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Production forestry and
nature conservation
Left
Fifty year-old blackbutt (Et~colyptrtspilrcloris)regenerallon after logging in the Nightcap Range, norlhcrn N.S.W. Pltoto by P. Hale
Above and below right
Scleelive logging far Etzcolyptns spp. in the Conondvlc Range, south-east Queensland. Pltoros by P. Hole.
Chapter 83
Management of disturbance and biodiversity in production
,
forests and forest reserves
PETER ATTIWILL'
Disturbance is common to all &osystems. it drives the cyclic renewal of community composition,and it releases resources and promotes nutrient
cycling. Ecosystems are dynamic entities and the pervasiveness of disturbance means that they are constantly changing. It is a basic ecological
tenetthat biodiversity is maximum at some intermediate level of disturbance. We are therefore managers of biodiversitythroughthe management
of the regime of disturbance, both human-generated and natural. In line with (Comprehensive, Adequate and Representative (CAR) Reserves
philosophy, management of our forests for timber production, water, flora and fauna values must be pmactive. The whole forest estate should be
manaeed
in a manner consistent with the defined goals of nature conservation. Much of the research in Australian forests has concentrated on
- ---- ..
11moer.prod~ction
forcsrs andv.c are now n the pos:l:on to control timocr producron in a number of forest types n a waywnich s compat:olcwirn
maintenance of b!od,uersilv. Tne challenge
. now s lo deve op ecological nno&ledges o that pro-active managemenr across the range of forest
values can be formulated.
Key words: forests, disturbance, biodiversity, management
~
~
INTRODUCTION
Disturbance is common to all ecosystems. It drives the
cyclic renewal of community composition, and it releases
resources and promotes nutrient cycling. These statements
are nothing new; they have been re-enforced in the
ecological literature in a number of major reviews (Pickett
and White 1985: Oliver and Larson 1990; Attiwill 1994a,
1994b). They contrast markedly. however, with the idea
that ecosystems must be protected, locked up, fenced-off,
if they are to survive. Shugart and West (1981) summarised
these contrasting ideas succinctly: on the one hand, 'forest
ecosystems are dynamic entities that may not be static in
either time or space; on the other, "'succession",
"wilderness", "virgin forests" and "climax forests" are all
concepts that appeal to the basic notion that forest systems
should approach some equilibrium state with time.'
.
.
.
Loucks (1970),,D I O D O S ~the
~ hvmthesis
that maximum
,
diversity a n d productivity of forest ecosystems are
maintained by random periodic disturbance. This solution
- o f maintaining diversity through s o m e level of
disturbance - is the outcome of Connell's (1978) muchquoted paper on diversity in tropical rainforests and coral
reefs. It assumes that disturbances prevent a state of
equilibrium ever being reached. The hypothesis is now
well-established through Miller's (1982) classic paper:
species diversity is maximum at some intermediate regime
of disturbance, the result depending on the frequency, size
and intensity of disturbance and on the life-histories of the
biota.
Then comes the difficulty: this is all fine in theory,
but how do w e manage it in practice? Ideally, w e should
have specific biodiversity goals, and an understanding of
the disturbance regimes that are necessary to achieve these
goals. The aims of this paper are, firstly, to outline the
nature of natural disturbance regimes, and to comment on
conservation measures across the whole of the forest estate
- timber production forests, water catchments, national
parks, etc.
'
The nature of natural disturbance
Forests throughout the world are affected by a variety
of major, natural disturbances. We distinguish between
endogenous disturbance (part of the natural system, and
part of autogenic developmentland exogenous disturbance
(introduced into the system, and part of allogenic
development). But this distinction is difficult in practice.
For example, does a tree break or fall because of wind or
because of its own ageing and decay? Wind varies from
zero to hurricane force - at what stage do w e say it is an
external force and not a part of the natural environment?
Fires start from lightniog strikes, from the normal pursuits
of humans over tens of thousands of years and from
deliberate arson - how do w e distinguish between natural
and unnatural fires, and should w e aim to suppress all fires?
Succession in some of the spruce, pine and fir forests of
North America is totally dominated by the events following
s w e r e insect attack; whal causes these outhreaks, and are
the outbreaks natural or should they he controlled?
These and other questions relating to the nature of
disturbance are critical both to our understanding of
ecological processes and to our management of forests.
For example, catastrophic hurricanes in parts of the tropics
(including northern Australia) are increasingly seen as part
of the natural order which preserves heterogeneity of
rainforests. This view contrasts with older ecological
theories of succession which were pre-occupied with a
natural order which progresses toward the stable, selfperpetuating 'climax' proposed by Clements (1916): 'as
an organism, the formation arises, grows, matures and dies
... The end of the process of stabilisation is a climax ...
Such a climax is permanent because of its entire harmony
with a stable habitat. It will persistjust as long as the climate
remains unchanged'. We are now increasingly aware that
there is no such end-state. Forests are dynamic in time
and space, and as with other ecological systems, maximum
diversity is reached at some level of random disturbance.
Disturbance has its own scales of intensity and frequency
School of Botany, The University of Melbourne. Parkvtlie, Victorla 3052
Pages 463-466 in CONSERVATION OUTSIDE NATURE RESERVES, ed. by P. Hale and D. Lamb. Centre for Conservation Biology, The University of
Queenstand. 1997.
ATTIWILL: MANAGEMENT OF DISTURBANCEAND BIODIVERSITY IN FORESTS
and so it providesa range of opportunities for plants and
animals, each with their own life histories and
developmental sequences. Through this interaction, and
under the range of environmental conditions (soils, climates
etc.) diversity is created and maintained.
FIRE AND FORESTS
Spurr and Barnes (1980) wrote that 'fire is the
dominant fact of forest history', and nowhere is this more
definitive than in the eucalypt forests ofAustralia. Australia
in its northward drift from the Gondwanan continent of
Jurassic times has now reached the position where the
greatest width of the continent lies at the driest part of the
world - the Tropic of Capricorn. With increasing aridity
and sclerophylly came an increasing incidence and spread
of fire from lightning. At some time - estimates vary from
30-40 thousand years ago up to 120 thousand years ago Aborigines came to Australia. The frequency of fire, as
estimated from the incidence of charcoal in lake sediments,
increased dramatically at that time, and it increased again
immediately following European settlement.This sequence
of evolutionary development has resulted in our native (or
'natural') forests which we must manage today. I accept
Taylor's (1990) concept of a 'natural' forest as one which
can be recognised - by simple field observation and the
application of conventional phytosociological criteria - as
supporting native vegetation. In dealing with the term
'natural forest', Taylor (1990) siates that 'the present
equilibrium vegetation (in Australia) has not been"iso1ated
in time" from the pre-Aboriginal native vegetation of the
late Pleistocene. It has descended from this late Pleistocene
native vegetation through an unbroken sequence of
autogenic and allogenic successional responses to humangenerated disturbance and other natural agents of landscape
change.'This raises the further question: can we distinguish
between autogenic and allogenic responses, and between
exogenous and endogenous fire? The distinction between
autogenic and allogenic responses is made even more
difficult if we take Mutch's (1970) hypothesis on hoard:
'Fire-dependent communities burn more readily than nonfire-dependent communities because natural selection has
favoured development of characteristics that make them
more flammable'.
Use of fire to manage biodiversity in national
parks
The developing program of Comprehensive, Adequate
and Representative (CAR) Reserves in Australia (Joint
ANZECCIMCFFA National Forest Policy Statement
Implementation Sub-committee 1996) recognises the need
for active management of biodiversity. This introduces the
difficult problem of the management of disturbance
regimes in national parks. Two case studies will be briefly
described - Yellowstone National Park in north-western
USAand Wilson's Promontory National Park in southern
Victoria.
The role of fire in regeneration and maintenance of
ecosystems in Yellowstone National Park has long been
known. However, inYellowstone National Park, as in most
national parks, there are aLtive programs of fire detection
and suppression rather than active fire regimes. Rowe and
Scotter (1973) placed the problem in a general context for
the land manager: 'The management of national parks,
nature reserves, and wilderness areas poses many questions
about the use of fire. The near exclusion of wildfires in
such places has had profound effects. If the major goal of
such areas is to perpetuate samples of as many landscapes
as possible with the recognition that fire is an inseparable
part and natural agent in the ecology of many ecosystems
-then land managers must "unsell" the false impression
that all fires are bad and be prepared to use both prescribed
fires and natural lightning fires in landscape management'.
Since controlled (or 'prescribed') burning is considered
inappropriate in national parks such as Yellowstone,
Romme (1982) proposed that most lightning-caused fires,
including the very large ones, should be allowed to burn
naturally. Romme stated that 'managers should allow an
occasional fire covering many square kilometers; these are
the fires that will exert a predominant influence on
landscape composition and diversity for many decades to
follow. Such large fires should not be viewed as unusual
events occurring because of unusually high fuel
accumulations'.
Again, allowing fires to burn in national parks is fine
in theory but it is a difficult message to sell and to
implement. Without fire, however, the fuel load
accumulates and the risk of fire increases; in 1988, the
inevitable happened and some 560,000 hectares of the
greater Yellowstone area burned, including 396,000
hectares of Yellowstone National Park. Following the fire,
BioScience devoted a whole issue to analysis of the various
ecological, management and socio-economic controversies
(Volume 39, Number 10, November 1989). There were
the usual recriminations and allocation of blame, as we
saw in New South Wales after the fires of 1994, and some
themes coming out of theBioScience issue were:
.
we never think of fire as good or even neutral. It's
bad, and someone must-be blamed for allowing it.
ecology and policy are not newsworthy
people think of parks as static curiosities rather than
as dynamic ecosystems; they see the role of national
parks as 'preserving pretty places'.
and, as the new growth emerged and Yellowstone
regenerated: 'I felt an exhilaration and relief as if
Yellowstone, for the first time in a century, had gotten
a deep breath of fresh air'.
The effects of disturbance in forests are mostly
difficult to document. In contrast, the effects of natural
disturbance on diversity are more readily illustrated for
those very diverse plant communities we call heathlands
which grow in areas having Mediterranean-type climates
(in parts of Australia, the Mediterranean countries,
California, Chile and South Africa). We can see change
within decades, and we can study a heathland more easily
than a forest since it is only knee-high.
ATTIWILL: MANAGEMENT OF DISTURBANCEAND BIODIVERSITY IN FORESTS
The fire-dependence of Mediterranean-type
vegetation has long been recognised by plant ecologists,
and we know that diversity decreases within about 20 years
following disturbance. For example, in each of some 30
comparisons of species numbers between paired plots of
older heathland and more recently-burned heathland i n
Victoria's mallee, diversity was greater in the more
recently-burned heath (D.C. Cheal, pers. comm.).
465
planning
forests rests fairly and squarely in the -of
and operation. Since most of the inventory and research in i
Australian forests has been in forests managed for timber ,
production, management has a good resource base from
which to operate.
The Mediterranean-type heathland illustrates a simple
point: we are managers of the land and its ecosystems. A
decision to suppress fires will have major consequences
for species diversity, consequences which may be as great
or greater than those resulting from other management
decisions.
Whitmore (1990) concluded his book on tropical
forests as follows: ' ...tropical forests are a renewable ,
resource which can be utilised and still retain their diversity
and richness for mankind's continuing benefit; but only
if we care to learn enough about how they work, and
also if utilisation (is) within the limits of the
forest's inherent dynamic processes'. Perhaps the most
detailed work and documentation on disturbance regimes
has been in the ecosystems of British Columbia,
Canada (Parminter 1992). In Australia, bushfire is a
natural disturbance which has its own regime of
diversity. Bushfires are unpredictable. They occur at
irregular intervals and at various times of the year, and
they burn at various intensities and over a range of areas.
All of this gives diversity to our forests, so that each patch
of bush is different, however subtly, from every other patch
of bush. A proper and thorough examination of the early
records, and the reconstruction of fire-histories for some
of our major forest types, is now needed in Australia to
advance the management over the whole of our forest
estate.
EFFECTS OF TIMBER HARVESTING
CONCLUSIONS
There is an extensive literature on the effects of timber
harvesting in Australian forests and it has been extensively
reviewed (e.g. Resource Assessment Commission 1992;
Attiwill 1994b). Many of the studies have compared the
biota following timber harvesting with the biota of oldage forest. It is difficult to summarise the results briefly
since both old-age forest and regrowth forest are variable.
The diversity of old-age forest is due to both environment
and past disturbance regimes, and the diversity of regrowth
is due both to environment and the quality of management
planning and forest operations. Where the quality of
planning and operation is high, the effects of timber
harvesting on flora are small or negligible. Similarly, for
many species of birds, small mammals and reptiles,
recovery after quality harvesting is similar to recovery after
fire. Specificmanagement options (the planning of wildlife
corridors; the protection of tree ferns during logging
operations; the retention of some old-age trees within
logging coupes; the retention of coarse, woody debris) are
available to create conditions for specific species. Indeed,
timber harvesting can be planned to supplement
biodiversity in reserves by creating a range of environments
and age-classes (since not all species of birds and mammals
are found in old-age forest, for example).
The three themes of forest ecology that I have
developed here are that:
The first two themes are inextricably linked. Our
forests are diverse because patterns of disturbance are
diverse. In Australia, bushfire is a natural disturbance
which has its own regime of diversity. Bushfires are
unpredictable. They occur at irregular intervals and at
various times of the year, and they burn at various
intensities and over a range of areas. All of this gives
diversity to our forests, so that each patch of bush is
different, however subtly, from every other patch of bush.
What is certain is that the diversity of ecosystems, from
coral reefs to forests, depends on natural disturbance. If
this were not so, diversity and patchiness would decrease.
It is due to natural disturbance that an equilibrium is never
reached.
I conclude that there is a scale of human disturbance
as there is a scale of natural disturbance.At points on these
scales, we could judge that the effects of human disturbance
on ecosystem structure and function are not significantly
different from those of natural disturbance. Thus the key
to the management of biodiversity in timber production
The challenge is to develop disturbance regimes
for management to achieve specific biodiversity
goals. Management for timber production has a
considerable greater research base at present than does
management of national parks, wilderness areas and other
reserves.
A particular problem in the coastal heathlands of
Wilson's Promontory National Park is the policy of
fire suppression which is promoting the invasion of
the senescent heathlands by the prolifically seeding
shrubs Coastal Tea-tree (Leptospermum laevigafum) and
White Kunzea (Kunzea ambigua). The replacement of
the low coastal heathlands by these taller shrubs is
drastically altering the nature of much of Wilson's
Promontory National Park. Furthermore, once the
heathland is invaded, firing is more likely to promote
dominance of the seeding shrubs than to restore the
heathland species.
there is no equilibrium, no pre-ordained state of
diversity
it is a general ecological truth that maximum diversity
depends on a regime of disturbance
as managers of the land, we are in charge of
determining this regime of disturbance.
CHRISTENSEN: FAUNA CONSERVATION IN PRC)DUCTION FORESTS IN WESTERN AUSTRALIA
of the native forests reserved in National Parks and
Reserves.
growth characteristics throughout the forest, habitat trees
are left in coupes, special communities and occurrences
of rare species are protected by buffer strips, fox control is
carried out on a large scale and there are species recovery
p l a n s and special management plans f o r rare and
endangered species.
In Western Australia, in the karri forest region in
particular, w e have attempted to strike a balance between
conservaGon through reservation and conservation in
production forest. Whether or not we have the balance
exactly right is not s o much the concern, what is important
is the concept that a mosaic of forest with areas managed
with different primary aims, v i z conservation and
production are far more advantageous for conservation than
a forest demarcated and gazetted entirely for wildlife
conservation purposes.
Forest management has always been based on and
s u p p o r t e d by s o u n d s c i e n t i f i c research. Detailed
information on the life cycle of forest trees was already in
use ensuring that the forest was regenerated successfully
following felling, long before such information became
available for other plants (Briedahl and Hewett 1995).
Pioneer research into the root rot disease, dieback
(Phylophthora cinnamomi) a threat to many species of
native plants, was carried out by foresters in the sixties
and seventies (Shearer andTippett 1989). Even in the field
of fauna and flora, forest researchers carried out some of
the initial work on fire and plants and were first responsible
for bringing to the notice of the scientific community the
problem of the European red fox in Australia (See
Christensen 1992 and Christensen 1980).
Because forestry is a practical profession all of this
work was not merely published in scientificjournals but it
was put into practice at the earliest opportunity. Ameasure
of the success of forest management over the last century
is the unprecedented interest in forest conservation in recent
times. Hardly a day goes by when there is'not some item'
in the media to do with forest conservation. This should
begood news but unfortunately it is not.Thegeneral public
through a well orchestrated campaign is being led to believe
that forest wildlife is in imminent danger of destruction
and extinction through logging by timber companies whose
only interest is in making a quick buck. Regrettably, it is
all too easy to sell a story of disaster about forests. Large
majestic trees invoke a sense of awe and wonder in most
people. G r a p h i c f o o t a g e o f f a l l i n g f o r e s t g i a n t s
accompanied by the screaming of chainsaws, dust and the
roar of huge logging machineryand trucks piled up with
logs, is emotive stuff for television viewers. More often
than not these scenes are accompanied by shots of black
desolate coupes still smouldering from a regeneration burn.
Commentaries sprinkled with a liberal dose of adjectives
such as disaster, destruction, tragic and so on re-inforce
the image of doom and gloom. Unfortunately, all too oftin
such presentations are supported by so called scientists
who should know better. We never see shots of the new
regenerating forests, of the vigorous young trees with their
thriving populations of birds and animals. How can anyone
believe anything other than that logging and burning spells
total destruction to the forest? This sort of portrayal of
forest management, some of it well meaning, albeit totally
naive and misinformed, isvery damaging. It is damaging
not only because it makes it difficult for.forest managers
to g o about their business of managing the forest but
especially because it is steering forest conservation down
the w r o n g path pathway which I am c o n v i n c e d
is not in the best interests of conservation. Thus the
f o c u s is on reservation, and those who push the hardest,
the extremists, if you like, want it all. They want all
467
HISTORICAL
Forests can be, and indeed have been, regenerated
successfully since early times in Western Australia. In
Western Australia the timber industry which had its birth
in the early days of settlement, developed rapidly from
the 1890's and reached an all-time peak of production in
1913. It was not until the passing of the Forests Act in
1918 however that proper conservation and regeneration
of the forest was ensured (Anon 1969). It should be
understood that the passing of the Forests A c t and
subsequent implemeniation of the Act was fraught with
difficu1ties.Theprevailingclimate was one where clearing
for agriculture held sway; conservation and reservation of
any description were difficult to achieve. The role of timber
as a commercial product of forests was the prime factor in
the success in passing the ForestsAct and in itssubsequent
implementation. Without this commercial incentive, little
would have been achieved and the area of forest which w e
have today would have been much reduced.
f
The few small National Parks which had been created
earlier in 1909 and 1910 were the only areas of forest which
were protected in the karri region at that time. Before the
time of the Forests Act much forest was cut and cleared
for farming, for example karri forest at Torbay near
Denmark on the south coast. Other areas of forest were
cut, often clear felled and regenerated successfully e.g
Boranup karri forest near Margaret River which was clear
felled in the 1980's. The success achieved in regenerating
the Boranup forest, which was done before any proper
forest management, is demonstrated by the fact that the
area was recently included in the Leeuwin-Naturalist
National Park.
The resilience of forest ecosystems 1s demonstrated
by the fact that Boranup forest still retains its natural
complement of flora and fauna despite the absence of any
scientif~cforest management at the time of cutting and
regeneration (See Christensen 1992). Following the
passing of the Forests Act in 1918, forest management
based on sound biological principles gradually started to
replace the exploitative forest utilisation techniques of
earlier times. Early results w e r e spectacular. T h e
magn~ficentkarri regrowth stands of Big Brook near
Pemberton resulted from regeneration in 1929/30.This area
of several thousand hectares which was clearfelled and
was ready for a regeneration burn when a wild fire swept
468
CHRISTENSEN: FAUNA CONSERVATION I N PRODUCTlON FORESTS IN WESTERN AUSTRALIA
the forest. The wildfire did the job of the regeneration burn
and results were spectacular and are a credit to the foresters
of that time.Apart from having no old growth trees present,
besides a few oldstags, these forests retain, as far as anyone
can tell, their full complement of fauna and flora. There
are many other examples of forest which was cut down in
the early days, much of it selectively felled, but also large
areas of clearfelling which differ little from the original
forest save for the paucity of old growth trees. Foresters
were pioneers in the management of natural systems. By
initially concentratingtheir efforts on the 'keystone'species
of the forest, the dominant tree species, (after all without
trees there can be no forest), they have successfully
preserved and managed the whole forest ecosystem.
In more recent times other forest values such as flora
and fauna have received increasing attention. Surveys of
flora and fauna are demonstrating the success of past
management practices. Recent reviews (Hopper et 01.1992
and Christensen 1992) point to the richness of the flora of
the karri forest area; there is no suggestion that logging
has in any way affected the flora. Christensen (1992) lists
14 Declared Rare flora in the Southern Forests in contrast
to 81 in the nearby Wheatbelt Region and 73 on the south
coast. Inions et al. (1990) in a study of karri forest floristics
concluded that all but one (a quadrat on a log landing) of
144 permanent quadrats, retained the same plant
community type following logging and burning. Although
Inions et al's. classification was based in regrowth, they
'concluded that edaphic and climatic variables rather than
disturbance were the major determinants of floristic
patterns.
South West forests are among the few places in
Australia where we can still find the pre-European
vertebrate fauna almost completely intact. No species of
forest mammal has become extinct even though some
mammals have declined in distribution in the forest because
of fox predation (Christensen 1992). Only one species of
vertebrate has apparently become extinct in State Forests.
This species, Lewin's water rail (Rallus pectoralis clelandi)
was last recorded in State Forest in Western Australia in
1932, and also disappeared from its habitat (swamps)
outside state forests. As swamps in State Forests are not
subject to logging (or prescribed burning until the 1950's)
neither factors can have caused the species demise (Abbott
and Christensen 199511996), In contrast 26 species have
become extinct on the South Coastal Plain, probably due
to clearing of nearly 80 percent of the habitat for
agricultural and urban development. An astonishing 43
species have disappeared from the Wheatbelt where 90
percent of the native vegetation has been cleared (See
Armstrong and Abbot 1995). Of the original forest 42 per
cent has been cleared for farming and 12species have been
lost from this part.
~ i o l o g i c surveys
i
during the 1970's suggest that
timber felling has had little effect on vertebrate species
distributions. The mosaic of cut and uncut, lightly and
heavily cut forest, in fact favours a range of species. The
western ringtail possum (Pseudocheirus peregrinus
occidentalis) for example may favour areas of lightly cut
over forest where young regrowth is present (Christensen
1992). The mardo (Antechinus flavipes) is common in
young karri regrowth (Wardell-Johnson 1986),Tingay and
Tingay (1984) record birds of more open habitat e.g.
yellow-rumped thornbill (Acanthiza chrysorrhoa) present
in karri (Eucalyptus diversicolor) forest soon after clear
felling, birds favouring dense understorey like the whitebrowed scrubwren (Sericornis frontalis) dominate the
young regrowth, whereas species like the western striketit (Falcunculus frontatus) and golden whistler
(Pachycephala pectoralis) are common in pole stands.
Clearly the evidence suggests that past forest protection
and management has conserved the forest environment in
excellent condition.What is being done by forest managers
to continue this work?
RECENT AND CURRENT FOREST
MANAGEMENT
In the late 1960's and early 70's the general public's
attitude to forests changed: people started to become
interested in the forests. Up until that time foresters had
assumed that everyone knew that they were doing a good
job looking after the forest, certainly we felt that we were.
In Western Australia the interest in forests manifested itself
firstly with concern expressed about controlled burning
policies. Sections of the general public were concerned
about what fire was doing to the forest environment,
especially the fauna. Following these early concerns in
the seventies emphasis and concern has shifted to logging
and its alleged disastrous effects on forest fauna.
Woodchipping became a major issue and most recently
the emphasis has centred on 'preserving' so called old
growth forest. This sudden onslaught by a public which
had always been regarded as being 'on side' came as a
shock to foresters. They were upset at what they saw as
the injustice of the never ending accusations of destroying
the forest. They never fully recovered to properly defend
themselves and have been unable so far to convince the
public that the forest is in good hands. In spite of this failure
on the public relations and political front, foresters
nevertheless have reacted with demonstrable success in
the area of their professional expertise, practical forest
management. Foresters have embraced the concept of total
forest management, with renewed enthusiasm and are
practicing true multiple use management in the forest.
During the early 1970's, following upon increasing
public concern over the use of prescribed fire as a fire
control strategy, research into fire effects was initiated.
One of the benefits of forestry research is having the
resources and facilities to conduct broad scale experimental
field trials. Through such trials by forest researchers it has
been amply demonstrated that most mammals can cope
with fairly frequent and recurring fire events (Recher and
Christensen 1981, Christensen andAbbott 1989).Although
there is an immediate impact, animals recover quickly to
recolonise burnt areas. The benefit of having a mosaic of
different ages and seasons of burn was demonstrated. Such
a mosaic makes it possible to retain larger populations of
a greater number of species of animals than is the case
CHRISTENSER FAUNA CONSERVATION IN PRODUCTlON FORESTS IN WESTERN AUSTRALIA
with either no burning or only one age of burn. This work
resulted in changes to prescribed burning patterns so as to
leave 20 to 30 per cent of the area unburnt each time and
an increase in the percentage of area burnt in Autumn.
Some 70 areas throughout State Forest are also set aside
for protection from fire (Christensen and Abbott 1989).
These changes to burning practices are ongoing, the best
practical methods of achieving results are still being
worked out. For example, it is now realised that attempting
to protect large areas, greater than 500ha from fire is not
practical and more, smaller areas are considered a better
practical alternative.
An ongoing programme of biological surveys during
the 1950's also produced practical results (Christensen et
al. 1985 and Christensen 1992). This work together with
other information available at the time resulted in the
concept and implementation the Management Priority Area
System (See Christensen 1974).
~ a n a ~ e m ePriority
nt
Areas (MPA)
The idea was to select the prime areas for various
management purposes, e.g timber, fauna recreation etc,
demarcate them on a map and manage-thoseareas of forest
accordingly. Thus in a Fauna Priority Area, logging, and
burning are not necessarily banned, but fauna would have
priority in the event that it could be shown that there was
conflict between uses. (See Christensen 1974) A number
of important areas containing sizeable populations of rare
and endangered fauna were designated Fauna MPA's.
These areas had the advantage over Nature Reserves at
that time in that Fauna management, for example using
prescribed fire, could be carried out. A classic example is
the management of tammar wallaby (Macrgus eugenii)
thickets by periodically regenerating them using fire. (See
Christensen 1987 and Christensen and Maisey 1987).
During this period also, research implicating the fox
in the decline of many forest species was initiated
(Christensen 1980). Experimental re-introductions and
broadscale fox 'baiting followed. This work has now
expanded into a huge programme of fox baiting in forest
areas coupled with rare and endangered species recovery
plans and re-introductions of several species including the
numbat (Myremecobius fasciatus) the woylie (Bettongia
penicillata), the tammar wallaby (Macropus eugenii) the
chuditch (Dasyurus geoffroii) the ring tail possum
(Pseudocheirus occidentalis) and the quenda (Isoodon
obeselus).
Early biological survey results also led to the
establishment of a series of river and stream reserves or
corridors, as well as uncut buffer strips around swamps,
and granite outcrops. pll areas of heath and sedgelands,
swamps, rockoutcrops and a range of woodland types were
also added to this system of non-dedicated reserves. These
non-dedicated reserves contain all of the richest fauna
habitat in the karri forest region as well as a very high
proportion of the flora. Together with the MPA's and the
dedicated areas of National Park and Reserves they form
a very substantial area reserved from logging (Christensen
1992).
469
Research on possums and chuditch led to
specifications on the number and types of trees and logs
to be left in felling coupes (Serena et al. 1991). This work
is presently being refined with better data from more
detailed research on these and other species. Detailed
research on dieback has been resulted in strict rules and
regulation relating to the placement of construction of log
roads, their surfacing, drainage and other features, designed
to minimise the spread and development of the disease.
There is also a comprehensive area with dieback quarantine
restrictions and all vehicles are subjected to washdown
and inspection (Shearer andTippett 1989). There are strict
regulations which enable closure of cutting coupes if the
soil is too wet and soil damage starts to occur. Timber
companies and others working in the forest are required to
use machinery which does minimum damage to the soil
and minimises any compaction. There are also detailed
specificationsfor re-habilitating disturbed area such as snig
tracks and log landings. Modern forest management is
subject to these and many other rules and specifications
(See Christensen 1992).
F U T U R E FAUNA M A N A G E M E N T I N
P R O D U C T I O N FORESTS
With this level of management there is the possibility
of manipulating forest structure and the spatial organisation
of stands cut at different times and to develop prescriptions
to the advantage of fauna. Research has started on
developing predictive models which can be used in
planning cutting and burning to best advantage for specific
species. A mosaic of different aged burns for example is
likely to maximise the number of different birds in a
community. Recently burnt areas may favour the scarlet
and the yellow robin and the white winged triller. The white
breasted robin prefers thickets which may take some years
to fully develop after fire (Christensen et al. 1986). The
grey-bellied dunnart (Sminthopsis grisioventer) favours
recent burns whilst the yellow-footed dunnart (Antechinus
flavipes) prefers 10 year old litter (Sawle 1979). By having
patchy burns or burns of different ages in close
juxtaposition it is possible to favour a maximum number
of birds and animals in a community.
The tammar wallaby and fire management of its
thickets has already been mentioned. Likewise with felling,
research in karri forest has shown that young regenerating
karri has very high numbers of scrub birds, such as the red
winged wren, spotted scrub wren and others. The crested
strike tit is common in older regeneration whilst the rufous
tree creeper and varied sitella prefer more mature forest.
ringtail possums are most common in cut overjarrah forest
where there are regrowth trees intermingled with mature
hole bearing trees. Numbats have been shown to use a high
proportion of log debris and rejected logs resulting from
felling operations where they occur in jarrah forest which
has been selectively cut (Inions 1985 and Christensen et
al. 1984). This whole area of stand manipulation and forest
planning to favour species or communities of animals and
birds is a rapidly developing one which has great potential
for the future of conservation in production forests. One
470
CHRISTENSEN: FAUNACONSERVATION IN PRO[ )UCl'ION FORESTS IN WESTERN AUSTRALIA
of the great advantages is that management of this'type if
planned properly need cost very little as it can be
incorporated into logging plans.
ACKNOWLEDGEMENTS '
I would like to thank Lachie McCaw who read and
commented on an early draft of this paper.
CONCLUSION
For the non foresters, and perhaps for some foresters,
although I would have hoped that they already knew, I
hope that I have opened their eyes to the value of production
forests in fauna conservation.
I quote from Abbott and Christensen (1995/1996) who
state; "The reason that extinctions of species have been
few in WA forests is that sustainable use of natural
resources, if properly managed, helps conserve the natural
environment. This insight seems to have first been recorded
in WAby eminent WAgeographer Dr Joseph Gentilli, who
wrote: 'Good forest stands are well preserved as areas of
natural environment for the very simple reason that they
are well protected because of their economic value'. No
matter what value is the motivating factor, protection is
protection. All evidence suggests that species are safe in
the forest, whether it is logged or not. Ironically, the people
often criticised for allegedly harming the forest are the
people who feel they have done most to protect it. The
foresters of Western Australia laid the foundations for forest
management in the State, which has helped to ensure that
these species are still present in the forests. In a series of
policies made possible by the ForestAct of 1919, the forests
have been looked after in ways that have sufficiently
sustained them. Managed burning has reduced the threat
and impact of wildfire, large areas have been placed into
reserves, and areas designated for timber production have
been logged on a sustainable basis. Without such controls,
our forests would presumably have gone the way of many
other forests elsewhere in the world-taking many species
with them". Production forests are not a disaster area, far
from it, they are well managed forests where only
imagination, resources and time impose limits on what is
possible to achieve for conservation.
The positive side to the forest debate'is that it has
stimulated a lot of sound field work and experimental
research which are being used to manage our forests even
better.This work I believe is pointing the way to the future.
Not only is it ridiculous not to utilise the native timber in
our forests but it makes good conservation sense. There
are opportunities to manage production forests in ways
which can benefit a whole range of fauna. Drawing lines
on maps and reserving our forests in National Parks and
Reserves is not the answer and never will be. Preservation
will ultimately lead to extinctions of species if such reserves
are the only option which is pursuedfor fauna conservation
in our forests. I believe we are close to the answer in
Western Australia where we have a dedicated system of
forest Reserves and National Parks which form a mosaic
with the production forest and non-dedicated reserves
.system. The management options as well as flexibility
which this system gives us guarantees the best chance of
success in conservation of our forests with all their biota
into the future.
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