Talking to the Kiwis
New PhD student Tanya Bailey visited Ensis in Christchurch for two
days in June with co-supervisor Dr Tony O'Grady (Research Fellow,
School of Plant Science, University of Tasmania) to meet with the
Bio-security group and to discuss forest vegetation management
issues. Brian Richardson hosted the visit and organised a series of
meetings with researchers working within the Forest Vegetation
Management theme from Ensis, Landcare NZ and the University of
Canterbury.
The first day provided some useful discussions -
Brian gave an overview of the work done so far in New Zealand
towards decision support systems for plantation managers. Areas of
study in relation to vegetation management undertaken by the New
Zealand Group include: weed risk analysis on national, regional,
forest and site scales; herbicide treatments, application systems
and efficacy modelling; weed ecology studies in population
dynamics, weed-crop interactions, resource competition and
development of competition indices. Much work has focused upon
major weeds such as broom and gorse and considerable effort has
been made into looking at patterns of dispersal, competitive
effects on crop growth, control methods and developing process
based models of growth for those weed species. These discussions
provided a useful background for Tanya who is exploring the weed
issues faced by forestry in Tasmania. Mike Watt of Ensis shared his
experience of, and lessons learnt from, a weed survey study similar
to that proposed in Tanya's PhD and thus provided technical
assistance and insight into relevant issues.
Day two involved a field trip to the Burnham field
trial with Peter Clinton and Euan Mason to look at the weed and
fertiliser trials and the impact of various weed and fertiliser
treatments on the growth of Pinus radiata. The trip also
included a stop at a University of Canterbury trial where a series
of clones were planted at different spacing and trees were guyed to
examine the development of wood "stiffness" as a function of clone
and spacing.
All in all, the trip was fruitful providing us with
useful contacts and highlighting many issues that should be taken
into account in the development of the CRC weeds programme. Thanks
to Brian Richardson, Mike Watt, Marika Ftitzsche, Nick Legard, and
Peter Clinton from Ensis, as well as David Whitehead from Landcare
and Euan Mason from the University of Canterbury in NZ who took the
time to meet up with us and discuss their research.
The Pittwater open-air forestry
laboratory
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The open-air forestry laboratory:
Pittwater plantation field day 18 May
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Friday 18 May showcased research at the Ensis/UTAS open air
forestry laboratory at Pittwater where some of the most intensive
field forestry research in the world is being focussed. Work
exploring wood formation, plant hydraulics, modelling and
physiology to uncover the biological drivers of dominance
hierarchies in forests and remote sensing for forest health and
forest stress assessment was on display. The aim of the day was to
showcase the science being funded through ARC Linkages, and the CRC
programmes and to share the important process-based research with
industry collaborators. Approximately 30 forest industry and
research collaborators attended from a range of institutions
including Forests and Forest Industries Council, (FFIC), Forestry
Tasmania, Ensis, Norske-Skog, Gunns, the University of Tasmania and
Monash University. Those attending heard presentations from Dale
Worledge, Tony O'Grady, Mike Battaglia, Libby Pinkard, Karen Barry
and David Drew and viewed the impressive instrument displays used
to probe this plantation; instrumentation including the
high-pressure flow metre, spectral radiometer, root and stem
respiration equipment, heat ratio sapflow sensors, point
dendrometers and soil moisture monitoring gear. Without getting to
the micro-level, it is indeed a comprehensive set of tools to
examine forest function.
The Pittwater research plantation was established
in September 2002 within the precursor of the CRC for Forestry, the
CRC for
Sustainable Production Forestry. Tony O'Grady and Dale Worledge
have managed the site since then, and have conducted research
focussing on the growth and distribution of fine roots in sandy
soils and the processes underlying the growth of trees with access
to a range of different water sources including; irrigation, soil
water and groundwater. The uniform nature of the soils and
proximity to Hobart make the site an ideal location for intensive
process-based research. The site comprises three-quarters of a
hectare of Tasmanian blue gum (Eucalyptus globulus)
planted on 2-3 metre deep sandy soil at a spacing of 3x3 metres
(about 900 trees). The trees are irrigated and fertilised with a
suite of macro and micro nutrients and the site is heavily
monitored with electronic equipment. At 3.6 years of age the
average height was 12.2 m and diameter at at 1.3 metres was 12.6
cm. The site is currently being used to conduct research that
describes the processes driving the development of stand structure
and size class distributions. This research is funded through the
ARC Linkage programme and is a collaborative effort between the
UNSW (Mark Adams, Ross McMurtrie), Ensis Forests (Mike Battaglia)
and the US Forest Service (Mel Tyree). The aim of the research is
to extend the way we currently model forests so that we not only
predict average stand attributes but the spread of tree sizes and
their mortality rate.
In true 'build it and they will come' style we are beginning to
capitalise on the research infrastructure and history at the site
to maximise its scientific outputs. The ARC group is working in
collaboration with Geoff Downes (Ensis) and David Drew (Monash
University) who have installed point dendrometers on trees of
different size classes in irrigated and rain-fed plots to examine
daily variations in stem diameter and their relationships with
daily patterns of sapflow and leaf water potential under a range of
atmospheric and water availability regimes. David and Geoff are
principally concerned with wood properties development and
modelling the differentiation of cambial cells (the layer of
cellular tissue from which phloem and xylem grow by division), and
there is considerable overlap in this programme with the aims of
the size class distribution modelling.
Forest health research was highlighted on the day
with presentations by Libby Pinkard and Karen Barry. The forest
health group have just established an extension to the main
plantation area and have appointed a new student, Audrey Quentin,
to examine the interactions of environmental stresses and pest
attack under various water and nutrient regimes on growth and
resource partitioning. Libby summarised the Barnback trials and the
impacts of artificial defoliation on stem growth, photosynthetic
capacity and crown recovery. She also highlighted some important
findings and knowledge gaps which they hope to address at the
Pittwater site. Karen Barry discussed her research at the site
exploring the potential of remote sensing canopy stresses. Karen is
using spectral reflectance as a tool to examine canopy structure
(leaf area index) and photosynthetic capacity. The Pittwater site
provides an ideal opportunity to examine the reflectance signatures
of canopies grown under differing water and nutrient regimes and of
different age classes.
A highlight of the day was the multi-disciplinary
research and the benefits of having purpose designed research
plantations. Over the years the site has become an important
stopover for visitors to Hobart. On the day, we received excellent
feedback from the industry representatives who were impressed with
the scope and depth of the research being conducted at the site,
although this was somewhat helped along by excellent weather, good
coffee and a sumptuous "Jackmann and McRoss" bakery morning tea -
all characteristics of a typical Pittwater visit.
Tony
O'Grady
Research Fellow, School of Plant Science, University of
Tasmania.
