No. 12 Getting the most out of MARVL
NEW ZEALAND FARM FORESTRY ASSOCIATION INFORMATION LEAFLET
How much is your forest worth? Look at the standing trees and estimate
the amount of logs you can cut from them. Sounds simple, however the
results vary largely depending on who looks at the trees, and which
logs they intend to sell. Will you as an owner allow someone else to
capture its true
value without thoroughly investigating all your options? If you’re not
skilled, you need a consultant that can give you impartial advice. A
good consultant will measure your trees using the MARVL system.
Experienced users of MARVL
can match the resource to log types for a range of market opportunities
and assess the potential woodlot value. This article will explain the
advantages of using MARVL 3.5 (the latest version), and highlight the
practical
implications of undertaking a MARVL inventory exercise.
MARVL, what is it?
Worked example
Results analysis
Summary
MARVL, what is it?
For those of you that are not familiar, MARVL is a Forest Research
software package that is defined as ‘Method for the Assessment of
Recoverable Volume by Log Type’. MARVL is a proven tool that has been
well used since 1976. Forestry consultants should utilise MARVL when
employed by woodlot owners.
If you own a woodlot you would like to know what to expect from MARVL
analysis and what to do with the information. In order to estimate the
log products from standing trees it is necessary to make a visual
assessment of the quality of the stem progressively from bottom to top.
This requires setting up a quality code dictionary. The dictionary is a
range of codes used to describe the stem characteristics in terms of
qualities such as branch size, straightness, and roundness. Trees are
coded into sections according to changes in these quality codes. The
logs that could be cut from a stand are defined in terms of size
(length and diameter), quality, those stem quality codes that are
permitted in the logs, and the relative values of the logs to one
another. Altering the log specifications or re-analysing the data can
show the changes in value that may occur if different buyers were
chosen. One example showed offers for a forest that was analysed by
different consultants ranging from $484,000 to over $800,000 (Tree
Grower, February 1997, page 24)
Worked example
The following tables show the changes in volume and value using MARVL
3.5 analysis when a decision is to be made whether to supply sawlogs,
poles, veneer logs or pulp to the market:
Product analysis -
Strategy 1
Product analysis -
Strategy 2
The most obvious comparison is the difference in value, with the first
strategy returning 10% more value per hectare than the second strategy.
The increase in value in the revised strategy is due to the selection
of higher value logs (veneer, poles) in the straighter better quality
stems. There is a price premium
for these products which has increased the revenue. If there was a real
market demand for these products, MARVL allows the cutting strategy to
be analysed prior to harvesting.
Results analysis
What sort of analysis should your consultant present you with?
Comparisons in cutting specifications could potentially be endless.
Firstly the consultant is able to simulate a range of potential cutting
dates and establish the tradeoffs.
Obviously the longer the stand is left to grow, the higher output of
larger more valuable logs it will produce. You might want to know if
the trees are large enough to cut a quantity of high quality logs that
you agreed to supply a local mill. As shown, other questions are easily
answered by altering the log specifications and re-running the data.
You can combine the two types of problems and decide how long you need
to grow your stands before obtaining a target volume of a particular
log grade. The new Windows-based environment in MARVL 3.5 allows
analysis of multiple cutting strategies and projection dates all in one
run, which is ideal for analyses of this type.
Summary
The best way to realise the value of using MARVL is to use it to solve
real questions. Put forward your questions to the consultant rather
than the consultant giving you a range of options to choose from. It is
recommended that forest owners employ experienced consultants who use
MARVL regularly.
Registered users are able to access a well-equipped software support
system provided by Forest Research that offers extensive user support
on the operating environment and inventory design.
(top)
This article by Nigel Pink of Forest Research, appeared in
the November
2000 issue of the New
Zealand
Tree Grower.
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