Search Results

1 - 10 of 15 items :

  • "breast height diameter" x
Clear All
Short Note: Genotype-Environment Interactions for Coastal Douglas-fir Grown to 21 Years Across Western Washington State, USA

Abstract

This study involves polymix families of coastal Douglas- fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii) that were created by crossing parents selected from the Cascade, Longview, Twin Harbors and Vail wild populations of western Washington State. Eight to 10 female parents from each population were crossed using pollen-mixes of males from either the same or different populations. In 1985 these polymix families were planted across six genetic tests located in Cascade, Longview and Twin Harbors (two tests per region). Variance components are reported for over-bark breastheight diameter measured at 21 years (DBH21). Genotype x environment (GE) interactions involving different wild populations of Douglas-fir accounted for little variation in DBH21 across the western Washington regions studied. Interaction involving female parents nested within populations was the most important GE effect; explaining 2% of total variation in DBH21. However, this interaction was of limited practical importance since the superior female parents for DBH21 generally showed good stability across tests. Results from this study support selection of superior coastal Douglasfir genotypes that can produce strong, stable growth across a range of site environments encountered in western Washington.

Open access
Tree diversity in the tropical dry forest of Bannerghatta National Park in Eastern Ghats, Southern India

Abstract

Tree species inventories, particularly of poorly known dry deciduous forests, are needed to protect and restore forests in degraded landscapes. A study of forest stand structure, and species diversity and density of trees with girth at breast height (GBH) ≥10 cm was conducted in four management zones of Bannerghatta National Park (BNP) in the Eastern Ghats of Southern India. We identified 128 tree species belonging to 45 families in 7.9 hectares. However, 44 species were represented by ≤ 2 individuals. Mean diversity values per site for the dry forest of BNP were: tree composition (23.8 ±7.6), plant density (100.69 ± 40.02), species diversity (2.56 ± 0.44) and species richness (10.48 ± 4.05). Tree diversity was not significantly different (P>0.05) across the four management zones in the park. However, the number of tree species identified significantly (P<0.05) increased with increasing number of sampling sites, but majority of the species were captured. Similarly, there were significant variations (p<0.05) between tree diameter class distributions. Juveniles accounted for 87% of the tree population. The structure of the forest was not homogeneous, with sections ranging from poorly structured to highly stratified configurations. The study suggests that there was moderate tree diversity in the tropical dry thorn forest of Bannerghatta National Park, but the forest was relatively young.

Open access
Relationships between selected tree characteristics and the properties of juvenile wood in Scots pine (Pinus sylvestris L.)

Abstract

The aim of this study was to determine relationships between selected properties of juvenile wood and characteristics of the stem and crown of Scots pine. Analyses were conducted in northern Poland on eight mature pine monocultures. Nine trees were selected in each experimental site and their stems were divided into five sections. The centers of the sections were established at a height of 1.3 m from the tree base and at points corresponding to 20, 40, 60 and 80% tree height. Samples were taken from these locations, and these samples were prepared for analyses of basic density, compressive strength along the grain and static bending, as well as the modulus of elasticity during bending. The mean height of the investigated group of trees was 26.0 m with an average diameter breast high of 33.6 cm. The mean crown depth was 7.8 m and crown diameter was 3.6 m, and the mean basic density (Qu) of juvenile pine wood was 416 kg/m3. The average compressive strength along the grain (CS) was determined to be 22.3 MPa, while static bending strength (BS) was 45.8 MPa. The recorded modulus of elasticity (MOE) was 4726 MPa.

Both in general terms and when dividing stems into sections, the wood properties correlated with tree characteristics to various degrees. All indexes were negative indicating that trees of greater dimensions produce juvenile wood of inferior quality. Properties of juvenile wood formed during various periods of tree life were mostly related to diameter breast high and crown depth. They were also correlated with tree height, but only to a limited extent. In contrast, properties of wood from the middle stem sections were significantly correlated with crown diameter.

Open access
Allocation of oaks to Kraft classes based on linear and nonlinear kernel discriminant variables

Summary

A method of discriminant variable determination was used to visualize the division of oak trees into Kraft classes. Usual discriminant variables and several types of kernel discriminant variables were studied. For this purpose the traits of oak (Quercus L.) trees, measured on standing trees, were used. These traits included height of tree, breast height diameter and crown projection area. The use of the Gaussian kernel and modified Gaussian kernel enabled the clearest division into Kraft classes. In particular, the latter method proved to be the most effective.

Open access
The influence of seed origin on stand variables of Scots pine (Pinus sylvestris L.) provenance trial in Ahunapalu

Seemnete päritolupiirkonna mõju hariliku männi (Pinus sylvestris L.) puistu takseerandmetele Ahunapalu geograafilises katsekultuuris

The aim of the present study is to analyse the influence of seed origin on the growth performance in Scots pine provenance trial at the age of 33 and 43 years. The provenance trial plantation with 18 provenances of Scots pine were established in Estonia, Järvselja Training and Experimental Forest District (58°19'47, 21"N. Lat. and 27°16'2, 79"E. Long) under the supervision of E. Pihelgas in 1965, using seeds from different regions of the former Soviet Union. The northernmost seeds were received from Arhangelsk province, Russia, (63° N. Lat.) and the southernmost seeds from Borjomi Forest Enterprise, Georgia, situated 800 m above sea level (42° N. Lat.). The westernmost seeds were from Latvia, Lithuania and Ukraine (23-24° E. Long.). Seeds of Estonian pine seedlings originated from the forest districts of Järvselja, Sõmeru, Vihula, Sagadi and Koorküla. Data used for above-mentioned study was collected during the years 1998 and 2008.

Statistical analysis was conducted using the software package R. The statistical analysis of the data obtained from provenance trials showed that under Estonian circumstances density, height and breast height diameter were stand variable which were depending on seed origin the most. The average survival percentage of progenies from southern provenances (with the northern latitude less than 52°) was lower than that in case of the progenies of the northern seed origin; a strong linear relationship was found between the stand breast height diameter and the northern latitude of seed provenance. The average breast height diameter of the stands from southern origin was larger than that of the stands from northern origin, whereas the plots of northern seed provenances had bigger survival percentage (density) than that of plots grown from southern seeds. Thus, the plots of northern seed origin had poorer conditions for diameter growth. The stands of northern seed provenance had slightly lower average height than that in the stands of southern seed origin.

Open access
Growth response of European larch (Larix decidua Mill.) populations to climatic transfer A Novel Approach for Controlled Pollination in Casuarina equisetifolia

Abstract

The study focuses on growth responses of Larix decidua provenances to climatic transfer based on a regional provenance experiment. This comprises a series of 5 trial plots situated in Germany and Slovakia, where 12 indigenous Sudetic and West-Carpathian larch provenances are planted. Transfer rates were defined as differences in altitudes or climatic variables between the site of plantation and the site of origin. 1st and 2nd-order polynomial regressions were used for the identification of overall trends of growth performance and responses to transfer.

Sudetic provenances clearly outperformed the Carpathian ones on all test sites. When all provenances were considered jointly, height and breast-height diameter mostly showed significant monotonous geographical and climatic trends: the performance generally decreased with increasing altitude and precipitations and decreasing temperatures. The relationships between growth response and transfer rates (ecodistances) were mostly linear. However, when Sudetic and Carpathian provenances were considered separately, most significant response curves were unimodal. There is a very good correspondence between the responses in height and diameter growth within geographic groups, but the responses are not consistent between groups. Joint regression analysis showed that most provenances exhibited average stability. Stability indices are quite consistent between the response traits and did not show any association with the geographical position, climate of origin, or growth performance.

The results indicate that populations in different climates remain adapted to a common optimum, the extent of local adaptation is quite limited. Possible explanations of this observation are briefly discussed.

Open access
Clonal Variation and Genotype by Environment Interactions in Growth and Wood Density in Eucalyptus camaldulensis at Three Contrasting Sites in Vietnam

Abstract

A total of 172 clones of Eucalyptus camaldulensis were tested in three clonal tests in northern, north-central and southern Vietnam, with 32 of them planted across all three sites. At age 3-5 years, the clonal repeatabilities were 0.18-0.42 for growth traits, 0.71-0.78 for wood basic density and 0.56-0.66 for pilodyn penetration. Genotypic correlations between growth and density at the three sites were from -0.24 to 0.17, and did not differ significantly from zero. Genotypic correlations between sites were 0.32-0.56 for growth traits at age 3 years, and 0.72-0.88 for density and pilodyn penetration. Selection gains for breast height diameter at individual sites at a selection proportion of 5% were 22-32%, with minor effects on density. Selection for diameter at one site gave indirect responses in diameter at the other two sites that were only 40-60% of the gains obtainable from direct selection at those sites. This study shows that fast-growing E. camaldulensis clones can be selected in Vietnam with only minor effects on density. Selection for growth should be regionally based to maximize selection gain whereas clonal rankings for density will change little across regions.

Open access
Deterministic Simulation of Gains for Seedling and Cloned Main and Elite Breeding Populations of Pinus radiata and Implications for Strategy

Abstract

Genetic gains in breast-height diameter were estimated using deterministic simulation. Simulations of gain from one generation of selection were undertaken in large Main and small Elite breeding populations for a range of heritabilities, with varying numbers of parents, families, seedlings/family, clones/family and ramets/ clone to aid revision of the New Zealand Pinus radiata breeding strategy. Cloned versus seedling populations of equal numbers of plants were simulated, derived from open pollination, polycrossing, and pair crossing. Balanced within-family selection was used for 200, 400 and 800-parent Main breeding populations and among- and within-family selection for 25-parent Elite populations of 25 up to 100 full-sib families. Predicted gains from within-family selection in the Main population were highest from cloned polycross families at all heritabilities and lowest for seedling fullsib families. Gains from cloned populations were higher than seedling equivalents at heritabilities ≤0.5, and their advantage in gain was greatest at lower heritabilities. Elite populations of 25 parents showed similar trends but intensive among- and within-family selection resulted in much higher gains than from the Main, highest from the cloned options. The increase in gain with increased number of families diminished with more than 2-3 times as many families as parents. A new strategy was proposed for P. radiata, based on the simulation results, involving an expanded Main breeding population of open-pollinated (OP) seedling families, together with pair-cross family seedlots already available, supported by parentage reconstruction using DNA markers. Forwards selection in small cloned Elite populations was proposed as the main source of seed orchard clones.

Open access
Changes in the size of curvature in larch trees from different provenances at the experimental site in Rogów

Zmiana wielkości krzywizn u modrzewi różnych pochodzeń na powierzchni doświadczalnej w Rogowie

Open access
Reconstructing past forest status using inventory and tree ring data to support uneven-aged forest management

: Kontrollstichproben im Plenterwald. Dissertation ETH Nr. 13 799. Eidgenössische Technische Hochschule Zürich. Ercanli, I., Gunlu, A., Başkent, E. Z., 2015: Mixed effect models for predicting breast height diameter from stump diameter of Oriental beech in Göldaǧ. Scientia Agricola, 72:245-251. Garman, S. L., Acker, S. A., Ohmann, J. L., Spies, T. A., 1995: Asymptotic height-diameter equations for twenty-four tree species in Western Oregon, Research Contribution 10, Forest Research Laboratory, Oregon State University, Corvallis, 22 p. Hann, D. W

Open access