Radial Growth Research Papers - Academia.edu (original) (raw)

Little is known concerning the effects of wildfires on tree radial growth and their climatic response under contrasting regimes of fog water inputs on oceanic islands. On Tenerife, Canary Islands, windward slopes are humid with high-fog... more

Little is known concerning the effects of wildfires on tree radial growth and their climatic response under contrasting regimes of fog water inputs on oceanic islands. On Tenerife, Canary Islands, windward slopes are humid with high-fog frequency due to influence of wet trade winds, while climate on leeward slopes is more arid. We used tree-ring records of Pinus canariensis Sweet ex Spreng. to quantify the effects of a fire of known date on radial growth and determine the main limiting climatic factors for growth. Radial growth patterns and their responsiveness to fire severity and climatic variation differed between windward and leeward slopes. Surface fire did not significantly impact growth, while crown fire caused short-term growth reduction, and even cessation, more pronounced on the windward slope. Growth rates, tree-ring common signal, and climate sensitivity were smaller on the windward slope, with cold winters, and summer water stress limiting growth. On the leeward slope, climate explained a greater amount of growth variation mainly due to negative effects of high October–December sea-level pressures causing dry winter conditions. Contrasting growth dynamics on both slopes may result from diverging physiological effects of water inputs and reduced radiation caused by fog drip. Our findings suggest that dating growth suppressions and absent rings are useful to date past high-severity crown fires in P. canariensis forests, in addition to ordinary fire scars dating indicative of low-severity surface fires.

Ganoderma boninense is a bracket fungus that is pathogenic on oil palms causing basal stem rot, while some members of the genus Trichoderma are good biological control agents against numerous plant fungal diseases. We isolated and tested... more

Ganoderma boninense is a bracket fungus that is pathogenic on oil palms causing basal stem rot, while some members of the genus Trichoderma are good biological control agents against numerous plant fungal diseases. We isolated and tested T. harzianum for in-vivo nursery to suppress diseases caused by G. boninense. A total of 48 local isolates of T. harzianum were selected for screening of their antagonistic properties against G. boninense (strain PER 71) by dual culture techniques. The results showed that all of the isolates of T. harzianum inhibited the growth of PER 71 with percentage of inhibition radial growth (PIRG) values ranging from 47.86 to 72.06%. The best eight samples from the dual cultures were then tested for their production of volatile antifungal compounds against PER 71, which gave PIRG values between 24.53 and 58.70% over 6 days. The values ranged from 18.35 to 40.16% over 6 days for the antifungal activities of their non-volatile compounds. Isolate FA 30 was demonstrated to be the best isolate not only to the dual culture inhibition tests but also the best for the production of inhibitory properties from both volatile and non-volatile antifungal compounds.

Laboratory experiment was conducted in Microbiology Laboratory of School of Science and Science Technology, Abubakar Tafawa Balewa University, Bauchi, Nigeria, to determine the antifugal effect of some plant extracts at different... more

Laboratory experiment was conducted in Microbiology
Laboratory of School of Science and Science Technology,
Abubakar Tafawa Balewa University, Bauchi, Nigeria, to
determine the antifugal effect of some plant extracts at different
concentration to control tomato fruit rot via both invitro and
invivo approaches. The aqueous moringa, Lantana, garlic and
pawpaw each with two varying concentrations (40 and 60g/l)
were evaluated along with carbendazin for comparison and
untreated tomatoes serving as control against Aspergillus flavus.
The treatments were laid in a Completely Randomized Design
(CRD) with three replications. The results showed a promising
antifungal activity of the crude extracts of these plants against A.
flavous. Among the various plant extracts with varying
concentrations, aqueous extracts of pawpaw (40 and 60g/l) was
found to have more significance (P< 0.01) inhibitory effect on
radial growth of A. flavus both invitro (0.30 and 0.24cm and
invivo 0.77 and 0.71) better than other extracts and is comparable
to carbendazim. On the other hand, lantana, garlic and moringa at
40 and 60g/l reduced radial growth of A. flavus better than the
control. This finding proved the potentiality of plant extracts for
the control of post harvest and transit fungal rot of tomato fruit
and could be applied to control fungal fruit rot of tomato in both
storage and on transit.

African Journal of Biotechnology Vol. 7 (8), pp. 967-972, 17 April, 2008 Available online at http://www.academicjournals.org/AJB ISSN 1684–5315 © 2008 Academic Journals ... Behzad Hajieghrari1*, Mousa Torabi-Giglou1, Mohammad Reza... more

African Journal of Biotechnology Vol. 7 (8), pp. 967-972, 17 April, 2008 Available online at http://www.academicjournals.org/AJB ISSN 1684–5315 © 2008 Academic Journals ... Behzad Hajieghrari1*, Mousa Torabi-Giglou1, Mohammad Reza Mohammadi2 and Mahdi

The accuracy of direct (based on increment cores) and indirect (based on age-size relationships) methods of tree age estimation in Fagus sylvatica and Quercus robur was tested. This was done through increment cores and stem discs taken in... more

The accuracy of direct (based on increment cores) and indirect (based on age-size relationships) methods of tree age estimation in Fagus sylvatica and Quercus robur was tested. This was done through increment cores and stem discs taken in an old-growth forest of Northern Spain. It was found that cross-dating was more precise than ring counting by up to 7 years per tree. Furthermore, cross-dating permitted the estimation of the age of trees with floating ring-width series, which were 7% of cored F. sylvatica and 40% of Q. robur ones. In partial cores with the arcs of the inner rings, the length of the missing radius was estimated with both a geometric method, based on the curvature of the arcs, and a new graphical method, based on the convergence of xylem rays at the pith. The graphical method was more accurate when the radial growth was eccentric, as happens in Q. robur, while both methods showed a similar accuracy for F. sylvatica, whose growth is relatively concentric. Empirical models of initial radial growth (IRG), built to estimate the number of missing rings, reduced the errors associated with other methods that assume constant growth rates. Age estimates obtained from the graphical method combined with the IRG models were within 4% of the actual age. This combination ensured age estimates with a mean accuracy of 8 years for 98% of the F. sylvatica trees, and 4 years for 89% of the Q. robur. In partial cores without the arcs of the inner rings, the length of the missing radius was estimated as the distance to the geometric centre of the tree. In that case, age estimates obtained by extrapolating the mean growth rate of the 20 innermost rings in the cores were from 10 to 20% of actual age, which coincided with results obtained in other tree species with this method. Finally, the age-diameter equations of the different cohorts produced better age estimates (from 8 to 14% of actual age) than equations of the population as a whole (from 20 to 40% of actual age). These results proved that the errors derived from doubtful assumptions, such as concentric radial growth, constant growth and recruitment rates, or the absence of anomalous rings, could be reduced by applying more realistic methods of tree age estimation.

Plant growth-promoting rhizobacteria (PGPR) strains CHA0 (Pseudomonas fluorescens), IE-6 S+ (Pseudomonas aeruginosa) and 569Smr (Bradyrhizobium japonicum) were tested singly and in combinations for biological control against multiple... more

Plant growth-promoting rhizobacteria (PGPR) strains CHA0 (Pseudomonas fluorescens), IE-6 S+ (Pseudomonas aeruginosa) and 569Smr (Bradyrhizobium japonicum) were tested singly and in combinations for biological control against multiple tomato pathogens (root-infecting fungi and root-knot nematodes). Strains CHA0 and IE-6S+ inhibited in vitro growth of 569Smr while IE-6S+ suppressed CHA0. The bacterial species not only inhibited the radial growth of three root-infecting

We have developed extensions of traditional distance-dependent, spatial competition analyses that estimate the magnitude of the competitive effects of neighboring trees on target tree growth as a function of the species, size, and... more

We have developed extensions of traditional distance-dependent, spatial competition analyses that estimate the magnitude of the competitive effects of neighboring trees on target tree growth as a function of the species, size, and distance to neighboring trees. Our analyses also estimate inter- and intra-specific competition coefficients and ex- plicitly partition the competitive effects of neighbors into the effects of shading