1,956 research outputs found
Mapping and explaining the productivity of Pinus radiata in New Zealand
No full textMapping Pinus radiata productivity for New Zealand not only provides useful information for forest owners, industry stakeholders and policy managers, but also enables current and future plantations to be visualised, quantified, and planned. Using an extensive set of permanent sample plots, split into fitting (n = 1,146) and validation (n = 618) datasets, models of P. radiata 300 Index (an index of volume mean annual increment) and Site Index (an index of height growth) were developed using a regression kriging technique. Spatial predictions were accurate and accounted for 61% and 70% of the variance for 300 Index and Site Index, respectively. Productivity predicted from these surfaces for the entire plantation estate averaged 27.4 m³ ha⁻¹ yr⁻¹ for the 300 Index and 30.4 m for Site Index. Surfaces showed wide regional variation in this productivity, which was attributable mainly to variation in air temperature and root-zone water storage from site to site
Distribution of Diplodia pinea and its genotypic diversity within asymptomatic Pinus patula trees
No full textDiplodia pinea (= Sphaeropsis sapinea) is an endophytic fungus and opportunistic canker pathogen of Pinus spp. The diversity of this fungus has been studied at broad geographic scales, but little is known regarding its population structure at smaller spatial scales such as within a single tree. This is despite the importance that diversity in a single tree might hold for understanding the biology of the fungus, especially the role of the endophytic or asymptomatic phase in disease development. Moreover there was not information regarding the distribution of the fungus within healthy trees and its persistence. The genotypic diversity of these isolates was investigated using microsatellite markers. Five polymorphic markers were developed and these were used together with eight previously developed markers and vegetative compatibility tests to study the genotypic diversity of D. pinea isolates. In this study, D. pinea was isolated for the first time in the well structured stems of healthy P. patula trees along with branches and cones. From a total of 44 isolates collected from five trees, 39 microsatellite haplotypes and 32 vegetative compatibility groups (VCG's) were identified. The results indicate high genotypic diversity of D. pinea within individual asymptomatic trees which will lead to disease outbreak when trees are physiologically stressed
Indirect Assessment of Beliefs About the Self: Implicit Self-Criticism - Materials, Data, and Analysis Scripts
No full textMaterials, data and analysis scripts accompanying Indirect Assessment of Beliefs About the Self: Implicit Self-Criticism, A doctoral dissertation submitted to Ben-Gurion University of the Negev by Michael Pinus, November 2020. The repository contains materials, analysis scripts, and data of five validation studies of indirect measures of self-criticism
Pinus monticola (Western White Pine) : Western White Pine
No full textClass: Coniferophyta
Family: Pinaceae
Genus: Pinus
Species: monticol
Influence of gap-scale disturbance on development and succession in a Cumberland plateau quercus-pinus forest
No full textElectronic Thesis or DissertationQuercus-Pinus forests of the eastern US span > 13 million ha. It is important for managers to understand the methods used to sustain Pinus spp. in these mixtures or progress toward a more natural mixture of hardwoods. Understanding developmental and successional patterns in this forest type can help assess the need to actively manage natural processes, or to inform silvicultural prescriptions to achieve management goals. Little research has been conducted on localized disturbance processes in Quercus-Pinus forests. I examined 60 canopy gaps in a Quercus-Pinus forest on the Cumberland Plateau in Alabama to analyze their influence on development and succession. Most canopy gaps (53%) were single treefall events caused by snapped stems. The majority of gap maker trees (56%) were Pinus individuals while 44% were hardwoods. Most gaps (58%) closed by height growth of subcanopy trees. The majority of these gap filler taxa were hardwoods: Quercus (39%), Carya (14%), Pinus (14%), Nyssa Sylvatica (12%), and other (15%). Significant positive relationships existed between gap size and sapling diversity (r² = 0.15, P = 0.002), tree diversity (r² = 0.21, P = 0.0002), and total stem diversity (r² = 0.29, P < 0.0001). The number of Pinus gap makers and the number of gaps projected to fill by subcanopy recruitment of hardwoods indicated the forest was in the latter stages of a composition shift from Pinus to a much stronger Quercus component. To maintain a Pinus component, managers would likely need to create canopy gaps larger than those documented here and remove hardwood competition from the regeneration layer
Pinus serotina Michx., Pond Pine
No full textThis publication provides an in-depth profile of Pinus serotina for the use of interested laypersons with some knowledge of biology as well as the academic audiences
Carbon fluxes in a mature deciduous forest under elevated CO₂
No full textThis PhD thesis addressed several major aspects of the carbon (C) cycle in a c. 100-year-old, mixed deciduous forest under elevated CO₂ with an emphasis on below-ground processes. The aim was to assess the responses of tree fine roots and soil respiration to canopy CO₂ enrichment (? 550 ppm) in this tallest forest studied to date. Furthermore, leaf gas-exchange of the five study species was examined to ascertain the long-term response of photosynthetic carbon uptake to elevated atmospheric CO₂. Investigations at the Swiss Canopy Crane (SCC) experimental site were guided by the following key questions: (1) Does below-ground C allocation to fine root production increase in response to CO₂ enrichment in order to acquire more nutrients to match the enhanced C supply in the forest canopy? (2) Is below-ground metabolism enhanced and therefore forest soil respiration stimulated by canopy CO₂ enrichment? (3) Is leaf-level photosynthesis persistently stimulated by elevated CO₂ in this stand or had these mature broad-leaved trees reduced their carbon up- take by photosynthetic down-regulation under long-term CO₂ enrichment?
Findings from earlier studies at the SCC site, including 13C isotope tracing, all point towards an in- creased flux of C through CO₂-enriched trees to the soil but neither fine root biomass nor soil respiration were stimulated by elevated CO₂. Surprisingly, fine root biomass in bulk soil and ingrowth cores showed strong reductions by ? 30% in year five and six but were unaffected in the following seventh year of CO₂ enrichment. Given the absence of a positive biomass response of fine roots, we assumed that the extra C assimilated in the CO₂-enriched forest canopy was largely respired back to the atmosphere via increases in fine root and rhizosphere respiration and the metabolization of increased root derived exudates by soil microbes. Indeed, 52% higher soil air CO₂ concentration during the growing season and 14% greater soil microbial biomass both in- dicated enhanced below-ground metabolism in soil under CO₂-enriched trees. However, this did not translate into a persistent stimulation of soil respiration. At times of high or continuous precipitation soil water savings under CO₂-exposed trees (resulting from reduced sapflow) led to excessive soil moisture (> 45 vol.-%) impeding soil gas-exchange and thus soil respiration. Depending on the interplay between soil temperature and the consistently high soil water content in this stand, instantaneous rates of soil respiration were periodically reduced or increased under elevated CO₂ but on a diel scale and integrated over the growing season soil CO₂ emissions were similar under CO₂-enriched and control trees. Soil respiration could therefore not explain the fate of the extra C. The lacking sink capacity for additional assimilates led us to assume downward adjustment of photosynthetic capacity in CO₂-enriched trees thereby reducing carbon uptake in the forest canopy. Photosynthetic acclimation cannot completely eliminate the CO₂-driven stimulation in carbon uptake, but a reduction could hamper the detection of a CO₂ effect considering the low statistical power inevitably involved with such large-scale experiments. However, after eight years of CO₂ enrichment we found sustained stimulation in leaf photosynthesis (42-49%) indicating a lack of closure in the carbon budget for this stand under elevated atmospheric CO₂
Place et rôle des espèces du genre Pinus dans la végétation du Sud-Est Méditerranéen Français
No full textTaking account of the plant communities and vegetation series from french mediterranean southeastern Region, the author analyses the distribution, the climatic and edaphic factors of the distribution and the practical importance of Pinus halepensis Mill., Pinus mesogeensis Fieschi et Gaussen and Pinus pinea L.En prenant pour cadre les associations végétales et les séries de végétation représentées dans le sud-est méditerranéen français, l'auteur précise la répartition, le déterminisme climatique et édaphique de la distribution, les possibilités d’extension et l'intérêt pratique de Pinus halepensis Mill., Pinus mesogeensis Fieschi et Gaussen et Pinus piriea L.Loisel Roger. Place et rôle des espèces du genre Pinus dans la végétation du Sud-Est Méditerranéen Français. In: Ecologia mediterranea, tome 2,1976. pp. 131-152
Branch architecture QTL for Pinus elliottii var. elliottii Pinus caribaea var. hondurensis hybrids
No full textPutative quantitative trait loci (QTL) of moderate, additive effect were
identified for branch diameter, average number of branches per whorl per tree, average whorl
spacing and regularity of whorl spacing in a single Pinus elliottii var.
elliottii
P. caribaea var. hondurensis family. There was no evidence of
additive additive epistasis or pleiotropy. No marker-trait associations were
detected for the average branch angle per whorl per tree. The detection of gene effects that
were seemingly larger but less numerous than those expected for traits with low to moderate
heritabilities was attributed to bias in the estimation of QTL magnitude and limited power to
detect QTL due to a small sample size. Branch architecture traits exhibited considerable
variation within the family with ranges of 4-6 standard deviations (SD) and tended to be less
variable than height and diameter. Branching characters were largely independent of one
another as well as growth, form and wood density properties. Branching characters other than
branch angle were not influenced by macro-environmental factors.QTL concernant l'architecture de la branchaison chez les hybrides entre Pinus
elliottii var. elliottii Pinus caribaea var. hondurensi.
On a identifié des QTL
qui semblent avoir un effet modéré et additif pour les caractères : (1) diamètre des
branches ; nombre moyen de branches par verticille ; espacement moyen entre verticilles et
régularité de cet espacement dans une famille de Pinus elliottii var. elliottii
Pinus caribaea var. hondurensi. Aucune épistasie additif
additif ou pléiotropie n'a pu être mise en évidence. Il n'a pas été possible non plus de
trouver un marqueur associé au caractère angle des branches au niveau verticille et arbre.
Les effets des gènes qui ont été détectés peuvent sembler plus importants, et le nombre de
gènes moins élévé que ce qu'on pourrait attendre pour des caractères à héritabilité faible à
moyenne. Ceci s'explique par la faible dimension de l'échantillon qui induit un biais dans
l'estimation de l'effet QTL et limite le pouvoir de détection de ces QTL. La variabilité
intra-famille des caractères de branchaison est considérable, avec une amplitude de 4-6
écarts-types ; elle tend à être moins élevée que celle de la hauteur et du diamètre. Ces
caractères de la branchaison sont largement indépendants les uns des autres, mais aussi des
caractères forme, densité du bois et vigueur. À l'exception de l'angle des branches, ils ne
sont pas influencés par les facteurs macro-environnementaux
- …
