C. J. Burrows

Distribution of subfossil forest remains, eastern South Island, New Zealand

Abstract The distnbutiOn of subfossil forest remains collected in the eastern part of the South Island of New Zealand 15 outlined. Surface logs, buried wood and charcoals, wind–throw dimples and buried podsols provide convincing evillence of a former widespread forest cover over now–treeless tracts of the South Island. Most of the Wood and charcoals discovered have been identitied, and collecting sites plotted on a map. A broad distinction can be drawn between probable podocarp and beech forest areas.Radiocarbon dates for a number of wood and charcoal samples are presented and most of these point to forest destruction by fire since the advent of man In New Zealand within the last 1.000 years or so.Older dates presented obviously lie outside the period of human occupatIOn of New Zealand and the fires that produced these ancient charcoah are assumed to have originated from mltural causes. The pre~ent vegetallon on former forest sites and the distribution of forest remains in relation to existing forest are ...

An analysis of the evidence for climatic change in New Zealand in the last thousand years: Evidence from diverse natural phenomena and from instrumental records

Abstract An analysis is made of the diverse evidence for climatic variation in New Zealand in the last 1000 years. After a brief account of the pressure systems and circulation pattern near New Zealand, indirect evidence from a range of phenomena which have been influenced by climate is discussed. The climatological evidence derived from instrumental records and observations is then considered, with emphasis on precipitation and temperature. Little reliance may be placed on some evidence which is weak, equivocal, difficult to interpret or difficult to place in time. The most reliable evidence is summarized in two overlapping time periods, 1000 A.D. to 1900 A.D. and 1850 A.D. to the present. Dated glacial episodes, speleothem palaeotemperatures and tree palaeotemperatures demonstrate that there have been many fluctuations of temperature in the last 1000 years, over a range of not much more than ± 0.5°C. The high temperatures since about 1950 A.D. have probably not been exceeded. Expansion of glaciers in th...

Germination behaviour of seeds of the New Zealand species Fuchsia excorticata, Griselinia littoralis, Macropiper excelsum, and Melicytus ramiflorus

Abstract Germination rates, percentage germination success, and phenomena related to germination delay for two provenances each of seeds from freshly collected fruit of Fuchsia excorticata, Macropiper excelsum, and Melicytus ramiflorus, and one provenance of Griselinia littoralis were determined. Normally the seeds of all four species are bird-dispersed. The experimental treatments simulated natural conditions that the seeds might experience after dispersal (well-lit; in the dark; in the fleshy pericarp tissues; on soil). A tetrazolium viability test was also performed. In the standard (cleaned, moist, well-lit) treatment, seeds of each of these species germinated rapidly in summer — early autumn, with high success. The dark treatment seeds of Fuchsia and Griselinia germinated more slowly than those in the standard treatment and the success was lower. Seeds surrounded by pericarp tissues either did not germinate (Griselinia), or germinated slowly, with low success (the other three species). Fewer seeds ge...

Fruit types and seed dispersal modes of woody plants in Ahuriri Summit Bush, Port Hills, western Banks Peninsula, Canterbury, New Zealand

Abstract In Ahuriri Summit Bush Scenic Reserve, a 5 ha area of mixed angiosperm-podocarp forest, are 56 wild woody plant species, including five adventives. Lists are given for fruit types, seed numbers per fruit, fruit sizes, degree of fleshiness of the pericarp or accessory tissues of ripe fruit, fruit colours, and dispersal modes for the seeds. Of the 22 tree species, 86% have fruit with fleshy pericarps or accessory tissues; corresponding values for the 20 shrub species are 80%, and for the 14 vine species 50%. Most of these fleshy fruit (87%) are between 2 and 8 mm in diameter. The fruit of only four species exceed 10 mm in diameter. The most frequent fleshy fruit colours are black to dark purplish-black (40%), or red (25%). Some fruit are purple, blue, orange, yellow, or white. It is assumed that birds eat the fruit and disperse the seeds of all fleshy-fruited species (and the seeds of Pittosporum spp.). Seeds of the dry-fruited species are dispersed by wind or gravity alone. One or more of kereru (...

A pollen diagram and macrofossils from Kettlehole Bog Cass, South Island, New Zealand

Abstract A long pollen diagram and a rich flora of macrofossils from a mire at Cass are used to interpret the vegetation changes and environmental changes since the end of the last large advance of the Waimakariri Glacier. The trend of the sequence is similar to those described by other workers for the same area, for Westland, and for Southland and Otago. It is proposed that the boundary between the cold Otiran glacial stage and the warm AranUlan stage should be placed where fossils and sediments indicate warming, i.e., at the transition from a Dacrydium Coprosma environment to a Phyllocladus environment. There is good evidence tor the existence of a wetter and milder climate than at present for part of the Aranuian period.

The seeds always know best

Abstract The New Zealand woody plant flora differs from those of temperate Northern Hemisphere regions by having: a very high proportion (70% cf. 17-47%) of tree species (but lower proportions of shrubs and vines) with fleshy fruit; a relatively low proportion of seeds with overwinter dormancy; and relatively few species that form long-term (i.e., 1 year or longer) seed banks. These differences are ascribed to the effects of: the phylogenetic history of the respective floras, with most tree species in New Zealand being closely related to tropical taxa; the evolution here, under isolation, of a small but effective group of seed-dispersing birds; and the selective influences of much more severe Quaternary climatic conditions in the north, affecting both the drying of fruit and seeds and seed dormancy properties. As a consequence, a New Zealand perspective on germination delay phenomena in seeds must differ, somewhat, from the Northern Hemisphere bias that is so evident in the plant physiological and ecologi...

Aranuian vegetation history of the Arrowsmith Range, Canterbury I. Pollen diagrams, plant macrofossils, and buried soils from Prospect Hill

Abstract Two pollen analyses are described from sediments in the mires at Quagmire Tarn and Windy Tarn, on the Prospect Hill plateau, upper Rakaia Valley, Canterbury. The sediments span most of the Aranuian period. Macrofossils from Quagmire Tarn supplement the pollen data. The vegetation sequences from the two sites are generally similar, although the Windy Tarn sequence begins later than that of Quagmire Tarn and differs in some details. The post-Otiran dominant pollen assemblages at Quagmire Tarn are: Poaceae and Coprosma (beginning probably about 13 000 yr B.P.) → Halocarpus (about 10000 yr B.P.) → { Phyllocladus and “Podocarpus” (just after 10 000 yr B.P.) → Nothofagus menziesii and N. fusca-type (about 2000 yr B.P.) → Poaceae, Cyperaceae, Asteraceae, and Apiaceae (beginning about 860 yr B.P.). Changes in the sediments, pollen assemblages, and macrofossils are correlated with the early Aranuian glacial history of the region, with subsequent climatic changes, and with the fire history. The fire histor...

Germination behaviour of the seeds of six New Zealand woody plant species

Abstract Germination rates, percentage germination success, and phenomena related to germination delay were determined for one provenance each of seeds from freshly-collected fruit (summer-autumn) of Dodonaea viscosa, Hedycarya arborea, Pennantia corymbosa, Pseudowintera colorata, Rhopalostylis sapida, and Streblus heterophyllus. Dodonaea has wind-dispersed fruit; the fruit of the others are eaten by birds which disperse the seeds. The experimental treatments simulated natural conditions that the seeds might experience after dispersal. In the standard treatment (seeds cleaned, moist, well-lit) each species behaved differently. Streblus seeds began to germinate a few weeks after the start of the experiment and germination continued at a gradual, even rate through the winter. Hedycarya seeds began to germinate within three months and underwent a germination flush in mid-winter, then a levelling off before the last few seeds germinated in spring. A few Dodonaea seeds germinated in autumn and a few more in la...

Moraines of the upper rakaia valley

Abstract Moraines in the Upper Rakaia Valley record glacial activity at intervals between about 12,000 yr BP and the last few decades. The Lake Stream and Jagged Stream advances occurred probably between 11,900 and 10,000 yr BP and extended 29 km and 21 km, respectively, from the valley head. One or more renewed advances occurred more than 4,500 yr BP and gave rise to the complex of drift near the Reischek River only 9 km from the valley head. Another phase of glacial activity began 4,500 yr BP (at least) and constructed moraines on the Meins Knob ridge, but no date is available for its end. Further advances formed a complex of moraines near the Lyell Hut more than 1,000 years ago. The most recent series of glacial events formed the Whitcombe group of moraines within the last few centuries.

Radiocarbon dates from Late Quaternary deposits in the Cass district, Canterbury, New Zealand

Abstract Radiocarbon dates from the Cass district provide estimates for: the end of the Otira Glaciation (a minimum age of 13 750 ± 200 yr B.P.); aggradation episodes (about 7550 ± 150 yr B.P. and about 2730 ± 60 yr B.P.); fires .about 2730 ± 60 yr B.P. and 531 ± 57 yr B.P.); existence of, or change in, prevailing vegetation (especially 13 750 ± 200 yr B.P. for early Aranuian grassland; 6620 ± 100 yr B.P. for the transition from mixed Phyllocladus and podocarp forest dominance to Nothofagus forest dominance; 531 ± 57 yr B.P. for widespread forest destruction by fire); and gross mire sedimentation rates in Kettlehole Bog and Remus Swamp.