Method for selecting conifer trees

Information

  • Patent Application
  • 20070017152
  • Publication Number
    20070017152
  • Date Filed
    June 29, 2005
    19 years ago
  • Date Published
    January 25, 2007
    18 years ago
Abstract
A method for selecting conifer trees is disclosed. This method relates to the early measurement of tree characteristics for selecting trees most likely to exhibit certain traits as they mature. This method can be used for implementing silvicultural treatments, thinning or further breeding.
Description
FIELD OF THE INVENTION

The present invention relates to a method for selecting conifer trees for improved volume, yield and wood quality.


BACKGROUND OF THE INVENTION

The growth attributes and physical characteristics of a conifer tree contribute to the value assessed that tree after a commercial harvest. Such value may be measured by the stem quality, volume of wood and wood quality measures such as strength and stiffness. The earlier these characteristics can be accurately assessed, the more a given site can be planted with trees that provide larger volume and more desirable wood characteristics per acre.


DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a method for selecting conifer trees. Conifer trees grow well in many regions, including Douglas-fir in the Pacific Northwest region of the United States and loblolly pine in the Southeast region of the United States. In the Southern hemisphere, radiata pine grows well.


The method of the present invention may be used in selecting trees for breeding based upon characteristics measured in those trees using the methods of the present invention. By using more elite trees for breeding, one is able to plant trees which are more likely to provide higher volumes of wood and more desirable characteristics.


The method of the present invention may also be used for selecting against trees for silvicultural treatments. This may include thinning or removal trees not selected based upon characteristics measured using the methods of the present invention.


The method of the present invention may also be used for a combination of selecting elite trees for breeding and later use of the method for selecting among the resulting trees for silvicultural treatments.


The method of the present invention may also be used to select a group of trees having a range of a certain characteristic to provide diversity in a site.


One factor which may be measured in the present invention is sinuosity. Generally, sinuosity is measured as the amount of stem deflection from vertical plumb in the tree. Increased amounts of sinuosity in a tree causes warped grain that impacts the quality of lumber and percent of yield of lumber and pulp from that tree.


Another factor which may be measured in the present invention is ramicorn branching or cluster knots. A ramicorn branch is highly angled (usually less than 30° to the trunk or stem).


Ramicorn branching may result from second flushing or damage to the terminal bud. Cluster knots or double whorls may result from second flushes during the same growing season. Both ramicorn branching and cluster knots can reduce the yield and quality of lumber from a tree.







EXAMPLE

Douglas-fir trees were planted on three Weyerhaeuser sites, one near Longview, Wash. (LG), one near Twin Harbors, Wash. (TH), one in Vail, Wash. (VL) and one in the Cascade mountain range in Washington (CA).


The trees were obtained by breeding 71 parents that were a combination of first- and second-generation selections from three first-generation provenances: Cascade, Longview, and Twin Harbors. These select parent were then mated with 4 to 6 “tester” parents from first-generation selections to produce a total of 274 full-sib families. The Genetic Controls (GC) (n=40) were open-pollinated first-generation families that served as a basis of comparison between the first- and second-generation trials. The Field Checks (FC) (n=3) were genetically unimproved seed sources or reference populations used to gauge changes in growth and stem quality through genetic selection.


The full-sib families were arranged as single-tree plots in 6 randomized complete replications. Thus, each site included 6 trees per full-sib family. Genetic Controls were located in 6 sub-blocks within each replication on a site. Each Genetic Control family was represented by 4 single-tree non-contiguous plots within each sub-block. Field Checks were planted in three 99-tree sub-blocks.


Height, diameter, terminal and lateral second flushing, and sinuosity were measured annually from ages 4- to 9-years. Double whorls and ramicorn branching were measured annually from ages 5- to 9-years. Spring bud flush was assessed at 2- to 4-years. Weekly observations were made of the site and when about fifty percent (50%) of the trees had flushed, bud flush was noted and trees were recorded as being early or later spring bud flush trees.


More intensive branch measurements were made on a sub-set of trees at each test site.


These measurements included branch number and angle, total knot area, and the percentage of fall growth due to second flushing. This sub-set of trees included 30 unrelated parents from 4 of the 6 replications as well as all the trees in 4 of the 6 Genetic Control sub-blocks and 1 of the 3 Field Check sub-blocks.


Final stem quality was assessed in 9-year-old trees in 4 of the 6 replications and retrospectively measured annual leader length, second flushing, ramicorn branching, and sinuosity. Results were averaged across years.

TABLE 1Descriptions of traits measured and number of observationsin the 3 generations of test trees pooled across the four test sites.Number of treesTraitGeneticFieldTraitAbbreviationFull-sibControlCheckDescriptionTree Improvement measuresH86293898923(dm)Tree height at 8-years.D86293898923(mm)Tree diameter at breast height (1.3 m) at 8-years.V8B6293898923(dm3)Bole volume at 8-years.BudFlush2-46644947958Phenology: 1 = flushed terminal bud. Averagebased on annual assessments at 2- to 4-yearswhen 50% of trees on a site begin springbudflush (approximately mid-May).Terminal5-95711791822Stem quality: 1 = second flushed terminal bud.Average of annual assessments from 5- to 9-years.Lateral6-96377913938Stem quality: 1 = second flushed lateral bud.Average of annual assessments from 6- to 9-years.Sinu5-96347902932(inches)Stem quality: Sinuosity or the amount of stemdeflection from vertical plumb. Average ofannual assessments from 5- to 9-years.DWhorl6-96377913938Stem quality: 1 = Double whorl or secondwhorl of branches from second flushing.Average of annual assessments from 6- to 9-years.Rami6-96322904934Stem quality: 1 = one or more ramicornbranches from second flushing. Average ofannual assessments from 6- to 9-years.Tree Improvement intensive branch measuresBranchNumber880294621Total number of branches >5 mm diameter inwhorl and internode immediately above breastheight.BranchAngle880294621Average branch angle in the whorl immediatelyabove breast height. Range was 15° to 37°above horizontal.KnotArea880294621Total cross-sectional area of all branchescalculated from total number of branchesmultiplied by the average diameter of branchesin the whorl and internode immediately abovebreast height.FallGrowth880294621Percent of annual height increment due tosecond-flushing. Measured on internodeimmediately above breast height.Silviculture measuresLeader5-94248594929(dm)Average of annual height increments from 5- to9-years. Assessed retrospectively at 9-years.SilvFlush3-94248593929Stem quality: 1 = branch or internode withsecond-flush. Average from 3- to 9-yearsassessed retrospectively at 9-years.SilvRami3-84248593929Stem quality: 1 = presence of one or moreramicorn branches. Average from 3- to 8-yearsassessed retrospectively at 9-years.SilvSinu3-94248592929(inches)Stem quality: Sinuosity or the amount of stemdeflection from vertical plumb. Average from3- to 9-years assessed retrospectively at 9-years.


Eight-year height was used to eliminate outlier trees from the dataset. Outliers were defined as those with heights that were more than three standard deviations below the average for the site.


Individual tree data was pooled across the four test sites and the data was analyzed with the AS Reml statistical package (available from VSN International Ltd. having an address of 5 The Waterhouse, Waterhouse Street, Hemel Hempstead, Herts, UK HP1 1ES) which fits linear mixed models using restricted maximum likelihood. Factors fitted included the fixed effect of site, the random effects of replicate within test site, the additive effect of each tree as estimated from its phenotype, the numerator relationship matrix, and family effects. Models were fitted both with and without the inclusion of the origin term or parent provenance to determine the origin effect on heritability estimates.


The ASReml model was equivalent to:

Traiti.j.k.l.m=mu+testi(+Originm)+(replication:test)ij+familyk+treel+residuali.j.k.l.m  II

    • Traitijkl represents the phenotypic value of an individual tree (tree l) for the trait under analysis;
    • mu is the fitted overall mean for the trait across all four tests;
    • testi is the effect of the ith test site (considered to be a fixed effect);
    • Originm is the effect of the mth origin (also fixed);
    • replication:testij, the effect of the jth block replication within each ith test site;
    • familyk, the non-additive effect specific to the cross that produced full-sib progeny l. A model was utilised that allowed this effect to be fitted to Set 1 (full-sib) progeny but not Set 2 (half-sib) progeny, as it is assumed that half-sib families do not contain a systematic effect for specific combining ability;
    • treel, the additive genetic effect of tree l; and
    • residualijkl, the residual error associated with tree l, assumed to be independent of the test site on which tree l is growing.


The additive genetic relationship matrix describes all known relationships among trees, parents and other ancestors, and its inverse elements augment the equations representing a tree's genetic effect. The additive genetic variance, dominance variance and individual heritability were estimated.


In an individual tree model, the additive genetic variation (σ2A) is given directly by the variance among trees, estimated from all phenotypic information, taking into account known genetic relationships and all other effects in the model.


The variance of family deviations, denoted σ2F, includes all the non-additive genetic variance components, the majority of which is expected to be dominance variance. Dominance genetic variance (denoted as σ2D) was approximated by four times the variance estimated among full-sib families when additive genetic effects are accounted for—

σ2D=4σ2F

A relatively minor amount of σ2F will be due to epistatic genetic effects, with this being included in the estimate of σ2D as calculated here. Note that if there were any non-genetic effects that make members of a full-sib family more alike, this will contribute to the estimate of dominance variance.


Individual heritability (h2) was calculated as the ratio of additive (σ2A) to phenotypic (σ2P) variance among trees—

h22A2P.

The phenotypic variance was calculated as the sum of the additive genetic variance (σ2A), variance due to families (σ2F) and the residual variance (σ2)—

σ2P2A2F2


Variance due to replications was not included in the estimation of phenotypic variance because replication effects were accounted for when estimating breeding values. Standard errors of all components were estimated directly by the ASReml program.


Genetic correlations were estimated in multi-variate ASReml analyses using an individual tree model:

(Traitm1Traitm2Traitmn)ijl=mum.+testi.m.+(replication:test)ijm.+tree.ijllm.+residualijlm.  III

where m1, m2 . . . mn denote the n traits in the multivariate analyses and tree l has a pedigree defined by its known parents and their ancestors. It was not feasible to simultaneous estimate all possible covariances using a maximum likelihood procedure, so the data were analysed in blocks of up to five traits. The additive correlations (rA) between trait1 and trait2 represent the ratio of additive genetic covariance between the traits (covA1A2) over the square root of the additive genetic variances of the same traits (σ2A1 and σ2A2)—

rA=(covA1A2)/√(σ2A1σ2A2)


Many traits with repeated measures were averaged over the years of observations for the correlation estimates. A correlation involving one trait with the average of another has the same expectation as the correlation between the first trait and any single component of the second, assuming they are genetically the same trait.

TABLE 4Genetic correlations comparing year of assessment forspring budflush (e.g., BudFlush4 = assessment at 4-years).Bold numbers on horizontal are individual heritability estimateswith standard errors.TraitBudFlush2BudFlush3BudFlush4BudFlush20.43 ± 0.060.880.81BudFlush30.41 ± 0.060.95BudFlush40.47 ± 0.06









TABLE 5










Efficacy of one- or two-year assessments of lateral flushing and


sinuosity as indirect measures of double whorls, ramicorn branching, and


sinuosity in a 9-year stem. The table shows individual


heritability estimates and genetic correlations between indirect


measures and average stem quality traits and volume.













Heritability
V8B
DWhorl6-9
Ramicorn6-9
Sinu5-9
















Lateral5
0.18 ± 0.03
0.14
0.92
0.91
−0.02


Lateral6
0.21 ± 0.03
0.06
0.98
0.98
0.01


Lateral5&7
0.29 ± 0.04
0.07
0.95
0.91
0.04


SilvFlush3-9
0.37 ± 0.05
0.22
0.93
0.93
0.03


Sinu5
0.21 ± 0.03
0.13
0.09
−0.02
0.95


Sinu6
0.13 ± 0.02
0.12
−0.03
−0.10
0.99


Sinu5&7
0.28 ± 0.04
0.08
0.09
−0.01
0.99









While the different embodiment of the invention has been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention.

Claims
  • 1. A method for selecting a conifer tree from a group of trees, comprising: noting the existence of lateral bud flush by the tree's fifth year; noting the existence of sinuosity by the tree's fifth year; and selecting the tree if it has minimal lateral bud flush by its fifth year and minimal sinuosity by its fifth year.
  • 2. The method of claim 1, further comprising noting the time of spring bud flush of the group of trees by the trees' second year and selecting a group of trees with a diverse range of spring bud flush.
  • 3. The method of claim 1, further comprising: measuring height of the group of trees by their fifth year; and selecting the tree if it has no lateral bud flush by its fourth year, minimal sinuosity by its fourth year and the height by its fifth year is greater than the majority of the group of trees.
  • 4. The method of claim 1, further comprising: noting the existence of lateral bud flush by the trees' seventh year; noting the extent of sinuousity by the trees' seventh year; and selecting a tree from the group of trees if the tree has no lateral bud flush by its seventh year and minimal sinuosity by its seventh year.
  • 5. The method of claim 4, further comprising: measuring the volume of each tree by their seventh year and selecting the tree from the group of trees if it has no lateral bud flush by its seventh year, minimal sinuosity by its seventh year and the height by its seventh year is greater than the majority of the group of trees.