scholarly journals Change of stand structure of mixed-species natural forest by selection cutting system : A case of compartment 105 in the Tokyo University forest in Hokkaido

1997 ◽  
Vol 29 (0) ◽  
pp. 35-40
Author(s):  
Tosiharu HONNAMI ◽  
Hirokazu YAMAMOTO ◽  
Isao SATO ◽  
Akio MICHIGAMI ◽  
Hiroshi INUKAI
Keyword(s):  
Stand Structure ◽  
Natural Forest ◽  
Mixed Species ◽  
Selection Cutting ◽  
System A ◽  
Cutting System

scholarly journals Stand Structure and Composition 32 Years after Precommercial Thinning Treatments in a Mixed Northern Conifer Stand in Central Maine

2011 ◽  
Vol 28 (2) ◽  
pp. 92-96 ◽  
Author(s):  
Aaron R. Weiskittel ◽  
Laura S. Kenefic ◽  
Rongxia Li ◽  
John Brissette
Keyword(s):  
Stand Structure ◽  
Abies Balsamea ◽  
Basal Area ◽  
Long Term Effects ◽  
Mixed Species ◽  
Precommercial Thinning ◽  
Large Trees ◽  
Stand Attributes ◽  
And Control

Abstract The effects of four precommercial thinning (PCT) treatments on an even-aged northern conifer stand in Maine were investigated by examining stand structure and composition 32 years after treatment. Replicated treatments applied in 1976 included: (1) control (no PCT), (2) row thinning (rowthin; 5-ft-wide row removal with 3-ft-wide residual strips), (3) row thinning with crop tree release (rowthin+CTR; 5-ft-wide row removal with crop tree release at 8-ft intervals in 3-ft-wide residual strips), and (4) crop tree release (CTR; release of selected crop trees at 8×8-ft intervals). PCT plots had more large trees and fewer small trees than the control in 2008. There were no other significant differences between the rowthin and control. The rowthin+CTR and CTR treatments had lower total and hardwood basal area (BA) and higher merchantable conifer BA than the control. CTR also resulted in more red spruce (Picea rubens [Sarg.]) and less balsam fir (Abies balsamea [L.]) than the other treatments. Although stand structures for rowthin+CTR and CTR were similar, the percentage of spruce in CTR was greater. Although the less-intensive rowthin+CTR treatment may provide many of the same benefits as CTR, the latter would be the preferred treatment if increasing the spruce component of a stand is an objective. Overall, early thinning treatments were found to have long-term effects on key stand attributes, even more than 30 years after treatment in areas with mixed species composition and moderate site potential.

Effects of variations in stand structure on development of mixed-species stands in eastern Washington

1993 ◽  
Vol 23 (3) ◽  
pp. 545-552 ◽  
Author(s):  
David F. Cobb ◽  
Kevin L. O'hara ◽  
Chadwick D. Oliver
Keyword(s):  
Stand Structure ◽  
Lodgepole Pine ◽  
Douglas Fir ◽  
Cascade Range ◽  
Stand Development ◽  
Mixed Species ◽  
Western Larch ◽  
Development Patterns ◽  
Large Numbers ◽  
Eastern Washington

The development of six mixed-species, even-aged stands was reconstructed in the eastern Washington Cascade Range. All stands were within the Grand Fir Climax Series and began following stand replacement disturbances. Western larch (Larixoccidentalis Nutt.) and lodgepole pine (Pinuscontorta Dougl. ex Loud.), when present, formed an upper stratum over interior Douglas-fir (Pseudotsugamenziesii var. glauca (Beissn.) Franco) and grand fir (Abiesgrandis (Dougl.) Lindl.) in all six stands. Establishment patterns and species composition affected stand development patterns. Douglas-fir benefitted from the absence of lodgepole pine; grand fir benefitted from the absence of Douglas-fir, but apparently not from the absence of lodgepole pine. Lodgepole pine had faster initial diameter growth rates than western larch when it became established relatively early and in large numbers.

Electronic Subdividing Method for Linear Encoder of High Speed Position Detection

2006 ◽  
Vol 315-316 ◽  
pp. 230-234
Author(s):  
W. Zuo ◽  
Jing Feng Zhi ◽  
S.T. Huang ◽  
G.M. Zhao
Keyword(s):  
Phase Shift ◽  
High Speed ◽  
Position Measurement ◽  
System A ◽  
Position Detection ◽  
Key Technologies ◽  
Linear Encoder ◽  
Cutting System ◽  
Speed Response

This paper presents an electronic subdviving method for linear encoder of high speed position detection. The method aims to enhance the resolution of position measurement and improve the precision of noncircular component cutting system. A 20-subdividing circuit based on resistor chain phase shift is researched and implemented, and some key technologies are discussed. The method is proved to be successful in raising the resolution and precision with a high speed response. The experiment result proves that electronic subdividing method is doable and effective to raise the resolution of the existing system.

scholarly journals Regeneration Success of Chamaecyparis obtusa after Selection Cutting Practice in a Natural Forest without Dwarf Bamboo Undergrowth

2021 ◽  
Vol 103 (3) ◽  
pp. 207-214
Author(s):  
Hisashi Sugita ◽  
Hiromichi Kushima ◽  
Haruhiko Mimura ◽  
Naoaki Tate ◽  
Masayuki Imamura ◽  
...  
Keyword(s):  
Chamaecyparis Obtusa ◽  
Natural Forest ◽  
Dwarf Bamboo ◽  
Selection Cutting

scholarly journals Spatio-temporal structure of natural forest: A structural index approach

Beskydy ◽  
2012 ◽  
Vol 5 (2) ◽  
pp. 163-172 ◽  
Author(s):  
M. Balanda
Keyword(s):  
Nearest Neighbor ◽  
Stand Structure ◽  
Temporal Structure ◽  
Structural Diversity ◽  
Horizontal Distribution ◽  
Natural Forest ◽  
Structure Characteristic ◽  
Middle Europe ◽  
Spatio Temporal ◽  
High Level

The submitted paper deals with the analysis of stand structure of mixed species natural forest located in the Carpathians, Middle Europe. In order to evaluation of structural diversity we chose the combination of distance independent and nearest-neighbor indices. Following structural indices were calculated: Shanon-Weaver index (S-W), diameter differentiation index (Td), Gigi coefficient (G), mingling index (DMi) and Clark Evans index (CEd). The permanent research plot with area of 2.5ha was established in National Naure Reserve Hrončecký grúň and subdivided into 25×25m subplots. The combination of mentioned indices was calculated for each subplot separately. Regarding the diameter heterogeneity, the most part of analyzed structures showed the moderate level of tree size differentiation (S-W value 0.393±0.074). The presence of high number of juvenile individuals which already reached the diameter category “above 2cm” did not significantly affect the diameter variation of investigated stand. On the other hand, a massive establishment of subsequent generation led to creation of spatial structure characteristic by high level of vertical differentiation (Gini coefficient 0.47 in the structure characterized as the breakdown with successive generation). High climax species richness was confirmed by calculated values of DMi index (maximum relative presence in the category from 0.3 to 0.4). Each tree was surrounded by two and more different species individuals. Analysis discovers the negative developmental shift in the DMi values towards to less differentiated structures. Regarding the horizontal distribution the analysis of CEd values indicated that investigated natural forest can reveal a random distribution of individuals regardless of developmental stage.

Growth performance, windthrow, and insects: meta-analyses of parameters influencing performance of mixed-species stands in boreal and northern temperate biomes

2011 ◽  
Vol 41 (6) ◽  
pp. 1141-1159 ◽  
Author(s):  
Verena C. Griess ◽  
Thomas Knoke
Keyword(s):  
Growth Performance ◽  
Tree Species ◽  
Stand Structure ◽  
Positive Impact ◽  
Meta Analysis ◽  
Positive Interactions ◽  
Negative Effects ◽  
Mixed Species ◽  
Financial Return ◽  
Meta Analyses

Stand structure is a key attribute of forest ecosystems. Mixed-tree plantations are widely felt to be the appropriate option for providing a broad range of goods and environmental services and to reduce susceptibility to natural hazards. However, the debate continues whether mixed plantations can achieve greater financial return than monocultures can. In this study, mixed-species stands of conifers and hardwood species were analyzed in consideration of economically relevant factors. Growth performance and resistance to hazards and pests are widely noted in the literature and are of general economic interest. Thus meta-analyses of relevant studies were conducted to test the following hypotheses: (1) mixing tree species has no significant influence on growth performance or resistance against hazards and pests and, if refuted, (2) mixing tree species causes mainly negative effects on growth performance and resistance against hazards and pests. However, a positive impact of mixing tree species was proven for resistance against windthrow and pests. The meta-analysis on growth performance just as well indicates a positive effect of mixing tree species. Overall, these positive results underscore the need for a large number of additional studies to examine different silvicultural systems to develop optimal management prescriptions to benefit from positive interactions.

scholarly journals Evaluating and modeling variation in site-level maximum carrying capacity of mixed-species forest stands in the Acadian Region of northeastern North America

2019 ◽  
Vol 95 (03) ◽  
pp. 171-182 ◽  
Author(s):  
Aaron R. Weiskittel ◽  
Christian Kuehne
Keyword(s):  
North America ◽  
Prediction Model ◽  
Carrying Capacity ◽  
Stand Structure ◽  
Regional Scale ◽  
Basal Area ◽  
Climatic Variables ◽  
Site Quality ◽  
Forest Stands ◽  
Mixed Species

Currently no universal approach exists to estimate regional site-level maximum carrying capacity in terms of stand densityindex (SDIMAX) of mixed species stands across contrasting forest ecosystems. Regional research efforts that account forinfluential stand-level variables and species traits are needed to reliably derive SDIMAX under varying environmental conditions and stand characteristics. This study used regionally comprehensive forest inventory data from various permanentsampling efforts to evaluate the effects of contrasting biotic and abiotic stand- and site-level factors on SDIMAX of multiple-species, structurally heterogeneous stands of the climatically diverse Acadian Forest Region of North America. Specifically,we aimed to i) quantify the stand-level maximum size-density line for an array of forest stands found across the study area,irrespective of stand structure; ii) evaluate the relationship between this stand-specific estimate of SDIMAX and various other stand-level attributes; and, iii) develop a generalized SDIMAX prediction model using SDIMAX estimates from objective i) aswell as potential regional drivers of SDIMAX from objective ii). The most influential stand-level factors on SDIMAX were proportion of total stand basal area in hardwood species, basal area weighted mean specific gravity, range in stem diameter, andspecies diversity. Direct climatic variables were not included in our SDIMAX prediction model due to the limited variationexplained, but relationships with elevation and a site quality index based on these climatic variables were. Overall, we con-clude that i) variation in SDIMAX appears to be mostly driven by the softwood to hardwood ratio of the mixed species,structurally complex stands evaluated in our study and ii) the general approach offers a viable framework for estimating sitemaximum carrying capacity at a regional-scale and effectively managing stand density accordingly.

Sampling design and precision of basal area growth and stand structure in uneven-aged northern hardwoods

2012 ◽  
Vol 88 (1) ◽  
pp. 30-39
Author(s):  
François Guillemette ◽  
Marie-Claude Lambert ◽  
Steve Bédard
Keyword(s):  
Sampling Design ◽  
Stand Structure ◽  
Basal Area ◽  
Systematic Sampling ◽  
Sampling Area ◽  
Diameter Class ◽  
Selection Cutting ◽  
Large Plot ◽  
Systematic Selection ◽  
Sufficient Precision

Sampling design (distribution of plots, plot sizes, and number of sample plots) is an important consideration in planning a field study since it determines the bias and precision of information obtained. In this study, we evaluated the effects of two commonly used sampling designs on the precision of estimates of means related to stand basal area, considered as a whole or by diameter class, and 10-year growth components, in six 2-ha areas located in uneven-aged northern hardwood stands of Quebec managed under selection cutting. The study compares random and systematic sampling designs of one to 10 plots, with plots varying in size from 0.05 ha to 1.25 ha. Increasing the total area sampled (i.e., sampling area) in a stand from 0.05 ha to about 0.25 ha resulted in large precision gains; further increases in sampling area had more limited effects on precision. A sampling area of at least 0.5 ha would be required to obtain a minimally acceptable precision in estimating means of total basal area and 10-year growth components. A much larger sampling area would be required to obtain sufficient precision in estimating mean basal area by diameter class, often required to study stand structure. Precision can also be increased by dividing the sampling area into several smaller plots rather than using a single large plot. We found no clear difference in the results between random and systematic selection approaches.

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