REGENERATION OF FLORA FOLLOWING TIMBER HARVESTING IN THE WET FORESTS OF THE OTWAY RANGES, VICTORIA

Prepared by S.G. Harris for the Department of Sustainability and Environment Victoria

Parks and Forests Report Series 04-2 May 2004 © The State of Victoria, Department of Sustainability and Environment, 2004

Published by the Department of Sustainability and Environment PO Box 500, East Melbourne Victoria 3002, Australia

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The National Library of Australia Cataloguing-in-Publication entry:

Harris, S. G. (Susan Gaye). Regeneration of flora following timber harvesting in the wet forests of the Otway Ranges, Victoria.

ISSN 1449-2067 ISBN 1 74106 860 6.

1. Logging - Environmental aspects - Victoria - Otway Range. 2. Forest plants - Victoria. 3. Otway Range (Vic.). I. Victoria. Dept. of Sustainability and Environment. II. Title. (Series : Parks and Forests Report series ; 04-2).

634.98099457

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Cover photographs: 1. Field assessment on West Barham coupe, 17 years post-harvest— S.G. Harris, 2. Young tree fern growing on cut stump, West Barham coupe, 17 years post- harvest —S.G. Harris. SUMMARY

A study of the impact of timber harvesting on vegetation of the wet forests of the Otway Ranges was established in 1983. Permanent vegetation quadrats were established on six coupes prior to timber harvesting to monitor regeneration following harvesting and identify the effects of harvesting on understorey species. The floristic composition of two coupes in the Redwater Track and West Barham areas were re-assessed in 2001. This paper describes the vegetation on these coupes prior to harvesting and records the development of the regenerating vegetation post-harvest to 16 and 17 years respectively.

The pattern of floristic response to the effects of timber harvesting was similar on both sites. A large number of colonisers previously unrecorded on the coupes appeared soon after harvesting. Apart from the shrub Ozothamnus ferrugineus, they were of short life span and declined in abundance within the first few years. Non-native species were insignificant in the long-term development of the vegetation.

The majority of understorey shrub and tree species regenerated well after timber harvesting, usually via prolific germination of soil-stored seed. There was one main period of germination that began soon after the completion of the treatment of the coupe for eucalypt regeneration. Shrub and tree species became dominant at an early age. The development of essentially single-aged vegetation for shrub and tree species that regenerate via soil-stored seed was apparent.

Although soil-stored seed accounted for the bulk of regeneration, vegetative regrowth from surviving rootstock was important for the shrubs, Olearia argophylla, Bedfordia arborescens, Hedycarya angustifolia and Coprosma quadrifida as well as the tree fern Dicksonia antarctica and some ground ferns. All these resprouting species declined in frequency on the Redwater coupe after harvesting. In contrast, on the West Barham coupe, greater seedling recruitment of O. argophylla, H. angustifolia and Tasmannia lanceolata lead to an increase in frequency of these species 17 years post- harvest.

Ferns were a significant feature of the vegetation of both coupes prior to harvesting. Most fern species, especially epiphytic ferns, were adversely affected by timber harvesting. However, some of the more robust epiphytic species, such as Microsorum pustulatum and Rumohra adiantiformis were actively recolonising the coupes at 16/17 years post-harvest.

The number of Dicksonia antarctica tree fern trunks declined on both coupes, with less than one third of pre-harvest levels being recorded on the Redwater coupe after 16 years. However at the 16/17 year assessment, many young plants and sporelings of D. antarctica were present on quadrats on both coupes indicating that significant recruitment was occurring and that numbers should continue to increase over time. The increased shade and shelter on the coupes 16/17 years after harvesting is conducive to fern recruitment. Epiphytic fern recovery is linked with that of tree ferns as tree ferns provide substrate for growth of epiphytic ferns. Streamside vegetation reserves adjacent to the timber harvesting coupes very likely provided an important refuge for fern populations from which recolonisation of the coupes was possible as microenvironment conditions improved.

iii CONTENTS

SUMMARY ...... iii

1 INTRODUCTION ...... 1

2 REDWATER TRACK COUPE ...... 2 2.1 Study Area...... 2 2.1.1 Harvesting and regeneration treatment ...... 3 2.2 Methods ...... 3 2.2.1 Pre-harvest assessment ...... 3 2.2.2 Post-harvest assessment ...... 4 2.2.3 Eucalypt germination...... 5 2.2.4 Data analysis ...... 5 2.3 Results ...... 7 2.3.1 Vegetation before timber harvesting...... 7 2.3.2 Vegetation after timber harvesting ...... 9 Species richness...... 9 Community composition...... 10 Temporal pattern of early species establishment ...... 14 Herbs ...... 14 Ferns...... 16 Understorey trees and shrubs ...... 18 Eucalypt regeneration...... 23 Nothofagus cunninghamii...... 25 Changes over time ...... 26 3 WEST BARHAM COUPE...... 27 3.1 Study Area...... 27 3.1.1 Harvesting and regeneration treatment ...... 27 3.2 Methods ...... 28 3.2.1 Pre-harvest assessment ...... 28 3.2.2 Post-harvest assessment ...... 28 3.2.3 Data analysis ...... 29 3.3 Results ...... 30 3.3.1 Vegetation before timber harvesting...... 30 3.3.2 Vegetation after timber harvesting ...... 32 Species richness...... 32 Community composition...... 33 Temporal pattern of early species establishment ...... 37 Herbs ...... 37 Ferns...... 38 Understorey trees and shrubs ...... 40 Eucalypt regeneration...... 44 Changes over time ...... 46 4 DISCUSSION ...... 47 Regeneration via seed...... 47 Vegetative regrowth ...... 49 Understorey islands ...... 49 Ferns ...... 50 Browsing...... 51 Eucalypt regeneration ...... 51 Timber harvesting debris...... 52 Eucalypt species composition...... 52 Eucalypt growth rate...... 53 Nothofagus cunninghamii ...... 53 Weed species ...... 54 Log landings and snig tracks...... 54 Structural changes...... 54 ACKNOWLEDGEMENTS...... 55

REFERENCES ...... 56

APPENDIX 1 PERMANENT QUADRAT DATA FOR REDWATER TRACK COUPE...... 58

APPENDIX 2 PERMANENT QUADRAT DATA FOR WEST BARHAM COUPE ...... 61

List of Tables and Figures

Figure 2.1 Location of the Redwater Track and West Barham coupes in Otway State Forest...... 2 Figure 2.2 Frequency distribution of eucalypt DBH prior to harvesting on the Redwater Track coupe ...... 9 Figure 2.3 NMDS ordination in 2D (stress=0.193) of frequency of occurrence data from Redwater Track coupe with fitted vectors...... 10 Figure 2.4 NMDS ordination in 2D (stress=0.210) of cover data from Redwater Track coupe...... 11 Table 2.1 ANOSIM R values for each pair of age classes for the Redwater Track coupe frequency of occurrence data ...... 11 Table 2.2 Species for which permutation tests suggested a significant difference in frequency of occurrence between pre-harvest and year 2 ...... 12 Table 2.3 Species for which permutation tests suggested a significant difference in frequency of occurrence between year 2 and year 16 post-harvest...... 13 Table 2.4 Species for which permutation tests suggested a significant difference in frequency of occurrence between pre-harvest and 16 years post-harvest ...... 13 Table 2.5 Species for which permutation tests suggested a significant difference in mean cover between pre-harvest and 16 years post-harvest ...... 14 Figure 2.5 Number of species in each plant lifeform group on the Redwater Track coupe pre- and post-harvesting ...... 15 Figure 2.6 Percentage frequency of occurrence in quadrats of selected plant species on the Redwater Track coupe pre- and post-harvesting ...... 15 Figure 2.7 Number of Dicksonia antarctica tree ferns recorded in 19 quadrats in each length class pre-harvest and 16 years post-harvesting on the Redwater Track coupe ...... 17 Figure 2.8 Tree fern recruitment on rotting log, 16 years post-harvest, Redwater coupe ...... 18 Table 2.6 Mean number (and standard deviation) of plants of seedling origin per m2 for tree and shrub species recorded post-harvesting on the Redwater Track coupe...... 19 Figure 2.9 Seedling regeneration at 1 year post-harvest (on quadrat 9) ...... 20 Table 2.7 Total number of seedlings on different seedbed types one year post-harvesting ...... 22 Table 2.8 Residuals from the Pearson chi-square analysis ...... 22 Figure 2.10 Pomaderris aspera on burnt seedbed, 1 year post-harvest, Redwater coupe...... 23 Table 2.9 Means of log transformed eucalypt seedling height per m2 on three seedbed types one year post-harvest ...... 23

v Figure 2.11 Average number of eucalypt seedlings per sub-plot since sowing on 25 March 1985, Redwater Track coupe ...... 24 Figure 2.12 Frequency distribution of eucalypt DBH 16 years post-harvest on the Redwater Track coupe ...... 25 Figure 2.13 Redwater coupe (near quadrat 9): after regeneration burn (A); 1 year post-harvest (B); and 16 years post-harvest (C)...... 26 Figure 3.1 Loading of sawlogs on the log landing, West Barham coupe...... 28 Figure 3.2 Frequency distribution of Eucalyptus regnans DBH prior to harvesting on the West Barham coupe ...... 32 Figure 3.3 Number of species in each plant lifeform group pre- and post-harvesting, West Barham coupe ...... 33 Figure 3.4 NMDS ordination in 2D (stress=0.117) of vegetation frequency data recorded in the West Barham coupe...... 33 Table 3.1 ANOSIM R values for each pair of age classes for the West Barham coupe frequency data ...... 34 Table 3.2 Species for which permutation tests suggested a significant difference in percentage frequency of occurrence on quadrats between pre-harvest and year 2, West Barham coupe...... 35 Table 3.3 Species for which permutation tests suggested a significant difference in percentage frequency of occurrence on quadrats between year 2 and year 17, West Barham coupe...... 36 Table 3.4 Species for which permutation tests suggested a significant difference in percentage frequency of occurrence on quadrats between year 17 and pre-harvest, West Barham coupe...... 37 Figure 3.5 Percentage frequency of occurrence on quadrats of selected plant species on the West Barham coupe pre-and post-harvesting ...... 38 Figure 3.6 Young tree fern growing on cut stump, West Barham coupe ...... 39 Figure 3.7 Frequency distribution of tree fern height (m) on quadrats in the West Barham coupe, 17 years after harvesting...... 40 Table 3.5 Mean number of plants of seedling origin per m2 (and standard deviation) for shrub and tree species recorded on sub-plots post-harvesting, West Barham coupe .....41 Table 3.6 Mean maximum height of seedlings of woody plants and Senecio linearifolius assessed at 2 and 3 years, and mean height 17 years post-harvesting, West Barham coupe ...... 42 Table 3.7 Mean number of understorey shrub and tree seedlings for each seedbed class, assessed 2 years post-harvesting...... 43 Figure 3.8 Frequency distribution of eucalypt DBH 17 years post-harvest on the West Barham coupe ...... 44 Table 3.8 Mean number of eucalypt seedlings on each seedbed type within each overwood shade class assessed 2 years post-harvesting...... 45 Table 3.9 Mean heights of eucalypt seedlings as influenced by seedbed (bare soil seedbed types only) and overwood shade, assessed two years post-harvesting ...... 45 Figure 3.9 West Barham coupe (looking along transect 5 to the edge of the coupe): immediately after harvesting but prior to mechanical pushing operation (A); 1 year post-harvest (B); 2 years post-harvest (C); and 17 years post-harvest (D) ...... 46 Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria 1

1 INTRODUCTION

The environmental impact of hardwood timber harvesting on the Otway forests has been the subject of ongoing debate. A State Government, Inter-Departmental Task Force (1982), investigating the possibility of pulpwood harvesting in the Otways, recognised the lack of information on the long term effects of timber harvesting on flora and fauna and, amongst other recommendations, called for an investigative study.

A report commissioned by the Board of Inquiry into the Timber Industry in Victoria (1985) noted that understorey species were not given any consideration in regeneration plans and warned that the loss of species and an overall decrease in the heterogeneity of the flora may result if this matter was not properly addressed. The West Victoria Regional Forest Agreement (2000) highlighted ecologically sustainable forest management as a key objective. Flora and fauna conservation was proposed as one of the major themes for research to monitor and improve the sustainability of forest management practices.

Victorian and Tasmanian studies on the impacts of harvesting on flora suggest that some understorey species characteristic of mature or old-growth stands may by prevented from achieving their pre-harvest abundance levels during standard harvest rotation times for managed forests and under current management practices (Turner et al, 2000). Tree ferns, ground ferns, epiphytes, nitrogen fixers, resprouters and those species that are targeted in selective logging programs were identified by Turner et al (2000) as deserving of attention in future studies.

Long term recording sites were established on timber harvesting coupes in the Otway Ranges in 1983 to 1986 with the aims of describing plant succession following timber harvesting and identifying the effect of harvesting on understorey species. Six timber harvesting coupes were selected covering a range of forest ages, vegetation communities and topography. Flora on the timber harvesting coupes was assessed in detail on permanent quadrats prior to harvesting and regeneration was monitored over a number of years following harvesting. The early stages of regeneration on the West Barham coupe were reported in Harris (1989).

This paper presents the results of the recent and previous four assessments of two coupes, the Redwater Track and West Barham coupes, harvested in summer 1984/85 and 1983/84 respectively. Results of the regeneration of each coupe are dealt with separately and the discussion covers both sites. 2 Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria

2 REDWATER TRACK COUPE

2.1 Study Area

The Redwater Track coupe is on the southern fall of the main Otway Range, approximately 10 km south west of Beech Forest. It is located in the upper reaches of a creek system that drains into the Aire River (Figure 2.1). The general aspect of the coupe is south westerly, elevation ranges from 200-240 m and slopes are moderate to flat. Mean annual rainfall is approximately 1500 mm (Land Conservation Council 1976).

Figure 2.1 Location of the Redwater Track and West Barham coupes in Otway State Forest

The Redwater Creek area is unusual as it has tall open forest developed on tertiary quartzitic sands. These sands occur as remnant cappings on ridge positions, overlying more fertile Cretaceous sediments (Pitt 1981). On slopes and towards creeks, the underlying Cretaceous sandstones and mudstones have been exposed and the soils and vegetation are more typical of Otway wet forest. The coupe was dominated by 1919 wildfire regrowth forest. Some selective timber harvesting in the form of timber harvesting small, scattered patches had occurred on the coupe, most likely in the 1960s (pers. comm., D. Scherger, former Forest Officer, DSE, Gellibrand).

"Otway messmate", the most frequent eucalypt recorded on quadrats, is a tall tree of messmate type with smooth bark on the upper trunk and branches. It is regarded as a natural E. obliqua and E. regnans hybrid and the pronounced variability of Otway messmate suggests that hybridisation and back crossing has proceeded for a number of Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria 3 generations. It occurs extensively throughout the Otway Ranges, commonly near the junction of stands of the two species (Pederick 1974).

2.1.1 Harvesting and regeneration treatment The 18.5 ha coupe was harvested by the clearfelling method from January to March 1985 and 2,580 m3 of sawlogs were removed. Trees were hand felled using chainsaws and a D7 bulldozer was used to snig logs to the landing. No pulpwood was harvested and this material was left on the ground. Some cull trees were felled and the basal area of standing overwood after harvesting was approximately 4m2/ha.

Timber harvesting slash on the coupe was broadcast burnt on 10 March 1985 using a hand lighting technique. A reasonably hot burn resulted. A mineral earth firebreak was created with a bulldozer around the whole coupe prior to burning to prevent the regeneration burn escaping into the surrounding unharvested forest.

The area was hand sown on 25 March 1985 with predominantly Eucalyptus regnans (mountain ash) seed collected on site from the heads of trees felled during harvesting operations. It is assumed that some E. obliqua x regnans (Otway messmate) seed was also collected and sown as it was carrying a heavy crop of seed at the time of harvesting (pers. obs.). The seed was extracted from the fruit in the drying kiln at the Department of Sustainability and Environment (DSE) depot at Forrest and bulked with mucilage, kaolin clay and yellow dye. Seed was sown at approximately 1 kg per hectare. Squash test results indicated that this was equivalent to 200,000 viable seeds per hectare (DSE records, Forrest), which was the recommended rate (CNR, 1995).

2.2 Methods

2.2.1 Pre-harvest assessment Twenty permanent circular quadrats with a radius of 5 m (78.5 m2 in area) were established prior to harvesting. Quadrats were located to sample the range of ridge (7 quadrats), mid slope (8 quadrats) and lower slope (5 quadrats) positions.

The distance and compass bearing to the centre of quadrats from various reference points was recorded to aid in the relocation of quadrats following harvesting. Metal plates were attached, below the anticipated cut stump height, to the three eucalypts closest to the quadrat centre and the distance and bearing from the centre of the quadrat was recorded. To further identify these eucalypts following harvesting their diameter at the height of the metal plate and species was recorded. Maps were prepared to assist with relocation of quadrats post-harvest.

All species1 of vascular plants on the quadrats were recorded with an estimate of their cover/abundance on the following modified Braun-Blanquet scale: += < 1% 1 = 1—5% 2 = 6—25% 3 = 26—50% 4 = 51—75% 5 = 76—100%

1 Nomenclature in this reports follows the DSE Flora Information System database. 4 Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria

The vegetation structure of each quadrat was assessed by recording the following: • number of eucalypts by species rooted on the quadrat and diameter at breast height (DBH) • number of understorey tree and shrub individuals by species rooted on the quadrat and DBH for stems >2 cm in diameter by species • height of eucalypts and of the general shrub strata • number and height of trees ferns with a definable trunk > 10 cm in height rooted on the quadrat.

The slope and aspect of each quadrat was recorded as well as any relevant descriptive information.

2.2.2 Post-harvest assessment Two weeks after the regeneration burn the quadrats were revisited and their centres marked with a steel picket. An additional 1 m2 sub-sample within each quadrat was established at this time to make detailed assessments of post-harvest regeneration. The centre of the original quadrat was used to locate the north east corner of this 1m x 1m sub-plot and wire pins were placed to mark the other corners. Fieldwork was carried out in either January or February for each subsequent assessment.

The following information was recorded on the 1 m2 sub-plot one, two, three and 16 years after harvesting: • all species of vascular plants • shrubs - number of individuals of each species - mode of regeneration, whether seedling or vegetative regrowth - maximum height for each species • eucalypts - number of seedlings and individual heights for each species, and DBH at 16 years. • tree ferns - whether survivors from pre-harvest vegetation or new plants, and trunk length at 16 years. • total percentage plant cover.

Any additional species found on the large pre-harvest quadrats were recorded at each assessment.

At 16 years, the cover value for each species was also recorded for the larger quadrat as the plants were of sufficient size to make meaningful comparisons with pre-harvest values. Structural information was recorded for eucalypts, understorey trees and tree ferns at 16 years. The location of key quadrats and reference points was recorded at 16 years with a Global Positioning System (GPS).

The health of Nothofagus cunninghamii in the streamside reserve was monitored during and following harvesting as it was thought it might have been adversely affected by the conditions of increased exposure following harvesting.

The coupe was visited 5 years post-harvest to make observations on the trends of the development of the vegetation. Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria 5

The influence of the eucalypt regeneration treatment on the seedling regeneration of woody understorey species was investigated by examining their germination on different seedbeds. Seedbed condition on the 1 m2 sub-plots was assessed two weeks after the regeneration burn into one of the six following classes: Burnt seedbed 1. Severe: Heavy fuel, long duration fire, sand burnt white 2. Moderate : Moderate fuel and duration 3. Light: very light fuel, short duration Unburnt seedbed 4. Loose, bare soil 5. Compacted, bare soil 6. Bare soil under timber harvesting slash

The seedbed classes were later grouped into three broad types - hot or moderate burn (7 quadrats), light burn (7 quadrats) or unburnt (5 quadrats).

2.2.3 Eucalypt germination A circular sub-sample, 4 m2 in area, centred on the original quadrat was used to record eucalypt germination. To obtain information on the pattern of eucalypt germination, all quadrats were assessed at 2, 5, 16 and 42 weeks as well as two years after sowing. Eucalypt seedlings were marked with colour coded bamboo pins allowing the number of eucalypts at each visit and the mortality from the previous visit to be recorded.

To obtain an estimate of eucalypt germination arising from natural seed-fall, seven additional plots (5 m x 5 m) were established prior to the hand seed sowing operation and located randomly across the coupe. These quadrats were excluded from the hand seed sowing process so that any eucalypt seedlings that germinated on them would be the result of natural seed-fall from remaining overwood. 2.2.4 Data analysis

Data preparation The cover/abundance classes for species recorded on quadrats pre-harvest and 16 years post-harvest were converted to a mid-point percentage cover value as follows: + = 1% 1 = 3% 2 = 15% 3 = 37.5% 4 = 62.5% 5 = 87.5% Species presence data on quadrats collected for the pre-harvest, Year 2 and Year 16 assessments were converted to frequency of occurrence.

Variables were generated to index the data by quadrat and sampling year. These were used for sorting and to provide classification factors for ANOSIM and permutation tests. In addition, binary variables were generated representing the transitions from pre- harvesting to Year 2 (with Year 16 set to "missing") and from Year 2 to Year 16 (with pre- harvesting set to "missing"). These were used in vector fitting to determine the directions of floristic change in the NMDS ordinations.

The data were captured into DECODA v3.00, an ecological database and analysis system (Minchin 1989).

Ordination Patterns of floristic variation among the quadrats were investigated using ordination by Non-metric Multidimensional Scaling (NMDS), a technique that has been shown to be robust and effective for ordination of community data (Minchin 1987). NMDS finds an ordination of quadrats in a specified number of dimensions, such that the distances among all pairs of quadrats in the ordination are, as far as possible, in rank-order agreement with compositional dissimilarities among the quadrats. Starting from an initial 6 Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria

ordination, the positions of quadrats are gradually adjusted, in order to minimise "stress", a measure of the badness-of-fit of a rank-order regression of ordination distances onto dissimilarities. NMDS was performed on each data set using 10 random starting configurations, with the number of dimensions ranging from 1 to 4.

Two ordinations were performed, using percentage cover data for the pre-harvesting and Year 16 quadrats and presence data for the pre-harvest, Year 2 and Year 16 assessments. Frequency and cover data were standardised by species' maxima (SMAX) and dissimilarities calculated using the Bray-Curtis index (Bray and Curtis 1957). This combination of standardisation and dissimilarity index is one of the most effective for community ordination (Faith et al. 1987, Sandercock 1997). Presence data were not standardised prior to computation of Bray-Curtis dissimilarities.

For the Year 2 data, Eucalyptus regnans and E. regnans x obliqua were omitted for both the NMDS ordinations and ANOSIM analyses, to avoid spurious contributions to dissimilarity, due to taxonomic uncertainties in the Year 2 data.

Vector fitting Vector fitting (Dargie 1984, Faith and Norris 1989, Kantvilas and Minchin 1989) was used to examine patterns of correlation between the NMDS ordinations and the binary variables representing the transitions from pre-harvest to Year 2 and from Year 2 to Year 16 and to determine the trajectories of floristic change, if any. Vector fitting is a form of multiple linear regression that finds the direction across the ordination along which coordinates have maximum Pearson product-moment correlation (r) with the fitted variable. Statistical significance of the correlation is tested by randomly permuting the values of the variable among sampling units, simulating the null hypothesis of no trend. Ten thousand random permutations were used.

ANOSIM The technique of ANOSIM, “analysis of similarities” (Clarke 1993) provides a way to test statistically whether there is a significant difference in species composition between two or more groups of quadrats. ANOSIM operates directly on the dissimilarity matrix. The method is philosophically allied with NMDS ordination, in that it uses only the rank order of the dissimilarity values.

If groups of quadrats are actually different in their floristics, it follows that dissimilarity values between pairs of quadrats that belong to different groups should, in general, be larger than dissimilarities between pairs of quadrats that belong to the same group. In other words, floristic dissimilarities between the groups ought to be greater than those within the groups. ANOSIM is based on a statistic that measures the extent to which this is true, using only the rank order of the dissimilarity values, rather than their arithmetic values.

The test statistic is computed as follows:

r − r R = bw nn()/− 14

where rb is the mean rank of the "between" dissimilarities (ie dissimilarities between two quadrats that belong to different groups) and rw is the mean rank of the "within" dissimilarities (those between pairs of quadrats that are in the same group). The − denominator of the expression nn()14/ is the maximum possible value of rb - rw for a given number of sampling units (n ). This standardises R to a range from -1 to +1.

A value of R close to zero suggests that there are no differences between species composition between the groups, while positive values suggest a difference. Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria 7

The statistical significance of R was tested using a random permutation procedure that simulates the null hypothesis of no real difference between the groups. Quadrats were randomly allocated to groups and the value of R recomputed. Values of R were computed for 10 000 random arrangements and a probability calculated as the proportion of randomised values that were at least as great as the R value for the real data.

Permutation tests When ANOSIM shows that groups of quadrats are floristically distinct, permutation tests can then be used to identify which species contribute to the difference. Differences in both mean cover values (pre-harvest and year 16) and frequency of occurrence (proportion of quadrats in which a species occurred for each of the three age classes) between groups of quadrats were evaluated using a permutation test, with quadrats randomly reassigned among the two groups 10 000 times.

The test statistic tabulated for difference in mean cover was calculated as: x − x D = 1 2 + (x1 x2 ) where x1is the mean cover of the species in the first group of quadrats and x2 is its mean abundance in the other group. For frequency of occurrence, the statistic was: = − D f1 f2 where f1 is the frequency of occurrence of the species in the first group and f2 is its frequency in the other group. Both these statistics range in value from 1, when the species is confined to the first group, to -1, when the species occurs only in the second group.

All taxa, including Eucalyptus spp., were included in the permutation tests. An alpha value of p=0.05 for significance of each test was used.

Analysis of seedbed association A Pearson chi-square test of independence of classifications was performed to determine if there was evidence of association between the number of seedlings of particular species and seedbed class at one year post-harvest. A one-way ANOVA was used to test for differences between eucalypt seedling height and seedbed class at one year. All analyses were performed using Genstat 5.4 (Genstat 5 Committee 1997).

2.3 Results

2.3.1 Vegetation before timber harvesting The tall eucalypt overstorey was composed primarily of Eucalyptus obliqua x regnans and E. regnans. The understorey vegetation of the site reflected the presence of two geological substrates. There was an interesting mix of species at the junction of the substrates. Broad-leaved shrubs such as Acacia melanoxylon (blackwood), Bedfordia arborescens (blanket leaf), Hedycarya angustifolia (austral mulberry), Nematolepis squamea ssp. squamea (satinwood) and Olearia argophylla (musk daisy-bush) are characteristic of fertile, moist sites on cretaceous soils. These species occurred with sclerophyll shrubs such as Leptospermum continentale (prickly tea-tree), Bossiaea cinerea (showy bossiaea) and Monotoca glauca (tree broom-heath) more typical of drier forests on Tertiary sand sites.

Fifty-seven species of vascular plants were recorded on the coupe prior to harvesting. The frequency of occurrence and cover values for all species is given in Appendix 1. 8 Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria

Nematolepis squamea ssp. squamea was the most common understorey tree species, occurring on 95 % of quadrats. It accounted for 61 % of all understorey shrub and tree stems greater than 2 cm in diameter and formed a tree layer with L. continentale and Acacia mucronata var. longifolia (narrow leaf wattle) at around 15–20 m. Its diameter reached a maximum of 35 cm DBH. An interesting variant of N. squamea ssp. squamea with corky bark was observed.

The occasional A. melanoxylon emerged above the understorey canopy, the largest specimen had a diameter at breast height (DBH) of 66 cm and height 28 m. Olearia argophylla, Monotoca glauca, Bedfordia arborescens and Hedycarya angustifolia contributed 11, 6, 5 and 3 % of woody stems respectively and formed a tall shrub or small tree layer at around 10-15 m. The largest specimens of M. glauca and B. arborescens had a DBH of 38 cm and 30 cm respectively. Of the low shrubs, Coprosma quadrifida (prickly currant bush), Pimelea axiflora (bootlace bush) and Zieria arborescens (stinkwood) were the most common. The remaining understorey shrub and tree species contributed 1 % or less of the total number of woody stems and often were represented on quadrats by a single plant.

Although understorey shrub and tree species were mixed across the site, B. cinerea, A. mucronata var. longifolia, L. continentale, M. glauca, Z. arborescens and E. obliqua x regnans showed a tendency for sandy ridge positions while Acacia melanoxylon, Nothofagus cunninghamii (myrtle beech), H. angustifolia, Lomatia fraseri (tree lomatia) and Tasmannia lanceolata (mountain pepper) were more likely to be found in gully locations.

The ground layer was not well developed and consisted mainly of ground ferns such as Blechnum wattsii (hard water-fern) and Pteridium esculentum (austral bracken) and scattered monocots such as Dianella tasmanica (Tasman flax-lily) and Drymophila cyanocarpa (turquoise berry). A thick layer of litter covered the forest floor. Clematis aristata (Australian clematis) formed strong lianes. An unusual occurrence of D. cyanocarpa growing as an epiphyte on D. antarctica was observed in the gully.

Dicksonia antarctica was common, occurring on 90 % of quadrats and accounted for 96% of tree fern numbers. Most plants were less than 1.5 m in height with occasional plants up to a maximum of 7 m tall (Figure 2.7). Additionally, there were many young plants without a definable trunk and numerous sporelings. The few specimens of Cyathea australis predominantly occurred on sandy ridge positions. Two small plants of Cyathea cunninghamii (slender tree fern) with heights of 1.5 m occurred in a minor drainage line.

Epiphytic ferns such as Grammitis billardierei (finger fern) and Microsorum pustulatum (kangaroo fern) were frequent across the site. Four species of filmy ferns, including three Hymenophyllum spp. and Polyphlebium venosum (veined bristle-fern) were recorded. As well as the usual hosts, Asplenium flaccidum ssp. flaccidum (weeping spleenwort) was recorded growing on Monotoca glauca. One plant of Tmesipteris obliqua (long fork-fern), which is of restricted distribution in the Otways, was observed near the gully.

Seedlings and juvenile plants were observed for Coprosma quadrifida, Dicksonia antarctica, Pimelea axiflora, Pittosporum bicolor (banyalla), Nothofagus cunninghamii and Tasmannia lanceolata. Recent germinants of Acacia melanoxylon, Monotoca glauca, Nestegis ligustrina (privet mock-olive), and Zieria arborescens were also present but no intermediate sized plants were observed. As well as growing on the forest floor, seedlings and young plants of Coprosma quadrifida, Pittosporum bicolor and Tasmannia lanceolata grew on the trunks of Dicksonia antarctica.

Large old specimens of Nothofagus cunninghamii dominated the shallow gully that formed the northern boundary of the coupe. The vegetation of this gully was interesting as the component of quartz sand in the soils influenced the otherwise typical mountain forest gully environment and occasional Leptospermum continentale and Monotoca glauca Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria 9 grew alongside the Nothogfagus cunninghamii. Nothogfagus cunninghamii formed only a narrow band along the gully and is classified as Otways Cool Temperate Rainforest EVC.

On one quadrat near this gully, four young trees of N. cunninghamii occurred with an average DBH of 8 cm and height of 14 m. Numerous seedlings of N. cunninghamii occurred on the forest floor in the vicinity of this and other quadrats that occurred above the gully for at least 200 m along the gully.

Eucalyptus obliqua x regnans was the most common eucalypt, accounting for 61% of eucalypts followed by E. regnans (30%), E. viminalis (manna gum, 9%) and an occasional E. cypellocarpa (mountain grey gum). The stand was mainly 1919 fire regrowth with an average DBH of 63 cm and around 50 m tall (Figure 2.2). Regrowth from scattered patches of selective timber harvesting in the 1960’s accounts for the smaller size classes in Figure 2. While the distribution of diameters was fairly similar for ridge and lower slope positions, average eucalypt height was less on ridge positions at 46 m compared with 53 m on lower slopes. Scattered overmature veterans that had survived previous wildfires were present, including a notable E. regnans of 380 cm DBH near the gully.

Figure 2.2 Frequency distribution of eucalypt species by DBH prior to harvesting on the Redwater Track coupe

10

9 E.viminalis 8 E.regnans E.obliquax regnans 7

6

5

4 Number of trees of Number

3

2

1

0 10--20 20-30 30-40 40-50 50-60 60-70 70-80 80-90 90-100 100-110 DBH Class (cm)

Note: The frequency distribution is based on all trees recorded in 19 quadrats.

2.3.2 Vegetation after timber harvesting All species recorded on the coupe and their frequency of occurrence on 80 m2 permanent quadrats before and after harvesting are recorded in Appendix 1. Due to exceptional timber harvesting debris in the vicinity, quadrat 6 could not be relocated with any degree of accuracy and was deleted from the study. The pre-harvest data for this quadrat were excluded from the data set. Therefore 19 quadrats were assessed after timber harvesting.

Species richness There was a slight increase in the total number of species recorded on the coupe two years after harvesting from 57 to 64, which declined to 43 after 16 years. The increase in the early years was largely due to an increase in herbaceous species (Figure 2.5) that had not previously been recorded on the coupe. On the other hand, many fern species were no 10 Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria

longer recorded on the quadrats post-harvest. The mean number of species recorded per quadrat increased following harvesting from 17.3 to 20.5 two years after harvesting and was 14.2 at 16 years (Appendix 1).

Community composition In the two dimensional NMDS of the presence (frequency of occurrence) data (stress=0.193) the three age classes are separated with only a little overlap (Figure 2.3). The Year 16 quadrats are intermediate to the pre-harvest and Year 2 quadrats. Fitted vectors for the binary variables pre-harvest vs Year 2 and Year 2 vs Year 16 are both highly correlated with the ordination (Pre-harvest – Year 2: r = 0.94, p <0.001; Year 2-Year 16: r = 0.81, p <0.001). The lengths of the plotted vectors are proportional to their correlations. The angle between the vectors is 175°, indicating that the floristic change from Year 2 to Year 16 is virtually opposite to the direction of change pre-harvest to Year 2. This indicates that the floristic composition of the Year 16 regeneration is more similar to the pre-harvest vegetation than the Year 2 regeneration. This is largely due to the many colonisers that were a large component of the vegetation at Year 2 but were not present in the older regeneration.

Figure 2.3 NMDS ordination in 2D (stress=0.193) of frequency of occurrence data from Redwater Track coupe with fitted vectors

Y2-Yr16 Axis 2

Pre-harvest

Year 2 Pre-Yr2 Year 16

Axis 1 The two dimensional NMDS of cover data has a stress of 0.210 and shows a very similar pattern of separation of pre-harvest and Year 16 data (Figure 2.4). The vector for Pre- harvest vs Year16 (r=0.93, p<0.001) is highly significantly correlated with the ordination, in the direction of separation of Year 16 from pre-harvest. This indicates that there was a significant difference in the floristics of the Year 16 vegetation compared with the pre- harvest vegetation. Cover data were not collected for individual species in Year 2 and comparisons with Year 2 vegetation could not be made. The NMDS ordination for species cover also indicated a greater variability in the Year 16 data relative to the pre-harvest data (Figure 2.4). Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria 11

Figure 2.4 NMDS ordination in 2D (stress=0.210) of cover data from Redwater Track coupe Axis 2

Pre-Yr16

Pre-harvest Year 16

Axis 1 Note: The vector for Pre-harvest to Year 16 is shown

ANOSIM tests (Table 2.1) indicate that the apparent differences in floristic composition among the three age classes observed in the presence ordination (Figure 2.3) are significant. For cover data, ANOSIM confirmed a significant floristic difference between pre-harvest and Year 16 (R=0.6034, p<0.001).

Table 2.1 ANOSIM R values for each pair of age classes for the Redwater Track coupe frequency of occurrence data Pre-harvest Year 2 Year 2 0.7946 Year 16 0.3385 0.3877 Note: The overall R, comparing all three age classes was 0.5124. All tests are significant (p<0.001), indicating floristic differences between each age class.

The permutation tests identified the species that contribute to the floristic differences detected by ANOSIM (Tables 2.2 to 2.5). Tables 2.2, 2.3 and 2.4 list species with significant differences in frequency of occurrence (proportion of quadrats on which a species occurred in each age class) between age classes. Table 2.5 shows species with significant differences in mean cover between Year 16 and Pre-harvest age classes.

Seventeen species were recorded in a significantly greater number of quadrats two years after harvesting (Table 2.2). Eight of these were coloniser species previously not recorded on the coupe including the forbs, Senecio minimus (shrubby groundsel), S. velleioides (forest groundsel) and Hydrocotyle hirta (hairy pennywort) and the tall shrub Ozothamnus ferrugineus (tree everlasting).

Ten species were significantly less frequent two years after harvesting (Table 2.2). Six of these were epiphytic ferns that were no longer present on quadrats. Grammitis billardierei, Hymenophyllum cupressiforme (common filmy-fern) and Microsorum pustulatum which were present at high frequencies prior to harvesting recorded the largest decreases in frequency. Eucalyptus viminalis also recorded a significant decrease in frequency. 12 Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria

Table 2.2 Species for which permutation tests suggested a significant difference in frequency of occurrence between pre-harvest and year 2 Frequency Species Pre-harvest Year 2 Probability Species more frequent at 2 years compared with pre-harvest Gahnia sieberiana 0.05 0.84 0.0000*** Senecio minimus 0 0.79 0.0000*** Hydrocotyle hirta 0 0.68 0.0000*** Histiopteris incisa 0.05 0.74 0.0000*** Billardiera longiflora var. longiflora 0.05 0.68 0.0001*** Senecio velleioides 0 0.47 0.0009*** Prostanthera lasianthos 0.21 0.68 0.0087** Ozothamnus ferrugineus 0 0.47 0.0011** Acacia melanoxylon 0.53 0.95 0.0074** Pomaderris aspera 0.11 0.63 0.0023** Olearia lirata 0.05 0.42 0.0179* Monotoca glauca 0.47 0.84 0.0419* Leptospermum continentale 0.26 0.63 0.0417* Hypochoeris radicata1 0 0.32 0.0186* Senecio linearifolius 0 0.26 0.0468* Solanum aviculare 0 0.26 0.0433* Cirsium vulgare1 0 0.26 0.0479* Species less frequent at 2 years compared with pre-harvest Microsorum pustulatum 0.63 0 0.0000*** Hymenophyllum cupressiforme 0.79 0 0.0000*** Grammitis billardierei 1.00 0 0.0000*** Ctenopteris heterophylla 0.47 0 0.0010** Hymenophyllum rarum 0.37 0 0.0085** Rumohra adiantiformis 0.37 0 0.0082** Eucalyptus viminalis 0.37 0 0.0092** Pittosporum bicolor 0.53 0.05 0.0027** Coprosma quadrifida 0.79 0.42 0.0425* Clematis aristata 0.63 0.21 0.0192* 1 denotes introduced species

There were significant changes in the floristic composition of the regenerating vegetation as it developed from the early years post-harvest to age 16 years (Table 2.3). Two epiphytic fern species, Microsorum pustulatum and Rumohra adiantiformis (leathery shield-fern) that were not present at age two, were recorded on quadrats at 16 years. Thirteen of the species that had been recorded at significantly higher frequencies at two years compared with pre-harvest, showed a significant reduction in frequencies at 16 years. Seven of these species were no longer present at 16 years including six herbaceous colonisers and Ozothamnus ferrugineus. Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria 13

Table 2.3 Species for which permutation tests suggested a significant difference in frequency of occurrence between year 2 and year 16 post-harvest Frequency Species Year 2 Year 16 Probability Species more frequent at 16 years compared to 2 years. Microsorum pustulatum 0 0.42 0.0032** Rumohra adiantiformis 0 0.26 0.0478* Species less frequent at 16 years compared to 2 years. Senecio velleioides 0.47 0 0.0007*** Gahnia sieberiana 0.84 0.26 0.0009*** Hydrocotyle hirta 0.68 0.05 0.0002*** Senecio minimus 0.79 0 0.0000*** Acacia melanoxylon 0.95 0.53 0.0091** Ozothamnus ferrugineus 0.47 0 0.0011** Histiopteris incisa 0.74 0.21 0.0027** Olearia lirata 0.42 0.05 0.0191* Senecio linearifolius 0.26 0 0.0454* Solanum aviculare 0.26 0 0.0472* Cirsium vulgare1 0.26 0 0.0425* Hypochoeris radicata1 0.32 0 0.0204* Billardiera longiflora var. longiflora 0.68 0.26 0.0201* 1 denotes introduced species

The frequency and mean cover of five species significantly declined from pre-harvest to 16 years post-harvest and were no longer recorded on quadrats (Tables 2.4 and 2.5). Four epiphytic ferns and one tree were present pre-harvest but were absent 16 years post- harvest. Another three species, Eucalyptus obliqua x regnans, Dicksonia antarctica and Nematolepis squamea ssp. squamea were present 16 years post-harvest but cover was significantly less than pre-harvest.

Table 2.4 Species for which permutation tests suggested a significant difference in frequency of occurrence between pre-harvest and 16 years post-harvest Frequency Species Pre-harvest Year 16 Probability Species more frequent at 16 years compared with pre-harvest Eucalyptus regnans 0.53 0.95 0.0063** Zieria arborescens 0.37 0.84 0.0056** Species less frequent at 16 years compared with pre-harvest Grammitis billardierei 1.00 0 0.0000*** Hymenophyllum cupressiforme 0.79 0 0.0000*** Ctenopteris heterophylla 0.47 0 0.0009*** Hymenophyllum rarum 0.37 0 0.0086** Eucalyptus viminalis 0.37 0 0.0083** 14 Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria

Two species, Eucalyptus regnans and Zieria arborescens recorded significantly increased mean cover and frequency values 16 years after harvesting. Other species to have a significant increase in mean cover 16 years after harvesting were Pomaderris aspera, Prostanthera lasianthos (Christmas bush), Acacia mucronata var. longifolia and Pimelea axiflora.

Table 2.5: Species for which permutation tests suggested a significant difference in mean cover between pre-harvest and 16 years post-harvest Mean Cover Species Pre-harvest Year 16 Probability Species with increased mean cover at 16 years compared with pre-harvest Zieria arborescens 0.8 24.1 0.0000*** Pomaderris aspera 0.1 11.6 0.0075*** Eucalyptus regnans 12.7 31.2 0.0034** Acacia mucronata var. longifolia 1.3 23.2 0.0017** Prostanthera lasianthos 0.2 5.0 0.0090** Pimelea axiflora 0.6 5.0 0.0398* Species with reduced mean cover at 16 years compared with pre-harvest Ctenopteris heterophylla 0.2 0 0.0009*** Grammitis billardierei 0.5 0 0.0000*** Hymenophyllum cupressiforme 0.4 0 0.0000*** Hymenophyllum rarum 0.2 0 0.0086** Eucalyptus viminalis 4.8 0 0.0083** Eucalyptus obliqua x regnans 25.2 8.6 0.0062** Dicksonia antarctica 23.9 10.2 0.0254* Nematolepis squamea ssp. squamea 30.1 14.6 0.0116*

Temporal pattern of early species establishment Regeneration of plant species occurred very quickly after the regeneration burn. The first seedlings to appear were those of Acacia melanoxylon and Eucalyptus spp., which were observed within two and three weeks of the regeneration burn respectively. Some species that are able to regenerate vegetatively from surviving rootstock, such as Olearia argophylla, Dicksonia antarctica, Pteridium esculentum and Tetrarrhena juncea (forest wire grass) were observed to be reshooting at this time.

By four weeks, large numbers of seedlings of Nematolepis squamea ssp. squamea, Hydrocotyle hirta, Hypochoeris radicata (cat's-ear), Solanum aviculare (kangaroo apple) and Hedycarya angustifolia were recorded and the ferns Blechnum wattsii and Polystichum proliferum (mother shield-fern) were reshooting. Both seedlings and regrowth from surviving rootstock of Hedycarya angustifolia were apparent at this time.

By six weeks, seedlings of Pelargonium australe (austral stork's-bill) and Bossiaea cinerea had appeared and Clematis aristata and Drymophila cyanocarpa were regrowing from surviving rootstock. At four months, seedlings of Pomaderris aspera, Pimelea axiflora, Zieria arborescens, Senecio spp. and Ozothamnus ferrugineus were recorded.

Herbs Large increases in herbaceous plants and to a lesser extent sedges occurred in the early years post-harvest (Figure 2.5). Twenty-two herbaceous species that had not previously been recorded on the coupe were recorded in the first year after harvesting. Most of these species began to decline in the third year after timber harvesting, with many no longer observed on the coupe at an inspection at 5 years post-harvest. Very few remained at Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria 15

16 years. The overall decline in floristic diversity after three years was attributed to the loss of early colonising species.

Figure 2.5 Number of species in each plant lifeform group on the Redwater Track coupe pre- and post-harvesting

30

25

20 Pre-harvest

Post - year 1 15 Post - year 2

Post - year 3 10

Number of species of Number Post - year 16

5

0 Trees and shrubs Forbs Tree ferns and ground Epiphytic ferns Sedges, graminoids and ferns grasses Senecio spp. were a frequent component of the post-harvest vegetation with S. minimus and S. velleioides occurring on 68% and 47% of quadrats respectively at three years (Figure 2.6). Senecio spp. flowered in the first summer and peaked in density by the second or third year. They are light demanding and required bare soil for germination. By three years, little suitable seedbed was available as vegetation covered 92% of the ground and further germination was not recorded. By 5 years, Senecio spp. had disappeared from the dense regenerating vegetation and were confined to tracks, in low numbers.

Figure 2.6 Percentage frequency of occurrence in quadrats of selected plant species on the Redwater Track coupe pre- and post-harvesting

120

100

80

Pre-harvest Post -Year 1 60 Post - Year 3 Post - Year 16

40 Frequency of occurrence (%) 20

0

n a ea a sii is ylo ylla m hirt x tifolia glauc ph wat form us rescens beriana yle i ano o t minimus antarctica nt el ang toca argo b sie co o a m a ar chnum nia adi ia y ono ia nia neci o a ar er ah Se Ble cac M Olearia Zi G Hydro Histiopteris incisa A Dicks mohr Hedyc Ru Ozothamnus ferrugineus olepis squamea ssp. squa

Nemat 16 Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria

The forb Hydrocotyle hirta was prolific occurring on 68% of quadrats at two years. Other colonising forbs occurred at low frequencies and appeared to be declining in numbers by three years.

Four introduced species, Hypochoeris radicata, Cirsium vulgare (spear thistle), Senecio jacobaea (ragwort) and Agrostis capillaris (bent grass) were recorded on quadrats after harvesting. These are common roadside or pasture weeds. They did not persist on the coupe. Senecio jacobaea was not recorded at three years and H. radicata and C. vulgare both peaked in occurrence at two years and then showed a dramatic decline to three years. At 5 years, only H. radicata was observed, with low numbers occurring on tracks. It was not present at 16 years post-harvest.

The tall sedge Gahnia sieberiana (red fruit saw-sedge) increased dramatically in occurrence after harvesting from 5% to 100% of quadrats at three years (Figure 2.6). The thick cover of this species along with prolific seedling regeneration of woody understorey species made walking progress through the coupe slow and difficult at three years. By 16 years, cover values for Gahnia sieberiana were low and no subsequent recruitment had occurred. Many dead plants were apparent. Some plants had scrambled up through the vegetation to heights of 5 m.

Apart form Tetrarrhena juncea, grasses were an insignificant component of the vegetation either before or after harvesting (Figure 2.5).

An unidentified liverwort colonised burnt ground especially areas that received a hot burn such as where there had been high levels of fuel accumulation. It occurred on half of the 1 m2 sub-plots at one year but at low cover values.

A general inspection of the coupe at 5 years indicated a few additional species colonising in low numbers. On areas of bare soil remaining on the main extraction track that received some sunlight at ground level species such as Thelymitra sp. (sun orchid), Pratia pedunculata (matted pratia) and Daucus glochidiatus (austral carrot) were present.

Ferns

Epiphytic ferns Of the 18 fern species recorded before harvesting, eight were no longer recorded on the coupe 16 years after harvesting. Epiphytic ferns, which were a significant feature of the pre-harvest vegetation, were most adversely affected (Figure 2.5). In the early years post- harvesting, none of the 10 species of pre-harvest epiphytic ferns were recorded on the coupe. Six species of epiphytic ferns recorded a significant decrease in frequency at two years (Table 2.2), including Grammitis billardierei, Hymenophyllum cupressiforme and Microsorum pustulatum which had high pre-harvest frequencies of 100, 79 and 63% respectively.

By 16 years post-harvest, three of the epiphytic species were starting to recover. The more robust epiphytic ferns, Microsorum pustulatum and Rumohra adiantiformis, were recorded on quadrats with frequencies of 42% and 26% respectively at 16 years. These species were observed growing on a range of substrates, including tree fern trunks, decaying tree stumps and the bark of Acacia mucronata var. longifolia. Young plants of Polyphlebium venosum, a delicate filmy fern, were located growing on the underside of a log on one quadrat.

The remaining seven pre-harvest epiphytic fern species were not recorded at 16 years, with Hymenopyllum cupressiforme, Grammitis billardierei, Ctenopteris heterophylla (gipsy fern) and Hymenophyllum rarum (narrow filmy-fern) recording significant reductions in frequency and mean cover (Tables 2.4 and 2.5). The less common epiphytic ferns, Tmesipteris obliqua (long fork-fern) and Asplenium flaccidum ssp. flaccidum were not recorded after the timber harvesting operation either. Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria 17

Ground ferns The main fern species to survive timber harvesting operations were hardier ferns that regenerated vegetatively such as Blechnum wattsii, Polystichum proliferum, Dicksonia antarctica and Pteridium esculentum. Regrowth from surviving rootstocks was observed within a few weeks of the slash burn for these species. However the actual number of these ferns (apart from P. esculentum which recovered and expanded via subterranean rhizomes) was lower than pre-harvest levels, which is not adequately reflected in the frequency or cover values.

Histiopteris incisa (bat's-wing fern) was one fern species that increased significantly in the early years following harvesting from a frequency of occurrence of 5 % pre-harvest to 74% at two years (Table 2.2). Numerous plants originating from sporelings occurred across the coupe. Hypolepis rugosula (ruddy ground-fern) also acted as a coloniser species. By 16 years, mean cover of Histiopteris incisa was similar to pre-harvest levels and Hypolepis rugosula was no longer present. A few plants of Blechnum nudum (fishbone fern) and Gleichenia sp. (coral fern) appeared on the coupe after harvesting.

Young plants of Asplenium bulbiferum ssp. gracillimum (mother spleenwort), absent from earlier assessments, were present at 16 years.

Tree ferns Dicksonia antarctica was the only tree fern recorded on quadrats after harvesting. Cyathea australis did not survive the harvesting and regeneration operation. Sixteen years after harvesting C. australis was not recorded on quadrats although some young plants were found on the main timber harvesting extraction track. The young plants of Cyathea cunninghamii recorded prior to harvesting survived the timber harvesting operation but then did not survive the regeneration burn.

Dicksonia antarctica was well distributed across the coupe with a frequency of occurrence on quadrats of 79% 16 years post-harvest compared with 90% pre-harvest but mean cover and actual numbers had been significantly reduced as indicated in Table 2.5 and Figure 2.7 respectively.

The number of D. antarctica with definable trunks greater than 10 cm in height at 16 years was less than one third of pre-harvest levels (Figure 2.7). A mean of 1.6 per quadrat (standard deviation = 2.0) of tree ferns with definable trunks greater than 10 cm in height was recorded at 16 years compared with 5.6 (standard deviation =5.1) prior to timber harvesting.

Figure 2.7 Number of Dicksonia antarctica tree ferns recorded in 19 quadrats in each length class pre-harvest and 16 years post-harvesting on the Redwater Track coupe

40 Pre-harvest 35 Post-harvest

30 Legend 25 Trunk Length** Class

20 (m) 1 0.1* - 0.49 15 2 0.5 - 0.99

10 3 1.0 - 1.49 4 1.5 - 1.99 Number of tree ferns tree of Number 5 2.0 - 2.49 5 6 2.5 - 2.99 0 7 3.0 - 3.49 12345678 8 3.5 - 7.00 Trunk Length Class *Only tree ferns with a definable trunk of height greater than 10 cm included. **Sections of trunk along the ground were included in length measurements post-harvesting. 18 Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria

Timber harvesting and regeneration procedures caused considerable loss of rootstock. About 16% of the original Dicksonia antarctica trunks survived the harvesting and regeneration operation and were present at 16 years. Some surviving tree ferns produced new fronds within 2.5 weeks of the regeneration burn. However, long term survival was not always readily apparent at the early years of assessment, as some tree ferns were slow to recover, while other plants survived for the first few years and then died.

While only 16% of tree ferns on quadrats survived harvesting operations and were healthy and actively growing at 16 years, they are an important contributor to tree fern numbers after harvesting. Around 50% of tree ferns with definable trunks on quadrats at 16 years were original plants that had survived harvesting operations.

Half of those tree ferns that did survive harvesting and regeneration operations had been knocked over during timber harvesting with part of their trunk lying on the ground. These ferns produced a new vertical trunk at the growing tip and the average increase in vertical growth over the 16 years was 0.6 m (standard deviation =0.3 m). One notable plant produced a new vertical section of trunk 1 m in length from the surviving prostrate trunk.

It should be noted that at 16 years post-harvest, many sporelings and young plants of Dicksonia antarctica were present on quadrats indicating that significant recruitment was occurring. Tree ferns were observed to be regenerating on a range of substrates, including soil, logs, rotted logs, stumps and old tree fern trunks (see Figure 2.8).

Figure 2.8 Tree fern recruitment on rotting log, 16 years post-harvest, Redwater coupe

Understorey trees and shrubs The majority of understorey shrub and tree species regenerated well after harvesting and regeneration operations. All pre-harvest shrub and tree species were represented on quadrats by 16 years post-harvest, except for Lomatia fraseri and Nothofagus cunninghamii. However, the relative proportions of some species changed compared to pre-harvest levels.

Seedling regeneration Seedling regeneration was the main mode of regeneration of shrub and tree species. This regeneration was dense and vigorous (Table 2.6). A large number of seedlings of woody plants were recorded after harvesting with 206 seedlings per m2 one year post-harvest (equivalent to an estimated average of 2 million seedlings per hectare). Approximately one third of these had died by the second assessment at year two and a further 10% had died by year three. There was a dramatic decline in the number of plants as the vegetation Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria 19 aged due to the natural thinning process, with an average of three plants of seedling origin per m2 recorded at 16 years.

Table 2.6 Mean number (and standard deviation) of plants of seedling origin per m2 for tree and shrub species recorded post-harvesting on the Redwater Track coupe Years Since Harvesting Species 1 1 2 3 16 Nematolepis squamea ssp. squamea 159.7 (135.1) 99.3 (84.4) 86.8 (74.9) 1 (1.4) Zieria arborescens 17.1 (43.9) 14.2 (36.4) 10.2 (24.9) 0.6 (1.1) Monontoca glauca 7.2 (11.2) 6.3 (9.6) 9.5 (15.0) 0.1 (0.5) Acacia melanoxylon 6.1 (8.1) 3.5 (4.1) 3.3 (4.9) 0.1 (0.2) Eucalyptus sp. 4.2 (3.7) 2.9 (2.9) 2.1 (2.7) 0.2 (0.4) Pomaderris aspera 3.9 (11.5) 1.9 (5.7) 2.3 (6.2) 0.1 (0.3) Acacia mucronata var. longifolia 1.4 (3.0) 1.4 (2.7) 1.5 (3.4) 0.5 (1.3) Bossiaea cinerea 1.4 (3.1) 1.1 (2.7) 1.4 (2.9) 0.2 (0.5) Leptospermum continentale 0.7 (2.1) 1.2 (1.8) 0.9 (1.9) 0.1 (0.2) Prostanthera lasianthos 0.5 (1.8) 0.6 (1.5) 0.8 (1.7) 0 Ozothamnus ferrugineus 0.4 (1.4) 0.3 (0.8) 0.6 (1.9) 0 Pimelea axiflora 0.9 (2.8) 0.2 (0.9) 0.5 (1.4) 0 Olearia lirata 1.0 (4.4) 0.2 (0.5) 0.3 (1.1) 0 Hedycarya angustifolia 0.8 (1.5) 0.3 (0.7) 0.1 (0.2) 0 Coprosma quadrifida 0.2 (0.7) 0.2 (0.6) 0.2 (0.5) 0.1 (0.2) Bedfordia arborescens 0.2 (0.5) 0.1 (0.5) 0.2 (0.7) 0 Olearia argophylla 0.2 (0.9) 0.1 (0.2) 0.2 (0.5) 0.1 (0.2) Pittosporum bicolor 0.1 (0.3) 0.1 (0.2) 0.1 (0.2) 0 Tasmannia lanceolata 0 0 0.1 (0.2) 0 Lomatia fraseri 00.1 (0.2) 0.1 (0.2) 0 Nothofagus cunninghamii 0000 Mean number of plants of seedling 206 134 121 3 origin per m2 for woody species Mean percentage plant cover per m2 32 68 92 n.a. Note: species were recorded in 19 permanent 1 m2 sub-plots. 1 Only plants rooted on sub-plots were counted.

There was one main period of germination, which began soon after the completion of the treatment of the coupe for eucalypt regeneration (see Figure 2.9). Shrub and tree species became dominant at an early age. The development of a single aged stand of vegetation for shrub and tree species that regenerate via soil-stored seed was apparent. At three years, mean plant coverage on 1 m2 sub-plots was 92% indicating that there was little available mineral earth seedbed for further seedling germination. 20 Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria

Figure 2.9 Seedling regeneration at 1 year post-harvest (on quadrat 9)

Among the first seedlings of woody species to appear on site were those of Nematolepis squamea ssp. squamea and Acacia melanoxylon. Nematolepis squamea ssp. squamea accounted for 77% of all seedlings of woody plants recorded at one year. An extraordinary number of seedlings of this species were observed with a mean of 160 (standard deviation = 135) seedlings per m2 at this time.

Along with Eucalyptus spp., Leptospermum continentale, Zieria arborescens and Acacia mucronata var. longifolia, Nematolepis squamea ssp. squamea was one of the most rapid growing shrub and tree species in the early years. Its high abundance and rapid growth rate gave the appearance at three years that it would dominate the understorey vegetation as it had before timber harvesting. However, its numbers were substantially reduced by 16 years, where it accounted for only one third of woody stems of seedling origin. Less than 1% of the seedlings of N. squamea ssp. squamea recorded at one year survived to 16 years. This species recorded a significant decrease in mean cover value from pre-harvest to 16 years (Table 2.5), however its frequency of occurrence on quadrats was not significantly reduced (Figure 2.6).

Zieria arborescens also regenerated prolifically from seed and increased in abundance following harvesting. At three years it accounted for 9% of all understorey shrub and tree stems compared with 1% before harvesting. This increase was carried through to 16 years, where a significant increase in mean cover was recorded compared to pre-harvest levels (Table 2.5).

Other species to increase in frequency in the early years following harvesting through seed regeneration were Monotoca glauca, Acacia melanoxylon, Pomaderris aspera, Acacia mucronata var. longifolia, Leptospermum continentale, Prostanthera lasianthos (Christmas bush), Ozothamnus ferrugineus and Olearia lirata. The former three species produced abundant amounts of seedlings. Additionally, significant increases in mean cover at 16 years were recorded for Pomaderris aspera, Prostanthera lasianthos, Pimelea axiflora and Acacia mucronata var. longiflora (Table 2.5).

Ozothamnus ferrugineus was the only new shrub species to be widespread across the coupe. The number of seedlings of this species was fairly low and proportionally it only accounted for 0.5% of the number of shrub seedlings at three years. It was no longer present at 16 years post-harvest. Occasional seedlings of Acacia verniciflua (varnish wattle) and Coprosma hirtella (rough coprosma) appeared following harvesting but these did not persist. Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria 21

Most understorey shrub and tree species had reached at least half of their pre-harvest height by 16 years. For example, Acacia melanoxylon had reached heights of 18 m and diameters of 18 cm compared with 28 m and 60+ cm pre-harvest. Acacia mucronata var. longifolia was just below its maximum pre-harvest height of 19 m.

A number of understorey shrubs and tree species were adversely affected by harvesting and decreased in frequency. These were Coprosma quadrifida, Pittosporum bicolor, Tasmannia lanceolata, Nothofagus cunninghamii and Lomatia fraseri. N. cunninghamii was not recorded after harvesting. Apart from C. quadrifida, only a few seedlings of the other species were recorded in the early years after harvesting. These species were slow to re-establish. Lomatia fraseri was present in the early years post-harvest but was not recorded at 16 years. Tasmannia lanceolata of seedling origin was recorded with heights of around 0.3 m at 16 years compared with plants in the pre-harvest vegetation of over 10 m tall and DBH of 10 cm. Further increases in abundance over time are expected via seedling recruitment under the forest canopy. The liane Parsonsia brownii (twining silkpod) can also germinate and develop under shade and while absent for the first three years post-harvest it had returned to its pre-harvest frequency at 16 years.

Vegetative regeneration A few species re-established both vegetatively and by seed. About 20% of Olearia argophylla and Hedycarya angustifolia plants present 16 years post-harvest had regenerated from rootstock. Some O. argophylla plants that had been partially uprooted and burnt survived. Regrowth of O. argophylla was observed within two weeks of the regeneration burn. Twenty-five percent of Bedfordia arborescens plants recovered vegetatively but only half of these survived to 16 years. Occasional plants of Tasmannia lanceolata recovered vegetatively, however none of these plants survived to 3 years post-harvest.

Plants regenerating vegetatively tended to have longer shoots at a given point in time than those that had regenerated from seed. After 3 months, vegetative shoots of 15 cm in length were recorded compared with tiny seedlings. At one year, vegetative shoots of O. argophylla and B. arborescens were 50 cm long with full size leaves compared with seedlings of 10 cm in height. Plants that can survive vegetatively had a distinct advantage and were able to become locally dominant.

The coppice regrowth plants had reached or were approaching their pre-harvest heights at 16 years with O. argophylla up to 10 m tall and H. angustifolia and B. arborescens to 13 m. The decrease in frequency of the former two species between 3 and 16 years was largely due to seedlings not surviving beyond the early years.

Effect of seedbed treatment The bulk of the understorey vegetation was flattened during the harvesting operations and the above ground portions were consumed by fire during the broadcast regeneration burn. Little of the understorey remained intact after the eucalypt regeneration treatment and the bulk of seed present in the understorey canopy would be lost. The germination of soil-stored seed is thus the main mechanism of regeneration available for many species.

The regeneration burn carried out on the coupe was considered to be a hot to moderate burn (pers. comm., D. Scherger, formerly DSE, Gellibrand), however it was not complete in its coverage and a range of seedbeds types were produced. The total number of seedlings of six abundant woody species for each of the three seedbed groups is shown in Table 2.7. 22 Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria

Table 2.7 Total number of seedlings on different seedbed types one year post-harvesting Total Number of Seedlings on 3 Seedbed Types Species Hot Burn Light Burn Unburnt Acacia melanoxylon 33 20 62 Eucalyptus spp. 43 9 26 Monotoca glauca 59 64 13 Nematolepis squamea ssp. squamea 789 1280 966 Pomaderris aspera 73 0 1 Zieria arborescens 39 279 7 Note: Seedlings were recorded on nineteen 1 m2 sub-plots.

Quadrat data were combined to overcome convergent problems with the analysis. A Pearson chi-square value of 556.72 with 10 df at probability level (under null hypothesis) p < 0.001 was obtained. Hence there is evidence of an association between number of seedlings and seedbed class.

The residuals from the analysis (Table 2.8), indicated that largest departures occurred for number of Pomaderris aspera seedlings and hot burn seedbed class and number of Zieria arborescens seedlings and light burn seedbed class. Hence there seems to be evidence of a relationship between these species and the corresponding seedbed class.

Table 2.8 Residuals from the Pearson chi-square analysis Seedbed Type Species Hot Burn Light Burn Unburnt Acacia melanoxylon 0.284 -5.824 6.119 Eucalyptus spp. 5.514 -5.824 0.947 Monotoca glauca 4.215 0.749 -4.993 Nematolepis squamea ssp. squamea -4.302 -4.423 9.116 Pomaderris aspera 13.818 -7.437 -5.485 Zieria arborescens -6.558 15.930 -11.020

Pomaderris aspera seedlings occurred in higher numbers on quadrats that received a hot burn (see Figure 2.10). Pomderris aspera had not been recorded before harvesting on the sub-plots that were burnt nor on the larger circular quadrats that enclosed these sub- plots. This suggests P. aspera seed had been lying dormant in the seed bank and that it requires a hot burn to stimulate germination. For Zieria arborescens, the greatest germination of soil-stored seed occurred on lightly burnt rather than heavily burnt quadrats.

Nematolepis squamea ssp. squamea germinated in very high numbers regardless of the seedbed type. A vast reservoir of soil-stored seed is indicated as well as the species adaptability to regenerate successfully over a range of conditions. Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria 23

Figure 2.10 Pomaderris aspera on burnt seedbed, 1 year post-harvest, Redwater coupe

Eucalypt regeneration The influence of seedbed preparation on eucalypts was of a different nature to that of the above mentioned woody species as eucalypt seed is not soil-stored but is applied to the soil surface by a combination of hand sown seed and natural seed fall. It is not the effect of heating of soil-stored seed that is being considered but the receptiveness of different seedbeds to eucalypt germination and subsequent growth. Eucalypt germination is shown in Table 2.7.

Seedling growth was affected by seedbed type (p<0.001). A one way ANOVA was used to test for differences between the seedbed classes for Eucalyptus spp. seedling height at one year post-harvest. The data were log transformed (natural log) to stabilise the variance (Table 2.9). The eucalypt seedlings on the hot burn seedbed were significantly taller than the other two classes. The light burn and unburnt seedbed classes were not significantly different to each other.

Table 2.9 Means of log transformed eucalypt seedling height per m2 on three seedbed types one year post-harvest Seedbed type Hot Burn Light Burn Unburnt l.s.d. (P=0.05) Log_height 2.248 1.454 1.206 0.5938

While eucalypt distribution was uneven and related to the above seedbeds, overall eucalypt regeneration on the coupe was successful with an estimated 27 000 seedlings ha-1 one year after harvesting. Approximately one half of those seedlings survived to two years. The bulk of eucalypt germination (95%) occurred within the first 16 weeks after hand-sowing of seed in late March up to mid-July (Figure 2.11). There was very little further germination over the first spring and summer. Seedlings still in the cotyledon stage over summer, which were probably spring or summer germinants, were very susceptible to browning off possibly due to drought stress. Mortality for the first 42 weeks after sowing was at least 45% with most mortality occurring after mid-winter. 24 Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria

Figure 2.11 Average number of eucalypt seedlings per sub-plot since sowing on 25 March 1985, Redwater Track coupe

20

18 Seedlings standing Cumulative germination 16 Cumulative mortality

14

12

10

8

6

4

verage number of eucalypt seedlings of eucalypt number verage 2 A

0 0 102030405060708090100

Time since sowing (weeks)

Note: Seedlings were recorded on nineteen 4 m2 sub plots.

At 16 weeks after the regeneration treatment, the average number of eucalypt seedlings standing on 4m2 plots was 15.8 (standard deviation = 16.7) and 3.4 (standard deviation = 3.6) on hand-sown and unsown plots respectively. Around 20% of the eucalypt germination recorded on the site may have been the result of natural seed-fall. A considerable amount of seed remained on the site following harvesting despite the loss of seed in the heads of felled trees and on the forest floor during the hot regeneration burn. The main sources of seed were from trees left standing on the coupe and trees outside the logged boundary. Eucalyptus regnans are able to shed seed for a distance of up to 1.5 times their height or 75 m in this case, however the majority of seedfall occurs within the first half-tree height (25 m) (Cremer, 1966).

After 16 years, the stand had naturally thinned to about 700 eucalypts per hectare (calculated from the number of trees recorded on large quadrats) with most trees having a diameter at breast height (DBH) of 10-20 cm (Figure 2.12).

Figures 2.2 and 2.12 indicate the diameter distribution of the eucalypt species at pre- harvest and 16 years post-harvest respectively. The proportion of E. regnans increased following harvesting apparently because it was the main species hand sown on the coupe during regeneration operations. The mean cover of E. regnans was significantly greater at 16 years compared to pre-harvest (Table 2.5) while that of E. obliqua x regnans and E. viminalis recorded a significant decrease. Eucalyptus cypellocarpa was present at similar low numbers as it was before harvesting. The regeneration of the latter two species occurred as a result of natural seed-fall. Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria 25

Figure 2.12 Frequency distribution of eucalypt DBH 16 years post-harvest on the Redwater Track coupe

45

40

35

30

25 Eucalyptus obliqua x regnans Eucalyptus regnans 20 Number of Trees Number

15

10

5

0 0-4.9 5-9.9 10-14.9 15-19.9 20-24.9 25-29.9 30-34.9 35-39.9 DBH Class (cm)

Note: The frequency distribution is based on all trees recorded in 19 quadrats.

Nothofagus cunninghamii Seedlings of Nothofagus cunninghamii were not recorded on the Redwater coupe in the early years after timber harvesting. Subsequent inspections, at 5 and 16 years failed to locate any seedlings around the edges of the N. cunninghamii gully. The track adjacent to the gully had become over grown with strong competing vegetation by three years and no longer provided a receptive seedbed.

A few trees on the margins of the streamside reserve were damaged during adjacent timber harvesting when they were knocked by falling branches of eucalypts. One small tree was broken off at 2 m above the ground. No other obvious decline in the health of N. cunninghamii was observed following harvesting. Trees appeared to be of good health, with healthy crowns at 16 years after harvesting. 26 Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria

Changes over time An indication of the recovery of the vegetation over the period of the study is provided in Figure 2.13.

Figure 2.13 Redwater coupe (near quadrat 9): after regeneration burn (A); 1 year post-harvest (B); and 16 years post-harvest (C)

A

B

C Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria 27

3 WEST BARHAM COUPE

3.1 Study Area

The West Barham coupe occurs within the tall mountain forest of the West Barham catchment and was harvested and regenerated in the 1983/84 timber harvesting season. The West Barham catchment occurs on the southern fall of the main Otway Range and the coupe is located in the headwaters of the catchment approximately 8 km north-west of Apollo Bay (Figure 2.1).

Elevation of the coupe is between 320 m and 360 m and the aspect is generally southerly with a slope range from 5 to 25 degrees. The West Barham catchment occurs within the high rainfall area of the Otways, with annual rainfall measured on the coupe in 1983 and 1984 being 2021 mm and 1797 mm respectively (Farrell and Novotny 1985). The young and moderately fertile soils are brown, gradational loams that have developed over Lower Cretaceous, feldspathic sedimentary sandstones and mudstones (Pitt 1981).

As for most of the Otways mountain forest, the West Barham catchment consists of a mosaic of age classes resulting from various wildfires, the more recent fires occurring in 1890, 1902, 1919 and 1939 (Clifford 1954). Eucalyptus regnans and E. obliqua (stringybark messmate) are the main eucalypt species of the catchment with E. viminalis and E. cypellocarpa occurring at lower elevations in the valleys.

An area along the northern boundary of the catchment was cleared for farmland around 1900 and since abandoned. Repeated fires, including the 1939 fire, have resulted in non- eucalypt regrowth of Acacia melanoxylon and other understorey species on this area (Clifford 1954). The West Barham Big Trees Flora Reserve, an area of undisturbed forest containing a stand of veteran E. regnans was created in October 1984.

Timber harvesting had been carried out in the catchment since 1973, mainly on the western side of the catchment mainly in 1902 fire regrowth.

3.1.1 Harvesting and regeneration treatment The 3 ha coupe was harvested by the clearfelling method from January to March 1984 and was part of a larger cutting area that could not be completed that season due to wet weather. The remainder of the cutting area was harvested over the next two years and the regeneration of this area was the subject of a separate study. A total of 677 m3 of sawlogs was removed from the coupe and the road line into the coupe (see Figure 3.1). A high proportion of trees were too defective for sawlogs and were not utilised. As parts of the coupe were clearfelled and as pulpwood was not harvested, a large quantity of material remained on the ground following harvesting.

An attempt to broadcast burn the area was made on 17 March 1984, however the burn was unsuccessful as the felled vegetation had not dried sufficiently and weather conditions were not favourable on the day. Only fine fuels (leaves, twigs) and elevated small branches were burnt. It was necessary to mechanically disturb the soil of the entire coupe with a bulldozer on 24 March 1984 to produce a mineral earth seedbed. This involved pushing timber harvesting debris (heads of eucalypts and material not suitable for sawlogs) and understorey plants into large heaps to expose areas of mineral soil suitable for eucalypt seed germination. The coupe was hand sown on the same day with a 2:1 mixture of Eucalyptus regnans and E. obliqua x regnans seed collected from the area. 28 Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria

Figure 3.1 Loading of sawlogs on the log landing, West Barham coupe

3.2 Methods

3.2.1 Pre-harvest assessment Seventeen permanent belt transects were established in January 1984 prior to harvesting of the coupe. The transects (50 m x 2 m) were divided into ten 5 m x 2 m contiguous quadrats giving 170 quadrats in total. Transects were located to sample upper, mid and lower slope positions and a range of aspects.

Steel pickets were placed to mark the start and end of transects and distances and compass bearings from permanent reference points were recorded. Following the harvesting and regeneration operations, transects were relocated and remarked.

All species of vascular plants were recorded on each quadrat. Slope, aspect and position were recorded for each quadrat.

Structural information (height and diameter) of shrub and tree species was collected. The diameter at breast height of all eucalypts on or partially on the transects was recorded as well as their position on the transect. As well as providing information of a structural nature, these measurements assisted in the accurate relocation of transects after timber harvesting.

3.2.2 Post-harvest assessment Seven of the original seventeen transects were selected for remeasurement. They were re- assessed annually for the first three years after harvesting in February 1985, January 1986, January 1987 and at 17 years in March 2001. The seven transects contained all of the species known from the coupe pre-harvest.

A 50 m steel chain was laid between the start and finish markers of the seven transects and 1 m x 1 m quadrats spaced at 5 m intervals were marked on the left side of the chain at the start of each original quadrat. A 1 m x 1 m frame made of light steel rod was used to delineate the quadrat on the ground. The corners were marked with wire pins so that the quadrat could be readily relocated. The frame was divided into four subplots to aid in the counting of seedlings and the delineation of seedbed types.

The following information was collected on the 1 m2 sample of the 2 m x 5 m quadrats: • all species of vascular plants Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria 29

• trees and shrubs - number of individuals of each species - mode of regeneration, whether seedling or vegetative regrowth • average top height of seedlings. (There were too many shrub seedlings to record individual heights so the maximum height of each species in each quadrat was measured.) • eucalypts - number of seedlings and individual heights • total percentage plant cover.

Additional species that occurred on the original 5 m x 2 m quadrats but not on the 1 m2 sub plot were recorded at the subsequent assessments.

The seedbed conditions on quadrats were assessed at age one year with each of the four quarters of the 1 m2 sub-plot being assessed separately and designated as having one of the following seven seedbed types: 1. friable, bare soil 2. bare soil but with sealed soil surface 3. compacted, bare soil 4. friable or compacted soil under timber harvesting debris 5. heavy debris - large diameter logs 6. loose, fragmented bark, wood, twigs 7. undisturbed litter layer.

No burnt seedbeds were recorded on quadrats following the pushing operation after the unsuccessful regeneration burn. The 1 m2 sub-plots were classified into two overwood shade classes, Full sun or Shade.

Sampling intensity was high. The assessment of sixty-eight 1 m2 sub-plots in the three hectare coupe post-harvest corresponded to a coverage of 0.23%, while seven 50 m x 2 m transects corresponds to a 2.3% sample.

The location of key quadrats and reference points was recorded at 17 years with a Global Positioning System (GPS). 3.2.3 Data analysis The same method of data analysis was used as for the Redwater Track coupe however as there were some differences in the field sampling method for each coupe, slightly different approaches were required for data preparation and ordination for the West Barham coupe as indicated below.

Data preparation The data were converted to percentage frequency of occurrence in quadrats for each species.

Variables were generated to index the data by transect and sampling year. These were used for sorting and to provide classification factors for ANOSIM and permutation tests. In addition, binary variables were generated representing the transitions from pre-harvest to Year 2 (with Year 17 set to "missing") and from Year 2 to Year 17 (with pre-harvest set to "missing"). These were used in Vector Fitting to determine the directions of floristic change in the NMDS ordinations.

The data were analysed using DECODA v3.00, an ecological database and analysis system (Minchin 1989).

Ordination Frequency data were standardised by species' maxima (SMAX) and dissimilarities calculated using the Bray-Curtis index (Bray and Curtis 1957). This combination of standardisation and dissimilarity index is one of the most effective for community 30 Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria

ordination (Faith et al. 1987, Sandercock 1997). Presence data were not standardised prior to computation of Bray-Curtis dissimilarities.

For both the NMDS ordinations and ANOSIM analyses, all species of Eucalyptus were omitted to avoid spurious contributions to dissimilarity, due to taxonomic uncertainties in the Year 2 data.

Permutation tests When ANOSIM shows that groups of quadrats are floristically distinct, permutation tests can then be used to identify which species contribute to the difference. Differences in frequency of occurrence (proportion of quadrats in which a species occurred for each age class) between groups of quadrats were evaluated using a permutation test, with quadrats randomly reassigned among the two groups 10,000 times.

The test statistic tabulated for difference in frequency of occurrence was calculated as: x − x D = 1 2 + (x1 x2 ) where x1is the frequency of occurrence of the species in the first group of quadrats and x2 is its frequency of occurrence in the other group.

All taxa, including Eucalyptus species, were included in the permutation tests. An alpha value of p=0.05 for significance of each test was used.

Relationships between regeneration and environmental factors at two years post-harvest The relationships between eucalypt regeneration, understorey vegetation and various environmental factors were examined by analysis of variance, correlation and log - linear models. Analyses were performed on data collected on sixty-eight 1 m2 sub-plots two years after harvesting, with the following variables included: • number and average height of eucalypt seedlings • for woody understorey species, the total number of plants, the number of species and the maximum height of these plants • total number of species and total plant cover • seedbed condition (recorded at one year) • extent of overwood shade. A logarithmic transformation was applied to variables where appropriate, in order to stabilise the variance. Where an analysis of variance showed a factor to be significant overall, comparisons between pairs of means were made using the Student-Newman-Keuls procedure (Sokal and Rohlf 1969). In the case of log-linear models, an observed difference between treatments was deemed significant (p<0.05) if it exceeded twice the standard error of that difference.

3.3 Results

3.3.1 Vegetation before timber harvesting The pre-harvest frequency of all species recorded on the seven transects selected for remeasurement after harvesting is presented in Appendix 2.

The overstorey was dominated by E. regnans, with a height of approximately 60 m. Four distinct tree and shrub understorey strata could be delineated beneath this overstorey. Acacia melanoxylon provided a discontinuous upper mid-storey with heights of 30 m on the ridge and 40 m down the slope. Nematolepis squamea ssp. squamea formed the next clear strata with heights of 20 m. Hedycarya angustifolia and Olearia argophylla formed Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria 31 an open continuous stratum at around 10 m in height. Coprosma quadrifida and Pimelea axiflora formed the lowest shrub layer with heights around 2 m.

Of the 48 species of vascular plant recorded on the coupe, 22 were ferns. The fern layer was very well developed with Dicksonia antarctica providing dense continuous cover above a ground stratum of Polystichum proliferum and Blechnum wattsii. Epiphytic ferns were very common with Microsorum pustulatum being particularly abundant.

Forbs were a very minor component of the understorey and only a few species such as Australina pusilla ssp. muelleri (shade nettle), Hydrocotyle hirta and Chiloglottis cornuta (green bird orchid), occurred at low frequencies.

Of the common species, N. squamea ssp. squamea, P. axiflora, Tetrarrhena juncea, Cyathea australis and Histiopteris incisa were more prevalent on the ridge. Acacia melanoxylon, Asplenium bulbiferum ssp. gracillimum, Grammitis billardierei, D. antarctica and other ferns were more prevalent on lower slopes and in gullies.

Interestingly, Pomaderris aspera and Bedfordia arborescens occurred at very low frequencies, only in lower slope positions, although they are common species in other areas of the West Barham catchment. Scattered trees of Pittosporum bicolor and Prostanthera lasianthos occurred mainly on slopes and near gullies. Nothofagus cunninghamii occurred in gullies below the coupe. A single specimen of Sarcochilis australis (Gunn's orchid) was recorded near the extraction track into the coupe.

Seedlings of Acacia melanoxylon, Coprosma hirtella, Coprosma quadrifida, Hedycarya angustifolia, Pimelea axiflora and Pittosporum bicolor were observed growing on the forest floor or on the trunks of Dicksonia antarctica. The number of seedlings increased towards the gully. No seedlings of Nematolepis squamea ssp. squamea were observed. No plants of intermediate age between seedling and mature plants of A. melanoxylon, H. angustifolia and P. axiflora were observed indicating that seedlings of these species are unlikely to develop into larger plants under shade.

The frequency distribution of mountain ash DBH encountered on transects is given in Figure 3.2. These ranged from 35 cm to 152 cm DBH. Almost half the trees occurred within the 80.1 to 100 cm diameter class and 29% occurred in the 90.1 to 100 cm class. The proportion of larger diameter trees tended to increase down the slope. 32 Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria

Figure 3.2 Frequency distribution of Eucalyptus regnans DBH prior to harvesting on the West Barham coupe

20

18

16

14

12

10

8 Number of trees

6

4

2

0 30-39.9 40-49.9 50-59.9 60-69.9 70-79.9 80-89.9 90-99.9 100-109.9 110-119.9 120-129.9 130-139.9 140-149.9 150-159.9 DBH class (cm) Note: The frequency distribution is based on all trees recorded in seven transects.

Two age classes of eucalypts were apparent in the field. Trees of 1919 fire regrowth origin (dated by ring counts of stem cross sections) occurred over most of the coupe. A smaller number of older trees were located on lower slopes and near gullies, areas apparently unburnt in the 1919 fire or not burnt with sufficient intensity to kill the eucalypts. The older trees were most likely the result of the 1890's fire (pers. comm., I. Roberts former Forest Mapper, DSE, Forrest.). Remnant old trees of mountain ash (maybe 200 years old) have survived in sheltered gullies in the vicinity of the coupe.

An isolated small patch (half a dozen trees) of small diameter E. obliqua x regnans occurred on the ridge.

3.3.2 Vegetation after timber harvesting All species recorded together with the percentage of quadrats on which they occurred for the seven transects chosen for remeasurement, before and after harvesting are recorded in Appendix 2.

Species richness There was an increase in the number of plant species in the early years following harvesting, with 48 species recorded on the coupe prior to harvesting and 65 species one year after harvesting. Forty-one species were present 17 years post-harvest. The early increase was due to a large increase in forb and grass species that had not previously been recorded in the area (Figure 3.3). On the other hand, many fern species were no longer located on the quadrats following harvesting. The mean number of species recorded per quadrat increased following harvesting from 7.6 to 12.2 three years after harvesting and was 10.3 at 17 years after harvesting (Appendix 2). Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria 33

Figure 3.3 Number of species in each plant lifeform group pre- and post-harvesting, West Barham coupe

20

Pre-harvest 15 Post - Year 1

Post -Year 2

Post - Year 3

Post - Year 17 10 Number of species

5

0 Trees and shrubs Forbs Grasses Sedges and Tree ferns and Epiphytic ferns graminoids ground ferns

Community composition In all NMDS analyses, the first two dimensions were judged to be sufficient to represent the pattern of floristic variation. The 2D NMDS of the frequency data (stress=0.117) is shown in Figure 3.4. It clearly separates the three age classes. Pre-harvest transects are at the left of the ordination, Year 2 transects are at the right and Year 17 transects are intermediate, appearing somewhat closer to pre-harvest than Year 2 composition. Fitted vectors for the binary variables pre-harvest vs Year 2 and Year 2 vs Year17 are both highly correlated with the ordination (pre-Yr2: r=0.96, p<0.001; Yr2-Yr17: r=0.92, p=0.001). The lengths of the plotted vectors are proportional to their correlations. The angle between the vectors is 176°, indicating that the floristic change from Year 2 to Year 17 is virtually opposite to the direction of change pre-harvest to Year 2. This indicates that the floristic composition of the Year 17 understorey has become more similar to its pre-harvest condition.

Figure 3.4 NMDS ordination in 2D (stress=0.117) of vegetation frequency data recorded in the West Barham coupe

Pre-harvest

Year 2

Yr2-Yr17 Year 17 Axis 2

Pre-Yr2

Axis 1

Note: The lengths of the plotted vectors are proportional to their correlations. The points represent quadrat data for each of the seven transects. 34 Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria

ANOSIM tests (Table 3.1) suggest that the differences in floristic composition among the three age classes observed in the ordination (Figure 3.4) are significantly different. The largest difference is between pre-harvest and Year 2, which is largely attributable to the influx of colonising plants and decline of ferns.

Table 3.1 ANOSIM R values for each pair of age classes for the West Barham coupe frequency data Pre-harvest Year 2 Year 2 0.9767 Year 17 0.7366 0.8882 Note: The overall R, comparing all three age classes was 0.8348. All tests are significant (p<0.001), indicating floristic differences between each age class.

The permutation tests identified the species that contribute to the floristic differences detected by ANOSIM (Tables 3.2-3.4). Tables 3.2, 3.3 and 3.4 list species with significant differences in mean percentage frequency between age classes.

Sixteen species were recorded at significantly higher frequencies two years after harvesting (Table 3.2). Nine of these were new species that had not previously been recorded on the coupe. New species included herbs such as Senecio linearifolius (fireweed groundsel) as well as the shrub/small tree species Olearia lirata (snow daisy-bush), Ozothamnus ferrugineus and Prostanthera lasianthos and graminoids/grasses e.g. Carex appressa (tall sedge) and Juncus spp. Two ground fern species, Histiopteris incisa and Hypolepis rugosula increased significantly following harvesting.

Seven species recorded a significant decrease in frequency two years after harvesting. These were all ferns apart from the liane, Clematis aristata.

There were significant changes in the floristic composition of the regenerating vegetation as it developed from the early years post-harvest to 17 years (Table 3.3). Seven species showed a significant increase in frequency. This included four ferns, the tree ferns Cyathea australis and Dicksonia antarctica and ground ferns Blechnum wattsii and Polystichum proliferum, the shrubs Olearia argophylla and Coprosma quadrifida and the liane Clematis aristata.

Eleven species decreased in frequency two years post-harvest. Five of these were species that had not been present in the pre-harvest vegetation and were again absent from the coupe at 17 years such as Senecio linearifolius, Juncus bufonius (toad rush) and Hypochoeris radicata. Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria 35

Table 3.2 Species for which permutation tests suggested a significant difference in percentage frequency of occurrence on quadrats between pre-harvest and year 2, West Barham coupe Mean Frequency Species Pre-harvest Year 2 Probability Species more frequent 2 years after harvesting Ozothamnus ferrugineus 0 69.4 0.0001*** Senecio linearifolius 0 37.4 0.0001*** Histiopteris incisa 4.3 69.7 0.0001*** Hydrocotyle hirta 5.7 79.4 0.0001*** Acacia melanoxylon 31.6 68.1 0.0059** Prostanthera lasianthos 0 13.3 0.0040** Carex appressa 0 39.0 0.0040** Hypochoeris radicata1 0 18.9 0.0040** Juncus bufonius 0 23.4 0.0040** Pimelea axiflora 13.0 48.0 0.0245* Olearia lirata 0 17.1 0.0194* Juncus planifolius 0 13.1 0.0212* Coprosma hirtella 2.9 33.4 0.0212* Hypolepis rugosula 2.9 24.9 0.0496* Australina pusilla ssp. muelleri 3.0 18.9 0.0231* Anthoxanthum odoratum1 0 17.3 0.0212* Species less frequent 2 years after harvesting. Dicksonia antarctica 91.4 59.4 0.0021** Microsorum pustulatum 59.4 4.3 0.0001*** Polystichum proliferum 51.7 28.6 0.0437* Grammitis billardierei 25.9 1.6 0.0068** Asplenium bulbiferum 21.7 4.3 0.0424* Rumohra adiantiformis 17.3 0 0.0209* Clematis aristata 52.0 15.7 0.0232* 1 denotes introduced species 36 Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria

Table 3.3 Species for which permutation tests suggested a significant difference in percentage frequency of occurrence on quadrats between year 2 and year 17, West Barham coupe Mean Frequency Species Year 2 Year 17 Probability Species more frequent at 17 compared to 2 years Coprosma quadrifida 18.7 56.6 0.0008*** Clematis aristata 15.7 53.7 0.0037** Olearia argophylla 20.4 44.9 0.0399* Cyathea australis 1.4 30.1 0.0087** Blechnum wattsii 30.9 74.3 0.0014** Polystichum proliferum 28.6 57.3 0.0477* Dicksonia antarctica 59.4 90.0 0.0155* Species less frequent at 17 compared to 2 years Hydrocotyle hirta 79.4 1.6 0.0008*** Senecio linearifolius 37.4 0 0.0008*** Acacia melanoxylon 68.1 34.6 0.0020** Ozothamnus ferrugineus 69.4 30.4 0.0093** Histiopteris incisa 69.7 26.1 0.0014** Coprosma hirtella 33.4 4.3 0.0244* Australina pusilla ssp. muelleri 18.9 1.4 0.0135* Anthoxanthum odoratum1 17.3 0 0.0200* Juncus planifolius 13.1 0 0.0200* Hypochoeris radicata1 18.9 0 0.0043** Juncus bufonius 23.4 0 0.0050** 1 denotes introduced species

Only two species were considered to have a significant decrease in frequency at year 17 compared to pre-harvest levels (Table 3.4). These were both epiphytic ferns, Grammitis billardierei and Microsorum pustulatum.

Eight species were recorded as significantly more frequent at 17 years post-harvest. Two ground ferns, Blechnum wattsii and Histiopteris incisa increased in frequency as did six shrub/small tree species, Coprosma quadrifida, Olearia argophylla, Pimelea axiflora, Olearia lirata, Ozothamnus ferrugineus and Tasmannia lanceolata. Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria 37

Table 3.4 Species for which permutation tests suggested a significant difference in percentage frequency of occurrence on quadrats between year 17 and pre-harvest, West Barham coupe Mean Frequency Species Pre-harvest Year 17 Probability Species more frequent 17 years post-harvest Pimelea axiflora 13.0 71.0 0.0017** Olearia lirata 0 20.3 0.0060** Ozothamnus ferrugineus 0 30.4 0.0060** Coprosma quadrifida 30.3 56.6 0.0147* Tasmannia lanceolata 0 11.9 0.0224* Olearia argophylla 18.7 44.9 0.0324* Blechnum wattsii 44.1 74.3 0.0194* Histiopteris incisa 4.3 26.1 0.0219* Species less frequent 17 years post-harvest Grammitis billardierei 25.9 3.0 0.0098** Microsorum pustulatum 59.4 13.0 0.0010**

Temporal pattern of early species establishment Seedling establishment was observed within three weeks of the site being treated to encourage eucalypt regeneration by soil disturbance with a bulldozer and hand sowing of eucalypt seed. Seedlings of Eucalyptus spp., Acacia melanoxylon, Hedycarya angustifolia and Pimelea axiflora were recorded at this time. By six weeks, prolific seed germination of the above species as well as Nematolepis squamea ssp. squamea, Ozothamnus ferrugineus, and the herbs Hydrocotyle hirta, Cirsium vulgare, and Senecio spp. were recorded. Seasonal conditions immediately following site treatment were favourable for germination, with ample rain interspersed with sunny periods.

Regrowth from surviving rootstock for the ground-ferns Blechnum wattsii and Polystichum proliferum, the shrub Olearia argophylla and the liane Clematis aristata was recorded at this early stage. By 19 weeks, fronds of the ground-ferns had reached full length.

Herbs Thirty-two species of vascular plants appeared after harvesting that had not previously been recorded on the coupe (Figure 3.3). Most of these were herbs. Most of these species peaked in occurrence at two or three years post-harvest and then declined. As there was no further recruitment, these species had largely disappeared from the coupe by 5 years.

Twelve introduced species were recorded in the area following harvesting with Anthoxanthum odoratum (sweet vernal-grass), Holcus lanatus (Yorkshire fog), Hypochoeris radiata, Agrostis capillaris var. aristata and A. capillaris var. capillaris surviving into the third year of regeneration. The remaining introduced species occurred at very low frequencies and were no longer recorded after three years. Rubus fruticosus spp. agg. (blackberry), in the form of small seedlings, was the only introduced species recorded on quadrats after 17 years.

The seven grasses that invaded after harvesting (Figure 3.3) were predominantly pasture grasses that didn’t persist beyond the early years. Tetrarrhena juncea, which occurred prior to harvesting was the only grass still present at 17 years (Figure 3.5). 38 Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria

Figure 3.5 Percentage frequency of occurrence on quadrats of selected plant species on the West Barham coupe pre-and post-harvesting

100

90

80

70

60 Pre-harvest Post - Year 2 50 Post - Year 3 Post - Year 17 40

30

20 Frequency of occurrence (%)

10

0

a a s* ta a a a is on ylla us s u lius e c is yl folia me h ti c m ti ine hir o nc attsii in or ox ua pres le ju w tarc f us q ug p ty a is nti an g a o an r a el s s argop err te proliferum i a f ex oc num a di m r r h ni op a ia lep us a d arrhen o ti a arya an leari n Pimeleaannia axiflora lanceolataC Holcus lanat r s is r c ato Hy necio linearif Blec k H tichum cac O m e Tet c A dy em ham S Di moh He N ot Tas Polys Ru Oz

* Introduced species.

Many of the introduced species and native herbs such as Senecio spp., Solanum aviculare (kangaroo apple) and Pelargonium australe (austral stork's-bill) flowered in their first year and quickly proceeded through their life cycles. These species were short lived and peaked in occurrence at two years. Pelargonium australe and Solanum aviculare had virtually died out by two and three years respectively.

Six species of Juncus were recorded in the early years post-harvest, with J. planifolius (broad leaf rush) being most frequent. These were restricted to specific sites created by timber harvesting operations, i.e. compacted, waterlogged soils on landings and snig tracks. Juncus spp. were not recorded at 17 years post-harvest.

Carex appressa which was present in the study area but not recorded on quadrats before harvesting, became very common after harvesting. It occurred on 44% of quadrats at three years and was still present at 17 years post-harvest (Figure 3.5).

A surprising record on the study area after harvesting was Isolepis wakefieldiana (tufted club-sedge), a species not previously recorded in the Otways and considered rare in Victoria and Australia.

Ferns All fern species except Histiopteris incisa and Hypolepis rugosula recorded a reduction in numbers in the early years following harvesting. Histiopteris incisa and H. rugosula were successful recolonisers on the exposed site with large quantities of sporelings being observed in the early years, particularly for H. incisa. It maintained a significant increased frequency at 17 years compared to pre-harvest levels (Table 3.4).

Dicksonia antarctica, Polystichum proliferum and Blechnum wattsii were the dominant fern species prior to harvesting. These species are able to regenerate vegetatively and have done so where their rootstocks were intact. In the early years, higher survival was recorded in locations where tree ferns were protected under heaped timber harvesting Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria 39 debris and where the soil had not been disturbed. Their frequency of occurrence on quadrats was substantially reduced in the early years following harvesting but had increased significantly by 17 years. However, their numbers were reduced, a feature which was not adequately reflected in the recorded frequency values. The density of ferns 17 years after harvesting was still much lower than the almost continuous layer of tree ferns and ground-ferns that existed before harvesting.

Only two plants of Cyathea australis recorded on quadrats survived to the first year post- harvesting. One notable 7 m tall plant was still standing at the first year post-harvest but its fronds had largely died back and it did not survive to the second year assessment. The frequency of C. australis increased with time through sporeling recruitment with its frequency increasing to 30% by 17 years.

The frequency distribution of Dicksonia antarctica and Cyathea australis tree fern size 17 years post-harvest is shown in Figure 3.7. The majority of tree ferns were D. antarctica. Recruitment at this age was high with many young plants with heights less than 0.5 m. Additionally, there were many smaller plants without a definable trunk and sporelings that were not included in the measurements. Sporelings and young plants of D. antarctica were observed growing on a range of substrates, such as rotted logs, tree stumps, fallen or standing tree fern trunks and soil (see Figure 3.6). C. australis was generally found growing on soil.

Figure 3.6 Young tree fern (D.antartica) growing on cut stump, West Barham coupe 40 Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria

Figure 3.7 Frequency distribution of tree fern height (m) on quadrats in the West Barham coupe, 17 years after harvesting.

12 0

10 0

80

60 Dicksonia antarctica Cyathea australis

40 Number of tree ferns tree of Number

20

0 0.1-0.49 0.5-0.99 1.0-1.49 1.5-1.99 2.0-2.49 2.5-2.99 Trunk Length Class (m)

Note: Only tree ferns with a definable trunk greater than 10 cm were included.

Epiphytic ferns All epiphytic ferns were adversely affected by harvesting (Figure 3.3). Four species of filmy fern, Hymenophyllum australe (austral filmy-fern), H. cupressiforme, H. rarum and Polyphlebium venosum were recorded before harvesting, and none of these were observed following harvesting. Ctenopteris heterophylla was not recorded on quadrats following harvesting.

Microsorum pustulatum, common before harvesting, was hardier than other epiphytic species and occasional plants were able to reshoot from surviving rhizomes and survive in full sun. Grammitis billardierei decreased in frequency from 27% to 2% at two years with little further recovery to 17 years. Rumohra adiantiformis with a pre-harvest frequency of 17% was not recorded in the first three years after harvesting but at 17 years it was recorded on 6% of quadrats. While M. pustulatum and G. billardierei showed recovery, their decreased frequency at 17 years is still a significant change compared with pre-harvest levels (Table 3.4).

These epiphytic ferns were recorded growing on a range of substrates, with Grammitis billardierei and Rumohra adiantiformis growing on rotted logs, eucalypt stumps, bark of Prostanthera lasianthos and Olearia argophylla and on dead and living Dicksonia antarctica trunks. Microsorum pustulatum occurred on the widest range of hosts being recorded on the above as well as Ozothamnus ferrugineus, Acacia melanoxylon, Nematolepis squamea ssp. squamea and Hedycarya angustifolia. Ozothamnus ferrugineus would not provide long-term substrate for epiphytic ferns as this species was approaching senescence.

Understorey trees and shrubs All tree and shrub species recorded on quadrats before harvesting were present on quadrats following harvesting, at similar or increased frequencies, except for Bedfordia arborescens (Appendix 2). Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria 41

Seedling establishment Seed germination was the major mode of regeneration. The number of plants of seedling origin of shrub and tree species recorded on the 1 m2 subplots one, two, three and seventeen years after harvesting is indicated in Table 3.5. Acacia melanoxylon, Nematolepis squamea ssp. squamea and Hedycarya angustifolia the dominant understorey species prior to harvesting regenerated successfully with large numbers of seedlings being recorded after harvesting. The low shrubs Pimelea axiflora and Coprosma quadrifida, common before harvesting, also recorded prolific seed germination.

Ozothamnus ferrugineus (Figure 3.5) and Olearia lirata were successful colonisers, neither being present on the coupe prior to harvesting.

Table 3.5 Mean number of plants of seedling origin per m2 (and standard deviation) for shrub and tree species recorded on sub-plots post-harvesting, West Barham coupe Years Since Harvesting Species 1 2 3 17 Nematolepis squamea ssp. squamea 7.34 (12.54) 7.32 (16.58) 5.03 (9.61) 0.35 (0.74) Hedycarya angustifolia 6.97 (9.88) 3.71 (5.28) 3.06 (4.43) 0.20 (0.63) Pimelea axiflora 4.28 (11.09) 1.67 (3.27) 1.12 (2.43) 0.19 (0.43) Acacia melanoxylon 3.77 (6.11) 2.14 (3.39) 1.79 (2.90) 0.07 (0.39) Ozothamnus ferrugineus 3.00 (7.29) 1.64 (3.92) 1.23 (1.96) 0.01 (0.12) Eucalyptus sp. 2.55 (4.00) 1.97 (3.43) 1.81 (3.17) 0.09 (0.28) Coprosma hirtella 0.54 (1.30) 0.30 (0.81) 0.36 (0.99) 0.01 (0.12) Coprosma quadrifida 0.42 (1.12) 0.22 (0.59) 0.25 (0.69) 0.20 (0.41) Olearia argophylla 0.14 (0.88) 0.06 (0.29) 0.07 (0.31) 0.03 (0.17) Olearia lirata 0.07 (0.31) 0.12 (0.36) 0.09 (0.28) 0.06 (0.30) Prostanthera lasianthos 0.01 (0.12) 0.04 (0.21) 0.04 (0.20) 0.01 (0.12) Pittosporum bicolor 0.01 (0.12) 0 0.01 (0.12) 0.01 (0.12) Pomaderris aspera 0.01 (0.12) 000 Mean number of woody plants of 29.13 19.19 14.83 1.23 seedling origin per m2 Note: Seedlings were recorded on 68 permanent 1 m2 sub-plots. Only plants rooted on the quadrats were recorded.

The total number of seedlings of woody plant species recorded on 1 m2 sub-plots decreased by a half from year one to year three from approximately 30 to 15 seedlings per m2 (Table 3.5). The number of woody plants had declined due to natural thinning to around 1 per m2 at 17 years. Competition between the densely stocked seedlings would be expected to be a major cause of mortality in the early years. The decrease in the number of seedlings with time suggests that there is one main period of germination of soil-stored seed that occurs soon after harvesting and regeneration operations are completed. Although a little germination of Nematolepis squamea ssp. squamea, Olearia argophylla, Prostanthera lasianthos and Acacia melanoxylon was still occurring at three years, it is unlikely that these seedlings would be able to compete with advance plants.

Shrub species that can regenerate under the canopy, such as Tasmannia lanceolata, Pittosporum bicolor and Coprosma quadrifida, increased in frequency at 17 years compared with pre-harvest levels. Tasmannia lanceolata was not recorded on quadrats prior to harvesting. Seedlings were not observed until 3 years after harvesting after which its numbers built up to a frequency of 12% at 17 years. Further increases in the representation of these species are expected over time.

Seedling development The average maximum height for seedlings of woody species on 1 m2 sub-plots at two and three years and mean height on quadrats at 17 years is shown in Table 3.6. Seedling height varied considerably within and between quadrats so the heights presented in 42 Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria

Table 3.6 are intended only to indicate the relative height of different species. Small seedlings, less than 10 cm, at year 2 and 3 were generally associated with poor seedbeds (e.g. compacted tracks) or more recent germination.

Table 3.6 Mean maximum height1 of seedlings of woody plants and Senecio linearifolius assessed at 2 and 3 years, and mean height 17 years post-harvesting, West Barham coupe Height and (Height range) in m Species Year 2 Year 3 Year 17 Eucalyptus spp. 2 0.93 (0.01-4.5) 1.84 (0.02-7.0) 26.4 (20-30.6) Ozothamnus ferrugineus 1.10 (0.01-3.0) 1.95 (0.15-3.5) 7.5 (6.0-11.2) Senecio linearifolius 0.85 (0.02-2.5) not measured not present Pimelea axiflora 0.56 (0.02-1.7) 0.86 (0.10-2.0) 5.0 (2.0-8.0) Nematolepis squamea ssp. squamea 0.28 (0.03-0.9) 0.59 (0.02-1.4) 7.5 (2.5-13.0) Acacia melanoxylon 0.24 (0.03-2.0) 0.34 (0.02-2.4) 11.1 (5.0-19.8) Hedycarya angustifolia 0.20 (0.01-0.8) 0.25 (0.02-1.2) 7.0 (0.5-10.0) Coprosma hirtella 0.16 (0.03-0.4) 0.39 (0.10-1.4) 4.5 (3.0-6.0) Note: Seedlings were recorded on 68 quadrats. 1 Shrubs with fewer than 10 height measurement records were not included. 2 For eucalypts, the actual mean height of all seedlings recorded on 1 m2 sub-plots was calculated for each year.

Eucalyptus spp., Ozothamnus ferrugineus and Senecio linearifolius were consistently taller than other species and had overtopped the rest of the vegetation as early as two years. The rapid early growth of O. ferrugineus and S. linearifolius reflects their shorter life span (especially for S. linearifolius) than that of shrub species that will be long-term understorey components. By three years, S. linearifolius had died out in some areas and its frequency on quadrats was on the decline. It was not recorded on the coupe at five years.

Ozothamnus ferrugineus was still present at 17 years but by this age, many plants had either fallen over or were bent over and many dead plants were noted. It had kept pace with the growth of the general understorey canopy, with the largest plants recording heights of 11 m and diameters of 13 cm at 17 years.

Different growth rates of the understorey species were observed. The shrub Pimelea axiflora was initially quick growing and after three years was taller than most understorey tree and shrub species. While it maintained a rapid growth rate, with larger specimens reaching heights of 8 m and diameters of 10 cm at 17 years, it was overtopped by other understorey species by 17 years post-harvest.

Nematolepis squamea ssp. squamea, Acacia melanoxylon and Hedycarya angustifolia, species that will form a major component of the long-term understorey of the developing forest had similar growth rates up to two years. By three years, N. squamea ssp. squamea was generally taller than the other two species. Occasional tall seedlings of A. melanoxylon were recorded and its apparent slower growth in the early years may relate to it being preferentially browsed by wallabies.

By 17 years, Acacia melanoxylon was the tallest of the understorey species recording heights of around 20 m and diameters of up to 19cm. This was approximately two thirds of its general pre-harvest height and one half the diameter. The general understorey canopy height of the taller species below A. melanoxylon, i.e. H. angustifolia, N. squamea ssp. squamea and Olearia argophylla, was around 7-10 m with diameters of up to 10 cm. Prostanthera lasianthos tended to be slightly taller than this canopy layer, recording heights of 12 m and diameters up to 15 cm. Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria 43

Younger plants of Pittosporum bicolor and Tasmannia lanceolata generally recorded heights of around 1.5 m at age 17 years. One advanced plant of P. bicolor recorded a height of 5 m at 17 years.

Effect of seedbed treatment The effect of the regeneration operations intended to encourage eucalypt regeneration on seedling germination of understorey species was examined after two years. The results were reported in Harris (1989) and are summarised below. The establishment of woody understorey seedlings varied due to seedbed, and significant differences (p<0.001) between the number of woody understorey seedlings growing on the various seedbeds were found (Table 3.7). Bare soil seedbeds had the greatest germination. These sites were suitable for the regeneration via soil-stored seed of the main understorey shrub and tree species, Acacia melanoxylon, Hedycarya angustifolia, Nematolepis squamea ssp. squamea and Pimelea axiflora.

Table 3.7 Mean number of understorey shrub and tree seedlings for each seedbed class, assessed 2 years post-harvesting Seedbed type Number of sub-plotsa Mean number of woody understorey seedlings per 1 m2 sub-plot Loose, bare soil 22 34.1 d1 Bare soil with sealed surface 6 23.3 cd Compacted bare soil 12 18.5 bc Soil under timber harvesting debris 9 3.2 ab Heavy debris, large diameter logs 10 1.2 a Loose fragmented bark, wood, twigs 6 8.5 bc Undisturbed litter layer 3 2.7 ab Note: Seedlings were recorded on sixty-eight 1 m2 sub-plots. a Each sub-plot was assigned only one seedbed type for this analysis of variance. 1 Different letters denote significant differences (p<0.001)

Vegetative regeneration Although seed germination was the main mode of regeneration, a number of species also recovered vegetatively from surviving rootstock. Regrowth from surviving rootstock is an important mode of regeneration for Olearia argophylla, Hedycarya angustifolia and Coprosma quadrifida. Although the number of coppice plants is small compared with the number of seedlings, (e.g. only four coppice plants of H. angustifolia were recorded on sixty-eight 1 m2 subplots at two years compared with over 200 seedlings) coppice regrowth was able to dominate a localised site. Regrowth plants of H. angustifolia and O. argophylla were generally multi-stemmed and occupied greater space than their seedling counterparts. Hedycarya angustifolia seedlings were reasonably slow growing with a mean maximum height of 20 cm at two years post-harvest, whereas coppice regrowth on quadrats were well over 1 m tall. The proportion of plants of regrowth origin compared with seedlings increased with time as many seedlings died whereas there was a high survival rate of coppice plants.

A notable specimen of Olearia argophylla, had a large lignotuber, over 80 cm in diameter. Twelve new stems had grown from this lignotuber, the largest stems with diameters of around 10 cm at 17 years post-harvest. This plant may have been a survivor of a number of previous wildfire events.

Coppice regrowth plants and seedlings of Bedfordia arborescens were recorded in the early stages of regeneration but these did not survive to 17 years. Bedfordia arborescens was the only shrub species to decline in frequency after harvesting. Very few plants of B. arborescens were recorded prior to harvesting though.

Stumps of A. melanoxylon were observed to be coppicing one year following harvesting but little of this coppice regrowth survived into the second year. Macropod browsing may 44 Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria

be a factor in the decline of coppice regrowth as reported by Hill and Read (1984). The liane Clematis aristata was also observed to coppice readily.

Eucalypt regeneration One year after sowing, approximately 26,000 eucalypt seedlings per hectare had established. Results from the assessment three years after sowing indicated that seedling numbers had declined by 30% to 18,000 seedlings per hectare. After 17 years, the stand had naturally thinned to around 750 eucalypts per hectare with most trees having a DBH of 10-20 cm (Figure 3.8).

Eucalyptus obliqua x regnans occurred on 13% of quadrats 17 years after harvesting while it hadn’t been recorded on quadrats prior to harvesting. The overstorey was almost pure E. regnans prior to harvesting.

Figure 3.8 Frequency distribution of eucalypt DBH 17 years post-harvest on the West Barham coupe

25

20

15

Eucalyptus regnans x obliqua Eucalyptus regnans 10 Number of trees

5

0 5-9.9 10-14.9 15-19.9 20-24.9 25-29.9 30-34.9 35-39.9 DBH Class (cm) Note: The frequency distribution is based on all trees recorded in seven transects.

Effect of seedbed and shade on eucalypt germination and growth The spatial pattern of eucalypt seedlings was not even but of a clumped nature. It was hypothesised that this was related to the uneven distribution of receptive seedbeds. A detailed examination of the effect of seedbed condition and overwood shade on eucalypt regeneration was carried out at two years. The results were reported in Harris (1989) and are summarised below.

Seedbed condition and amount overwood shade was found to have a significant effect on eucalypt germination and subsequent growth. Large differences in the receptivity of different seedbeds were apparent. The growth rate and number of eucalypt seedlings was greatest on areas of maximum soil disturbance that received full sun (Table 3.8). Two years after harvesting, 95% of eucalypt seedlings occurred on seedbeds where the soil surface had been bared to mineral earth and cleared of timber harvesting debris. This type of seedbed occupied 56% of the area.

No seedlings were observed where the litter layer was undisturbed or where large diameter logs had been heaped and covered the localised soil surface. Large heaps of Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria 45 unutilised logs (up to 4 m in height) were encountered on over 20% of quadrats post- harvest. These log heaps were still apparent at 17 years.

Table 3.8 Mean number of eucalypt seedlings on each seedbed type within each overwood shade class assessed 2 years post-harvestingα Seedbed type Mean Number of Eucalypt Seedlings per 1 m2 sub- plot Full Sun Shade

Loose, bare soil 6.8 cβ (9) χ 1.4 bc (13) Bare soil with sealed surface 6.2 bc (5) 3.0 c (1) Compacted, bare soil 1.4 ab (10) 1.0 bc (2) Soil under timber harvesting debrisδ - (0) 0.33 b (9) Heavy debris – large diameter logsδ -(0)0 a (10) Loose fragmented bark, wood, twigs 0.25 a (4) 1.5 bc (2) Undisturbed litter layer - (0) 0 a(3) Note: Seedlings recorded on sixty–eight 1 m2 sub-plots. α As a significant (p<0.01) interaction was found between seedbed and shade, it was necessary to compare the number of eucalypts on each seedbed within each shade class. β Different letters (a,b,c,d) denote significant differences (p<0.05) between seedbed types within either “full sun” or “shade” classes. χ Values in parentheses are the number of 1 m2 sub-plot of each seedbed type. Each sub-plot was assigned only one seedbed type. δ All sub-plots that occurred on these seedbed types were recorded as occurring under shade, as although the sub-plot itself may have received full sun, the seedbed would have been shaded by the timber harvesting debris on the sub-plot.

While a large proportion of the coupe was clearfelled, some transects sampled areas where eucalypt overwood remained after harvesting. Shade effects from retained eucalypts were detected. On the seedbed class, “loose, bare soil", a significantly greater (p<0.01) number of eucalypts seedlings occurred in full sun than in partial shade (Table 3.8). Height growth on bare soil seedbeds was significantly greater in full sun than in shade (p<0.001) (Table 3.9). This combination would appear to represent the optimum germination and growing condition for eucalypt seedlings.

Table 3.9 Mean heights of eucalypt seedlings as influenced by seedbed (bare soil seedbed types onlyα) and overwood shade, assessed two years post-harvesting Number of Mean height Height range quadrats (cm)β (cm) Seedbed type Loose, bare soil 18 96 b χ 2-450 Bare soil with sealed surface 6 79 ab 2-250 Compacted, bare soil 6 34 a 2-150 Overwood shade class Full sun 17 113 δ 2-450 Partial shade 13 37δ 2-160 Note: Seedlings assessed on thirty 1 m2 sub-plots. α Only seedlings on quadrats of bare soil seedbed were included in the analysis of variance because so few seedlings occurred on the other seedbed types. β Calculated using mean height on each quadrat χ Different letters indicate significant (p<0.05) differences δ Difference is significant (p<0.001) 46 Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria

Changes over time An indication of the recovery of the vegetation over the period of the study is provided in Figure 3.9.

Figure 3.9 West Barham coupe (looking along transect 5 to the edge of the coupe): immediately after harvesting but prior to mechanical pushing operation (A); 1 year post-harvest (B); 2 years post-harvest (C); and 17 years post-harvest (D)

A B

D

C Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria 47

4 DISCUSSION

The vegetation of both coupes was categorised as wet forest by Ecological Vegetation Class classification (VicRFASC 2000). However, on the Redwater Track coupe the influence of the tertiary sands lead to a number of additional species more typical of drier sites. Even so, the floristic responses to clearfell timber harvesting were similar on the Redwater Track and West Barham coupes.

Regeneration via seed For both coupes, most species that showed an increase in frequency/cover following harvesting regenerated via seed germination. The rapid appearance of prolific numbers of seedlings indicates a vast reservoir of soil-stored seed for many species. The seed source on site is vital to the process of enabling many species to re-establish following the major disturbance of timber harvesting.

Both short-lived plants such as Senecio spp., Hydrocotyle hirta and Juncus spp. and long- lived woody plants regenerated via soil-stored seed. Seeds of Acacia melanoxylon, Bedfordia arborescens, Coprosma quadrifida, Hedycarya angustifolia, Olearia argopyhlla, Pomaderris aspera and Prosthanthera lasianthos have been recorded in soil-stored seed banks in Victorian E. regnans vegetation (Tumino 1992). Acacia melanoxylon, Pomaderris aspera, Zieria arborescens and Nematolepis squamea ssp. squamea have long- lived seeds that can accumulate in the soil (Cremer and Mount 1965). On both coupes, N. squamea ssp. squamea produced the greatest number of seedlings compared with other species.

The tall shrub Ozothamnus ferrugineus was not present on either coupe prior to harvesting but prolific and immediate appearance of O. ferrugineus seedlings suggest that seedlings arose not as a result of wind blown seed but of germination of long-lived, dormant seed buried in the soil produced by plants that had died out in an earlier stage of the vegetation's development. Ozothamnus ferrugineus is a very common component of timber harvesting regeneration in the Otways regardless of the forest type. It persisted longer on the West Barham coupe than the Redwater coupe where no trace of this species was evident at 16 years.

Most of the 38 herbaceous and sedge species that appeared following harvest had disappeared from the coupes within five years. While no longer present on the coupes, these species are likely to be represented in the soil seed bank, dormant until the next major disturbance. Tumino (1992) reporting on soil stored seed banks in E. regnans vegetation of three ages in Sherbrooke Forest found that herbaceous plants dominated the seed bank. Early successional species were considered to generally disperse seed through time. As these species tend to be short-lived and shade intolerant, their regeneration strategy is to germinate quickly after disturbance, have a fast growth rate and produce many small seeds to store in the soil. The seed stage phase of their life cycle is much longer than the plant phase. Tumino found that seedbanks differed greatly from the contemporary vegetation and concluded that seedbanks can provide insight into the potential floristic diversity and structure of vegetation communities following disturbance.

There was one main period of germination of soil-stored seed that began soon after the completion of eucalypt regeneration operations. Shrub and tree species became dominant at an early age. Seedlings that appeared after the initial flush of germination were handicapped as they had to compete with advanced seedlings that had germinated earlier on site. At three years, Eucalyptus spp. dominated the vegetation of the Redwater Track coupe and Eucalyptus spp. and Ozothamnus ferrugineus the West Barham coupe. The growth of the remaining species would have depended in part, on how they survived under shade from these species. Competition between the densely stocked seedlings for 48 Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria

light, space and other factors would have been intense and would be expected to be a major cause of mortality in the early years.

Plant coverage of the ground increased rapidly as the vegetation developed. On the Redwater Track coupe at three years, average plant coverage on 1 m2 sub-plots was 92% indicating that there was little available mineral earth seedbed for further seedling germination. Only shade tolerant species that are able to germinate and develop under the canopy such as Coprosma quadrifida, Tasmannia lanceolata and Pittosporum bicolor and a range of fern species will increase in abundance over time. Coprosma quadrifida, T. lanceolata and P. bicolor have seed enclosed in fruits that are dispersed by birds. On both coupes, these species increased in frequency with increased time since timber harvesting. The development of the main understorey tree and shrub species was essentially single-aged with the exception of shade tolerant species that can increase in abundance over time and species such as Olearia argophylla and Hedycarya angustifolia where individuals have survived via coppice regrowth from the previous stand.

The stimulation of germination of soil-stored seed can be achieved by a hot regeneration burn as on the Redwater Track coupe or by the mechanical disturbance of the soil with a bulldozer as on the West Barham coupe. One year after harvesting, the approximate number of seedlings of woody plants on the Redwater Track and West Barham coupes was 2,000,000 and 300,000 per hectare respectively. Burning of the timber harvesting debris to create an ash bed rather than clearing it by bulldozer may have been a factor in the increased germination of soil-stored seed. Floyd (1976) observed greater seed germination of woody species in response to burning following timber harvesting in wet sclerophyll forests in Northern NSW. Floyd also reported that the species composition of the regeneration varied depending on the duration and intensity of the fire and depth of buried seed. In laboratory tests, Floyd showed that a light burn (soil heated to 55 degrees C for 100min) is most favourable for germination of Zieria arborescens seed. On the Redwater Track coupe, Z. arborescens regenerated in greatest numbers on seedbeds classified as receiving a light burn. Pomaderris aspera, on the other hand, responded well to burning, regenerating prolifically in areas that received a hot burn and poorly on pockets of unburnt seedbed despite the presence of a seed source. This concurs with Ough and Murphy(1999), who recorded significantly greater cover of Pomaderris aspera and lower cover of Zieria arborescens following high intensity wildfire compared with low intensity wildfire sites.

Fire is not a pre-requisite for the germination of many species. On the West Barham coupe, the regeneration burn failed requiring the coupe to be mechanically disturbed. Disturbance of the soil with a bulldozer and the opening of the canopy were adequate stimulus for the germination of soil-stored seed of Acacia melanoxylon, Nematolepis squamea ssp. squamea, Hedycarya angustifolia, Pimelea axiflora and Ozothamnus ferrugineus. The greatest germination of soil-stored seed occurred on seedbeds that received thorough disturbance where the soil surface had been cleared to mineral earth and was loose and friable. The seedbed conditions created to encourage eucalypt regeneration were also suitable for the regeneration of many understorey species with soil-stored seed.

On the West Barham coupe, similar seedbeds were found to be suitable for the germination of eucalypt and woody understorey species seedlings even though the process of seed arrival on the seedbed was quite different for each. Eucalypt seed was largely (some natural seedfall is assumed to have occurred) artificially sown onto the seedbed and loose bare soil allowed for penetration of the applied seed into the seedbed, whereas seedlings of woody understorey species arose mainly from soil-stored seed already on site. In this case, "loose, bare soil" seedbeds are favourable, as the seed source stored in the top soil is largely intact, while soil disturbance is adequate to stimulate germination of the seed. The lower number of woody understorey seedlings recorded on the "bare soil, sealed surface" and "compacted, bare soil" seedbeds may relate to the removal of some top soil during the regeneration operations or that the seedbed is less conducive to the survival of seedlings. Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria 49

At two years, the number of eucalypt seedlings was found to be significantly (positively) correlated with a number of components of the understorey, including the total number of vascular plant species and the total number of woody understorey seedlings (Harris 1989). Quadrats which recorded a large number of eucalypt seedlings also supported a diverse range of understorey species at two years. Eucalypt seedling height and that of woody understorey species was also highly positively correlated.

While the conditions of high exposure and soil disturbance created for eucalypt regeneration were favourable for seedling regeneration of a number of understorey tree and shrub species, most fern species and understorey species that regenerate vegetatively were negatively affected.

As species respond differently, the method of regeneration treatment has the potential to affect the relative abundance of various species. The current practice of burning some coupes and not others provides a range of conditions for the regeneration of a variety of species. The response of different species to different regeneration treatments would be a valuable area for future research.

Vegetative regrowth For the Redwater Track coupe, species capable of vegetative regrowth were adversely affected by harvesting. Considerable loss of rootstock of these species occurred during timber harvesting operations as plants are uprooted, flattened, buried or otherwise damaged. Further loss of rootstock occurs during the hot regeneration burn or the mechanical pushing operation required to create a seedbed. On the Redwater Track coupe, Hedycarya angustifolia, Olearia argophylla, Bedfordia arborescens, Tasmannia lanceolata, Coprosma quadrifida, Lomatia fraseria and Dicksonia antarctica declined in frequency following harvesting. On the West Barham coupe, the decline of vegetative resprouting species was not as apparent as there was greater seedling recruitment of Olearia argophylla, Hedycarya angustifolia and Tasmannia lanceolata leading to an increase in frequency for these species by 17 years. However, for O. argophylla and H. angustifolia there was considerable loss of rootstock of original plants leading to an age structure change. On the West Barham coupe, coppice regrowth was often confined to areas under windrows were the timber harvesting debris had been heaped but the ground surface beneath the heaps was not heavily disturbed.

On both coupes, where rootstocks have survived, plants are quickly able to re-establish themselves. Olearia argophylla and Bedfordia arborescens, in particular, developed as large multi-stemmed tall shrubs arising from a lignotuber. Coprosma quadrifida regenerated well from surviving rootstock on the West Barham coupe.

The ability to regenerate vegetatively is an important mechanism to assist understorey species to persist beyond a major disturbance that may kill the eucalypt overstorey. Radiocarbon dating of Dicksonia antarctica and Olearia argophylla by Mueck, Ough and Banks (1996) in 1939 fire regrowth stands in the Central Highlands, Victoria indicated that these species are long-lived with life expectancies equal to or greater than the E. regnans overstorey. Specimens of Dicksonia antarctica were recorded with ages greater than 350 years and Olearia argophylla greater than 230 years. Dicksonia antarctica had survived wildfire via regrowth from a terminal bud at the top of the trunk and O. argophylla from either resprouting from above-ground stems and/or the lignotuber depending on the fire intensity.

Understorey islands Ough and Murphy (1998) proposed the practice of creating “understorey islands” to protect vegetative resprouting species from the effects of mechanical disturbance during clearfelling operations. Machinery is excluded from understorey islands but merchantable timber may still be harvested from within the understorey island. A trial in wet forest of Central Victoria recorded high survival rates of targeted species within the understorey islands in post-clearfelling regeneration. Understorey islands were recommended as a low cost means of retaining in-coupe biodiversity. 50 Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria

A modified version of understorey islands was trialed on a 1919 regrowth E. regnans coupe in the wet forests of the Otways in the 1999/2000 timber harvesting season. Little timber was removed from within the islands so they received less disturbance than understorey islands described by Ough and Murphy (1998). One island was established to protect a range of species that can regenerate vegetatively. The coupe received a hot regeneration burn that was aerially ignited. An inspection of the health of the O. argophylla two years after the burn indicated that while the original stems of the plants were often killed by the burn, most individuals had survived by copious reshooting from the base or where the burn was less intense from reshooting from trunks and stems. Bedfordia arborescens also produced vigorous coppice regrowth. Hedycarya angustifolia plants and Dicksonia antarctica within the island had survived the fire and were reshooting. This area was effective in protecting these long-lived understorey plants.

Ferns Abundant ferns typical of wet forests were a feature of both the Redwater and West Barham coupes prior to harvest. Most ferns declined significantly following timber harvesting and subsequent regeneration operations. Tree fern numbers were reduced on both sites. Cyathea australis rarely survived the harvesting and regeneration operations. Around 16% of Dicksonia antarctica on quadrats survived harvesting operations and were actively growing at 16 years on the Redwater Tracks coupe. A decrease in tree fern numbers following harvesting has been recorded in a number of Victorian studies. Ough and Murphy (1996) quantified tree fern survival in the wet forests of the Central Highlands following clearfell timber harvesting. They found that 14% remained alive and 6% remained upright 2.5 years post-harvest.

While the number of tree ferns after 16/17 years was still less than prior to timber harvesting, significant recruitment of Dicksonia antarctica was occurring on both coupes and Cyathea australis recruitment was proceeding on the West Barham coupe. Numbers will continue to increase over time as the increased shade and shelter conditions on the coupes are conducive to tree fern recruitment.

Dicksonia antarctica trunks are an important substrate for epiphytic ferns and for seedling germination of some shrub and tree species (Ough and Murphy, 1996). Coprosma quadrifida, Tasmannia lanceolata, Acacia melanoxylon and Pittosporum bicolor were recorded growing on D. antarctica in both coupes prior to harvesting. The recovery of D. antarctica, along with improved microclimatic conditions as the vegetation develops, is an important requirement for epiphytic fern recovery. As well as the trunks providing substrate, the fronds of trunked tree ferns cast considerable shade and thus are likely to have an important role in maintaining the moist, stable microclimate necessary for the persistence of many species of ferns and bryophytes (Turner et al, 2000).

The ground ferns, Hypolepis rugosula and Histiopteris incisa increased in frequency on both coupes after harvesting. They have been observed as successful colonisers on many Otway coupes (pers. obs.).

Epiphytic ferns The decline in epiphytic fern species diversity and frequency is an important floristic difference between the pre-harvest and regenerating flora in both coupes. The major cause of loss of epiphytic ferns is due to the extreme conditions of exposure in the early years post-harvest, loss of suitable substrate on which to grow and for the Redwater Track coupe being consumed by fire during the regeneration burn. Decline of epiphytic ferns post-timber harvesting has been recorded in a number of studies in south-eastern Australia (Cook and Drinnan 1984, Harris 1996, Harris 1989, Ough and Ross 1992, Hickey 1994).

None of the four species of Hymenophyllum filmy ferns or the less frequent Tmesipteris obliqua present prior to harvesting had returned to the coupes by 16/17 years. Further monitoring is required to determine when these species will recolonise Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria 51 these sites. Hickey (1994) noted in a floristic comparison of Tasmanian old growth mixed forest with regeneration resulting from timber harvesting and wildfire that epiphytic ferns, in particular filmy ferns, may be representative of a suite of specialised taxa which includes lichens and bryophytes that may be progressively eliminated from sites after successive timber harvesting.

Recovery of some species of epiphytic fern was recorded by 16/17 years. Microsorum pustulatum and Rumohra adiantiformis were present on both sites and low frequencies of Grammitis billardierei and Polyphebium venosum were recorded at this age. The dense eucalypt and understorey shrub and tree canopy had created a more shady, protected environment suitable for the establishment and growth of these species.

Streamside buffers, a requirement of the Code of Forest Practices for Timber Production (NRE 1996) primarily for the protection of water quality and streamside environs are important for protecting vulnerable fern species. They provide a refuge from which fern species can recolonise the coupe, via wind blown spores, when conditions become more amenable. This recolonisation process had begun before the assessment at 16/17 years post-harvest on both coupes.

As epiphytic ferns are sensitive to fire and exposure, the understorey island concept designed to protect vegetative regenerating shrub and tree species and tree ferns may not be as effective in protecting epiphytic ferns. Most epiphytic ferns within understorey islands would probably perish during a regeneration burn or from exposure if the coupe was not burnt, although this has been little studied. In the Otways1999/2000 understorey island trial, some epiphytic species such as Polyphebium venosum, Rumohra adiantiformis and Microsorum pustulatum did survive but only on unburnt tree ferns trunks on areas where the fire had not reached. On burnt tree fern trunks within the understorey island they had succumbed. Where appropriate, extending buffers or locating understorey islands adjacent to buffers and protecting them from the regeneration burn would assist in the protection of vulnerable epiphytic fern species. For maximum efficiency, these areas could be located to protect a range of sensitive understorey species such as vegetative resprouters.

Browsing The native mammal, swamp wallaby (Wallabia bicolor) is common in the Otway forest, especially in young regeneration following timber harvesting (Sebire, 2001). Preferential browsing by swamp wallaby was observed on the West Barham coupe with Acacia melanoxylon, Coprosma quadrifida, C. hirtella, Eucalyptus spp. and Prostanthera lasianthos being the preferred woody species. Advanced seedlings of these species were able to recover following browsing.

For species that produced large numbers of seedlings and grow very rapidly (e.g. eucalypts) browsing did not appear to have a significant effect on the overall regeneration success. The effects of browsing are difficult to determine however without comparative studies of fenced and unfenced plots. Acacia dealbata (silver wattle) seedlings may be browsed and killed by native animals before they exceed a few centimetres in height (Cremer and Mount 1965). As no traces of these seedlings would remain it would be easy to underestimate the effect of browsing on survival. Acacia melanoxylon has been shown to be very susceptible to macropod browsing (Hill and Read 1984).

Eucalypt regeneration Eucalypt regeneration was successful on both coupes as indicated by Stocking Surveys carried out at two years (DSE records Forrest, and Dignan and Fagg, 1997). On the West Barham coupe, bare soil seedbeds in full sun provided the best conditions for eucalypt germination and development. On the Redwater coupe, greater eucalypt germination and height growth occurred on seedbeds that had received a hot burn. Previous studies of mountain ash forest regeneration have indicated that seedbeds of open, friable soil produced by either deep disturbance of mineral soil or high intensity burns of long 52 Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria

duration are optimum for eucalypt germination, growth and survival (King et al. 1993). Campbell and Bray (1987) in their study of mountain ash regeneration in the Central Highlands, Victoria, documented in detail the conditions required for successful eucalypt regeneration. The entry of the seed into the seedbed rather than remaining on it was highlighted as important, to prevent harvesting of seed by insects and to improve conditions for seed imbibition, germination and seedling root development.

An “ash-bed effect” can be induced by intense heating of the soil that causes a partial sterilisation of the soil. The effect of heat and site disturbance on the soil stimulates nutrient mineralisation and produces changes in microbial equilibrium favourable to seedling germination and development (Florence 1969). Marked changes in the soil microbes such as fungi and bacteria are not evident following fires of low intensity. Significantly taller seedling height growth was recorded on high fire intensity seedbeds on the Redwater coupe at one year. King et al (1993) found that seedling competitive position is strongly influenced by growth over the first year and that increased fire intensity will increase the probability of stocking the site with competitively viable seedlings.

On the Redwater coupe, 95% of eucalypt germination occurred within the first 16 weeks of hand-sowing eucalypt seed. This highlights the importance of carrying out regeneration works early (late summer to early autumn) to coincide with conditions favourable for germination and growth.

Timber harvesting debris A large amount of debris remained on the West Barham coupe after harvesting, which was attributed to a high amount of timber defect, causing many trees to be unsuitable for sawlogs. It was also attributed to portions of the stand being clearfelled, with cull felling of trees unsuitable for sawlogs to reduce overwood stocking to a low level to prevent excessive competition with the young crop of eucalypts and subsequent detrimental effects on eucalypt growth. Residual roundwood (pulpwood) was not harvested from the site. The sawlog to pulpwood ratio was estimated as 1:2 to 1:3, indicating around 2000 m3 of unutilised residual roundwood remaining on site (pers. comm., D. Scherger, former Forest Officer, DSE, Gellibrand). Areas occupied by log heaps were unavailable for eucalypt germination and it was initially thought that this could have important implications for the long-term productivity of the site (Harris 1989). However, the canopy of the developing eucalypt stand has occupied the aerial part above the heaps and it is assumed that the tree roots have encroached the soils beneath the heaps. The heaps of debris may increase the difficulty of any future harvesting of the site though.

The amount of debris remaining on the West Barham would have been substantially reduced, had residual roundwood been harvested or if a hot burn had been achieved as unsuccessfully attempted during regeneration operations.

Eucalypt species composition The occurrence of tall eucalypts usually associated with gradational clay soils, including E. regnans, on the tertiary quartzitic sands of the Redwater area is very unusual. The tertiary sands of low inherent fertility occur as remnant cappings on ridge positions, overlying cretaceous sediments. The tall eucalypts are able to extract nutrients from the more fertile underlying cretaceous rocks. Nutrient cycling by leaf fall and decay has built up the fertility of the sands far above that normally encountered (Pitt 1981).

Prior to timber harvesting, the hybrid E. obliqua x regnans (Otway messmate) was the main eucalypt on the sandy ridge of the Redwater coupe. The higher proportion of this species may result from past wildfire, harvesting history or other environmental factors. Following harvesting, the proportion of E. regnans increased significantly as it was the main species artificially sown on the coupe. Adaptations of particular species to particular sites are not adequately understood but since E. regnans is generally confined to the most fertile sites of the Otway wet forest, it may be less adapted to cope with the poorer fertility and lower water storage capacity of the sandy ridgelines. Increasing the Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria 53 proportion of E. regnans at the expense of E. obliqua x regnans in these environments may have ramifications for the long-term health and productivity of the stand.

Little regeneration of E. viminalis or E. cypellocarpa was observed after harvesting on the Redwater Track coupe. E. viminalis tends to be a variable seed producer in mountain forest situations, making it difficult to collect adequate quantities of seed. Poor regeneration of E. viminalis, E. cypellocarpa and E. brookeriana following timber harvesting has been observed previously in other Otways coupes (Harris 1986).

The overstorey of the West Barham coupe was virtually pure E. regnans prior to harvesting but the hand sowing of a large quantity of E. obliqua x regnans led to an increase in its frequency post-harvest, representing a change in eucalypt species composition. A 2:1 mixture of E. regnans and E. obliqua x regnans was hand sown on the site as there were insufficient supplies of E. regnans seed of West Barham provenance in the 1983/84 season and it was necessary to utilise E. obliqua x regnans seed collected from this catchment.

The intention of eucalypt regeneration operations is to replicate the pre-harvest eucalypt species composition of the coupe as far as possible. Collections from the coupe or at least the general locality are required to maintain genetic resources (NRE 1996). Changes in the proportion of different species noted on these coupes reflect the difficulty of collecting sufficient quantities of all species from the coupe due to intermittent seeding habits of different species. Greater effort is currently taken to maintain the balance of eucalypt species post-harvest.

Eucalypt growth rate The growth rate of eucalypts was similar on both sites. Diameter distributions 16/17 years after harvesting were similar with most trees in the 10-20 cm DBH class and an occasional tree in the 35-40 cm DBH class.

Both stands had naturally thinned down to a stocking of around 700 trees per hectare by 16/17 years post-harvest.

Nothofagus cunninghamii Seedlings of Nothofagus cunninghamii were not recorded on the Redwater Track coupe after timber harvesting. As well as regenerating under a closed canopy, N. cunninghamii can regenerate on bare mineral soil. Hill and Read (1984) recorded copious numbers of seedlings on a track after fire in a western Tasmanian rainforest. On the Redwater coupe, a section of the mineral earth track pushed around the perimeter of the coupe to prevent the regeneration burn from escaping was adjacent to the myrtle beech gully and would have provided suitable seedbed for N. cunninghamii seedlings. A possible explanation for the absence of seedlings on the track is that viable seed was not being carried on adjacent trees at the completion of regeneration operations. N. cunninghamii does not flower or produce seed every year. Its seed is poorly dispersed, short-lived and unable to survive fire after being shed. It is not thought to be able to regenerate from seed stored in the soil (Cremer and Mount 1965).

Subsequent inspections, at 5 and 16 years post-harvest failed to locate any seedlings around the edges of the N. cunninghamii gully. The track had become over grown with strong competing vegetation by age three years and no longer provided a receptive seedbed. A viable seed source was present in later years as indicated by germinated seedlings on decaying logs within the streamside reserve but conditions on the coupe were not yet receptive to seed germination for this species.

Nothofagus cunninghamii in the streamside reserve did not appear to be affected by the increased exposure following harvesting. The exposure following removal of surrounding eucalypts would have been high as the myrtle beech occurred in a shallow gully, rather than in a more typical steep sided Otways gully that would have provided topographic protection. Additionally the forest on the opposite side of the shallow gully in its upper 54 Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria

reaches was harvested two years previous to this coupe. The removal of adjacent eucalypts would allow greater light penetration and air movement resulting in changes in the microclimate. This was reflected in the desiccation of epiphytic ferns on the exposed edge of the streamside reserve in the early years following harvesting. Increased exposure following harvesting has been proposed as causing N. cunninghamii to become more susceptible to “myrtle wilt” (Elliot et al. 1984). However, no obvious decline in the health of N. cunninghamii in the streamside reserve was observed following harvesting during this study. Current harvesting practice requires the retention of a wider buffer, which would have provided further protection to N. cunninghamii (NRE 1996).

Weed species Although introduced weed species were recorded on the coupes soon after timber harvesting, they were short-lived and did not persist beyond 5 years. None were present on quadrats on either coupe at age16/17 years, apart from occasional seedlings of Rubus fruticosus spp. agg. in the West Barham coupe. Rubus fruticosus spp. agg. is a common roadside and pasture weed in the Otways and is spread by birds and foxes.

Log landings and snig tracks Log landings and snig tracks recovered well on the Redwater Track coupe as indicated by the very low representation of Juncus spp. This is in contrast to observations on other Otway coupes where vegetation on landings is modified for many years (Harris 1986). Juncus spp. are generally indicators of compacted or poorly aerated soils (Harris 1986). The sandy, well-drained nature of the soil of the Redwater Track coupe would have ameliorated the compaction problems usually associated with landings and snig tracks. The log landing was not sampled after harvesting on the West Barham coupe.

Structural changes By its very nature, a major impact of timber harvesting is on the structure of the forest i.e. replacing tall forest with young regenerating stands. Timber harvesting creates a mosaic of small coupe-sized regenerating stands limited in age by the rotation length. Average coupe size over the last five years of the study was 15 ha (pers. comm., Ian Shurvell, DPI, Colac). As rotation age is much less than the natural longevity of the forest, mature stands of vegetation would not have sufficient time to develop on harvested areas. Mature forests have greater structural diversity with complex foliage arrangements and diverse collections of ferns, liverworts and mosses (Campbell et al, 1984). However, mature forest will continue to be well represented within the extensive areas of the Forest Management Area excluded from timber harvesting such as streamside reserves, steep slopes and wildlife corridors and also within the Parks and Reserve system.

There has been considerable change in the structure and species composition of the regeneration since the previous assessments at three years post-harvest. As further changes are anticipated as the vegetation develops, it would be very informative to continue monitoring over a longer period of time. Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria 55

ACKNOWLEDGMENTS

Author: Sue Harris, for the Department of Sustainability and Environment Victoria

The author would like to thank the following people for their help during the study:

• Vivienne Turner, Joshua Dorrough, Peter Fagg, Pam Dennison and Yue Wang of DSE for providing valuable comments on the report • Frances Cincotta, Belinda Gardiner, Kerry Mitchell, Warwick Williams, Athol Sumner, Cliff Phell, Kevin Tolhurst, Andrew Pearson, Don Oswin and Gill Earl for assisting with field work at various times • Dr Peter Minchin, Louisiana State University, USA for providing statistical advice and performing ordinations and statistical tests • Vivienne Turner, Keely Ough, Peter Tange and Simon Murphy of DSE for providing useful ideas and encouragement • Pam Dennison for formatting the report • Graeme Hepworth (formerly Research Branch, Department of Conservation, Forests and Lands) for statistical analysis of the West Barham seedbed data, Gavin Kearney, DPI, Hamilton for other statistical tests • David Rourke, DSE Gellibrand, for providing logistic support in the field • Ian Shurvell, DSE, Colac for preparing Figure 2.1.

Parks and Forest Stewardship, DSE, through the Forest Science Centre provided funds for the most recent assessment of the study areas.

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APPENDIX 1:PERMANENT QUADRAT DATA FOR REDWATER TRACK COUPE

Mean cover values and percentage frequency of occurrence of plant species on 19 2 permanent quadrats (size = 80 m ) before and after timber harvesting on the Redwater Track coupe. Species Pre-Harvest Post-Harvest Years Since Harvesting 1 2 3 16 16 Mean % Frequency % Frequency of Occurrence Mean Cover of Occurrence Cover Value Value Trees and Shrubs Acacia melanoxylon 253899589532 Acacia mucronata var. longifolia 121374253473 Acacia verniciflua 00500 Bedfordia arborescens 231374337161 Bossiaea cinerea 331373732372 Coprosma hirtella 050 x0 Coprosma quadrifida +7942424258+ Correa lawrenciana x0000 Eucalyptus cypellocarpa 25555 x Eucalyptus obliqua x regnans 368323232372 Eucalyptus regnans 253797979953 Eucalyptus viminalis 2 37 x x x x Hedycarya angustifolia 137584747211 Ozothamnus ferrugineus 03747470 Leptospermum continentale 126636368471 Lomatia fraseri 11105 x0 Monotoca glauca 2 47 84 84 100 68 1 Nestegis ligustrina 11155511+ Nothofagus cunninghamii 1110000 Olearia argophylla 268585353422 Olearia lirata + 5 37 42 37 5 1 Olearia sp. aff. lirata 01111110 Nematolepis squamea ssp. squamea 3 95 100 100 100 95 2 Pimelea axiflora +37373237421 Pittosporum bicolor +53115521+ Pomaderris aspera +11636374372 Prostanthera lasianthos +21586868471 Tasmannia lanceolata 131 x5521+ Zieria arborescens +37686879843 Forbs and Sedges Agrostis capillarisab 0 xxx0 Amphera xiphloclada 01111115+ Australina pusilla ssp. muelleri x0000 Billiardiera longiflora var. longifora + 5 53 68 63 26 + Carex appressa 051150 Cirsium vulgarea 0112650 Chiloglottis cornuta +110XX0 Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria 59

Species Pre-Harvest Post-Harvest Years Since Harvesting 1 2 3 16 16 Mean % Frequency % Frequency of Occurrence Mean Cover of Occurrence Cover Value Value Forbs and Sedges cont’d Clematis aristata +6326211632+ Dianella tasmanica +3732423232+ Drymophila cyanocarpa +265505+ Epilobium billardierianum 0 x500 Euchiton collinus s.l. 0x5x0 Gahnia sieberiana 1 5 74 84 100 26 1 Galium propinquum 00050 Gastrodia spp. x000 x Geranium potenilloides 0 x x50 Hydrocotyle hirta 04768535+ Hypochoeris radicataa 0263250 Juncus planifolius 0 x x x0 Juncus amabilisb 0 x x x0 Juncus pauciflorus 0 x x x0 Juncus procerus 0 x x x0 Lepidosperma elatius + 11 11 5 11 16 + Microtis oblonga 00500 Nertera repens x0000 Parsonsia brownii +1100011+ Pelargonium australe 05500 Pseudognaphalium luteoalbum 0x550 Sambucus gaudichaudiana +55 x x0 Senecio jacobeaa 0 x1100 Senecio linearifolius 02626110 Senecio minimus 03279680 Senecio velleioides 03747470 Solanum aviculare 02626 x0 Tetrarrhena juncea 158637474681 Uncinia tenella x0000 Viola hederacea s.s. 01116160 Vulpia bromoidesa 0 x000 Ferns Asplen.bulbiferum ssp.gracillimum +500011+ Asplenium flaccidum ssp.flaccidum x0000 Blechnum nudum 00xxx Blechnum wattsii 274686868792 Ctenopteris heterophylla +470000 Cyathea australis 116000 x Cyathea cunninghammii x0000 Dicksonia antarctica 389686879792 Gleichenia sp. 000 x0 Grammitis billardierei + 100 0 0 0 0 Histiopteris incisa + 5 53 74 68 21 + Hymenophyllum cuppressiforme +790000 Hymenophyllum flabellatum +50000 Hymenophyllum rarum +370000 60 Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria

Species Pre-Harvest Post-Harvest Years Since Harvesting 1 2 3 16 16 Mean % Frequency % Frequency of Occurrence Mean Cover of Occurrence Cover Value Value Ferns cont’d Hypolepis rugosula 01621210 Microsorum pustulatum +6300042+ Polyphlebium venosum +50005+ Polystichum proliferum 1165511161 Pteridium esculentum +4258636847+ Rumohra adiantiformis +3700026+ Tmesipteris obliqua x0000

Total number of species recorded on the 57 60 64 60 43 coupe Mean number of species per 80 m2 17.3 18.3 20.5 19.5 14.2 quadrat Mean % plant cover on 1 m2 sub-plots 32 68 92 Not recorded x = Species observed on the coupe but not recorded on quadrats a = Denotes introduced species b = Voucher specimens held at National Herbarium of Victoria Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria 61

APPENDIX 2: PERMANENT QUADRAT DATA FOR WEST BARHAM COUPE

Percentage frequency of occurrence of plant species on 68 permanent quadrats pre- and post-harvesting on the West Barham coupe. Species Pre-Harvest Years Since Harvesting and Quadrat Size Year 1 Year 2 Year 3 Year 17 5 m x 2 m 1 m x 1 ma 5 m x 2 m 5 m x 2 m 5 m x 2 m Trees and Shrubs Acacia melanoxylon 32 58 69 72 35 Acacia verniciflua 0 0 ++0 Bedfordia arborescens 3+330 Coprosma hirtella 32134374 Coprosma quadrifida 29 27 19 29 57 Eucalyptus obliqua x regnans ++++12 Eucalyptus regnans 97 + + + 93 Eucalyptus spp. b 50 69 75 Hedycarya angustifolia 62 77 84 81 64 Nematolepis squamea ssp. squamea 53 62 78 87 86 Nestegis ligustrina +0000 Olearia argophylla 19 6 21 26 45 Olearia lirata 0 6 18 25 20 Ozothamnus ferrugineus 053717830 Pimelea axiflora 13 41 44 49 71 Pittosporum bicolor 223612 Pomaderris aspera +2637 Prostanthera lasianthos + 2 13 15 9 Prostanthera melissifolia 0000+ Tasmannia lanceolata +00312 Forbs and Sedges Agrostis avenaceac 03340 Agrostis capillaris var. aristatacd 041090 Agrostis capillaris var. capillariscd 0+420 Aira caryophyllead 0+200 Anthoxanthum odoratumd 021890 Arctotheca calendulad 0+000 Australina pusilla ssp. muelleri 31519131 Billardiera longiflora var. longiflora 00001 Carex appressa +13384416 Chiloglottis cornuta 32440 Cirsium vulgared 022+0 Clematis aristata 53 15 15 21 54 Cyperus tenellusc 0+000 Dianella tasmanica 00342 Dichondra repens +0000 Euchiton involucratus s.s.c 0+240 Holcus lanatusd 0 3 24 28 0 Hydrocotyle hirta 65779751 Hypericum androsaemumd 00+0+ Hypochoeris radicatad 0 3 19 18 0 Isolepis inundata-habra complexc 02320 Isolepis wakefieldianac 0+220 Juncus bufoniusc 01624150 Juncus pallidusc 0+1090 Juncus pauciflorusc 04970 62 Regeneration of Flora Following Timber Harvesting in the Otway Ranges, Victoria

Species Pre-Harvest Years Since Harvesting and Quadrat Size Year 1 Year 2 Year 3 Year 17 5 m x 2 m 1 m x 1 ma 5 m x 2 m 5 m x 2 m 5 m x 2 m Forbs and Sedges cont’d Juncus planifoliusc 0181360 Juncus procerusc 0+240 Juncus sarophorusc 0 + ++0 Lepidosperma elatius +3349 Lobelia pedunculata 00003 Lotus corniculatusd 02240 Pelargonium australe 0+000 Pseudognaphalium luteoalbum 0+230 Rubus sp. 02000 Rubus fruticosus spp. aggd 00004 Sambucus gaudichaudiana 2 + ++1 Senecio glomeratus 0+220 Senecio linearifolius 0 9 38 28 0 Senecio minimus 01210120 Senecio velleioides 0++30 Solanum aviculare 0161320 Tetrarrhena juncea 21 25 37 46 57 Uncinia tenella ++329 Urtica incisa + + ++0 Vulpia bromoidescd 0+000 Ferns Allantodia australis +0001 Asplen. bulbiferum ssp. gracillimum 22 2 4 6 6 Asplenium flabellifolium +0000 Asplenium flaccidum ssp. flaccidum 20000 Blechnum chambersii +0000 Blechnum fluviatile +0000 Blechnum nudum 00001 Blechnum wattsii 44 15 31 40 74 Ctenopteris heterophylla 70000 Cyathea australis 16 3 2 2 30 Dicksonia antarctica 91 34 60 62 90 Grammitis billardierei 26 + 2 2 3 Histiopteris incisa 441718126 Hymenophyllum australe +0000 Hymenophyllum cupressiforme 40000 Hymenophyllum rarum 70000 Hypolepis rugosula 312255012 Lastreopsis acuminata +0000 Microsorum pustulatum 59 2 4 9 13 Polyphlebium venosum 30000 Polystichum proliferum 52 15 28 38 58 Pteridium esculentum +2220 Rumohra adiantiformis 18 0 0 0 6 Total number of species recorded on the 48 65 63 62 41 coupe Mean number of species per quadrat 7.6 7.5 11.4 12.2 10.3 + Species observed on the coupe but not recorded on quadrats. a 1 m2 sub-plots were a sample of the 2 m x 5 m quadrats. b For the first three years following harvesting, eucalypt seedlings were listed together as Eucalyptus spp. Eucalypt seedlings were either E. regnans or E. obliqua x regnans c Voucher specimen held at the National Herbarium of Victoria d Denotes introduced species.