Phenology of Eucalyptus marginata on Sites Infested With Phytophthora cinnamomi

Abstract

The phenology of Eucalyptus marginata (jarrah) was followed at three sites, Churchmans, Karnet and Ross, in the high rainfall zone of the jarrah forest for a minimum of 3 years. On each site, trees growing in an area infested with the soil-borne, pathogenic fungus Phytophthora cinnamomi (dieback area) were compared with trees of similar diameter in the adjacent, uninfested forest (healthy area). Phenology of jarrah on these dieback sites did not follow a consistent pattern. In the dieback area at Churchmans, the cambium was active more often, and trees had young leaves in their crown more frequently than trees in the healthy area, while at Karnet the reverse occurred. This is consistent with growth measurements. At Ross, in the dieback area, the cambium was active less often but young leaves were seen more frequently than in trees in the healthy area. The trees did not flower every year. At Ross flowering started in early October while at Karnet and Churchmans it started at least 1 month later. New leaves were produced intermittently during autumn and winter while the main leaf flush occurred in spring and summer. Data from all years showed that the leaf flush started earlier at Ross than at Karnet and Churchmans. The cambium was intermittently active throughout the year with most trees growing in late autumn, winter and spring. Observations of stem growth following unseasonable summer rainfall suggest that cambial activity is triggered by high, surface soil moisture, but only if soil aeration is adequate. It is unlikely that timing of the main leaf flush and flowering are determined solely by temperature, soil moisture or photoperiod.

Recruitment limitation in dry sclerophyll forests: Regeneration requirements and potential density-dependent effects in Eucalyptus tricarpa (L.A.S. Johnson) L.A.S. Johnson & K.D. Hill (Myrtaceae)

“…In long-lived species the increased competition for resources generated by increased density tends to minimize resource allocation to growth rather than reproduction (Sugiyama & Bazzaz 1998). In eucalypts this may be illustrated by the response of several growth-related traits after flowering or seed set; delayed vegetative growth (House 1997), reduced cambial growth (Davison & Tay 1989) and reduced leaf production (Pook 1984).…”

Provenance variation of ecologically important traits of forest trees: implications for restoration

“…In a study of flowering at sites within the northern Jarrah forest, maximal flowering time was found to vary from October to January, occurring earliest in the most southerly populations and later in populations further north (Davison & Tay 1989). Furthermore, flowering in the Jarrahdale division was found to be maximal in November–December, which coincides with the measurement of this trial (Davison & Tay 1989).…”

Aridity drives coordinated trait shifts but not decreased trait variance across the geographic range of eight Australian trees

“…We selected terminal branches (typically c. 1 mm in diameter, see Table S2 for details) with intact 'mature' leaves (i.e. fully expanded, not soft green new growth), although most of the study species flush sporadically throughout the year (Davison & Tay, 1989;Heatwole et al, 1997) so it was not possible to perfectly control for leaf age. Sampling periods (November in Western Australia and February in Tasmania) avoided large leaf flush events for all species with the exception of Corymbia calophylla at two of its five sample sites.…”