Nothofagus Species Research Articles

Beziehungen zwischen mikroklimatischen Faktoren und natürlicher Verjüngung araukano-patagonischer Nothofagus-Arten

Summary Climatic conditions under which Nothofagus species regenerate spontaneously were investigated. For this purpose, temperature and relative humidity of the air in the herb layers of numerous habitats in Southern Chile were recorded between the latitudes 37°30′ and 42°30′. In the North of the above region, summer climate is determined by radiation and irradiation processes, strongly modified by topographic factors. The influence of maritime winds increases southward, and for these reasons, the mosaic of microclimates and plant communities manifold in the North, become more simple to the South Daily temperature fluctuations were used to appraise continentality of the stands. To caracterize the thermic requirements of the species, temperature averages of complete days (from 0 to 24 hrs.) and of the warmer half-day (from 10 to 20 hrs.) were used. The latter values in relation to saturation deficit of the air were used to describe xerothermic conditions of the regeneration habitats The above values are used to determine ranges of tolerance of the different species. To characterize optimal conditions of the latter, daily average temperature curves were calculated. By means of a statistical analysis, probability of the occurrence of nocturnal freezing in the summer season was determined for typical habitats of the species Results are discussed, relating them with climatic and fitogeographic aspects: Nothofagus obliqua proved to be extraordinarily thermophilic with a certain continental tendency. This species is characteristic for occasional dry zones, even invading the region of sclerophyllous forests, but it does not reach up to the litoral zone. The regeneration habitats of Nothofagus antarctica present strong daily amplitudes and therefore, are considered as relatively continental. Nocturnal freezings are frequently observed during the summer. Similar to the former species, it also supports considerable dryness. Accordingly with these characteristics, N. antartica reaches up to the Patagonic grasslands. Nothofagus procera is a tree of the subandine region. This species, with respect to its climatic requirements, occupies an intermediate place. In relation to continentality, it coincides with N. obliqua , and relative to its thermic requirements is comparable to N. dombeyi . Preferring habitats with deep soils, in these conditions the tree even supports considerable deficits of air saturation. N. procera shows greater affinity with evergreen species than the other decidous Nothofagus . In the “typical habitat” of this tree, the frequency of freezings is relatively low, due to nocturnal warm air currents. Nothofagus pumilio , as N. antarctica , is an andine, subantarctic species, although it displays less marked continentality. Its ecological range is clearly displaced towards low temperatures. It requires rather high relative humidity and regenerates with preference in shadowy sites. Compared with the decidous Nothofagus mentioned before, following evergreen species present a more distinct tendency for oceanic climate. Nothofagus dombeyi , which possesses the greatest ecological range, occurs optimally on humid slopes of the West side of the Andes. Nevertheless, in an oceanic climate, it is also able to propagate in sporadically dry and warm stands The range of tolerance of Nothofagus nitida is more reduced than the above species. It is the only tree not present at the Eastern side of the Andes. This species regenerates in stands with constant humidity and intermediate thermic conditions. It shows a special adaptation to wet soils, and this property is essentially the ecological difference between this species and N. dombeyi . Nothofagus betuloides forms the “maritime timberline” in Southern Patagonia. Their habitats are characterized by relatively low temperatures, reduced thermic fluctuations and strong winds. Relative to their climatical ecological range, it is evidently inferior to that of N dombeyi and superior to N. nitida

Montane-Alpine vegetation near Lake Shirley, Fiordland 2. Additions and corrections

Summary Ecological and floristic studies of alpine and montane vegetation near Lake Shirley, Fiordland, have been supplemented by further observations during a subsequent visit. Futher communities are described and additional comments are made on others. Sampling of stands near upper forest limits shows that vegetation patterns at and above this level are complex, and this is discussed chiefly in relation to the distribution of Chionochloa and Nothofagus species. Comments are made on local distribution patterns and on data from other published sources relating to the influence of browsing mammals. Additions and corrections make the list of vascular plants from the area substantially complete, with a total of 202 species and 2 hybrids.

Breeding systems in New Zealand grasses

Summary Flowering seasons in C. rigida occur most commonly at three-year intervals, and for the period 1948/49 to 1965/66 are coincident with those in species of Nothofagus. The relationship between flowering and burning, tillering, and autumn initiation of inflorescences is discussed.

The extractives of New Zealand Nothofagus species

The extractives of New Zealand Nothofagus species

The biology of Nothofagus

Dr R. Melville (Royal Botanic Gardens, Kew) I believe that most species of Nothofagus are adapted to warm climates. Only N. antarctica is quite hardy in cultivation in Britain and a few others, like N. cera , can be grown in southern England. The deciduous habit, as found in N. antarctica and N. gunnii , is probably a response to cold climates and short winter days. The m ajority of Nothfagus spp. are evergreen and w arm th loving. This is consistent with a subtropical to tropical centre of dispersal for the genus. If this is accepted, then the centre of origin should be looked for in New Guinea and New Caledonia, rather than in cool tem perate regions.

Transport of Driftwood from South America to Tasmania and Macquarie Island

IN February 1955, a log about 10 ft. long and 5 ft. in girth was found washed up on a sandy beach just inside Port Davey harbour on Tasmania's south-west coast. It was lying between two logs of Huon Pine (Dacrydium franklinii Hook f.), an endemic conifer of Tasmania. Unlike these logs which were well covered with marine growth it was free from such growth although the surface was ‘woolly’ with many pebbles embedded in it. The ends of the log were sawn and one end grooved for towing by a wire rope. The wood was identified from its anatomy as a species of Nothofagus, which genus is represented in Tasmania, the south-eastern portion of the Australian mainland, New Zealand, New Guinea, New Caledonia and South America1. Anatomically the genus can be divided into two easily distinguishable groups, the one covering the species of New Guinea and New Caledonia, and the other the remaining species2. The log in question was derived from the second of these two groups and, because of the presence of spiral thickenings in the vessel elements, its specific identity could be narrowed down to one of three possibilities, namely, N. moorei (F. Muell.) Krasser of northern New South Wales and south-eastern Queensland, N. pumilio (Poepp. and Endl.) Krasser and N. obliqua (Mirb.) Oerst. from South America. The spiral thickenings in N. moorei differ from those of the two South American species; those of the unknown resembled the thickenings observed in the South American species. Both N. pumilio and N. obliqua are restricted to South America, the former occurring from Tierra del Fuego north to latitude 36° S. on the western side of the Andes. N. pumilio, N. antarctica (Forst.) Oerst. and N. betuloides (Mirb.) Oerst. are logged commercially in the southernmost tip of the continent3. All the anatomical evidence thus pointed to a South American origin of the log in question although this conclusion met with some initial opposition.

The Comparative Morphology of the Fagaceae I. The Genus Nothofagus

1. Anatomical features, not hitherto reported, found to characterize the foliar organs, expecially of the evergreen species of the genus Nothofagus, include: (a) heavy cuticularization; (b) lignification of the cells of both the epidermal and the hypodermal tissues, the latter occasionally several layers in extent; (c) grouping of hypodermal cells into ribs in association with the vascular tissues; and (d) occurrence in the larger-leaved species of scalariform-perforated transfusion elements bordering, or in the immediate vicinity of, the sclerenchyma-sheathed veins. 2. Internal morphological characters in the flowers and fruits, which have been determined to be sufficiently constant in nature to supplement external morphological characters in a definition of this genus, include: (a) the occurrence of generally heavy, though variable, amounts of sclerotinization both of the ovary wall and of the cupular valves; (b) a distinctive type of origin and vascularization of the placentae; (c) the occurrence of di...