Pine Progeny Research Articles

Five-Year Heights of Pitch Pine Progeny at Two New Jersey Plantations

Abstract Within-species selection was chosen as the method to improve pitch pine for a seed orchard to furnish seedlings for revegetation in southern New Jersey. In a progeny test of 68 families of open-pollinated plus tree seedlings at two plantation sites, after 5 growing seasons the top family among selected pitch pine progeny was as tall as the best pitch x loblolly check stock, and the best five pitch families were in the same range with another pitchlob and two loblolly families. Mean heights were slightly greater on a worked-out sandpit site than on an undisturbed sandy topsoil. North. J. Appl. For. 11(4):146-149.

An empirical evaluation of a three-dimensional crown model for predicting volume growth

A three-dimensional geometric model of crown competition was developed which can be used for empirical distance-dependent individual-tree models or biologically based process models. The crown model calculates the shape of a subject tree's crown based on the positions of its competitors' crowns and the rules of competition. It is necessary to use a crown profile equation to use the crown model. The crown profile equation was estimated from the crown width of open-grown trees at the base of the live crown. Ten replicates of a loblolly pine ( Pinus taeda L.) progeny study planted in a variable density Nelder's wheel layout re-measured annually from Ages 6 to 10 and at Age 12 were used for the analysis. The use of two different rules of competition and two different methods of calculating crown volume, surface area, and exposed surface area resulted in eight different estimates related to the geometry of each crown. The relationships of the natural logarithm of periodic annual wood volume growth of different time lengths were fit to geometric estimates generated from the crown model. These relationships were compared with crown length and wood volume relationships to evaluate the utility of the three-dimensional crown model. Exposed surface area of the crown was the best predictor of volume growth produced by the crown model. Wood volume was the single best predictor of growth until Age 9, when exposed surface area became superior. The best model of all possible models was wood volume, exposed surface area, and surface area. Wood volume, exposed surface area, and total surface area length accounted for 1–11% more of the variability than crown length and wood volume. This indicated that the crown model offered benefits over the use of the raw data. The relative performance of the crown model compared with wood volume and crown length improved as competition increased. The crown model appears to offer potential for growth and yield modeling; it must be further evaluated, however, for use in mature stands.

Genetic Improvement of Volume and Wood Properties of Jack Pine: Selection Strategies

Six selection strategies aimed at genetically improving volume production and wood quality factors such as density, heartwood content, and stem taper are compared in a 20-year-old jack pine progeny trial. Selection indices were computed under various assumptions about economic values of the traits under selection and with contraints on the magnitude and direction of expected genetic gain. Stem taper, wood density, and heartwood content were under strong genetic control; however, the low phenotypic variation of wood density limits its potential for genetic improvement. Heartwood content emerged as a trait amenable for rapid genetic improvement. Despite low heritabilities the prospect of improving size-related traits was promising due to substantial phenotypic variation. Economic weights were important for the selection outcome and good progress was reported in all traits when volume received the highest weight. It was feasible to limit genetic gain in individual traits to predetermined relative levels but the cost in terms of reduced gain in unrestricted traits was economically debilitating. Concerns about undesirable concomitant changes in wood density, heartwood, and stem taper when breeding is based solely on growth traits were not confirmed by our data.

Microgeographic Adaptation to Temperature in Pitch Pine Progenies

-Localized variation in cold tolerance of pitch pine (Pinus rigida Mill.) seedlings from an area including a large frost pocket was examined over an autumn, winter and spring. Sizable differences in cold tolerance were discovered among population and individual-tree progeny samples, as measured by patterns of acclimation and maximum levels of cold tolerance achieved. Differences in cold tolerance were associated with local differences in temperature between populations separated by 8 km (over most of which the species occurs only sporadically), but not within a continuous population over a distance of 3.4 km.

Selection system efficiencies for computer simulated progeny test field designs in loblolly pine

Six simulated progeny test field designs in combination with three within-family selection systems were tested on three loblolly pine (Pinus taeda L.) progeny test sites in southeastern Oklahoma and southwestern Arkansas, to compare genetic gains for the single trait, height. Residual deviations obtained by subtraction of family and plantation mean effects for each plantation were combined with simulated genetic effects with known family variance structure. The simulated genetic populations, arranged in the following progeny test field designs - large square or almost square plots, five- and ten-tree row plots, five-tree noncontiguous plots, two tree row plots, and single-tree plots - were superimposed on the residual data for each plantation. Within-family selection methods based on deviations from block means, deviations from neighborhood means and deviations from plot means were built into the model. Realized genetic gain attained by each design - selection system combination was compared with the genetic gain theoretically possible if selection accuracy were perfect, and with expected gain estimated using the general linear model. In general, average realized genetic gain compared well with expected gain. Differences between designs with large versus small plots were generally lower than expected, although the single-tree plot design always yielded highest realized gain. Realized gain was generally higher than expected when within-family selection was based on deviations from block or neighborhood means, but equal to or lower than expected when selection was based on deviations from plot means.

Relationship between Pinus sylvestris L. origin and browsing preference by moose in Finland

The degree of moose damage was estimated for 32 Finnish pine progenies grown in two field trials in Central Finland. In both trials, the browsing intensity correlated negatively with the increasing geographical latitude of the progeny origin. The lower susceptibility of northern pine progenies to moose was associated with the higher dry matter content of current and 1‐year‐old needles of these progenies.

Statistical efficiency of six progeny test field designs on three loblolly pine (Pinustaeda L.) site types

The environmental variance, defined in this study to include all nonfamily variances, associated with family mean estimates for height were compared among six progeny test field designs on three loblolly pine (Pinustaeda L.) progeny test sites in southeastern Oklahoma and southwestern Arkansas. Twenty-five-tree (or 30-tree) square (or almost square) plots, 5- and 10-tree row plots, 5-tree noncontiguous plots, 2-tree row plots, and single-tree plots were compared. The 5-tree noncontiguous, 2-tree, and single-tree plot designs consistently resulted in lower environmental variance associated with family means than the larger plots. The noncontiguous plot design resulted in environmental variances almost as low as those for the single-tree plot design, except on a site with a strong gradient. The environmental variance associated with family means was as small with 30 trees per family arranged in single-tree or 5-tree noncontiguous plots as with 60 trees per family arranged in 5-tree row plots on the most uniform site.

Picking Early Winners Among White Pine Progeny

Abstract After four seasons of field growth, height differences among seedlings from various seedlots of improved eastern white pine are highly significant at plantations in Connecticut, Maryland, New Hampshire, New Jersey, and New York. Survival varies from 53% to 83%, and plantation mean heights vary from 47 cm to 100 cm. Rank correlations of mean heights of seedlots at the five plantations are all positive and 8 of 10 are significant, indicating stability of performance. Two major trends show: (1) trees of a few seedlots are taller at all plantations, while those from Lake States and two Quebec seedlots grow relatively slowly wherever tested; and (2) trees of northern origin are more often taller at northern plantations, and those of central origin are taller at central plantations. North. J. Appl. For. 4:66-69, June 1987.

Genotype by Environment Interactions in South African Pine Progeny Trials: Implications for Tree Breeding

SYNOPSIS Genotype by environment interactions (GEI) can occur within a trial and between different sites. In the first case, more research is needed before deciding whether it is necessary to adopt single tree plot designs or to isolate the blocks and/or the genotypes which are responsible for the interactions. In case of GEI between sites, costly and complex ecophysiological studies are necessary to determine which factors of the environment are responsible for the interaction and how the genotypes react, if we must classify sites into subregions of minimal GEI and then adopt a multiple breeding and production population approach. The cheaper and quicker method, if it is feasible, is to eliminate the genotypes which mainly cause the interactions, thus breeding for stable genotypes. There are sites where tree breeding is uneconomical and other options should be considered, including silvicultural ones.

Correlation of Seed Weight and Nurserybed Traits with 5-, 10-, and 15-Year Volumes in a Loblolly Pine Progeny Test

Abstract Seed weight and nurserybed traits of loblolly pine families measured in detail in 1958 were compared to volumes attained 5, 10, and 15 years after outplanting. Three out of eight characteristics showed significant correlations. These were: (1) percent of seedlings within a family with distinct terminal buds in December, (2) percent of seedlings within a family without basal branches and (3) seed weight. A multiple regression was developed using two of these characteristics to predict volume at age 15. Although the regression R² value was low, a genetic gain of 8.0 percent could have been realized by selecting the best 20 percent of the families from the nurserybed. Forest Sci. 25:591-596.

Growth Data for 29 Years from the California Elevational Transect Study of Ponderosa Pine

Ponderosa pine progenies from parents restricted in latitude but spanning 7.000 feet of elevation show significant growth differences in plantations at low-, mid-, and high-elevation test sites. At low- and mid-elevation sites tree heights and diameters of progenies from high-elevation parents were the smallest; those from the low-elevation parents. intermediate: and those from mid-elevation seed parents. largest. At the high­ elevation site. trees from mid- and high-elevation sources grew equally well, whereas trees from low-elevation parents showed poorest growth. The variation associated with elevation zone of parent trees accounted for 8 percent of the total experimental varia­ tion. About 9 percent of the total was attributed to the interaction between parent tree elevational zones and plantations. Height rankings of progenies for different ages showed little change over the 29-year growth period of the study in low- and mid­ elevation test sites. But at the high-elevation test site, height means for zone groups shifted with age as the relative heights of the higher elevation progenies increased. Forest Sci. 19:31-39.

Differential Responses of Slash Pine Progeny Lines to Some Cultural Practices

AbstractIn three experiments involving intensities of management' slash pine (Pinus elliottii Engelm. var. elliottii) progenies of selected lines and crosses varied greatly in their growth rates on unaltered sites and in growth responses to environmental improvements. In three tests, some selections made poor growth in unfertilized soil, but responded well to fertilizer applications, while others made good growth in unfertilized soil, but were little affected by fertilizers. Of greater importance, some progeny lines made good growth in unfertilized soil and at the same time responded to fertilizer treatments.There were greater growth differences within progeny lines due to variations in the immediate environment than there were among lines of different geographic origin.These results emphasize the importance of testing progenies of plus trees on soils as productive and similarly managed as under plantation conditions.

Variation in the Ability of Slash Pine Progeny Groups to Absorb Nutrients

AbstractTwenty‐seven variables were tested to determine whether five slash pine (Pinus elliottii var. elliottii) progeny groups of known parentage differed in ability to absorb and efficiently utilize nutrients. Fertilization × progeny group interactions were significant for N and K in needles and stems, and for CO2 absorption by needles during the first year of growth in an environmental control room. Phosphorus‐32 in stems varied between progeny groups, and relative amounts of P32 absorbed were ascertained from radioautographs.