Diameter and height distributions in genetically improved Pinus radiata

1998 ◽  
Vol 28 (2) ◽  
pp. 248-258 ◽  
Author(s):  
S D Carson ◽  
J D Hayes
Keyword(s):  
Pinus Radiata ◽  
Genetic Improvement ◽  
Diameter Distribution ◽  
Size Distributions ◽  
Quadratic Mean ◽  
Similar Tendency ◽  
Genetically Improved ◽  
Large Plot ◽  
Quadratic Mean Diameter ◽  
The Right

Diameter and height distributions for Pinus radiata D. Don trees grown from seed lots representing a range of genetic improvement were compared at midrotation (age 14 or 15) in seven large-plot trials at six sites. In one of the trials, comparisons were made at year 5 and annually from age 8 to 16. These are the first data from plantation conifers comparing tree size distributions of commercially planted seed lots. Differences among seed lots for quadratic mean diameter and mean height were statistically significant and generally reflected the expected level of genetic improvement. Standard deviation, skewness, and kurtosis were not significantly different among seed lots. However, diameter distributions of higher rated seed lots sometimes appeared very slightly more skewed to the right and flatter than the lower rated seed lots, a similar tendency observed as stands age. Models used to predict diameter distribution from stand parameters are not likely to require modification for genetically improved seed lots.

Incorporating the effects of interspecific competition and vegetation management treatments in diameter distribution models for Douglas-fir saplings

1992 ◽  
Vol 22 (9) ◽  
pp. 1255-1262 ◽  
Author(s):  
Steven A. Knowe ◽  
Timothy B. Harrington ◽  
Robert G. Shula
Keyword(s):  
Interspecific Competition ◽  
Douglas Fir ◽  
Diameter Distribution ◽  
Cumulative Probability ◽  
Quadratic Mean ◽  
Vegetation Control ◽  
Mean Diameter ◽  
Coast Ranges ◽  
Siskiyou Mountains ◽  
Quadratic Mean Diameter

A parameter recovery procedure for the Weibull distribution function, based on diameter percentiles, was modified to incorporate the effects of interfering vegetation in young Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco var. menziesii) plantations. The applicability of the system was tested by using data from sites in the Coast Ranges of Oregon and Washington and in the Siskiyou Mountains of southwestern Oregon. Four percentiles (0, 25th, 50th, 95th) of the cumulative probability distribution were predicted as functions of quadratic mean diameter and age. In the Siskiyou study, cover and total vegetation control affected quadratic mean diameter and all four percentiles; intensity of the vegetation treatments affected the 0 and 25th percentiles, and the interaction between intensity and timing of treatment affected quadratic mean diameter. In the Coast Ranges study, only quadratic mean diameter was affected by cover of woody vegetation, while quadratic mean diameter and the 25th percentile were significantly affected by total vegetation control. The predicted distributions showed decreasing variance with increasing cover, particularly in the Siskiyou Mountains. In the Coast Ranges study, the coefficient of variation increased with increasing cover, indicating that the variance of stem diameters was affected by average size. On xeric sites in the Siskiyou Mountains, high diameter variability in plots with total vegetation control suggests that interspecific competition may inhibit the expression of microsite variation.

Eastern cottonwood clonal mixing study: predicted diameter distributions

1994 ◽  
Vol 24 (2) ◽  
pp. 405-414 ◽  
Author(s):  
Steven A. Knowe ◽  
G. Sam Foster ◽  
Randall J. Rousseau ◽  
Warren L. Nance
Keyword(s):  
Weibull Distribution ◽  
Basal Area ◽  
Diameter Distribution ◽  
Minimum Diameter ◽  
Quadratic Mean ◽  
Parameter Recovery ◽  
Eastern Cottonwood ◽  
Mean Diameter ◽  
Quadratic Mean Diameter ◽  
Diameter Distributions

A parameter recovery procedure for the Weibull distribution function was modified to incorporate monocultures and mixtures of eastern cottonwood (Populusdeltoides Bartr.) clones planted in Mississippi and Kentucky. Components of the system included functions to predict stand-level basal area and four percentiles (0th, 25th, 50th, and 95th) of the cumulative diameter distribution. Basal area was predicted as a function of surviving number of trees, dominant height, age, planting location, and the proportion of each clone planted. Clonal proportions, which accounted for 3.6% of the variation in observed basal area, were more important than differences in planting locations, which accounted for 3.0% of the variation. Interactions between clones in mixtures were not significant (p = 0.5676), but some cases of both over- and under-compensation appeared to be developing. Percentiles of the cumulative diameter distribution were predicted as functions of quadratic mean diameter, and therefore included indirect effects of both genetic and planting site differences. Only the minimum diameter (D0) was directly affected by proportions of clones planted. Most of the monocultures and mixtures of clones had smaller minimum diameters than expected for a given value of quadratic mean diameter. The predicted quadratic mean diameter and percentiles were used to recover parameters of the Weibull distribution such that the predicted diameter distribution has the same quadratic mean diameter as obtained from the stand basal area model. The predicted distributions indicated that a common stand-level model was not sufficient for accounting for variations in diameter distributions of eastern cottonwood clones. As a result of the differences in diameter distributions, monocultures and mixtures of the Texas clones appeared to have less volume and greater stand variance than the Mississippi clones.

Properties of the quadratic mean diameter in balanced diameter distributions

1985 ◽  
Vol 15 (2) ◽  
pp. 474-476
Author(s):  
Donald J. Weatherhead ◽  
Roger C. Chapman ◽  
John H. Bassman
Keyword(s):  
Stand Structure ◽  
Basal Area ◽  
Tree Size ◽  
Diameter Distribution ◽  
Quadratic Mean ◽  
Growing Stock ◽  
Mean Diameter ◽  
Quadratic Mean Diameter ◽  
Stand Basal Area ◽  
Diameter Distributions

Balanced diameter distributions are widely used to describe stand structure goals for residual growing stock in uneven-aged forests. The quadratic mean diameter is frequently used as a descriptor of a balanced diameter distribution. In this paper the quadratic mean diameter is shown to be independent of stand basal area for balanced diameter distributions with a common class width, maximum and minimum diameters, and de Liocourt's q ratio. Additionally it is shown that the quadratic mean diameter is relatively insensitive to changes in maximum tree size and q ratios for q ratios 1.5 and larger.

Predicting Future Diameter Distributions Given Current Stand Attributes

2022 ◽  
Author(s):  
Quang V. Cao
Keyword(s):  
Prediction Method ◽  
Diameter Distribution ◽  
Tree Level ◽  
Individual Tree ◽  
Distribution Parameters ◽  
Level Model ◽  
Novel Method ◽  
Quadratic Mean Diameter ◽  
Stand Attributes ◽  
Individual Trees

This study discussed four methods to project a diameter distribution from age A1 to age A2. Method 1 recovers parameters of the distribution at age A2 from stand attributes at that age. Method 2 uses a stand-level model to grow the quadratic mean diameter, and then recovers the distribution parameters from that prediction. Method 3 grows the diameter distribution by assuming tree-level survival and diameter growth functions. Method 4 first converts the diameter distribution at age A1 into a list of individual trees before growing these trees to age A2. In a numerical example employing the Weibull distribution, methods 3 and 4 produced better results based on two types of error indices and the relative predictive error for each diameter class. Method 4 is a novel method that converts a diameter distribution into a list of individual-trees, and in the process, successfully links together diameter distribution, individual-tree, and whole stand models.

A Stocking Guide for Southern Bottomland Hardwoods

1995 ◽  
Vol 19 (3) ◽  
pp. 103-104 ◽  
Author(s):  
J. C. G. Goelz
Keyword(s):  
Basal Area ◽  
Bottomland Hardwoods ◽  
Quadratic Mean ◽  
Mean Diameter ◽  
Quadratic Mean Diameter

Abstract A stocking guide was developed from the data of Putnam, et al. (1960). The form of the stocking guide follows Gingrich (1967), although the “B”-line is based on the suggested residual stocking of Putnam, et al. (1960) rather than on minimum full stocking. This stocking guide is similar to the stocking guide for central upland hardwoods constructed by Gingrich, except that 100% stocking is 5-7 ft2² of basal area lower for the southern bottomland guide, across a range of quadratic mean diameter. South. J. Appl. For. 19(3):103-104.

Genetic improvement programs for aquaculture species

2003 ◽  
Vol 2003 ◽  
pp. 225-225
Author(s):  
B. Gjerde ◽  
B. Villanueva
Keyword(s):  
Genetic Improvement ◽  
Human Population ◽  
Feeding Practices ◽  
Food Crops ◽  
Genetic Quality ◽  
Genetically Improved ◽  
Improvement Programs ◽  
High Yields ◽  
Aquaculture Production

The high yields obtained in agriculture rely heavily on the use of domesticated and genetically improved breeds and varieties. Until quite recently this has not been the case for most farmed aquaculture species that, in the genetic sense, are still much closer to the wild state than are the major terrestrial animals and food crops. Less than 10 % of the total world aquaculture production is based on improved strains. Due to a growing human population and a decline in production from capture fisheries, there is therefore a great disparity between the need for increased aquaculture production and the genetic quality of the strains available to meet that need. Moreover, full benefits of investments in management improvements (feed and feeding practices, control of diseases, etc.) can only be obtained through the use of genetically improved animals.

Compatible basal-area growth and yield model for thinned and unthinned stands

1983 ◽  
Vol 13 (4) ◽  
pp. 563-571 ◽  
Author(s):  
Robert L. Bailey ◽  
Kenneth D. Ware
Keyword(s):  
Loblolly Pine ◽  
Basal Area ◽  
Growth And Yield ◽  
Yield Model ◽  
Projection Model ◽  
Quadratic Mean ◽  
Basal Area Growth ◽  
Area Growth ◽  
Mean Diameter ◽  
Quadratic Mean Diameter

A measure of kind and level of thinning is developed and its relationship to other stand attributes such as number of trees, basal area, and volume removed in thinning is quantified. This measure or thinning index is based on the ratio of the quadratic mean diameter of thinned trees to the quadratic mean diameter of all trees before thinning. The thinning index is then logically incorporated into a thinning multiplier from which is derived a compatible basal-area growth projection model to generalize the previous concepts for thinning effects in systems for predicting growth and yield. Empirical tests with data from thinned and unthinned natural stands of loblolly pine, from thinned and unthinned slash pine plantations, and from thinned western larch stands show the model to provide estimates with improved properties. Hence, the thinning index and the thinning multiplier are also proposed for other situations involving effects of thinning.

Erosion, deposition and size distributions of sand

1988 ◽  
Vol 417 (1853) ◽  
pp. 335-352 ◽  
Keyword(s):  
Depositional Environments ◽  
Natural Environments ◽  
Size Distributions ◽  
Scale Invariant ◽  
Erosion And Deposition ◽  
Triangular Domain ◽  
Hand Part ◽  
Mass Size ◽  
Two Parameters ◽  
The Right

A mathematical–physical model for erosion and deposition of sand is formulated and related to the logarithmic hyperbolic distributional form of mass–size distributions. The location-scale invariant parameters χ and ξ of the hyperbolic distribution express, respectively, the skewness and the kurtosis of that distribution, and the triangular domain of variation of these two parameters is referred to as the hyperbolic shape triangle. The erosion–deposition model implies that erosion will tend to move the ( χ , ξ)-position of a given sediment to the right-hand part of the shape triangle and that deposition will move the ( χ , ξ)-position towards the left part of the triangle, along specified curves. This is confirmed by sediments from a variety of natural environments. An empirically determined curve bisecting the shape triangle is found to separate the samples from predominantly depositional environments as compared with the samples from predominantly erosional environments. The hyperbolic shape triangle is also found to discriminate well between samples of different but closely related origins.

Structural stocking guides: a new look at an old friend

2004 ◽  
Vol 34 (5) ◽  
pp. 1044-1056 ◽  
Author(s):  
Jeffrey H Gove
Keyword(s):  
Basal Area ◽  
Primary Objective ◽  
Diameter Distribution ◽  
Minimal Amount ◽  
Forest Types ◽  
Quadratic Mean ◽  
Parameter Recovery ◽  
Distribution Shape ◽  
New Information ◽  
New Type

A parameter recovery-based model is developed that allows the incorporation of diameter distribution information directly into stocking guides. The method is completely general in applicability across different guides and forest types and could be adapted to other systems such as density management diagrams. It relies on a simple measure of diameter distribution shape, the basal area larger than quadratic mean stand diameter, to estimate the parameters of the unknown distribution. This latter quantity is shown to have high correlation with stocking guide variables in northeastern forest types. A primary objective of this new type of guide is that its use should require a minimal amount of new information from the user and that the underlying model should be as simple as possible.

scholarly journals An evaluation of agroforestry on a Bay of Plenty hill country farm

1991 ◽  
pp. 161-168
Author(s):  
R.L. Knowles ◽  
G.M. Brann ◽  
G.J. Brann
Keyword(s):  
Cash Flow ◽  
Pinus Radiata ◽  
Carrying Capacity ◽  
Low Cost ◽  
Agroforestry System ◽  
Economic Return ◽  
Hill Country ◽  
Genetically Improved ◽  
Gross Margins

Between 1970 and 1991,53 ha of Pinus radiata plantations were established and managed in an agroforestry system on a 245 ha farm at Roydon Downs in the eastern Bay of Plenty. Plantations on a further 30 haareplanned. This paperoutlines the experience gained, and uses recently developed agroforestry modelling systems to evaluate the current and projected physical yields, cash flow and profitability of several agroforestry options when applied to a typical Bay of Plenty sheep and beef farm, The increasing availability of genetically improved tree stocks, together with developments in silvicultural techniques, have resulted in a low cost, easily managed tree crop, using mainly family labour. The objective is to produce high quality domestic or export sawlogs and peeler logs. Planting the least productive third of the farm is predicted to more than double the total farm surplus. For farming to provide an equivalent economic return from the same land, gross margins would have to increase from $29 to $60/livestock unit (LSU). or livestock carrying capacity would have to increase from 8 to 16 LSU/ha. Options involving 135 stems/ha and 225 stems/ha gave a similar economic return. However, concerns about the quality of the final product indicate that cash flow constraints should be met by varying the size and rate of planting, rather than by reducing final crop stocking. A method of financing initial costs based on sharing final revenues with investors is presented. Keywords agroforestry, Pinus radiata, estate model, profitability

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