Wachstum und Wertleistung der Douglasie in Abhängigkeit von der Standraumgestaltung

2012 ◽  
Vol 163 (3) ◽  
pp. 96-104 ◽  
Author(s):  
Joachim Klädtke ◽  
Ulrich Kohnle ◽  
Edgar Kublin ◽  
Andreas Ehring ◽  
Hans Pretzsch ◽  
...  

Growth and value production of Douglas-fir under varying stand densities The investigation is focused on the effects of initial tree number and thinning on growth and value performance of Douglas-fir stands. Data base is a coordinated Douglas-fir spacing experiment in South Germany, started 40 years ago and comprising variants of tree numbers with 500, 1,000, 2,000 and 4,000 Douglas-firs per hectare. The treatment was performed according to a standardized experiment program. The results show that at low initial tree numbers, the diameter on breast height (DBH) of (pre)dominant trees at the beginning of the observations (with 12 m top height) is bigger than at higher initial plant numbers. Accordingly, the quotient of height (H) to DBH (as an indicator for tree's static stability) is lower. The further development of DBH and H/DBH quotient is decisively determined by stand treatment, which superimposes the effect of the initial tree number. The total volume growth shows a clear differentiation, too, the variants with initially high tree numbers appearing on top. In the monetary analysis, this ranking is reversed: despite a supposed inferior wood quality, the variants with lower initial tree numbers clearly outperform the ones with higher numbers in terms of value. From these results, the following silvicultural recommendations for Douglas-fir can be derived: the initial tree numbers should be in the range from 1,000 to 2,000 plants per hectare. On technically not accessible sites, even lower tree numbers may come into question. The strong influence of stand treatment on DBH and H/DBH development highlights the problem of postponed thinnings, for this causes growth and stability losses even under favorable starting conditions in terms of competition.

1989 ◽  
Vol 4 (4) ◽  
pp. 116-119 ◽  
Author(s):  
Linda S. Heath ◽  
H. N. Chappell

Abstract Response surface methodology was used to estimate six-year volume growth response to 1 application of 200 lb nitrogen per acre in unthinned and thinned Douglas-fir (Pseudotsuga menziesii) stands of breast height age (bha) 25 years or less. Regional mean fertilizer response was 16% in unthinned stands and 20% in thinned stands. Site index had an increasingly inverse effect on response as basal area increased in both unthinned and thinned stands. Response varied little over site index in regions of low basal area, decreased moderately as site index increased in the intermediate region, and decreased rapidly in the high basal area region. West. J. Appl. For. 4(4):116-119, October 1989.


2016 ◽  
Vol 65 (1) ◽  
pp. 16-23 ◽  
Author(s):  
Silva Šēnhofa ◽  
Mārtiņš Zeps ◽  
Arnis Gailis ◽  
Rolands Kāpostiņš ◽  
Āris Jansons

Abstract Cracks expose wood to fungal infections that significantly affects wood quality, while rapid wound occlusion decreases probability of infections. Assessment of scars was done at four grade scale in three adjacent hybrid aspen trials at the age of 8-10 years in central part of Latvia three years after bark crack occurrence. Occluded wounds were found for 95% of damaged trees, regardless of tree age. Among trees that had cracks wider than 1 cm, 42% had uniformly healed bark, but 7% still had open wounds. Wound development was significantly affected by crack width and length (both p < 0.001), but had no clear relation with tree DBH (diameter at breast height) and relative DBH increment (both p > 0.05). At clonal mean level, scar grade was significantly affected by grade of crack three years earlier and clone (both p < 0.001), but mean DBH of clone had no relation (p > 0.05) to proportion of trees evaluated by any of the scar grades. The results suggest that three years after the bark crack formation most of them had successfully occluded and selection of clones with better diameter growth has no influence on development of cracks.


1984 ◽  
Vol 14 (6) ◽  
pp. 879-884 ◽  
Author(s):  
A. J. Thomson ◽  
H. J. Barclay

The effects of fertilization and thinning of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) on the distribution of area increment along the bole were assessed using radial growth measurements 6 and 9 years after treatment. Within treatments, the average area increment per tree was linearly related to diameter at breast height, and this relationship was used to evaluate the effects of treatment on growth rate. Fertilization had the greatest effect on average area increment, and for a particular fertilization regime, thinning increased the response. Thinning modified the distribution of growth over the bole of all trees and increased butt flare, especially in smaller trees. The effect declined from the 4- to 6-year measurement period to the 7-to 9-year measurement period. Fertilization had no consistent effect on growth distribution. The regression methods used in this study provided a more sensitive measure of form changes than previous methods, were independent of size distribution, and facilitated extrapolations and evaluation of temporal trend.


2002 ◽  
Vol 32 (2) ◽  
pp. 233-246 ◽  
Author(s):  
Ronald Heninger ◽  
William Scott ◽  
Alex Dobkowski ◽  
Richard Miller ◽  
Harry Anderson ◽  
...  

We (i) quantified effects of skidder yarding on soil properties and seedling growth in a portion of western Oregon, (ii) determined if tilling skid trails improved tree growth, and (iii) compared results with those from an earlier investigation in coastal Washington. Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings were hand planted at eight recent clearcuts in skid ruts in either nontilled or tilled trails, in adjacent soil berms, and in adjacent logged-only portions. Four and 5 years after skidding, rut depths averaged 15 cm below the original soil surface; mean fine-soil bulk density (0–30 cm depth) below ruts of nontilled trails exceeded that on logged-only portions by 14%. Height growth on nontilled trails averaged 24% less than on logged-only portions in year 4 after planting and decreased to 6% less in year 7. For years 8–10, mean height growth was similar for all treatments. Reduced height growth lasted for about 7 years compared with 2 years for coastal Washington. Ten years after planting, trees in skid-trail ruts averaged 10% shorter with 29% less volume than those on logged-only portions. Tillage improved height and volume growth to equal that on logged-only portions. Generalizations about negative effects of skid trails on tree growth have limited geographic scope.


2020 ◽  
Vol 66 (3) ◽  
pp. 275-283 ◽  
Author(s):  
Halli Hemingway ◽  
Mark Kimsey

Abstract Accurate measures of forest site productivity are essential for forest-management planning. The most common measure of site productivity is breast height–age site index (BHASI)—the expected height at a reference age. Error from including early growth in productivity estimates and limited applicability of any one BHASI model warrant development of alternative methods. Exploring alternatives may only be necessary if regional BHASI models are not accurately predicting growth rates. We compared modeled height growth rates for Rocky Mountain Douglas-fir (Pseudotsuga menziesii var. glauca) to felled-tree measurements to evaluate relative performance of a regional BHASI model. An orthogonal sampling design ensured samples were collected across a range of site factors known to influence Douglas-fir growth rates. Growth rates for each 10 m section were calculated and compared to BHASI modeled growth rates. The regional BHASI model underpredicted growth rates from breast height to 30 m. Observed growth rates from 10 to 30 m accounted for the majority of underprediction relative to BHASI modeled growth rates. An alternative multipoint method of defining site productivity is described. More research comparing BHASI and alternative methods is needed, given the growth rate error associated with one-point site productivity assessment.


2008 ◽  
Vol 54 (No. 7) ◽  
pp. 321-332 ◽  
Author(s):  
P. Kantor

: The study evaluates production parameters (height, diameter at breast height, volume) of Douglas fir (<I>Pseudotsuga menziesii</I> [Mirb.] Franco) at mesotrophic sites of the Křtiny Training Forest Enterprise in mature stands. In total, 29 mixed stands were assessed with the registered proportion of Douglas fir at an age of 85 to 136 years. Comparing the 10 largest Douglas firs with the 10 largest spruces or larches higher, and as a rule markedly higher, production potential of introduced Douglas fir was found in all assessed stands. There were also groups of trees where the volume of Douglas fir was twice to 3 times higher than the volume of spruce or larch (see Tabs. 5 to 10). For example, in stand 177B11, the mean volume of 9.12 m<sup>3</sup> was recorded in the 10 largest Douglas fir trees but the volume of spruce reached only 3.17 m<sup>3</sup> and the volume of larch was 3.70 m<sup>3</sup>. Differences in mensurational parameters of Douglas fir found on the one hand and of Norway spruce (<I>Picea abies</I> [L.] Karst.) or European larch (<I>Larix decidua</I> Mill.) on the other hand compared by ANOVA tests were statistically highly significant. Annual ring analyses have shown that at present the volume increment of particular Douglas fir trees ranges from 0.12 to 0.16 m<sup>3</sup> per year in mature stands (i.e. about 1.5 m<sup>3</sup> every 10 years).


1990 ◽  
Vol 5 (1) ◽  
pp. 5-8 ◽  
Author(s):  
Douglas A. Maguire ◽  
David W. Hann

Abstract A segmented polynomial taper equation for southwestern Oregon Douglas-fir (Pseudotsuga menziesii) predicts double bark thickness (dbt) at any point above breast height. Below breast height predictions assume conformity to a neiloid frustrum. The equations facilitate estimation of inside bark diameter (dib) given outside bark (dob) measurements. Bark volume and bark biomass can also be estimated when supplemented with existing dib taper equations developed for southwestern Oregon. West J. Appl. For. 5(1):5-8.


FLORESTA ◽  
2013 ◽  
Vol 43 (2) ◽  
pp. 327 ◽  
Author(s):  
Elder Eloy ◽  
Braulio Otomar Caron ◽  
Rômulo Trevisan ◽  
Denise Schmidt ◽  
Magda Lea Bolzan Zanon ◽  
...  

 Este trabalho teve como objetivo avaliar a variação longitudinal e o efeito do espaçamento de plantio na massa específica básica das árvores de Mimosa scabrella Benth e Ateleia glazioveana Baill, aos 36 meses de idade. Analisou-se um experimento instalado em delineamento de blocos completos casualizados, com três repetições. Os tratamentos foram definidos em função dos espaçamentos (2,0x1,0 m, 2,0x1,5 m, 3,0x1,0 m e 3,0x1,5 m). Foram avaliadas 72 árvores, sendo essas medidas e cubadas pelo método de Smalian. Em seguida, foram retirados discos nas posições do tronco: 0,10 m (base), 1,30 m do solo (DAP – Diâmetro a Altura do Peito), 25%, 50% e 75% da altura total da árvore, para determinação da massa específica básica. A massa específica básica em árvores de Mimosa scabrella apresentou um decréscimo até a região do DAP, seguido de acréscimo, sem tendência de estabilização com a altura. A Ateleia glazioveana apresentou uma tendência de decréscimo no sentido base-topo das árvores. Os espaçamentos influenciaram a variação da massa específica básica em árvores de Mimosa scabrella e Ateleia glazioveana, não sendo verificada uma variação sistemática positiva ou negativa em relação ao espaço vital proporcionado.Palavras-chave:  Variação axial; característica tecnológica da madeira; qualidade da madeira; espaçamento de plantio. AbstractLongitudinal variation and effect of spacing on basic density wood of Mimosa scabrella and Ateleia glazioveana. This study aimed to evaluate the variation in length and effect of spacing of the basic density of Mimosa scabrella Benth e Ateleia glazioveana Baill, trees with 36 months of age. We analyzed an experiment set up in randomized complete block design with three replications. The treatments were defined by the spacing (2.0x1.0 m, 2.0x1.5 m, 3.0x1.0 m, 3.0x1.5 m). 72 trees were evaluated, and these measures and scaled by the method of Smalian. Then, the disks were removed from the trunk positions: 0.10 m (base), 1.30 m (DAP - diameter at breast height), 25%, 50% and 75% of the total height of the tree, determining the basic density. The basic density in trees of Mimosa scabrella showed a decrease to the region of the DAP, followed by addition, without a tendency to stabilize with time. The Ateleia glazioveana showed a decreasing trend towards bottom-up tree. The spacing influenced the variation of basic density in trees of Mimosa scabrella e Ateleia glazioveana not been verified a systematic positive or negative trend in relation to the living space provided. Keywords: Axial variation; technological characteristic of wood; wood quality; planting space.


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