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Coniferous Tree Species (coniferous + tree_species)

Distribution by Scientific Domains

Life Sciences	50%

Selected Abstracts

The accuracy of matrix population model projections for coniferous trees in the Sierra Nevada, California

JOURNAL OF ECOLOGY, Issue 4 2005
PHILLIP J. VAN MANTGEM
Summary 1We assess the use of simple, size-based matrix population models for projecting population trends for six coniferous tree species in the Sierra Nevada, California. We used demographic data from 16 673 trees in 15 permanent plots to create 17 separate time-invariant, density-independent population projection models, and determined differences between trends projected from initial surveys with a 5-year interval and observed data during two subsequent 5-year time steps. 2We detected departures from the assumptions of the matrix modelling approach in terms of strong growth autocorrelations. We also found evidence of observation errors for measurements of tree growth and, to a more limited degree, recruitment. Loglinear analysis provided evidence of significant temporal variation in demographic rates for only two of the 17 populations. 3Total population sizes were strongly predicted by model projections, although population dynamics were dominated by carryover from the previous 5-year time step (i.e. there were few cases of recruitment or death). Fractional changes to overall population sizes were less well predicted. Compared with a null model and a simple demographic model lacking size structure, matrix model projections were better able to predict total population sizes, although the differences were not statistically significant. Matrix model projections were also able to predict short-term rates of survival, growth and recruitment. Mortality frequencies were not well predicted. 4Our results suggest that simple size-structured models can accurately project future short-term changes for some tree populations. However, not all populations were well predicted and these simple models would probably become more inaccurate over longer projection intervals. The predictive ability of these models would also be limited by disturbance or other events that destabilize demographic rates. [source]

Performance of the potentially invasive Siberian moth Dendrolimus superans sibiricus on coniferous species in Europe

AGRICULTURAL AND FOREST ENTOMOLOGY, Issue 3 2009
Natalia I. Kirichenko
Abstract 1,The native range of the Siberian moth extends from the Pacific Ocean (Russian Far East, Japan and Northern Korea) across Siberia, Northern China and Mongolia to the Ural Mountains. At the beginning of the 21st Century, this species was documented west of the Ural Mountains in the Republic of Mari El, indicating range extension toward the west. 2,The Siberian moth has recently been suggested for regulation as a quarantine pest for European and Mediterranean Plant Protection Organization member countries. However, no specific report on European host plants for this pest has been published so far. 3,In the present study, larval host plant choice and performance was tested for the first time on coniferous tree species that are widely distributed and of commercial value in Europe. 4,Based on dual-choice tests on neonates and mortality, developmental duration and relative growth rates of the first- to sixth-instar larvae, we found European larch Larix decidua to be the most suitable host for the moth larvae, whereas European black pine Pinus nigra and Scots pine Pinus sylvestris were the poorest hosts. The remaining conifer species tested, European silver fir Abies alba, Nordmann fir Abies nordmanniana, and Norway spruce Picea abies, were intermediate host plants. Douglas-fir Pseudotsuga menziesii, originating from North America, was chosen by the larvae to the same extend as European larch, and was also highly suitable for larval development. 5,If the moth is introduced to European countries, it will become damaging in stands of European larch and Douglas-fir, mixed stands of fir and spruce; however, it will be less damaging in forests dominated by two-needle pines. 6,We predict that Dendrolimus superans sibiricus will be able to survive and develop on the main European coniferous tree species, including non-native coniferous tree species, resulting in severe damage to large areas of forests. [source]

The hydraulic architecture of Juniperus communis L. ssp. communis: shrubs and trees compared

PLANT CELL & ENVIRONMENT, Issue 11 2008
BARBARA BEIKIRCHER
ABSTRACT Juniperus communis ssp. communis can grow like a shrub or it can develop a tree-like habit. In this study, the hydraulic architecture of these contrasting growth forms was compared. We analysed the hydraulic efficiency (leaf-specific conductivity, kl; specific conductivity, ks; Huber value, HV) and the vulnerability to cavitation (the water potential corresponding to a 50% loss of conductivity, ,50), as well as anatomical parameters [mean tracheid diameter, d; mean hydraulic diameter, dh; cell wall reinforcement (t/b)h2] of shrub shoots, tree stems and tree branches. Shrub shoots were similar to tree branches (especially to lower branches) in growth form and conductivity (kl = 1.93 ± 0.11 m2 s,1 MPa,1 10,7, ks = 5.71 ± 0.19 m2 s,1 MPa,1 10,4), but were similar to tree stems in their vulnerability to cavitation (,50 = ,5.81 ± 0.08 MPa). Tree stems showed extraordinarily high kl and ks values, and HV increased from the base up. Stem xylem was more vulnerable to cavitation than branch xylem, where ,50 increased from lower (,50 = ,6.44 ± 0.19 MPa) to upper branches (,50 = ,5.98 ± 0.13 MPa). Conduit diameters were correlated with kl and ks. Data indicate that differences in hydraulic architecture correspond to changes in growth form. In some aspects, the xylem hydraulics of tree-like Juniperus communis differs from that of other coniferous tree species. [source]