Showing papers by "Forest Research Institute published in 1984"

Effects of Acidic Deposition on Forest Soil and Vegetation

Abstract: The paper concerns the potential effects of acidic deposition on the nutrient status of soil and forest and on the possible toxic effect of increased Al solubility. The nutrient status of trees may be influenced by pollutants interacting with the foliage and also by changing availability of nutrients in the soil. N compounds are often absorbed by the canopy whereas base cations are lost to the soil by foliar leaching. Cation leaching increases with increased acidity of precipitation. Throughfall acidity varies with tree species, season and distance from the emission areas. The impact of increased foliar leaching of base cations is not well known. In soil, acid deposition may have three effects: (i) a fertilizer effect caused by the deposition of N, and possibly, under specific conditions, also of S; (ii) an acidification effect caused by increased leaching of base cations; and (iii) an Al toxicity effect in cases where soil acidity is increased. Results of fertilizer experiments indicate that the atmospheric deposition of N is likely to increase forest growth especially in the northern parts of North America and Europe. At more southerly latitudes, nutrients in addition to N are often deficient. Therefore the N deposition is less likely to stimulate forest growth. Sulphur deposition is not likely to increase forest growth in most areas of the temperate zone. On the contrary, S deposition will mostly increase leaching of base cations such as Mg $^{2+}$ and Ca $^{2+}$ , and possibly K. Experiments with artificial acidification together with observations of increased Mg-deficiency in central Europe, indicate that Mg-deficiency might become a problem on sensitive soils exposed to acid deposition. The possibility of Al toxicity caused by increased soil acidity is discussed on the basis of experiments with seedlings of Norway spruce. It is concluded that Al toxicity appears to be unlikely unless the Al concentrations in the soil solution increase to about 20 mg l $^{-1}$ .

Ammonium nitrate as extractant for soil exchangeable cations, exchangeable acidity and aluminum

Abstract: NH4NO3 (1 M) has been used as an extractant for soil exchangeable cations, exchangeable acidity and aluminum. The results obtained using NH4NO3 were identical to those using KC1 and NH4Cl as extractants for the purpose of evaluating soil chemical status. The NH4NO3 extraction has practical analytical advantages.

Attraction of bark beetles (Coleoptera: Scolytidae) to a pheromone trap - Experiment and mathematical models

Abstract: The movement of bark beetles near an attractive pheromone source is described in terms of mathematical models of the diffusion type. To test the models, two release experiments involving 47,000 marked spruce bark beetles [Ips typographus (L.)] were performed. The attractive source was a pheromone trap, surrounded by eight concentric rings with eight passive trap stations on each ring. Captures were recorded every 2–10 minutes for the pheromone trap and once for the passive traps. The models were fitted to the distribution in time of the central pheromone trap catch and to the spatial distribution of catch among the passive traps. The first model that gives a reasonable fit consists of two phases: Phase one—After release the beetles move according to a diffusion process with drift towards the pheromone trap. The strength of the drift is inversely proportional to the distance from the traps. Phase two—those beetles attracted to, but not caught by, the pheromone trap are no longer influenced by the pheromone, and their movement is described by a diffusion process without drift. In phase two we work with a loss of beetles, whereas the experiment seems to indicate that the loss of beetles in phase one is negligible. As a second model, the following modification of phase one is considered: After release the beetles move according to a diffusion process without drift, until they start responding to the pheromone (with constant probability per unit time), whereafter they start moving according to a diffusion process with drift. This study, like other release experiments, shows that the efficiency of the pheromone trap is rather low. What is specific for the present investigation is that we try to explain this low efficiency in terms of dynamic models for insect movement. Two factors seem to contribute: Some beetles do not respond to pheromone at all, and some beetles disappear again after having been close to the pheromone trap. It also seems that the motility of the beetles decreased after they ceased responding to the pheromone. Furthermore, the data lend some support to the hypothesis that flight exercise increases the response of the beetles to pheromone.

Response of a brush-tailed possum population to intensive trapping

Abstract: Three years after a population of brush-tailed possums (Trichosurus vulpecula Kerr) in 100 ha of podocarp/mixed hardwood forest in Westland had been trapped to extinction, the study area had been recolonised and the population density was lowest in the alpine forest (> 600 m) and highest in the forest which bordered improved pasture (< 400 m). Animals dispersed upwards from this low-altitude forest and laterally into the area along the altitude gradient. Few adults entered the area, and immature (8-18 months old) males constituted the largest dispersive class. Sex-specific and age-specific dispersal rates led to an unstable age structure in the post-kill population. A higher proportion of breeding females and good condition in the post-kill population favoured an accelerated recovery of the population in the area.

A post-fire succession in the northern Urewera forests North Island, New Zealand

Abstract: Where fire has destroyed podocarptawa forest in the northern Urewera Ranges, dense pole stands of Leptospermum ericoides are characteristic of the early stages of the succession. Although young Leptospermum stands contain many woody seedlings ( 50 cm and saplings of species other than Leptospermum ericoides, are almost completely absent. Where fire occurred 60–80 years ago, however, Weinmannia racemosa is either the dominant canopy species or is co-dominant with Leptospermum ericoides. The understoreys in these stands are typically open, and woody seedlings (> 50 cm) and saplings are rare. Where localised mortality has occurred in Weinmannia stands, succession is similar to that on recent bum sites, with Leptospermum ericoides the dominant canopy species. Older stands of this type show no evidence of re-invasion by Weinmannia racemosa and few seedlings (> 50 cm) or saplings of other woody species. The absence of regeneration suggests suppression of Wein...

Extreme intraspecific chemical variability in soldier defense secretions of allopatric and sympatric colonies ofLongipeditermes longipes.

Abstract: The chemical defense secretions of major and minor soldiers of over 18 colonies of the primitive glue-squirting nasute termiteLongipeditermes longipes (Isoptera, Termitidae, Nasutitermitinae) were analyzed chormatographically. The colonies, collected from four rainforest sites in peninsular Malaysia, showed monoterpene patterns rich in pinenes and limonene but with few quantitative differences between colonies. In marked contrast, the diterpene chemistry is high variable, and includes tricyclic (trinervitane), tetracyclic (rippertane), bicyclic (secotrinervitane), and a new spirotetracyclic (longipane) skeleton. Three new natural products are included in this remarkable and unprecedented example of structural diversity among different colonies of a single species.

Relationships of bio-climatic zones and lithology with various characteristics of forest soils in Greece

Abstract: Soils derived from a number of different parent materials (lithologies) and developed along a climatic gradient, manifested by the altitudinal succession of natural vegetation zones (Mediterranean, sub-Mediterranean, Mountainous and Pseudoalpine), were sampled throughout mainland Greece.

Chromosome morphology in 4 species of Eucalyptus L. Her.

Abstract: Somatic chromosome studies in 4 species of Eucalyptus viz., E. torelliana F. Muell., E. citriodora Hook., E. camaldulensis Dehn., E. tereticornis Sm. were carried out with a view to determine the similarity or dissimilarity if any, in their chromosome morphology. All the species had 2n=22 very small chromosomes. No significant differences in the chromosome complement of any species were found except in the pair with secondary constriction which was larger. All the 4 species had more or less symmetrical karyotype.

Adhesives from Pinus Radiata Bark Extractives

Abstract: Extracts containing tannins and related polyphenols were obtained from Pinus rudiata bark by extraction with hot water containing small amounts of sodium carbonate and/or sodium sulphite. The extracts had excessive viscosities (< 10 Pa.s) at the concentrations required for adhesive formulation, but this problem was readily overcome by reducing the pH of the extract solution to below 4.5 with acetic acid, adding a small amount of phenol, and heating the mixture. Adhesive performance was best between pH 4.5–6.0, and the bonds were resistant to boiling water. However, joints bonded with early adhesive formulations tended to fail within the adhesive, necessitating some form of adhesive fortification in later formulations. The results obtained with a number of different additives as fortifiers are presented. Softwood plywood which passed the bond quality requirements of the boiling test described in U.S. Product Standard 1-74 was made in the laboratory using these fortified adhesives.

Mycoplasma and allied diseases of forest trees in India and vector-host-pathogen interactions.

Abstract: Mycoplasma and allied diseases of forest trees in India have been described,mlo disease has been intensively studied in ‘sandal’ (Santalum album L.). Other forest trees showing typicalmlo etiology are ‘toon’(Toona ciliata), Acacia catechu, A. mearnsii, Eucalyptus grandis andE. tereticornis. Disease symptoms, collateral hosts, transmission tests with possible insect vectors and vector biology have been described for sandal spike disease. Reasons for contradictory results for sandal spike vectors have been discussed and possible lines of vector search for woody plants are described. Vector-host-pathogen interactions have been reviewed. During the feeding process, phloem cells are punctured, torn and disturbed by vectors. The hypertrophy of the plant cells around the site of puncture is caused by the action of injected salivary secretion. Vector borne procaryotic disease pathogens multiply within the vectors and circulate through a sequence of tissues and organs of vectors when the latent period of pathogen is long. These initiate both harmful and beneficial interactions within the vector. Possible lines of research to fill up the existing lucunae for insect vectors of mycoplasma and allied diseases of forest trees and vector-host-pathogen interactions have been discussed.

Brush-tailed possum (Trichosurus vulpecula) movements about an erosion-control planting of poplars

Abstract: Live-trapping and radio-tracking were used to monitor the movements of brush-tailed possums in and around an erosion-control planting of poplars. Possums' use of the planted area was monitored by traffic counters and by marking (with Rhodamine B dye) possums which climbed the poplars. The extent of browse damage to the poplars was also recorded. Over a period of 20 months, 358 individuals were trapped, marked, and released, and 50 were fitted with radio transmitter collars. The study area was mapped into nine 100-m-wide annular zones radiating out from the focus, Zone 0, which contained the poplars. Seventy percent of possums assigned to Zone 1 were caught in Zone 0, but only 24%, 5%, and 0% assigned to Zones 2, 3, and 4–8 respectively were caught in Zone 0. Trapping and radio-tracking revealed no increase in the use of the planted area during the spring flush although the poplars were being damaged. Traces of Rhodamine B dye on the possums showed that 87% of animals caught in Zone 0 had visited ...

Pinus radiata needle trace studies: fine structure of immature sieve cells in the primary phloem

Abstract: The development of sieve cells in the primary phloem of Pinus radiata needle traces was followed with the electron microscope. Sieve cell precursors have thin walls, a more or less spherical nucleus containing small evenly scattered masses of condensed chromatin, dense cytoplasm and several small vacuoles. Among the most obvious early changes are increase in cell size, condensation of chromatin, nuclear lobing, changes in the location and orientation of microtubules, modifications in the ER, increase in vacuolar size, increase in wall thickness, and sieve pore development. Later in the development of sieve cells and prior to their maturation the nucleus with greatly condensed chromatin and disrupted envelope assumes a necrotic appearance, and most of the cytoplasmic structures disappear with the exception of mitochondria, plastids and elements of ER. Callose and P-proteins are not seen at any stage in the development of sieve cells.

Microfilaments in the Phloem of Pinus radiata Cotyledons

Abstract: Differentiating sieve cells and neighbouring parenchymatous elements of Pinus radiata cotyledons contain a large number of bundles of microfilaments, the majority of which occur peripherally, Microfilament bundles are seen in association with the plasmalemma and several other cell structures. Sometimes a filament bundle was seen in association with more than one cell structure.