Superior Trees Research Articles

Performance of localized regression tree splitting criteria on data with discontinuities

SummaryProperties of the localized regression tree splitting criterion, described in Bremner & Taplin (2002) and referred to as the BT method, are explored in this paper and compared to those of Clark & Pregibon's (1992) criterion (the CP method). These properties indicate why the BT method can result in superior trees. This paper shows that the BT method exhibits a weak bias towards edge splits, and the CP method exhibits a strong bias towards central splits in the presence of main effects. A third criterion, called the SM method, that exhibits no bias towards a particular split position is introduced. The SM method is a modification of the BT method that uses more symmetric local means. The BT and SM methods are more likely to split at a discontinuity than the CP method because of their relatively low bias towards particular split positions. The paper shows that the BT and SM methods can be used to discover discontinuities in the data, and that they offer a way of producing a variety of different trees for examination or for tree averaging methods.

Exploiting the potential of indigenous agroforestry trees: Parkia biglobosa and Vitellaria paradoxa in sub-Saharan Africa

Parkia biglobosa (nere) and Vitellaria paradoxa (karite) are indigenous tree species that are economically and socially important for local people in sub-Saharan Africa. Farmers deliberately maintain these trees on farms mainly for their fruits and nuts. The kernels of karite yield shea butter, which is rich in fatty acids; it is used locally for food and internationally in chocolate, pharmaceutical and cosmetic products. Nere seeds are ground into a pungent nutritious spice or condiment, soumbalaor dawadawa, which is added to soups and stews throughout the savanna regions of sub-Saharan Africa. The tree is also important in improving soil fertility and in traditional medicine. Despite their important uses, the populations of both species are in decline and they remain semi- or undomesticated. Recent research has shown that both species are genetically diverse, which indicates their potential for domestication through selection and breeding, and that crop production under the trees could be improved by crown pruning. Research also has helped develop vegetative propagation methods that allow multiplication of superior trees and on-farm domestication of the trees. Domestication should enhance their role in improving rural livelihoods. New knowledge on reproductive biology should be used to increase fruit production in both species. Prevailing social conditions in relation to tree tenure, marketing and processing are the major constraints to successful domestication and proper management of these valuable trees. Changes in tree tenure policy, development of local and national markets, access to market information for producers, establishment of a system for standardizing product quality at national level, and development of improved village processing technologies are needed.

A multivariate statistical approach to predicting mature tree performance based on seedling characteristics

A common objective in commercial reforestation is to plant seedlings that will produce superior adult trees. Long forest management planning horizons and life spans of most forest trees complicate the prediction of growth and performance of adult trees originating from planted seedlings of unknown genetic origin. We used multivariate statistics to identify and rank a set of seedlings characteristics that could predict the performance of mature trees in Pinus ponderosa. Results indicated that metabolic heat rate (q), a measure of total metabolism, of one-year-old foliage during the peak growth in May, was the most important seedling characteristic that predicted mature-tree performance. Increased metabolic heat rate in seedlings corresponded with greater vigor of mature trees. Additionally, seedling basal stem diameter (D), height (H), and needle length (NL), measured in November, were, in order of importance, other variables that defined the vigor class of the mature clones. However, these seedling morphological characteristics correlated negatively with vigor classification of the mature clones, contradicting the notion that greater D and/or H during the seedling stage may indicate a greater vigor at maturity.

The utility and limitations of chloroplast DNA analysis for identifying native British oak stands and for guiding replanting strategy

We report a method using variation in the chloroplast genome (cpDNA) to test whether oak stands of unknown provenance are of native and/or local origin. As an example, a sample of test oaks, of mostly unknown status in relation to nativeness and localness, were surveyed for cpDNA type. The sample comprised 126 selected trees, derived from 16 British seed stands, and 75 trees, selected for their superior phenotype (201 tree samples in total). To establish whether these two test groups are native and local, their cpDNA type was compared with that of material from known autochthonous origin (results of a previous study which examined variation in 1076 trees from 224 populations distributed across Great Britain). In the previous survey of autochthonous material, four cpDNA types were identified as native; thus if a test sample possessed a new haplotype then it could be classed as non-native. Every one of the 201 test samples possessed one of the four cpDNA types found within the autochthonous sample. Therefore none could be proven to be introduced and, on this basis, was considered likely to be native. The previous study of autochthonous material also found that cpDNA variation was highly structured geographically and, therefore, if the cpDNA type of the test sample did not match that of neighbouring autochthonous trees then it could be considered to be non-local. A high proportion of the seed stand group (44.2 per cent) and the phenotypically superior trees (58.7 per cent) possessed a cpDNA haplotype which matched that of the neighbouring autochthonous trees and, therefore, can be considered as local, or at least cannot be proven to be introduced. The remainder of the test sample could be divided into those which did not grow in an area of overall dominance (18.7 per cent of seed stand trees and 28 per cent of phenotypically superior) and those which failed to match the neighbouring autochthonous haplotype (37.1 per cent and 13.3 per cent, respectively). Most of the non-matching test samples were located within 50 km of an area dominated by a matching autochthonous haplotype (96.0 per cent and 93.5 per cent, respectively), and potentially indicates only local transfer. Whilst such genetic fingerprinting tests have proven useful for assessing the origin of stands of unknown provenance, there are potential limitations to using a marker from the chloroplast genome (mostly adaptively neutral) for classifying seed material into categories which have adaptive implications. These limitations are discussed, particularly within the context of selecting adaptively superior material for restocking native forests.

DOMESTICATING PRIORITY MIOMBO INDIGENOUS FRUIT TREES AS A PROMISING LIVELIHOOD OPTION FOR SMALL-HOLDER FARMERS IN SOUTHERN AFRICA

ISHS XXVI International Horticultural Congress: Citrus and Other Subtropical and Tropical Fruit Crops: Issues, Advances and Opportunities DOMESTICATING PRIORITY MIOMBO INDIGENOUS FRUIT TREES AS A PROMISING LIVELIHOOD OPTION FOR SMALL-HOLDER FARMERS IN SOUTHERN AFRICA

Leaf Curl and Water Relations of Kousa Dogwoods Showing Resistance to Summer Stress

Abstract Kousa dogwood (Cornus kousa Hans.) trees often develop unattractive leaf curling throughout canopies during hot and/or dry weather. Aesthetically superior trees were compared to control trees for their ability to tolerate summer stress, in an established kousa dogwood plantation in 2000 and 2001. An index of leaf curl revealed that superior trees showed less curling than controls during June, July and August of 2000 and 2001. Superior trees often had higher stomatal conductance than trees in both control groups during both years, with seasonal averages 16 to 40% higher in superior than in control trees. Leaf water status, characterized by leaf osmotic potential, remained similar in superior trees and control trees throughout the 2000 summer season. Leaf temperatures were similar between groups during each summer. We confirmed that trees initially selected as having superior visual appearance had measurable differences in foliar characteristics compared to control trees, and that these trees better tolerated summer stress.

Molecular analysis of micropropagated neem plants using aflp markers for ascertaining clonal fidelity

The importance of neem (Azadirachta indica A. Juss.) as a medicinal tree species has been acknowledged worldwide. Superior trees with desired traits such as high azadirachtin content have been identified and micropropagated. Somaclonal variants that may arise in vitro, however, pose limitations to large-scale micropropagation. It is, therefore, imperative to establish genetic uniformity of such plantlets by ensuring strict quality checks at various stages of in vitro culture. This is the first study that evaluates the applicability of amplified fragment length polymorphism (AFLP) markers in establishing clonal fidelity of tissue culture(TC)-raised neem plants. Seven AFLP primer combinations generated a total of 334 amplified fragments across the mother plant, TC progenies, and other neem accessions that were included as controls. Two hundred and thirty-nine amplified fragments were monomorphic across the mother tree and its TC progenies. No extra band was detected in the TC plantlets that was absent in the mother tree, indicating that the TC plantlets regenerated through nodal explants are indeed true-to-type. Ninety-five AFLP fragments were detected in the controls, which allowed their discrimination from the elite mother tree and its TC progenies. Similarity matrix based on Jaccard's coefficient revealed that the pair-wise value between the mother tree and its TC plantlets was ‘1’, indicating perfect similarity. Phenetic dendrogram based on UPGMA (unweighted pair group method of arithmetic averages) analysis further confirmed the true-to-type nature of TC progenies, since a tie was observed between the mother tree and its TC plantlets. On the contrary, the control neem accessions were distinct from the mother and its TC progenies. AFLP markers proved to be an ideal tool for routine analysis and certification of genetic fidelity of micropropagated plants prior to commercialization, especially in tree species because of their long generation time.

DOMESTICATION OF DACRYODES EDULIS: STATE-OF-THE-ART

ABSTRACT Dacryodes edulis is one of the important local fruit tree species of West and Central Africa. This paper reviews the activities of a regional programme to domesticate high-value indigenous fruit trees in the region. This programme is coordinated by the International Centre for Research in Agroforestry (ICRAF) and implemented in Cameroon in collaboration with the Institute of Agricultural Research for Development (IRAD), National Agricultural Extension and Research Programme (PNVRA) agents and NGOs and universities of the region. It is based on a participatory approach to domestication that is in marked contrast to that of food crop domestication under the Green Revolution. The participatory process with farmers started with priority setting between species, progressed to germplasm collection and the establishment of village nurseries for clonal propagation of superior trees, and is currently involved in the selection of superior trees for cultivar development. Work is also in progress on post-harvest processing, market development and the integration of cultivars into agroforestry systems.

Propagation of Robinia pseudoacacia Linn. and Grewiaoptiva Drummond from rooted stem cuttings

Rapid vegetative propagation of promising multipurpose trees is an important need in agroforestry development. Grewia optiva andRobinia pseudoacacia are two such species, about the propagation of which very little is known. The rooting ability of stem cuttings harvested from juvenile (2 year-old) and mature hardwood(15 year-old) trees of Robinia pseudoacacia andGrewia optiva was significantly influenced by the period or season of harvesting cutting. Juvenile cuttings of both species rooted significantly better (42.9% in R. pseudoacacia and 46.6% in G. optiva) than mature hardwood cuttings (34.7% in R.pseudoacacia and 41.4% in G. optiva). The effect was more pronounced in auxin treated cuttings. InR. pseudoacacia, the highest rooting in juvenile(83.3%) and mature (66.6%) cuttings prepared in spring season was observed with the NAA (500 mg/l) treatment. InG. optiva, IBA (250 mg/l) in the monsoon season was most effective and recorded a maximum of 80% and 70%rooting in juvenile and mature cuttings, respectively. The auxin treatments also significantly enhanced the number of roots (23.8 inR. pseudoacacia and 17.6 in G.optiva) and their mean length (14.3 cm inR. pseudoacacia and 16.1 cm inG. optiva). Interactions between age, season and treatments were significant at P < 0.05 level for rooting percent in R. pseudoacacia and non-significant for G. optiva. The results of this study suggest that it is possible to develop clones of genetically superior trees of R. pseudoacacia and G.optiva for use in agroforestry or afforestation programmes.

Propagation of two miombo woodland trees by leafy stem cuttings obtained from seedlings

The rooting ability of leafy stem cuttings harvested from four to five month old seedlings of B. spiciformis Benth and P. angolensis DC was tested in low-technology non-mist propagators suitable for the rural tropics. Both species were successfully rooted; P. angolensis was a faster rooting species (86% after 61 days) compared with B. spiciformis (59% after 154 days). Regression analysis suggested that P. angolensis had more stored carbohydrates, which facilitated its rooting while B. spiciformis was more dependant on current assimilates produced during the period of propagation. The results of this study suggest that it is possible to develop clones of genetically superior trees of B. spiciformis and P. angolensis for use in agroforestry or reforestation programmes.

Selecting trees for structural timber

Twenty-eight cubic metres of timber (i.e. a total of 2248 boards) cut from 108 Pinus radiata trees from two 25-year-old plantations from Canterbury and Nelson in the South Island of New Zealand were tested in tension. Within- and between-tree variations of stiffness, strength and density were examined. Comparisons between density and stiffness for selecting trees for structural timber indicated that stiffness is the better parameter for selecting superior trees within the natural population of a forest stand; and the quality and grade recovery of structural timber would be increased significantly if trees were to be selected on the basis of stiffness. These conclusions apply to both stands although regional differences are evident with the Nelson timber being somewhat stiffer.

Meristem culture of Acacia mearnsii

The Black Wattle (Acacia mearnsii) is aneconomically important forest tree hence the need forefficient methods of amplification and clonalpropagation of superior trees. To overcome maturationeffects and the number of diseases infecting thewattle, rejuvenated tissue such as apical meristems,can be used. Meristems were taken from 30-day-old in vitro grown plants, from coppice (rejuvenatedtissue) and adult material from trees of fivedifferent ages over two seasons. Meristems from the coppice and adult material was successfullydecontaminated. Shoot production was obtained bymeristems from in vitro grown plants, coppiceand adult material, irrespective of plant age, onsolidified Murashige and Skoog (MS) medium alone orsupplemented with 2.0 mg l−1 benzyladenine,half-strength MS and Woody Plant Medium (WPM), underlight or dark culture conditions. The age of theparent tree, from which plant material (adult orcoppice plant material) was obtained, did not have asignificant effect on the degree of shoot production.Apparently the use of coppice material was notnecessary as shoot production from the meristems takenfrom the adult material was equal, if not greater,than that obtained by meristems from the coppicematerial. Adult trees, of different ages, weresuccessfully rejuvenated through the use of meristemculture.

Assessment and Restoration of a Condensate Spill in the Atchafalaya Basin, Louisiana

ABSTRACT Pioneer Natural Resources USA, Inc. (Pioneer) experienced a gas well blowout on December 5, 1996 at Myette Point within a lacustrine delta in Louisiana's Atchafalaya Basin. For a period of 5 days, gas condensate erupted from the well head, covering the surrounding bottomland hardwood forest. Over the next 6 weeks, oil spill response contractors recovered gas condensate from access canals, distributary channels, and small ponds. The total volume spilled was estimated at 4,700 barrels. The state of Louisiana issued a letter of intent to conduct a Natural Resource Damage Assessment (NRDA) to determine a plan of restoration to the impacted bottomland hardwood forest. Pioneer worked cooperatively with Louisiana's Department of Wildlife and Fisheries (lead agency), Department of Environmental Quality, Department of Natural Resources, and the Oil Spill coordinator's Office to conduct a cooperative NRDA. A Shoreline Cleanup Assessment Team (SCAT) survey was conducted to map the surface oiling cover. A classification was developed by the NRDA team defining heavy (&amp;gt;50% cover), moderate (&amp;lt;50% cover), and light (only film) oiling classes. Using GPS technology, the NRDA team surveyed the spill area and mapped 164 acres of oiled forest broken into three classes: 106 acres of light, 29 acres of moderate, and 29 acres of heavy. The natural resource trustees determined the degree of injury based upon plant mortality of 10% for light, 50% for moderate, and 90% for heavy oiling classes during the winter survey (1997) for a total spill mortality of 51.2 acres. Based upon the early summer (1997) NRDA team survey, the mortality of the oiling classes were revised. Pioneer negotiated with the NRDA team and developed a plan to clear cut 30 acres of injured forest and plant a new forest of superior quality trees which was completed during the winter 1998. Pioneer working cooperatively and proactively with the natural resource trustees, started and completed the Myette Point NRDA in 14 months.

Establishment and growth of sandalwood (Santalum spicatum) in south-western Australia: the Northampton pilot trial

Summary Direct seeding sandalwood (Santalum spicatum) beneath 1–2 year old host (Acacia acuminata) seedlings was found to be a successful establishment technique at Northampton. Mean survival of S. spicatum rows ranged from 50 to 87%. after 8–9 years. Growth was also good, with mean stem diameter increasing at a rate of 4–7 mm yr−1, and mean estimated stem weight gaining 0.28–0.46 kg yr−1, between 4.5 and 9 years. However, a high proportion of host trees had died, and the remaining trees were in poor health at the time of assessment (November 1997). After 10 years. A. acuminata survival in rows seeded with S. spicatum in 1988 was significantly lower than rows seeded in 1989. Differences in host survival between S. spicatum planting years may be due to the initial period of growth without a root parasite, or the S. spicatum to host ratio. Growth of S. spicatum was also variable between planting years and provenances. At age 5.5. mean tree height of the Hazelby's provenance (194 cm) was significantly taller than all other provenances (157 cm). The variability in growth rate may have been due to differences in rainfall between planting years or genetic differences between provenances. A selection program should be conducted to identify superior provenances or individual trees with desirable plantation characteristics, such as fast growth or high oil content. Plantations could be established in a range of locations in West- em Australia to test site suitability of different provenances.

Clonal production of tea tree oil high in terpinen-4-ol for use in formulations for the treatment of thrush.

A programme of evaluation and selection of superior trees has led to the vegetative propagation of highly productive clones which produce tea tree oil high in terpinen-4-ol. These will soon provide commercial quantities of a particularly active oil of consistent quality for use in formulations for therapeutic use and in particular for vaginal thrush.

In vitro fertilization from co-cultured pollen tubes and female gametophytes of Douglas fir (Pseudotsuga menziesii)

Our previous attempt on in vitro fertilization (IVF) in conifers resulted in pollen tube penetration of female gametophytes, but because of the rapid decline in egg viability, no further interaction occurred. In this report, we describe for the first time that IVF has been achieved in conifers. Using Douglas fir (Pseudotsuga menziesii), we describe a two-step process which involved induction of pollen tubes in culture followed by introduction of isolated female gametophytes at the tips of growing pollen tubes. Pollen tubes penetrated the introduced isolated female gametophytes at various places, but a number of tubes entered the egg cell through the neck cells similar to the in vivo condition. Under our current culture conditions, longevity of pollen tubes and eggs has been improved resulting in the release of sperms, fusion of gametes, and initial formation of the proembryo. Continued plasmolysis of the egg limited the number of successful gametic interactions. IVF has been accomplished in flowering plants in several ways, but the gametophyte-gametophyte IVF system described in this paper is unique. IVF offers a novel breeding technology that takes advantage of the sexual reproductive route. When coupled with hybridization and genetic transformation, IVF could result in the development of stable novel genotypes of economically superior trees.

Clonal Selection in Kabaası Apricot Cv.

This paper reports studies on clonal selection in Kabaaşı apriciot cv. at Kale, Malatya. 450 superior trees of Kabaaşı cv. were examined during two years 1994-1995. The samples were investigated for important dry fruit characteristics. At the end of this study, 13 superior trees were selected. In selected trees, average fruit weight varied between 31.81±4.7 g-60.91±5.9 g, seed weight varied between 2.35±1.5 g - 3.81±0.8 , kernel weight varied from 0.52±0.1 to 0.98±0.1 g. flesh/seed ratio varied between 12.38/1-16.64/1, total soluble solid contents ranged between % 22.44±3.8- % 29.68± 1.7 . fruit length varied between 40.27±1.2 mm - 52.72±4.1 mm, fruit suture varied from 32.71±1.5 to 43.15±5.0 mm, and fruit cheek varied between 34.64±2.3 - 47 .32±1.5 mm.

The use of RAPD markers for the identification of Sitka spruce (Picea sitchensis) clones

DNA from 57 superior clones was amplified using arbitrary primers in the polymerase chain reaction, in order to assess the genetic variation within Sitka spruce and to investigate if individual clones could be identified. Six out of 30 primers gave reproducible banding patterns. Twenty-four polymorphic bands were scored for the 57 clones studied and all the clones could be identified using a combination of four or more primers. Nei's estimate of similarity was calculated and cluster analysis was used to generate a dendrogram showing considerable variation among the superior trees. Clonally produced material (ramets) could be recognized and mislabelled ramets were identified.

Cyclic Microirrigation in Container-grown Landscape Plants Improves Plant Growth and Water Conservation

Abstract Four tree (Acer rubrum L., Ulmus alata Michx., Quercus virginiana Mill, and Lagerstroemia indica L.) and two landscape shrub species (Rhododendron indicum L. ‘Formosa’ and Elaeagnus pungens Thunb.) were grown in 10-liter (#3) polyethylene containers. Plants were irrigated with overhead impact sprinklers (control) or with individual low volume spray stakes. Microirrigated treatments consisted of same or double volume per day per container as controls applied as one to three cyclic subvolumes. Shrub growth was seldom influenced by irrigation treatment. Xeric tree species (U. alata and Q. virginiana) grew as well with single volumes applied in 2 cycles as double volumes applied in 3 cycles; both produced significantly larger trees than the control. Mesic species (A. rubrum and L. indica) irrigated with double volumes in 3 cycles produced the largest trees that were significantly larger than single volume microirrigated or control trees. Growth of single cycle, single volume trees (overhead and microirrigation) was equivalent; thus, growth effects were due to cycling, not microirrigation. With commercially representative container spacings used, superior trees were produced with cycled microirrigation using 25% (xeric) or 50% (mesic) of the water volume per area applied through the overhead sprinkler. Further aspects of irrigation requirements and water efficiency are discussed.

Site-fitness and growth-rate selection of Eucalyptus for biomass production

Abstract Calorespirometric investigation of the metabolism and temperature responses of tissues from Eucalyptus trees can be used to identify plants with superior growth characteristics. Measurements of the metabolic heat rate, rate of CO 2 evolution and O 2 uptake over a range of temperatures are analyzed with a mechanistic model of plant growth to allow early selection of superior trees. This analysis provides information about indexes of genetic characteristics to use in breeding programs and guidelines for matching trees to appropriate climatic conditions. These procedures can enhance the rate of production of biomass by shortening the time to harvest and can increase total economic returns.