5/10/89. The lefthand side was prepared at the commencement of the experiment on the 27{1/89; the righthand side was prepared at the time the plot was sown,
6.3 Methods
6.3.1 Experimental Design
The experiment was established as a blocked split plot design. Each site represented a block. Within each block 36 plots were created, comprising three replicates of 12 times of sowing. Each plot was split twice; in the first instance into two seedbed preparation times and in the second into 1 m2 sub-plots onto which were sown the four differing seedlots. Each plot, comprised of the eight sub-plots, was surrounded by a one metre buffer (Figure 6.2,). The first seed bed preparation time was two weeks prior to the start of the experiment. At this time the vegetation was removed from the whole of the site and the soil cultivated. At the Mount Connection site this was done using a John Deere Loader and at the Bicheno site vegetation was removed by hand and the block rotary hoed. The seedbed on the other half of each plot was given a second preparation by hand hoeing immediately prior to the sowing of seed (Plate 6.3). Each site was surrounded by a 1.3 m high ringlock fence, with a single strand electric wire on an "outrigger'' 20 em below the top of the fence, to exclude browsing animals.
Seed was applied to each sub-plot using a salt shaker with enlarged holes. Seed was not sown on the outer 10 em of each sub-plot but was spread uniformly over the remainder. 8.4g of the M38 E. delegatensis� 6.7g of the M36 E. delegatensis
and 2.5g of the E. amygdalina was sown, corresponding to 420±60, 900± 20 and 210± 25, seeds respectively. Seed was sown on twelve dates spread over the twelve months following the initial preparation of the seedbed at each site. The times of sowing were most heavily concentrated in spring and autumn when it was presumed conditions for germination would be changing the most rapidly. The sowing dates are given in Fig. 6.2.
6.3 2 Data Collection
Censuses of seedlings were conducted approximately fortnightly for the first twelve months and less frequently over the next fourteen months. Detailed demographic data were collected for the M36 E. delegatensis seedlot, both stratified and unstratified, and the E. amygdalina seedlot on seedbeds prepared immediately prior to sowing. For these treatments, at each census a colour coded skewer was placed next to each seedling observed since the last scoring (Plate 6.4a&b). In this way recruitment and mortality of 25 cohorts were recorded. Germination of seeds sown on to seedbeds prepared at the commencement of the
experiment only, and germination of the M38 E. delegatensis seedlot were
recorded in this way until 1 8/9/89, and then on the 12/4/90 the number of
seedlings present was recorded. At all censuses, seedlings were considered germinated when any evidence of cotyledon emergence was detected. Seedlings were considered dead when 100% of above ground biomass was necrotic.
Seedlings recorded as dead were physically removed from the plot if any material remained. Thus, any dead seedlings discovered on a plot at the time of scoring without an adjacent marker were presumed to have germinated and died since the last scoring and allotted the current scoring date as the germination date. Height data were collected on the 18/5/89, 13/1 1/89;12/4/90, 29/10/90 and 10/4/91 (only B125 site for last two scoring dates). The height of ten randomly selected
seedlings from each age cohort was measured at each scoring.
Seasonal variation in insect predation of seed was measured by laying out 10
baits at each time of sowing. Each bait consisted of a 9 em diameter plastic petri
dish in which two offset entrances had been cut (Plate 6.5). Fifteen apparently
viable seeds were placed in each petri dish. The proportion of seeds taken in the first two weeks was recorded
At the Bicheno site, daily temperature maxima and minima, and half hourly recordings of wind speed and rainfall were recorded from the 22/3/89 till 22/6/90
using electronic sensors and a STARLOG® datalogger (Plate 6.6). Equipment
failure meant that only the latter two parameters were recorded at the Mount Connection site. Equipment was calibrated before and after installation at the Meteor�logical Bureau weather station at Battery Point, Hobart. Additionally, at each visit to the sites, maximum and minimum temperatures from a max.-min. thermometer, rainfall from a rain-gauge since the last visit, and soil water potential at time of visiting using a dewpoint microvoltmeter (Wescor 33-RT),
were recorded. Weather readings were taken within 10 metres of experimental
plots. Soil samples for soil moisture estimates were collected from randomly located positions within the experimental plots.
Temperature estimates for the Mount Connection site were made by using a nearby, and climatically similar meteorological station at Lake Leake (Fig. 6. 1).
This station, however, only collected data from October 1989 onwards and it was necessary to establish the r'elationship between this station and the next most comparable East Coast climatic station at Storey's Creek (Fig. 6. 1 ) to complete the coverage of temperature data.
Plate 6.4. Seedlings were