Crown-scale evaluation of spectral indices
for defoliated and discoloured eucalypts
Remote sensing for evaluation of canopy condition
in plantation eucalypts is a realistic option for forest managers
in the near future. To achieve this, reliable and robust methods of
spectral analysis must be developed through studies of reflectance
spectra of stressed eucalypts. This involves developing and testing
spectral indices which are used to "reduce" the information from
the whole spectra to key wavelengths which correlate well to
specific vegetation properties or biochemicals.
Research by Dr Karen Barry in the ARC Linkage
project, titled "Determining generic indicators of stress in
eucalypt leaves for application to the remote sensing of canopy
condition and productivity modelling", has begun testing the
effects of common symptoms of stress on reflectance spectra. Using
a novel crown-scale approach, factors such as defoliation,
discolouration and the effect of background surface (such as soil
type) could be tested in a controlled way. In this study, indices
based on the "red edge" wavelengths (680-740nm) had excellent
potential to discern vegetation differences including species and
stress effects whilst not being affected by soil type. The
red-green index was best correlated to the proportion of red leaves
of stressed plants and may be useful as a generic index to detect
the stress that appears as red discolouration, as it was not
affected by species differences in this study. Defoliation from the
top of crowns could be detected with a range of spectral indices
but when the same amount of foliage was lost from the bottom of the
crown it was undetectable.
Of the indices tested, some use narrow bands (e.g.
red edge indices) which can only be obtained with hyperspectral
remote sensing data (e.g. CASI) while others are broad-band (e.g.
NDVI or the red-green index) and can be determined with
multispectral instruments (e.g. airborne digital multispectral
camera or high resolution satellite data such as Quickbird). At
present it is the multispectral instruments that are most
affordable for routine use at a plantation-scale.
A range of ongoing studies at the crown and leaf
scale will expand these initial results. Leaf-scale studies are
providing more detailed analysis of relationships between
reflectance and leaf structure or biochemicals such as chlorophyll
and anthocyanins in stressed eucalypts.
- Karen
Barry.
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Industry insights
An opinion piece from Glen Samsa, Great
Southern Plantations
Not so short-term plantation forestry
In the last decade we've seen much excitement in
the plantation forestry sector with advent of the Kyoto Protocol.
In many cases the potential carbon economy the protocol created was
seen as a mechanism to make plantation forestry more attractive as
an investment, and extend plantation forestry into regions
considered marginal for plantation forestry, creating many social
and environmental benefits. Unfortunately, many of the carbon
commodity opportunities that the Kyoto Protocol promised have not
materialised in Australia, at least. That was until the Kyoto
compliant and Independent Pricing and
Regulatory Tribunal (IPART) administered NSW Government
Greenhouse Gas Abatement Scheme was introduced recently. Carbon
fixed by compliant plantation forests in NSW is now a sellable
commodity in that market place. There are many issues associated
with selling carbon into Kyoto compliant schemes, and the issue of
permanence is among these. That is, once you sell a piece of carbon
you have to guarantee its existence for 100 years. This in effect
turns a 10 year forestry business into a 100 year one, as such many
risks and uncertainties exists. Comprehensive and easy-to-use
process-based models that are able to deal with the complexities of
multi-rotation sites and climate regimes are integral to
understanding the risks and uncertainties associated with the
permanence requirement for carbon. For example, an integrated
process-based modelling framework that helps plantation managers
understand the impacts of today's management decisions on a
forest's ability to fix carbon in future decades is essential.
Moreover, process-based models will be integral to understanding
the impacts of climate change on future carbon stocks. Research
Programme One is exciting in many respects and has the ability to
add much value to plantation forestry in Australia, and its ability
to help contribute to "carbon forestry" (not often considered) is
one of them.
- Glen
Samsa.
For the next edition feel free to provide an
industry perspective (a short piece) on science or practise
relevent to project activities. Please send your submission ideas
to Michael
Battaglia.
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Quips, comments and
questions
The programme would like to announce its first
deliverable - we congratulate Darius Culvenor and Bronwyn on the
birth of daughter Zoe. Anyone who knows Darius' work habits will
know that he will be a natural for the nocturnal rigours of being a
Dad.
Libby Pinkard, who has been working for the
University of Tasmania in Project 1.2, has taken up a position with
Ensis. However she has not escaped the CRC and will carry on
providing science input into the 'Managing for forest health'.
Audrey Quentin, a PhD student in "1.2 Managing and
sustaining" has recently come to us from France. The words to the
La Marseillaise appeared in the tea room after France made
it to the final of the world cup, but alas with Italy's triumph
they remain unsung!
For the next edition feel free to send in short
comments about project, programme or industry activity that will be
of interest to programme members. Please send your submission ideas
to Michael
Battaglia.
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Guest spot
The pulp and paper industry and forest
research in Brazil
by Dr
Auro Almeida, Senior Research Scientist, Ensis - forests
(Ensis: the joint forces of CSIRO and Scion)
The pulp and paper industry in Brazil is growing as
fast as the Eucalyptus plantations in that country (very
fast!) and has become much more competitive than in the northern
hemisphere. According to the Brazilian Pulp and Paper Association,
Brazil has around 220 pulp and paper companies, generating 108,000
jobs. These companies planted 1.7 million hectares of which 75% are
Eucalyptus species. Brazil's pulp and paper industry
exported US$3.4 billion in 2005, representing a growth of 17%
compared with 2004 (Bracelpa, 2006).
The main reasons for the success of the Brazilian
industry are based upon a combination of factors such as:
favourable climate conditions, low cost of production with a
constant reduction of cost per produced unit, constant
modernisation, high-technology, and an increasingly large
investment in forest, pulp and paper research.
In terms of forest research, most of the effort and
investment has been applied to improving breeding and genetics,
with very good results. However, during recent years the research
areas are changing due to new market requirements and
globalisation. Questions about forest sustainability, environmental
concerns and certification processes have become part of the
industry's reality. New investments or expansions must consider new
factors such as landscape management, environmental fragility, the
potential forest productivity over several rotations and, not less
important, the social aspects. The industry has begun to consider
the full process of production and how it is possible to manage
natural resources efficiently and with a long-term perspective. It
has started to understand that the investment in forest research is
much more than just breeding trees. The use of new technologies and
advanced tools - such as high resolution remote sensing, precision
silviculture and process-based modelling - start to give a new
perspective on decision making processes and the future of some
these companies. Some companies have already integrated forestry
research with the science of the pulp and paper mill process. This
includes a focus upon the needs of the paper producers and other
stakeholder demands. Other companies are yet to take up this
approach. Companies that concentrate their efforts upon operational
costs only may have problems surviving in this very competitive
sector.
