 cm,N=496).1-Loggedhad a lower diameter of 27.7 cm,N=530. In the three forest types, the diameter distribution followed the inverse J-shaped curve frequently observed in natural forests. The stand basal area increased from 29.4 m2/ha in2-Logged, to 32 m2/ha in1-Logged, and to 35.3 m2/ha inUnlogged. These results indicated that logging affected natural regeneration in2-Logged. Above 60 cm dbh, the logging effect was not visible. On 103 tree species found in the sample forest, only nine were classified as harvestable commercial species.

scholarly journals Cavity Trees, Snags, and Selection Cutting: A Northern Hardwood Case Study

2007 ◽  
Vol 24 (3) ◽  
pp. 192-196 ◽  
Author(s):  
Laura S. Kenefic ◽  
Ralph D. Nyland
Keyword(s):  
Sugar Maple ◽  
Stand Structure ◽  
Basal Area ◽  
Diameter Distribution ◽  
Maximum Diameter ◽  
Northern Hardwoods ◽  
Selection System ◽  
Habitat Features ◽  
Northern Hardwood ◽  
Selection Cutting

Abstract Although traditional application of the selection system includes a focus on high-value trees that may reduce cavities and snags, few studies have quantified those habitat features in managed uneven-aged stands. We examined the effects of single-tree selection cutting on cavity trees and snags in a northern hardwood stand immediately prior to the second cutting. Marking followed guidelines proposed by Arbogast, C., Jr. (1957. Marking guides for northern hardwoods under selection system. US For. Serv. Res. Pap. 56, Lake States Forest Experiment Station. 20 p.), with the objective of improving stand quality for timber production while maintaining a balanced diameter distribution. The stand contained seven species of cavity trees and snags; sugar maple and American beech were most common, the latter comprising 20% of snags and 26% of cavity trees despite its relatively minor (7%) contribution to stand basal area. We found that 92% of cavity trees were live, underscoring the value of living trees as sources of cavities. Precut cavity tree density (25.2 live cavity trees per hectare) was more than twice that found in other studies of selection stands, although density of snags (11.0 snags per hectare) was comparable or lower. More than 50% of sampled cavity trees were designated for removal in the second selection cut, reducing projected postcut density to 11.0 live cavity trees per hectare, a density similar to that found in other studies. Postcut density of large cavity trees (3.3 live trees >45 cm dbh per hectare) exceeded published guidelines for northern hardwoods (0.25 to 2.5 live cavity trees >45 cm dbh per hectare). We speculate that the relatively high maximum diameter (61 cm dbh) and long cutting cycle (20 years) used to define the target stand structure may have contributed to the number of cavity trees observed. Nevertheless, selection cutting as applied in this study will likely reduce cavity abundance unless retention of trees with decay is explicitly incorporated into the management strategy.

Basal area and diameter growth in high-graded eastern temperate mixedwood forests: the influence of acceptable growing stock, species, competition and climate

2019 ◽  
Vol 92 (5) ◽  
pp. 659-669 ◽  
Author(s):  
Hugues Power ◽  
Patricia Raymond ◽  
Marcel Prévost ◽  
Vincent Roy ◽  
Frank Berninger
Keyword(s):  
Abies Balsamea ◽  
Basal Area ◽  
Balsam Fir ◽  
Diameter Growth ◽  
Yellow Birch ◽  
Mixed Stands ◽  
Growing Stock ◽  
Mixedwood Forests ◽  
Stem Quality ◽  
History Of

AbstractHarvesting practices in temperate mixedwoods of eastern North America have a history of diameter-limit cuts, which have often resulted in degraded residual stands. In this study, we examined the factors influencing stand basal area (BA) and tree diameter growth in previously high-graded mixedwood forests, to understand which stands are more likely to recover from high-grading. Over 15 years, we monitored tree growth, recruitment and stem quality of 532 sample plots that were located in high-graded stands of Quebec’s mixedwood forest. We found that diameter growth rates were positively correlated with precipitation-related variables for balsam fir (Abies balsamea) and for yellow birch (Betulla alleghaniensis) but opposing trends for temperature-related variables were found. Conversely to balsam fir, yellow birch growth was positively correlated to temperature variables. Our results also show that BA growth was greater for plots with a larger acceptable growing stock (AGS: trees with potential sawlog production) and that the increase in AGS was greater for plots with larger amount of conifer BA. These result highlights the importance to maintain a proportion of conifer trees in these mixed stands. Moreover, the significant effect of asymmetric competition in our study underscores the relevance of considering the spatial distribution when choosing crop trees.

scholarly journals Importance of the first thinning in young mixed Norway spruce and European beech stands

2017 ◽  
Vol 63 (No. 6) ◽  
pp. 254-262 ◽  
Author(s):  
Novák Jiří ◽  
Dušek David ◽  
Slodičák Marian ◽  
Kacálek Dušan
Keyword(s):  
Norway Spruce ◽  
Basal Area ◽  
European Beech ◽  
Static Stability ◽  
Diameter Distribution ◽  
Mixed Stands ◽  
Lower Altitude ◽  
Commercial Thinning ◽  
Dead Trees ◽  
Study Sites

Experimental results from the first thinning in mixed stands are not broadly experienced by forestry practice. To extend the experience with the thinning of a mixed stand, we studied thinned and unthinned mixtures of Norway spruce with European beech on two study sites in the Czech Republic, which represented different conditions: Všeteč (age of 19–35 years) – originally beech dominated site at 440 m a.s.l. and Deštné (age of 17–33 years) – originally spruce with beech site at 990 m a.s.l. Spruce and beech were mixed individually or in small groups. As the for number of trees, mixtures were 35–54% beech and 46–65% spruce at a lower altitude and 7–30% beech and 70–93% spruce at a higher altitude. In the period 1997–2013, we observed annually: mortality, diameter at breast height of all trees and height of trees (minimum 30 individuals) that represented diameter distribution. Results showed that the growth and development of young mixed spruce/beech stands were positively influenced by the first pre-commercial thinning on both locations. The most pronounced effect of thinning consisted in a decreased amount of basal area of dead trees. On control plots, salvage cut accounted for 34 and 46%, while on thinned plots it reached only 7–8% (thinned from above) and 18% (thinned from below) of basal area periodic increment during the 16-year study period. In contrast, diameter distribution was still relatively wide (i.e. an important amount of thin trees was left) at the end of observations on all plots of both study sites. Thinned stands also showed the better static stability (expressed as an h/d ratio) of dominant spruces compared to unthinned stands on both locations. Additionally, thinning supported the spruce share at a lower altitude and the  beech share at a higher altitude.

scholarly journals Height-diameter allometry of tropical forest trees

2011 ◽  
Vol 8 (5) ◽  
pp. 1081-1106 ◽  
Author(s):  
T. R. Feldpausch ◽  
L. Banin ◽  
O. L. Phillips ◽  
T. R. Baker ◽  
S. L. Lewis ◽  
...  
Keyword(s):  
Tropical Forest ◽  
Large Scale ◽  
Amazon Basin ◽  
Stand Structure ◽  
Forest Type ◽  
Structural Characteristics ◽  
Basal Area ◽  
Tree Height ◽  
Geographic Region ◽  
True Value

Abstract. Tropical tree height-diameter (H:D) relationships may vary by forest type and region making large-scale estimates of above-ground biomass subject to bias if they ignore these differences in stem allometry. We have therefore developed a new global tropical forest database consisting of 39 955 concurrent H and D measurements encompassing 283 sites in 22 tropical countries. Utilising this database, our objectives were: 1. to determine if H:D relationships differ by geographic region and forest type (wet to dry forests, including zones of tension where forest and savanna overlap). 2. to ascertain if the H:D relationship is modulated by climate and/or forest structural characteristics (e.g. stand-level basal area, A). 3. to develop H:D allometric equations and evaluate biases to reduce error in future local-to-global estimates of tropical forest biomass. Annual precipitation coefficient of variation (PV), dry season length (SD), and mean annual air temperature (TA) emerged as key drivers of variation in H:D relationships at the pantropical and region scales. Vegetation structure also played a role with trees in forests of a high A being, on average, taller at any given D. After the effects of environment and forest structure are taken into account, two main regional groups can be identified. Forests in Asia, Africa and the Guyana Shield all have, on average, similar H:D relationships, but with trees in the forests of much of the Amazon Basin and tropical Australia typically being shorter at any given D than their counterparts elsewhere. The region-environment-structure model with the lowest Akaike's information criterion and lowest deviation estimated stand-level H across all plots to within amedian −2.7 to 0.9% of the true value. Some of the plot-to-plot variability in H:D relationships not accounted for by this model could be attributed to variations in soil physical conditions. Other things being equal, trees tend to be more slender in the absence of soil physical constraints, especially at smaller D. Pantropical and continental-level models provided less robust estimates of H, especially when the roles of climate and stand structure in modulating H:D allometry were not simultaneously taken into account.

Influence of species proportion and timing of establishment on stem quality in mixed red alder – Douglas-fir plantations

2004 ◽  
Vol 34 (4) ◽  
pp. 863-873 ◽  
Author(s):  
Amy T Grotta ◽  
Barbara L Gartner ◽  
Steven R Radosevich
Keyword(s):  
Stand Structure ◽  
Stand Density ◽  
Douglas Fir ◽  
Stem Form ◽  
Mixed Stands ◽  
Red Alder ◽  
Stem Quality ◽  
Multiple Stems ◽  
Old Trees ◽  
Species Proportion

The relationships among stand structure, Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) branch characteristics, and red alder (Alnus rubra (Bong.)) stem form attributes were explored for 10- to 15-year-old trees growing in mixed Douglas-fir – red alder plantations. Treatments included a range of species proportions, and red alder was either planted simultaneously with Douglas-fir or after 5 years. Both replacement effects (total stand density held constant) and additive effects (stand density doubled) of competition were considered. When the two species were planted simultaneously and red alder proportion was low, red alder trees had low crown bases and much stem defect (lean, sweep, and multiple stems). Douglas-fir grew slowly when the two species were planted simultaneously. When red alder planting was delayed, species proportion did not affect red alder stem form, and height to the base of the Douglas-fir live crown decreased with increasing red alder proportion. Doubling Douglas-fir density increased the height to the base of the Douglas-fir live crown; however, doubling stand density by adding red alder did not affect Douglas-fir crown height. Douglas-fir lumber coming from mixed stands may be inferior because of the changes in knot characteristics associated with these different patterns of crown recession. In stands with a low proportion of red alder, red alder product recovery may be compromised because of the stem defects described above.

scholarly journals Height-diameter allometry of tropical forest trees

2010 ◽  
Vol 7 (5) ◽  
pp. 7727-7793 ◽  
Author(s):  
T. R. Feldpausch ◽  
L. Banin ◽  
O. L. Phillips ◽  
T. R. Baker ◽  
S. L. Lewis ◽  
...  
Keyword(s):  
Tropical Forest ◽  
Large Scale ◽  
Amazon Basin ◽  
Stand Structure ◽  
Forest Type ◽  
Structural Characteristics ◽  
Basal Area ◽  
Tree Height ◽  
Geographic Region ◽  
True Value

Abstract. Tropical tree height-diameter (H:D) relationships may vary by forest type and region making large-scale estimates of above-ground biomass subject to bias if they ignore these differences in stem allometry. We have therefore developed a new global tropical forest database consisting of 39 955 concurrent H and D measurements encompassing 283 sites in 22 tropical countries. Utilising this database, our objectives were:   1. to determine if H:D relationships differ by geographic region and forest type (wet to dry forests, including zones of tension where forest and savanna overlap).   2. to ascertain if the H:D relationship is modulated by climate and/or forest structural characteristics (e.g. stand-level basal area, A).   3. to develop H:D allometric equations and evaluate biases to reduce error in future local-to-global estimates of tropical forest biomass. Annual precipitation coefficient of variation (PV), dry season length (SD), and mean annual air temperature (TA) emerged as key drivers of variation in H:D relationships at the pantropical and region scales. Vegetation structure also played a role with trees in forests of a high A being, on average, taller at any given D. After the effects of environment and forest structure are taken into account, two main regional groups can be identified. Forests in Asia, Africa and the Guyana Shield all have, on average, similar H:D relationships, but with trees in the forests of much of the Amazon Basin and tropical Australia typically being shorter at any given D than their counterparts elsewhere. The region-environment-structure model with the lowest Akaike's information criterion and lowest deviation estimated stand-level H across all plots to within a median –2.7 to 0.9% of the true value. Some of the plot-to-plot variability in H:D relationships not accounted for by this model could be attributed to variations in soil physical conditions. Other things being equal, trees tend to be more slender in the absence of soil physical constraints, especially at smaller D. Pantropical and continental-level models provided only poor estimates of H, especially when the roles of climate and stand structure in modulating H:D allometry were not simultaneously taken into account.

scholarly journals Habitat selection of secondary hole-nesting birds in riverine forests along Drava river in Croatia

2020 ◽  
Vol 144 (11-12) ◽  
pp. 558-558
Author(s):  
Mario Slatki ◽  
Jelena Kralj
Keyword(s):  
Tree Species ◽  
Structural Characteristics ◽  
Bird Species ◽  
Rank Correlation ◽  
Basal Area ◽  
Principal Component ◽  
Relative Number ◽  
Bird Community ◽  
Habitat Characteristics ◽  
Mixed Stands

The correlation between secondary hole-nesters community characteristics and floristic and structural characteristics of their habitat was studied in riverine forest stands near river Drava in Croatia. Standard point count method was used for bird community sampling and circular plot method for habitat sampling. Sampling was carried out on 66 points. PCA analysis that included 28 independent habitat variables was used, followed by Spearman rank correlation between principal component scores and bird community variables (number of species and number of pairs). Tree basal area was used as an indication of stand maturity and to classify studied points into four forest types (ash, poplar, alder and mixed). Eight secondary hole-nesting species and 14 tree species were recorded. The average forest age was 59.8 ± 20.5 years, with ash and mixed stands being on average older than alder and poplar stands. Shannon-Wiener index of secondary hole-nesters diversity was highest in stands with dominant ash and was increasing with stand maturity. A significant positive correlation was found between number of bird species as well as number of pairs and older stands with lower number of tree species and lower relative number of poplar and alder. It can be concluded that diversity of secondary hole-nesting bird species as well as their abundance is correlated with structural habitat characteristics and that older stands show greater bird biodiversity and abundance.

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