Stand structure and growing space efficiency following thinning in an even-aged Douglas-fir stand

1988 ◽  
Vol 18 (7) ◽  
pp. 859-866 ◽  
Author(s):  
K. L. O'Hara
Keyword(s):  
Stand Structure ◽  
Volume Growth ◽  
Basal Area ◽  
Stand Density ◽  
Douglas Fir ◽  
Stem Volume ◽  
Projection Area ◽  
Individual Tree ◽  
Space Efficiency ◽  
Individual Trees

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.

Stand structure, thinning prescriptions, and density indexes in a Douglas-fir thinning study, Western Washington, U.S.A.

1983 ◽  
Vol 13 (1) ◽  
pp. 126-136 ◽  
Author(s):  
Chadwick Dearing Oliver ◽  
Marshall D. Murray
Keyword(s):  
Stand Structure ◽  
Volume Growth ◽  
Basal Area ◽  
Stand Density ◽  
Close Relation ◽  
Douglas Fir ◽  
Volume Number ◽  
Large Trees ◽  
Before And After ◽  
Number Of Stems

A Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) thinning study was established in 1959 in a stand begun after logging in 1930. Thinnings to set basal area densities were done in 1959, 1962, 1966, and 1970. On each plot both large and small trees were removed since average basal area per tree was kept constant before and after thinning. Volume growth varied greatly between plots of the same age, initial basal area, and site because of differences in stand structure. Large trees on a plot grew more per tree and per basal area than small trees. Stand basal area, stand volume, number of stems, or number of dominant and codominant trees were not closely related to volume growth per hectare, although density indexes giving weight to larger trees showed the closest relation. The lack of close relation between stand density indexes and growth found here and elsewhere probably means the indexes do not uniquely define stand structures; it does not necessarily mean that thinning will not increase volume growth per hectare. Volume growth per hectare after thinning to a given basal area density will be greater and probably more consistent if larger trees are left and enough time is allowed for the stand to recover following thinning.

Twelfth-year response of Douglas-fir to area of weed control and herbaceous versus woody weed control treatments

2006 ◽  
Vol 36 (10) ◽  
pp. 2464-2473 ◽  
Author(s):  
Robin Rose ◽  
Lee S Rosner ◽  
J Scott Ketchum
Keyword(s):  
Weed Control ◽  
Stand Structure ◽  
Volume Growth ◽  
Woody Species ◽  
Douglas Fir ◽  
Stem Volume ◽  
Coast Range ◽  
Vegetation Control ◽  
Hardwood Species ◽  
Individual Trees

Coastal Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii) response to eight weed control treatments was measured 12 years after planting at two Oregon sites. Treatments included four areas of weed control around individual trees (0.375, 1.49, 3.35, and 5.95 m2), no weed control (check), total vegetation control, control of herbaceous competition only, or control of woody competition only. Douglas-fir growth and woody-species invasion differed between the Coast Range site (Summit) and the Cascade Range foothills site (Marcola). Woody species reinvasion was more intense at Summit, with Douglas-fir cumulative mortality in the check treatment reaching 23% in year 12. Woody-only control improved Douglas-fir growth at Summit but had no significant effect on growth at Marcola. Total vegetation control had a profound effect on stem volume growth 12 years after planting. At Summit, total vegetation control resulted in a 355% increase in volume per hectare relative to the check. At Marcola the increase was only 63%. At Summit, growth increased with each increase in area of weed control, whereas at Marcola growth increased with increasing area of weed control up to 3.35 m2 of control. Results suggest that much of the gain in volume growth attributable to weed control may be lost if weed-control treatments are not highly efficacious. The differential response to woody control indicates that its benefit at a given site is strongly related to the abundance of competitive hardwood species, which may be predicted from the preharvest stand structure and vegetation community.

Reconstructing structural development of even-aged larch stands in Siberia

2000 ◽  
Vol 30 (4) ◽  
pp. 580-588 ◽  
Author(s):  
Akira Osawa ◽  
Anatoly P Abaimov ◽  
Olga A Zyryanova
Keyword(s):  
Power Distribution ◽  
Volume Growth ◽  
Stand Density ◽  
Stem Volume ◽  
Volume Distribution ◽  
Structural Development ◽  
Individual Tree ◽  
Stem Size ◽  
Tree Ring Data ◽  
Time Observation

A method was proposed for quantitatively reconstructing structural development over time of even-aged monospecific forests and was applied to a larch (Larix gmelinii (Rupr.) Rupr.) stand in Siberia. It relies on samples obtained at one-time observation and some simple assumptions considered general in even-aged stands. Tree-ring data taken from breast height of a group of the largest trees and those measured at various stem heights of several individuals representing the range of tree sizes in the plot are used for the estimation. Stand density and parameters of stem volume distribution at a given time in the past were calculated with the "stem slenderness index," and with an assumption of the -3/2 power distribution for the distribution function of stem size, respectively. By developing time-dependent allometric relationships for individual tree attributes, the whole-stand values of stem volume and its increment were reconstructed for several decades of stand development. Estimated history of the changes in stand density, total stem volume, and stem volume growth for the dense larch stand examined, mostly agreed with a separate estimation by the self-thinning assumption.

Development and growth of even-aged stands of Douglas-fir and grand fir

1986 ◽  
Vol 16 (2) ◽  
pp. 367-372 ◽  
Author(s):  
Bruce C. Larson
Keyword(s):  
Growth Rates ◽  
Volume Growth ◽  
Basal Area ◽  
Douglas Fir ◽  
Stem Volume ◽  
Mixed Stands ◽  
Site Class ◽  
Development Patterns ◽  
Western Washington ◽  
Eastern Washington

Stand development patterns and growth rates of even-aged mixed stands of Douglas-fir (Pseudotsugamensiesii Mirb. Franco) and grand fir (Abiesgrandis Dougl. Lindl.) were investigated by stand reconstruction in eastern Washington. Although Douglas-fir dominated the stands early, grand fir of the same age eventually overtook the tallest Douglas-firs. Dominant trees of both species were found to have highly variable taper form (based on basal area to height ratios), although a linear relationship existed in other crown classes. Stem volume growth rates were determined by reconstructing past diameters and heights and were found comparable to site class IV Douglas-fir in western Washington. Intensive management, especially planting and thinning, could improve upon the observed mean annual increments of 800 board feet per acre at 80 years of age.

scholarly journals Low Thinning as a Forest Restoration Tool at Redwood National Park

2011 ◽  
Vol 26 (2) ◽  
pp. 91-93 ◽  
Author(s):  
Jason R. Teraoka ◽  
Christopher R. Keyes
Keyword(s):  
Forest Restoration ◽  
Stand Structure ◽  
Basal Area ◽  
Stand Density ◽  
Variable Density ◽  
Douglas Fir ◽  
Redwood National Park ◽  
Second Growth ◽  
Need To Evaluate

Abstract A growing interest in the restoration of young second-growth forests by managers of reserves in the redwood region has led to a need to evaluate restoration-based silvicultural strategies. This case study assessed the effectiveness of low thinning as a forest restoration tool via analysis of stand structure at Redwood National Park's Whiskey Forty Forest Restoration Study. The second-growth stand had more than 5,500 trees ha−1 and 57.0 m2 ha−1 basal area and consisted chiefly of three species: Douglas-fir (the dominant species), redwood, and tanoak. Low thinning reduced stand density but also reduced species richness by eliminating scarce species. Seven years after thinning, growth was enhanced (33.6% gain in basal area), and mortality was minor (3% of all stems); however, Douglas-fir remained competitive in the upper canopy. Its average basal area increment was less than redwood's, but its radial growth was equal and its rate of basal area growth was greater in the years following thinning. We conclude that the thinning improved stand conditions but did not fully satisfy restoration goals and that other thinning methods, such as variable-density thinning, are likely to be more effective at promoting redwood dominance.

Développement d'un modèle de type arbre appliqué à la croissance des peuplements feuillus irréguliers du sud de la Belgique

1996 ◽  
Vol 26 (10) ◽  
pp. 1838-1848 ◽  
Author(s):  
P. Lejeune
Keyword(s):  
Stand Structure ◽  
Basal Area ◽  
Tree Stand ◽  
Individual Tree ◽  
Growing Period ◽  
Site Characteristics ◽  
Individual Tree Growth ◽  
Forest Mensuration ◽  
Individual Trees ◽  
Changes Over Time

A model predicting circumference growth of individual trees has been developed for mixed irregular stands dominated by Fagussilvatica L. in southeastern Belgium. This model integrates simultaneously tree, stand, and growing site characteristics without considering distances between individual trees. It has a determination coefficient of 40.1% and a residual standard deviation of 0.45 cm/year. Forest mensuration variables considered in the model are circumference, tree social position represented by the total basal area of trees greater than the subject tree, stand basal area, and some index of stand structure corresponding to the ratio of the variance over the mean circumference. The site component is essentially expressed by the length of the growing period. The low accuracy obtained for individual tree growth is relative because the results are used mainly after individual trees have been distributed into size classes. We have been able to show that the introduction of crown description in the model can increase its accuracy. But this modification requires a submodel describing crown changes over time.

scholarly journals Growth and Mortality of Residual Douglas-Fir after Regeneration Harvests under Group Selection and Two-Story Silvicultural Systems

2011 ◽  
Vol 26 (2) ◽  
pp. 64-70 ◽  
Author(s):  
Sean Garber ◽  
Tzeng Yih Lam ◽  
Douglas A. Maguire
Keyword(s):  
Term Structure ◽  
Group Selection ◽  
Volume Growth ◽  
Basal Area ◽  
Douglas Fir ◽  
Stem Volume ◽  
State University ◽  
Management Objectives ◽  
Integrated Research ◽  
Overstory Trees

Abstract Complex management objectives for many publicly owned Douglas-fir forests have prompted renewed interest in silvicultural systems other than clearcutting. The College of Forestry Integrated Research Project at Oregon State University was implemented to test for differences in economic, biological, and human responses to group selection and two-story silvicultural systems. Three separate blocks were established and treated between 1989 and 1991. Trees were measured immediately after the harvest treatments (1991 or 1992) and after the 2004 growing season. Responses of residual overstory trees to initial group selection and two-story treatments were tested relative to untreated controls units in terms of (1) gross basal area and stem volume growth of all residual trees and of the 10 largest trees per acre; (2) gross basal area and stem volume growth conditional on initial basal area and stem volume, respectively, of all residual trees and of the 10 largest trees per acre; and (3) mortality of all overstory trees. Basal area and volume growth were greatest in the control and least in the two-story treatment, but volume growth conditional on initial volume did not differ significantly among treatments. Mortality was significantly greater in the two-story treatment. Overstory growth release in residual Douglas-fir may require 10 years or more to appear after regeneration cuts on some sites, and the possibility of increased overstory mortality complicates attainment of desired long-term structure under two-story silvicultural systems.

Effects of fertilization and thinning on 8-year growth responses of second-growth Douglas-fir stands

1991 ◽  
Vol 21 (4) ◽  
pp. 516-521 ◽  
Author(s):  
K. A. Stegemoeller ◽  
H. N. Chappell
Keyword(s):  
Combined Treatment ◽  
Volume Growth ◽  
Basal Area ◽  
Douglas Fir ◽  
Site Quality ◽  
Growth Responses ◽  
Positive Interaction ◽  
Individual Tree ◽  
Growing Stock ◽  
Area And Volume

Fertilization of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) stands generally increased both basal area and volume growth for at least 8 years. Thinning tended to have an even greater effect than fertilization on basal area and volume growth, increasing both on an individual-tree basis. On a land-area basis, however, the removal of growing stock by thinning caused volume growth to be less than that of the control. The magnitude and duration of this negative response was dependent on the level of thinning and the site quality. A significant positive interaction between fertilization and thinning exists. The combined treatment resulted in the greatest absolute basal area and volume increments, and the response became greater than that to fertilizer alone in the 3rd and 4th years, and remained so through at least 8 years.

Effects of high levels of fertilization with urea on growth of thinned and unthinned Douglas-fir stands

1985 ◽  
Vol 15 (4) ◽  
pp. 730-733 ◽  
Author(s):  
H. J. Barclay ◽  
H. Brix
Keyword(s):  
Volume Growth ◽  
Basal Area ◽  
Douglas Fir ◽  
Stem Volume ◽  
Growth Responses ◽  
Positive Interaction ◽  
Fertilizer Use ◽  
Response Period ◽  
Volume Response ◽  
Fertilizer Rates

The diameter and volume growth of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) were documented 9 years after thinning and fertilization. The treatments involved three levels of thinning (0, 1/3, and 2/3 of basal area removed) and six levels of fertilization (0–1344 kg N/ha) with urea. Increments for both diameter and gross volume increased with the rate of fertilization and responses were still apparent 9 years after treatment. For unthinned plots, the 9-year volume growth responses were 30, 50, and 80% with fertilizer rates of 224, 448, and 896 kg N/ha, respectively. The efficiency of fertilizer use, measured as stem volume response per unit of nitrogen applied, decreased with the rate of fertilization, but this picture may change over a longer response period. There was a positive interaction between fertilization and thinning such that high levels of both mutually enhanced growth. Mortality increased with fertilization, but only noticeably in unthinned plots.

Effects of intermediate silvicultural treatments on the distribution of within-stand growth

1994 ◽  
Vol 24 (2) ◽  
pp. 398-404 ◽  
Author(s):  
James A. Moore ◽  
Lianjun Zhang ◽  
James D. Newberry
Keyword(s):  
Stand Structure ◽  
Statistical Tests ◽  
Relative Size ◽  
Basal Area ◽  
Stand Density ◽  
Relative Distribution ◽  
Growth Responses ◽  
Stand Growth ◽  
Silvicultural Treatments ◽  
Individual Trees

The distribution of within-stand basal area growth following silvicultural treatments was investigated using a relative size–relative growth (RSG) function. The effects of thinning on the distribution of tree basal area, including changes in location or scale, can be incorporated into the estimation of the RSG function parameters. Additional stand growth due to fertilization can also be allocated to individual trees using the same RSG function, since the contribution of a tree's response to total stand treatment response depends on its relative size in the stand. Statistical tests and validation of the RSG function indicated that thinning and fertilization do not alter the characteristic relationships between tree size, stand density, stand structure, and the relative distribution of growth across size classes within a stand. Therefore, silvicultural treatment growth responses predicted at a whole-stand level of resolution can be disaggregated to a list of individual trees using the RSG function developed from untreated plots.

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