Stand dynamics of mixed red alder – conifer forests of southeast Alaska

2004 ◽  
Vol 34 (4) ◽  
pp. 969-980 ◽  
Author(s):  
Robert L Deal ◽  
Paul E Hennon ◽  
Ewa H Orlikowska ◽  
David V D'Amore
Keyword(s):  
Stand Structure ◽  
Large Diameter ◽  
Basal Area ◽  
Height Growth ◽  
Diameter Distribution ◽  
Height Distribution ◽  
Conifer Forests ◽  
Red Alder ◽  
Southeast Alaska ◽  
Dead Trees

Stand structure and dynamics were evaluated in mixed red alder (Alnus rubra Bong.) – conifer forests of southeast Alaska. We assessed stand development, tree density, total basal area, diameter distribution of live and dead trees, height distribution of live trees, and mean diameter of all and largest conifers in 40-year-old red alder – conifer stands that developed following logging. Forty-five plots were established in nine stands sampled across a com po si tional range of 0%–86% alder. Alder height growth was initially rapid then slowed considerably, whereas conifer height growth was initially slow then rapidly increased with conifers now being 4–9 m taller than associated alders. Most alder diameters were 20–30 cm and conifer diameters were more variable with numerous small (3–10 cm) and a few large (>25 cm) trees. Total stand basal area significantly decreased (p = 0.013) with increasing proportions of alder, but density of live and dead trees was not closely associated with alder composition. More than 60% of all dead trees died standing regardless of size or species. Overall, these mixed red alder – conifer stands provided more heterogeneous structures than pure conifer stands, with more even diameter distributions, multiple canopy layers, and similar numbers of large diameter conifers.

Tree mortality and forest structure in the temperate rain forests of southeast Alaska

2003 ◽  
Vol 33 (9) ◽  
pp. 1621-1634 ◽  
Author(s):  
Paul E Hennon ◽  
Michael H McClellan
Keyword(s):  
Tree Mortality ◽  
Stand Structure ◽  
Woody Debris ◽  
Basal Area ◽  
Structural Diversity ◽  
Small Scale ◽  
Southeast Alaska ◽  
Dead Trees ◽  
Fall Direction ◽  
High Degree

Tree mortality in 27 old-growth stands at three locales in southeast Alaska was evaluated to determine how types of tree death contributed to stand structure and the production of woody debris and to interpret small-scale disturbance. Basal area, density of stems, and the condition of dead trees were described for each tree species. Dead trees with broken boles were observed most frequently, followed by dead standing intact and uprooted trees. The frequencies of dead trees within snag and log deterioration classes indicated that most trees died standing and subsequently broke. Reconstructed annual mortality rates for overstory trees averaged 0.3–0.5%·year–1 for the three locales and were relatively stable through the previous century. Tree fall direction for both uprooted and broken trees aligned significantly with the downslope direction. All three types of tree mortality contributed substantially to structural diversity, reflecting a high degree of complexity associated with small-scale disturbance at these three study locales.

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 New Silvicultural Treatments for Conifer Peri-Urban Forests Having Broadleaves in the Understory - The First Application in the Peri-Urban of Xanthi in Northeastern Greece

2019 ◽  
Vol 10 (2) ◽  
pp. 107-116 ◽  
Author(s):  
Elias Milios ◽  
Kyriaki Kitikidou ◽  
Kalliopi Radoglou
Keyword(s):  
Urban Forest ◽  
Urban Forests ◽  
Basal Area ◽  
Conifer Forests ◽  
Research Hypothesis ◽  
Silvicultural Treatments ◽  
Dead Trees ◽  
Selective Approach ◽  
Conifer Trees ◽  
Cutting Intensity

Background and Purpose: In Greece, forest practice did not develop special silvicultural treatments for planted conifer peri-urban forests where broadleaf trees appear as natural regeneration in the understory. The aims of this study are: a) to analyze the new proposed selective silvicultural treatments for the planted peri-urban forest of Xanthi and for analogous planted conifer forests, where broadleaf trees are naturally established in the understory b) to check the research hypothesis that the new selective silvicultural treatments exhibited higher intensity in terms of the basal area of cut trees, compared to that of traditional treatments in the studied peri-urban forest. Materials and Methods: In the traditional treatments, in the pine overstory cuttings, apart from the dead trees, mainly the malformed, damaged, suppressed and intermediate trees were cut. In the lower stories, the goal of the thinning was the more or less uniform distribution of broadleaf trees. In the proposed selective treatments, the main aim of pine cuttings is to release the broadleaf formations growing in the lower stories, while the treatments of the broadleaf trees will be a form of “positive selection” thinning. Plots were established in areas where the two types of treatments were going to be applied. In each plot, tree measurements and a classification of living trees into crown classes took place. After the application of the treatments the characteristics of cut trees were recorded. Results: In the established plots, before the cuttings (and thinning), total basal area was not statistically significantly different between the two types of treatments. In selective treatments, the basal area of all cut trees was statistically significantly higher than that of the results of traditional treatments. In the broadleaf cut trees there were statistical differences in the ratios of dominant, intermediate and suppressed trees between the two silvicultural approaches. Conclusions: The research hypothesis was verified. The intensity of treatments in terms of the basal area of cut trees was higher in the selective approach, compared to the traditional treatments in the Xanthi peri-urban forest. However, the overstory cutting intensity of the selective treatments depends on the spatial distributions and densities of broadleaved and conifer trees. In the broadleaf trees, the different objectives of the two types of treatments resulted in thinning with different qualitative characteristics. The proposed silvicultural treatments will accelerate the conversion of peri-urban conifer forests having an understory of broadleaf trees into broadleaved forests, or into mixed forests of conifers and broadleaf trees.

INVESTIGATING SILVICULTURAL CHARACTERISTICS OF YEW (TAXUS BACCATA L.) STAND USING FULL-CALLIPERING IN NORTHERN FORESTS OF IRAN

2013 ◽  
Vol 06 (01) ◽  
pp. 1250067 ◽  
Author(s):  
MIR MOZAFFAR FALLAHCHAI ◽  
SEYED ARMIN HASHEMI ◽  
GASEM RAHANJAM
Keyword(s):  
Distribution Curve ◽  
Basal Area ◽  
Diameter Distribution ◽  
Maximum Height ◽  
Taxus Baccata ◽  
Height Distribution ◽  
Annual Increment ◽  
Restricted Area ◽  
Northern Forests ◽  
Low Rate

In this research, some of site and silvicultural characteristics of Yew stand in northern forests of Iran was studied. For this purpose, compartment number 16 of district 4 Shir-ghalaye was selected. According to research purposes, stands with an area of 20 ha were chosen in center of the compartment and was separated from map. Due to restricted area of region and according to few number of Yew trees in the stand, the full-callipering method was conducted for measuring quantitative and qualitative characteristics. In the stand diameter at breast height (D.B.H.), height and canopy diameter of all Yew trees were measured. The results showed that the diameter distribution curve and height distribution curve of Yew trees were similar to even-age forests curve. But according to average annual increment, mixture type of Yew trees in stand, diameter distribution of other species and low rate regeneration of Yew, it can be concluded that the studied Yew stand, is an uneven-age stand and because of low rate regeneration in previous years the number of young Yew trees were reduced and even-age forest curve was formed subsequently. The maximum height and diameter of Yew trees were recorded 26.8 m and 112 cm, respectively. Also, the number of trees per hectare and basal area per hectare of Yew trees were calculated 14.55 and 3.23 m2 respectively.

Relations between red alder composition and understory vegetation in young mixed forests of southeast Alaska

2006 ◽  
Vol 36 (3) ◽  
pp. 738-748 ◽  
Author(s):  
Thomas A Hanley ◽  
Robert L Deal ◽  
Ewa H Orlikowska
Keyword(s):  
Carrying Capacity ◽  
Basal Area ◽  
Picea Sitchensis ◽  
Understory Vegetation ◽  
Wildlife Habitat ◽  
Red Alder ◽  
Southeast Alaska ◽  
Net Production ◽  
Understory Biomass ◽  
Young Growth

Interest in mixed red alder (Alnus rubra Bong.) – conifer young-growth stands has grown in southeast Alaska, USA, because they appear to provide much more productive understory vegetation and wildlife habitat than do similar-aged pure conifer stands. We studied understory vegetation in nine even-aged young-growth stands (38–42 years old) comprising a gradient of red alder – conifer overstory composition, with red alder ranging from 0% to 86% of stand basal area. Conifers were Sitka spruce (Picea sitchensis (Bong.) Carr.), western hemlock (Tsuga heterophylla (Raf.) Sarg.), and western redcedar (Thuja plicata Donn ex D. Don). We measured understory biomass and net production (current annual growth) in each stand by species and plant part and estimated carrying capacity for black-tailed deer (Odocoileus hemionus sitkensis Cowan) with a food-based habitat model. Highly significant positive relations (P < 0.002) were found between red alder basal area and all of the following: total understory biomass (r2 = 0.743), net production of shrubs (r2 = 0.758) and herbs (r2 = 0.855), and summer carrying capacity for deer (r2 = 0.846). The high correlation between red alder and herbaceous production is especially important, because herbs are least abundant and most difficult to maintain in young-growth conifer forests of this region. Red alder offers prospects for increasing understory vegetation biomass and its food value for deer and other wildlife when included as a hardwood overstory species in mixed hardwood–conifer young-growth forests.

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.

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.

Relations among stand structure, dispersal of second-instar western spruce budworm, defoliation, and height growth of young conifers

1988 ◽  
Vol 18 (6) ◽  
pp. 796-802
Author(s):  
Clinton E. Carlson ◽  
Ward W. McCaughey ◽  
Leon J. Theroux
Keyword(s):  
Ponderosa Pine ◽  
Stand Structure ◽  
Basal Area ◽  
Spruce Budworm ◽  
Height Growth ◽  
Western Montana ◽  
Western Spruce Budworm ◽  
Mature Trees ◽  
Subalpine Fir ◽  
Host Trees

Local stand structure had little influence on dispersal of second-instar western spruce budworm (Choristoneuraoccidentalis Freeman). Numbers of dispersing larvae caught on traps averaged 37 larvae/m2 in the cut stands, as high as were found in adjacent uncut stands, and were not related to basal area of overstory in harvested stands, distance to the adjacent uncut stands, or budworm populations in the uncut stands. Despite high numbers of dispersing larvae, defoliation of host regeneration in cut stands was low (87% of the nonlarch host incurred less than 25% defoliation) and was not predictable (p ≤ 0.05) from dispersing larvae. Defoliation of mature trees in the adjacent uncut stands averaged 20% and ranged to 45%. Three-year height growth of postharvest host conifers in the cut stands increased with smaller overstory basal area, greater initial height, and greater crown ratio, but was not affected by the small amount of budworm defoliation. Regression models of 3-year height growth were similar among host western larch (Larixoccidentalis Nutt.), grouped nonlarch hosts (Douglas-fir, Pseudotsugamenziesii var. glauca (Beissn.) Franco; grand fir, Abiesgrandis (Dougl.) Forbes; and subalpine fir, A. lasiocarpa (Hook.) Nutt.), and grouped nonhosts (ponderosa pine, Pinusponderosa Dougl.; and lodgepole pine, P. contorta var. latifolia). Larval dispersal may be influenced more by forestwide conditions and spring weather than by local stand factors. Larvae reaching target seedlings likely are removed by predators such as birds and ants. Vigorous small host trees appear to be poor habitat for budworms; the insect had little effect on height growth of 5- to 20-year-old seral conifer stands of western Montana.

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.

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