News
IC
FR
November 2002
The ICFR mission is to contribute to the global effectiveness
of our sponsors through excellence in technical innovation
in sustainable plantation silviculture
Predicting Forest Productivity with
process-based models
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Before process based models can be used, climatic data and information inherent to
the species (parameter set) is required. To this end, using ICFR research trials comprising commercially planted E. grandis, Luke Esprey, Chris Komakech and Michael Buthelezi
have embarked on a whole tree harvesting operation (see below) spanning high
(>40 m3 ha-1 yr-1), medium (25 to 40 m3 ha-1 yr-1) and low (<25 m3 ha-1 yr-1) productivity
sites within four age classes. For each of the 12 trees over 13 pre-selected sites wet and
dry biomass data pertaining to branch, bark, stemwood, foliage and capsules is being
collected. Other data collected includes sapwood, heartwood and specific leaf area,
wet and dry stemwood density, leaf area index and monthly litterfall rates.
An interesting result shows the leaf area (and leaf area index) on medium productivity sites to be larger than those at higher productivity sites (Zululand) with the reverse
occurring on lower productivity sites of the same age. Furthermore, on the Zululand
sites, the sapwood area at a height of 1.3 m exceeds those found at both the low and
medium productivity sites.
Information and data from this work will give insight into biomass partitioning and
allometric relationships between sites plus help understand factors driving productivity for a
range of site types. Such
knowledge will further
help in the development
of a more accurate and
robust E. grandis parameter set for the process based model 3-PG
(Physiological Processes
Predicting Growth). It is
anticipated that subsequent applied research
will help identify physiological and silvicultural
constraints of site productivity experienced at
the lower productivity
sites.
Contact: Luke Esprey
ABOVE: Labourers helping in the stripping of foliage
lukes@icfr.unp.ac.za
biomass at the Baynesfield site preparation trial.
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In this issue…
Predicting Forest Productivity with
process-based models
Woodfor 2002 Reportback
Tracking changes at the ICFR
4th International Conference on
Forest Vegetation Management
www.icfrnet.unp.ac.za
New Staff at the ICFR
Eucalypt productivity re-visited
Wheelbarrow Patterson put to
shame
The effect of black wattle seedling
age at planting
A new decision support software
tool for tree growers and water
resource managers
Interaction between rainfall,
under-canopy vegetation and the
debarking of Eucalyptus grandis x
E. camaldulensis
SAIF News
Zululand Interest Group Field Day
UNP Forestry News
Latest ICFR Bulletins
Diary of Forthcoming Events
Christmas message from
Colin Dyer, ICFR Director
I would like to take this opportunity to wish all
of our sponsors and research partners well
during the festive season.
Thank-you for your continued support
and enthusiasm for the work
that we do at the ICFR.
We look forward to an exciting
and challenging 2003.
WoodFor 2002 Reportback
The Wood for Africa exhibition and conferences were held at
the Hilton College during the first week of July 2002. Over
840 delegates attended the conferences on 2, 3 and 5 July,
and the number of visitors to the exhibition was significantly
higher than previously recorded. As part of the WoodFor conference, the ICFR hosted a one-day symposium entitled “Creating and Growing trees through Innovation and Technology”
featuring 14 papers showcasing the latest developments in
South African forest science.
The symposium was a huge success, attracting by far the
greatest proportion of delegates at WoodFor. The papers delivered were of an exceptionally high standard and the full text
ICFR News – November 2002
of these will appear as a dedicated edition of the Southern
African Forestry Journal in October 2002. The ICFR would like
to thank Dr Colin Smith for the co-ordination of this symposium and acknowledges the valuable inputs made by Dr Andrew
Morris and Flic Blakeway on the editorial committee.
Based on the success of this event, the ICFR is planning to host a similar forest science symposium every two
years creating the opportunity for researchers to present
their findings to peers and colleagues from the forestry
industry.
Contact: Colin Dyer, colind@icfr.unp.ac.za
Page 1
Tracking changes at the ICFR
Recently three of the programmes at the ICFR have undergone restructuring to accommodate staff changes. The programmes affected include the Vegetation and Coppice
Management programme, the Hardwood Nutrition programme, and the Plantation Management programme. The
Plantation Re-establishment Research Programme
Manager: Keith Little
Ecophysiological Regeneration Research
Carol Rolando, Paul Viero and Keith Little
Assisted by Gavin Higgs
Adaptive Vegetation Management Research
Keith Little and Carol Rolando
Assisted by Gert van den Berg, Gavin Higgs,
Denis Oscroft and Greg Fuller
Coppice Management Project
Keith Little
Assisted by Gert van den Berg, Denis Oscoft
and Greg Fuller
Commercial Deployment of Weed Control Standards
Keith Little and Carol Rolando
Assisted by Gert van den Berg, Gavin Higgs, Denis
Oscroft and Greg Fuller
Plantation Management programme research team formerly
comprised Sabie-based Colleen Carlson and Ross Allan, and
was a combination of three project areas (Re-establishment
research; Research to improve the productivity of young stands
and Mature stand research) dealing primarily with pines (80%)
in the Mpumalanga region. When Colleen and Ross left the
ICFR (2001) an opportunity was taken to incorporate these
projects into existing programmes, whilst retaining the integrity of the research that was being conducted on behalf of the
sponsor companies.
To do this, the research conducted in the Plantation Management programme was split into two components as follows:
Research dealing with the nutritional component of the Plantation Management programme has been incorporated into
the Hardwood Nutrition programme (now called the Forest Nutrition programme). Benefits of this include the common grouping of nutritional and sustainability issues relating to both
hardwoods and softwoods. Janine Campion has been appointed as researcher in the Forest Nutrition team with effect
from 1 July 2002 (see New Staff). Steven Dovey, Sam Soko
and Anthony Job provide technical support, with part time assistance from Denis Oscroft and Greg Fuller. The Forest Nutri-
tion team works with an experimental base covering the whole
of the eastern seaboard of South Africa. Trials are situated in
the Limpopo Province, Mpumalanga (Highveld and Escarpment), KwaZulu-Natal (Midlands and Coastal areas) as well
as the Eastern Cape.
The Vegetation and Coppice Management programme has
been renamed the Plantation Re-establishment Research programme and includes all the past projects (Adaptive vegetation
management research; Coppice management; Weed control
standards) as well as that component of the old Plantation Management programme dealing with issues relating to re-establishment research. This project has been renamed “Ecophysiological
Regeneration Research” (EPRR) and is ably headed by Carol Rolando who will devote 50% of her time to its development. Assisting Carol in this project is Paul Viero who joined the ICFR from
Mondi at the beginning of September (see New Staff). The change
in name from “Re-establishment Research” to “Ecophysiological
Regeneration Research” describes more specifically the area of
research focused on in this project, which aims to investigate and
quantify the environmental and physiographic factors that adversely alter the physiology of planting stock causing a reduction
Forest Nutrition Programme
Manager: Ben du Toit
Site Management for Sustained Productivity
Ben du Toit & Janine Campion
Assisted by: Steven Dovey & Anthony Job
Development of core expertise
Ben du Toit
Janine Campion and Steven Dovey
Hardwood Nutrition
Ben du Toit, Steven Dovey & Anthony Job
Softwood Nutrition
Ben du Toit and Sam Soko
in growth or an increase in mortality. The understanding gained
will be used to develop cost effective recommendations that minimize stress during regeneration and maximize survival, growth
and uniformity for a range of sites, species and management
objectives within commercial plantations. It is envisaged that this
project will grow to incorporate eucalypts as well as pines grown
in the summer rainfall regions of South Africa.
4th International Conference on Forest Vegetation Management
In June 2002 Dr Keith Little, project leader
of the ICFR’s Plantation Re-establishment
Research Programme (formerly Vegetation
and Coppice Management programme)
attended the 4th International Conference
on Forest Vegetation Management (FVM)
held in Nancy, France. He was also afforded
the opportunity to take part in the postconference tour of north-eastern France,
northern Switzerland and southern Germany.
This IUFRO Research Group 1.13.00
Conference is held every three years and is
the only international conference dealing
specifically with the management of vegetation in natural or managed forests. It was
jointly organised by INRA, AFPP, IUFRO,
Page 2
CEMAGREF, Conseil Général de Meurtheet-Moselle, Communauté Urbaine du
Grand nancy, Région Lorraine and Ville de
Nancy.
The aim of the conference was to provide a forum for presentation of the latest
global research in FVM research and to
encourage debate around critical issues
relating to FVM among forest scientists, forest managers, FVM specialists, ecologists,
regulators and policy makers.
Ninety-five papers and 58 posters
were presented focusing on three
themes: Economic, environmental and
social aspects of FVM; Biological basis
of FVM and Technical and operational
considerations for FVM. Of these, two
oral papers and one poster were presented by the ICFR:
1.“The relationship between vegetation
management and the wood and pulping
properties of a Eucalyptus hybrid clone”
by Little K.M., van Staden, J. and Clarke,
G.P.Y.
2.“Competitive interactions between
grasses or broadleaves and early P.
greggii growth” by Little K.M., du Toit B
and Esprey L.J.
3.“The impact of vegetation control on the
establishment of pine in the summer
rainfall region of South Africa” by Little
K.M. and Rolando C.A.F
ICFR News – November 2002
www.icfrnet.unp.ac.za
In recognising the importance of information management, usage and efficient
flow as key resources within an organisation, the ICFR maintains a web site designed to give ICFR sponsors access to all publications in electronic format. Sponsors no longer have to order and wait for copies of publications, only to find out the
information contained therein is not relevant. In situations where plantation managers do not have direct access to the web, they can request the ICFR librarian to
conduct information searches on their behalf. Regular users of this facility have
become aware of the efficiency and usefulness of this tool and are more proficient
at focusing search requirements. The ICFR continues to distribute printed copies of
all documents to those on its mailing list.
Did you know that this is the 49th ICFR Newsletter produced since the series
was started in 1990? Did you know that 168 Bulletins have been published since
this series was initiated in 1992? Did you know that all of these documents are
available on the ICFR’s web site? The ICFR’s Annual Research Reports/Reviews
published since 1995, as well as the Innovation reports produced since 2000, are
also available electronically via the Internet. These publications have been
sub-divided into smaller sections to reduce the frustration of waiting for large articles to download. Each document is prefaced by a contents page enabling visitors
to find a specific section (e.g. a summary or recommendations). All of the ICFR
publications available on-line are password protected. ICFR sponsors can contact
Sally (033-386 2314 or email sally@icfr.unp.ac.za) to obtain access control details.
A list of forestry-related web sites (under “Links”) is also available via the site
and serves as a useful guide to information sources on the Internet. Other information on the Internet includes a list of staff members and e-mail addresses, complete
with photos. It is planned to extend this to include expertise profiles of staff to
facilitate searching for research assistance in specific areas. The South African Forestry Journal Index, volumes 1 to 190, is also available on the ICFR home page
and can be searched according to key word (author names included) or volume.
Reprints of the articles can be obtained directly from the South African Institute of
Forestry (visit their web site at http://www.foresters.org.za/ for more information).
ICFR’s website also has a search facility, enabling sponsors to search over 3000
files on-line for particular keywords, enhancing accessibility to valuable data and
information. To use the search service correctly, it is important to note that the search
“engine” is case-insensitive and punctuation marks as well as single character words
and very short words (e.g. in, the) are ignored. The search service has three keyword
text entry fields. If more than one word is entered into one field, a phrase search is
performed. Phrase search means that all the words in the field must be in the document, next to each other, and in the order they appear in the search field. A phrase
search is particularly useful when searching for an author’s name. For example,
entering “colin smith” into the first field, will produce a list of all documents in which
this word phrase is found. The three entry fields are separated by the following options which select the kind of search you may want to perform:
and – means that both of the words on each side of the “and” must be in the
document. For example, entering “little” in the first field and “smith” in the second
field and setting the search option to “and” will result in documents that contain
both words appearing in the results page.
or – means that if either one of the words is in the document, it is a match. For
example, entering “little” or “smith”, will generate a list of documents containing
either or both words.
not – means that if the word in the field to the right is in a document, i.e. a
document containing both words, it will not appear in the results list.
The ICFR’s web site is currently under revision and we welcome any feedback
from sponsors visiting the site to ensure the information is both relevant and easily
accessible.
Contact: Sally Upfold, Editor/PRO, sally@icfr.unp.ac.za
Desiree Lamoral, Librarian, desiree@icfr.unp.ac.za
Richard Kunz, Information Manager, richard@icfr.unp.ac.za
E A copy of the summaries of all
presentations is available for loan from the
ICFR library as well as a special edition of
the Annals of Forestry Science containing
full texts of selected presentations. (not yet
available)
While providing the opportunity to renew contacts, share opinions, compare exICFR News – November 2002
perimental techniques and benchmark research efforts, Keith felt the conference was
disappointing with respect to the poor
Southern Hemisphere representation and
the few talks on fast grown hardwoods and
softwoods. In addition he noted a lack of
talks relating to the practical implementation of research findings on a commercial
New Staff at ICFR
ICFR recently acquired three new staff members. Janine Campion joined the Forest Nutrition team from 1 July 2002, Paul Viero is
the newest member of the Plantation Reestablishment Research programme (September 2002) and Sally Upfold has taken
over the role of Editor/ Public Relations
Officer from September 2002.
Before joining the
ICFR
Janine
Campion completed
her bachelor training
at the University of
Witwatersrand, majoring in Microbiology and Botany, with
a special interest in
whole-plant physiology and soil and environmental biology.
She obtained her BScHons degree from
Wits University in 1998, and is currently
conducting research towards a PhD involving a nutrient optimisation and irrigation
trial on Eucalyptus grandis, located near
Seven Oaks.
Sally
Upfold
came to the ICFR
from the University of
Natal, with six year’s
experience as the
Faculty of Science &
Agriculture’s Public
Relations Officer,
where she was responsible for all the
marketing, recruitment and outreach initiatives of the Faculty. Prior to this she was
employed as Research Assistant in the Faculty’s discipline of Botany where she completed BSc, BScHons cum laude and MSc
cum laude degrees.
Paul Viero joined
the ICFR from Mondi
where he held the
post of Technical
Transfer Forester in
Mondi’s Zululand
department
at
Kwambonambi.
Prior to this Paul
gained experience
as silvicultural manager, senior estate
manager, weed control forester and planting forester with Mondi Forests. Paul holds
National Diplomas in Forestry and Nature Conservation as well as a BTech. degree in Forestry and is currently
completing an MTech. degree also in Forestry.
basis and the failure to use economics in
determining the efficiency of different FVM
systems.
Thanks are extended to Professor Colin
Dyer, (Director, ICFR) and ICFR’s sponsor
companies for facilitating Keith’s attendance at the conference.
Contact: Keith Little, keith@icfr.unp.ac.za
Page 3
Eucalypt productivity re-visited
As part of her doctoral research, Diana Rietz, currently registered with the University of Natal’s Forestry programme, is investigating the effect of site and stand density on biomass allocation
and fibre yield in Eucalyptus nitens.
stand density and age. Traditionally measurements have only
been taken regarding merchantable stemwood volume, so why
investigate biomass allocation patterns? Stemwood productivity
can be increased by increasing the total productivity of the stand
or by increasing the proportion of biomass allocated to stemwood.
Therefore, if factors or combination of factors which affect the
fraction of biomass allocated to stemwood can be determined,
this knowledge can be applied to improve economic yield and
predict combinations of site and silviculture which optimise productivity. In addition, the effects of site and stocking on fibre quality
of these trees will be determined using appropriate techniques.
These results combined with stemwood volume values will give
pulp yield, which once again relates to economic yield. The results will enable detailed parameterisation of a process-based
model (such as 3-PG) for the growth prediction of this species in
South Africa.
Contact: Diana Reitz , diana@icfr.unp.ac.za
ABOVE: A healthy seven year old tree in a Eucalyptus nitens
stand. How do biomass allocation patterns affect productivity
and wood quality of such stands?
E. nitens is a commercially important, cold-tolerant eucalypt
known to have a rapid early growth rate, with frost tolerance and
good pulping properties. Little is known however, on the combination of silvicultural and site factors affecting productivity in terms
of fibre yield for example. This project aims to determine which
combination of site factors and stand density will optimise the
productivity of this species by investigating biomass partitioning.
This will be done by destructively harvesting and investigating
varying patterns of biomass allocation in the harvested trees.
The trees will be sampled from compartments varying in site,
ABOVE: The canopy of an eight year old Eucalyptus nitens
stand (MAI 45 m3ha -1yr-1 ) Canopy processes and the factors
influencing them are key determinants of forest productivity.
Wheelbarrow Patterson put to shame
Ever heard of Wheelbarrow Patterson, a legendary figure dur-
ing the gold-digging days at Pilgrim’s Rest? The story goes that
he appeared from nowhere in Pilgrims Rest, having apparently
pushed his gold digging tools in a wheelbarrow, all the way from
Kimberley. He could also dig out a “claim” in no time at all. Well,
poor old “Wheelbarrow” has met his match. Some fast and furious digging has taken place at the Karkloof Project trial (near
Howick) during the past year, as part of a number of projects
aimed at studying tree roots. Zola Sithole, a 4th year student of
the UNP Forestry Programme is busy with a project entitled: “The
effect of site preparation on root growth and nutrient content of
a 3 year-old Eucalyptus grandis plantation”. Another final year
student, Marc Crookes, is focusing on root distribution patterns
as affected by treatment. Last but not least, Mbeko Nkosana, an
MSc. student from Wits University, is currently completing research
on fine root dynamics in a project entitled “Some effects of early
silvicultural management operations on root turnover in Eucalyptus grandis plantations”. The results from the three studies will
improve understanding of the effects of environmental conditions and treatments on root formation and growth, root mortality and decay, root distribution, carbon and nutrient dynamics,
and below-ground nutrient pools. The “pieces” of data also form
part of a bigger “puzzle” at the stand level, namely the partitionPage 4
ing of carbon to above- and below-ground tissues as well as
stand growth efficiency. ICFR’s Greg Fuller (using his experience
from studying roots in the mature stand at Karkloof) played a
leading role in assisting the students. The ICFR nutrition team is
also grateful for the effort made by the three students themselves
and their supervisors (Mary Scholes and Janusz Zwolinski). Tribute must of course also be paid to the shining example set by
poor old Wheelbarrow Patterson at the turn of the century.
Contact: Ben du Toit, ben@icfr.unp.ac.za
Extra copies of
SA Forestry Journal available
The ICFR library has a number of extra copies of the
South African Forestry Journal issue no 86-182 available to anyone who wishes to have them.
Contact Desiree Lamoral, ICFR librarian,
desiree@icfr.unp.ac.za
ICFR News – November 2002
Table 1: Black wattle seedling growth results from sowing of four age classes.
Sowing
date
Mean
seedling
height
(mm)
Mean
collar
diameter
(mm)
Root
plug
dry mass
(g)
Rooting
capacity
(range)
Dry mass
Total
number
blanked
(max. 175)
Aug 2001
600
6.3
1.62
0.03-1.23
77
Dec 2001
550
5.0
0.55
0.21-1.61
47
Jan 2002
40
3.1
0.23
0.20-1.10
31
Feb 2002
20
2.4
0.23
0.24-1.12
46
FIGURE 1a: Inconsistent and in some cases very poor root development
in trees grown from the August 2001 sowing (old seedlings).
FIGURE 1b: More consistent root development in trees from January
2002 (four month) seedlings.
ICFR News – November 2002
ABOVE: Process-based models have the potential to realistically
account for site and climatic influences in predicting forest
productivity, of plantations.
A new decision support
software tool for tree growers
and water resource
managers:
harnessing physiological information to improve
productivity and water use assessment of forest
plantations
Experience overseas is showing that relatively simple process-
based models are proving increasingly useful in predicting rates
of growth and water use in forest plantations. Such models simulate the major physiological processes behind growth and water
use (e.g. light interception, photosynthesis, carbon allocation to
different parts of the tree, leaf litter production, etc) and take into
account the many climatic, stand and soil characteristics that affect trees during the course of a rotation. The process of setting
up the model for a given species and range of site conditions
leads to useful advances in understanding of forest growth determinants.
Fund administrators (NRF) recently approved a research proposal aimed at setting up such a model for use in South Africa
and a three-year project began in August 2002. The project consortium consists of ICFR, MMRC, Environmentek (CSIR), UNP Forestry Programme and Brousse-James and Associates. The project
will include; a survey of user needs, a review of existing processbased models and model modifications to simulate, for example
drought effects, stand density and early growth up to canopy
closure. The models will be parameterised for relevant South African commercial species. The development of a prediction tool
for growers is envisaged aimed at two types of forest growers
• Industrial growers, where a GIS-based system is appropriate
• Small-scale growers, where a PC-based system is more
appropriate
These products are designed to compliment existing forestry
information-based systems such as the ICFR Forest Productivity
Toolbox.
Contact: Dr Peter Dye (CSIR) Project co-ordinator,
pdye@csir.co.za
Luke Esprey Principal ICFR investigator,
lukes@icfr.unp.ac.za
Dr Colin Smith Manager: Forest Productivity,
colin@icfr.unp.ac.za
Page 5
r e s e a r c h
As part of the Acacia Research programme, ICFR’s Sieg
Hagedorn is currently conducting research on the effect of age
on black wattle seedlings at planting. Containers produce seedlings where the root system is confined to the growing medium
available in the container. Depending on how long the seedling
is kept in the nursery, the root systems will become more or less
pot-bound which will determine both root development and the
type of root system in the soil after planting, and consequently
the stability of the tree at a later stage.
At the end of April this year, the ICFR established a replicated
trial at Bloemendal where seedlings of four age classes are being
compared. Five replications will serve for long-term observation
while two will be used for destructive sampling, looking at the
development of the root systems. Sowing dates were August 2001,
December 2001, January 2002 and February 2002. Height and
root collar diameters were measured at planting as well as the dry
root mass of seedlings from each age class. At the same time 10
seedlings of each age class were planted in vermiculite and kept
in the nursery for 45 days to determine the root regeneration capacity of each seedling type. The field trial was blanked three times.
Early results indicate that the four-month-old seedlings (January sowing) look the most promising with more consistent root
development and fewer total numbers blanked (Table 1 and Figure 1a & 1b).
Contact: Sieg Hagedorn, sieg@icfr.unp.ac.za
u p d a t e s
The effect of black wattle seedling
age at planting
Interaction between rainfall, under-canopy vegetation and the
debarking of Eucalyptus grandis x E. camaldulensis
Bark-wood bond strength (BWBS) is one of the measurements
used to determine the bonding strength between wood and bark,
and is one of the most important properties affecting debarking.
There have been a number of studies to determine the influence
of various factors on BWBS, but few have used eucalypts as experimental material. Those BWBS studies that have been conducted on Eucalyptus species showed the following results:
• During the drying of sample discs, the sapwood moisture
content was a good predictor variable for determining BWBS.
• BWBS parallel to the grain was consistently greater than when
perpendicular to the grain.
• No significant relationships have been found between BWBS
and log diameter or bark type.
However, none of these previous studies have investigated
the influence of vegetation control and rainfall on soil and wood
moisture content, both of which could influence BWBS and therefore the debarking of logs.
To address this, an experiment was carried out to investigate
the impact of water availability on the debarking of Eucalyptus
grandis x E. camaldulensis (E. gxc) logs. The trial was conducted
on an 8-year old E. gxc stand and consisted of two treatments (a
weedy and weed-free treatment) each replicated six times. Vegetation had been allowed to develop from when the trees were
two years of age in the weedy treatment, whereas complete vegetation control had been carried out in the weed-free treatment.
Despite the presence of vegetation in the weedy treatment for six
years (biomass of 12.65 t ha-1), no significant differences were
detected between the two treatments in terms of tree performance. Each treatment plot consisted of 6 x 6 trees, from which
four sample trees were selectively felled. From the treatment plots
the following factors were assessed:
1. Vegetation cover abundance and biomass (Braun Blanquet).
2. Water potentials of the sample trees by means of a “pressure
bomb”.
3. Soil moisture content
4. Moisture content in the bark and wood using sample discs.
5. Ability to debark where sampled trees were cut into 2.4m
logs of which the second log from the bottom of the tree was
selected for measurement. On this log a 10 cm bark strip,
free from any defects, was selected. This strip was then removed, and the resistance to remove measured in kPa, over
1cm intervals for a distance of 90 cm. This was done by means
of a modified soil penetrometer (Figure 1).
FIGURE 2: Percentage reduction in soil moisture from the wet to the
dry period.
Page 6
All the above measurements were carried out after a period
of high rainfall (48 mm within 15 days, and 94 mm within 30
days prior to measurements) and after a dry spell (2 mm within
15 days, and 11 mm within 30 days prior to measurements).
Results showed that the interaction between the timing of felling and the absence or occurrence of rainfall and vegetation
could play an important role in the availability of soil moisture to
FIGURE 1: Debarking by means of a modified penetrometer.
the trees and therefore the ability to debark E. gxc logs. This
reduction in soil moisture, from the wet to the dry period was
significant (p < 0.05) for the two treatments. Due to the presence of vegetation there was a higher reduction in soil moisture
for the weedy treatment than for the weed-free treatment (Figure
2). This reduction in soil moisture limited the water available to
trees and had a significant (p < 0.05) impact on the debarking
ability. The resistance to remove the bark was significantly higher
in the dry period than in the wet period (Figure 3). Although this
difference was greater in the weedy than in the weed-free plots
(Figure 3), both were equally as difficult to debark. No significant differences were detected for the water potentials of the
sampled trees, or for the moisture contents of the sample discs
taken for the different treatments at any measured date.
Contact: Gert van den Berg, gert@icfr.unp.ac.za
Keith Little, keith@icfr.unp.ac.za
FIGURE 3: The mean maximum pressure to debark logs for the
different treatments at different time periods.
ICFR News – November 2002
Southern African Institute of Forestry
The Southern African Institute of Forestry (SAIF) aims to represent the profession of forestry by promoting all aspects of forestry
and improving the standards of practice in the professional and technical aspects of forestry.
KwaZulu-Natal branch
There have been a number of changes in the local Southern African Institute of For-
estry (SAIF) branch with the previous chairman, Dr Colin Smith recently being elected
national SAIF President. The new KZN Branch Chairman is Craig Schutte, a member
of the marketing department of Natal Co-operative Timber (NCT) (Pmb). Craig holds a
BSc in Forestry from Stellenbosch. ICFR’s Trevor Morley has become Vice-Chairman.
The KZN branch of the SAIF has had a very busy year and has a full programme
planned for the remainder of 2002. Monthly meetings continue to be very well attended and have included a talk by Mr Ian Henderson, Forestry Manager of Masonite
on “Masonite To-day: A close up look at the Company – where it is, what it does”
(August), as well as Development Manager of FESA Francois Oberholzer’s, wellillustrated talk on a visit to Australia and New Zealand earlier in the year (September).
Upcoming talks:
Dr Colin Smith, Project Manager of the
Forest Productivity programme at ICFR.
New SAIF
President
Earlier this year Dr Colin Smith became
the new President of the SAIF taking over
from the previous incumbent, Patrick
Kime. Prior to his appointment, Colin was
the chairman of the KZN branch of the
SAIF, a role he filled for two and a half
years. He is currently project manager of
Forest Productivity Research at the Institute for Commercial Forestry Research
(ICFR) in Pietermaritzburg.
In taking on this role, Colin cites his
main goals as:
v Promoting the ideals of the SAIF for
the benefit of its membership;
v
Taking steps to ensure the future organisational and financial well-being
of the SAIF;
v
Strengthening the role of the SAIF in
all aspects of forestry by highlighting
forestry as a legitimate land use in harmony with social and environmental
principles;
v
Improving the quality and format of the
v
Fostering a more integrated approach
with those representing forestry interests to speak with a unified voice on
principal issues.
Southern African Forestry Journal and
making it a true flagship for research
in all aspects of forestry in southern
Africa and
11 NOVEMBER
Gerritt Marais, SGS will speak on General Forest Certification and the SGS
Programme.
Contact: Sue James (Stuart Communications) 033-342 5779 sc@futurenet.co.za
Craig Schutte 033-394 1202 craigs@nctforest.com
Zululand Interest Group Field Day
The Zululand Interest Group meeting held on 24 July focused on harvesting im-
pacts and nutrition. Dr Colin Smith, project leader of the Forest Productivity programme presented results on the effects of old extraction roads and harvesting
operations on productivity of eucalypts in Zululand at five to eight years. Research
showed that although old extraction roads cause spatial effects on growth, provided controlled traffic is practised, especially on sensitive soils, the effect of old
extraction rows on the productivity of eucalypts in Zululand is not pronounced.
Even when moderate to severe compaction may exist on old harvesting extraction
roads as indicated by high bulk density levels, soil strength levels remain relatively
low on very sandy soils (< 5% clay content), available water may increase and
compaction is offset by old tree roots. Compaction is a problem on the soils with
more clayey subsoils (> 5% clay content), particularly Constantia soil forms, but
growth losses will be minimised by practising controlled traffic.
Ben du Toit and Steven Dovey delivered a presentation on “Plantation nutrition
and sustainability issues on the Zululand coast: Lessons from the Congolese ”littoral”” drawing parallels between the Congolese and Zululand coastal plains, which
have many similarities with respect to soils, climate and tree crops. Nutritional
research in Congo (both on nutrient dynamics and fertilization) yielded results comparable to Zululand studies. These results have improved understanding of nutrient
supply and demand in these (sub)tropical systems. Ben and Steven also painted a
picture on nutritional sustainability in coastal Zululand, drawing on concepts recently presented at the Woodfor Africa Symposium. The presenters summarised the
key issues and threats concerning sustainable forestry on the Zululand coast, and
concluded by highlighting the implications of these for management and research.
The day ended with Colin and Ben giving a field presentation on a harvesting
impact trial at Rattray near Kwambonambi. This trial showed no significant growth
differences between mechanical and manual felling operations on a very sandy soil (<
5% clay content). Interestingly, although there was no significant interaction between
harvesting operation and fertiliser application, there was evidence to suggest that some
disturbance when travelling over slash during the harvesting operation may provide an
initial nutrient boost. In general it was shown that mechanical harvesting had no adverse effects on both productivity and the soil environment and that wheeled mechanical harvesting can be implemented where total clay content does not exceed 5% (i.e.
sands) throughout the top 100 cm and where waterlogging is not present in this zone.
Contact: Colin Smith, colin@icfr.unp.ac.za
Ben du Toit ben@icfr.unp.ac.za
ICFR News – November 2002
Page 7
University of Natal Forestry News
International Forestry School 2002
For the third consecutive year, the UNP Forestry programme
organised an International Forestry School, and in June 2002
for the first time, the 24 students participating represented three
tertiary South African education institutions (University of Natal,
University of Stellenbosch and PE Technikon at Saasveld) as well
as countries such as Sweden and Brazil. The programme was
prepared by Ockert le Roux (Sappi), Marius du Plessis (Mondi),
George Theart (SiyaQhubeka) and Vusi Dladla (NCT), and the
organization of the School and co-ordination of various inputs
was the responsibility of Professor Janusz Zwolinski from University of Natal with assistance from Mr Pierre Ackerman from
Stellenbosch. The students engaged in field programmes prepared by the major commercial organizations including Mondi
Forests and SiyaQhubeka, Sappi Forests, NCT, KZN Parks Board
and CSIR. Students were also offered the opportunity to participate in Woodfor Africa 2002, and benefited from two days of
research conferences and demonstrations on a diversity of subjects such as timber production, nature conservation, water and
certification, forest products and processing, social issues and
land rehabilitation.
Silva Network Conference in Warsaw
(4-8 September 2002)
Professor Janusz Zwolinski was recently invited to participate
in a workshop at the Silva Network Conference in Warsaw. Silva
Network is a large organization integrating and unifying efforts
of forestry faculties across Europe many consisting of over 1000
staff and students. Silva Network also engages in building links
with organizations and networks beyond Europe. South Africa
attracted its attention because of high-class forestry recognized
internationally. At the workshop, Janusz argued for the high class
South African commercial forestry, long and successful history of
indigenous forest preservation and forestry contributions to employment and rural prosperity as the critical elements for extended
education of European forestry students. His presentations were
combined with those of Professor Erik Sundström from the Swedish University of Agricultural Sciences who has encouraged his
students’ participation in the International Forestry School. Silva
Network expressed interest in extending their collaboration with
South African academic institutions and it is hoped they will use
the School as a pilot project leading to a large-scale platform for
academic and research cooperation.
Diary of Forthcoming
Events
November 2002
13th SAIF Mpumalanga AGM & Social “Forestry Ball”
Contact: nikki@soft.co.za
25th – 6th Dec Graduate course on
“Estimating nutrient dynamics and productivity in South
African Plantations” Contact: mary@gecko.biol.wits.ac.za
Winning Stand at Woodfor Africa 2002 Show
The University of Natal participated for the first time in the
exhibition component of Woodfor Africa 2002 with a prominent
input from the Faculty of Science and Agriculture and especially
its Forestry Programme. Students and academics supported by
some ICFR staff established a stand ranked the best indoor exhibition by an independent jury during the show. The stand included large-size posters and a water screen on which forestry
and Faculty video material were shown. Large-size posters and
informative pamphlets were supplemented with plants and forestry components. There was a great interest in prospective postgraduate studies, and a good number of visitors investigated
opportunities to upgrade academic qualifications in forestry.
Visit to China
At the invitation of the Beijing Forestry University, Professor
Janusz Zwolinski recently undertook a trip to China aimed at
establishing academic contacts with forestry faculties, and to learn
more about the principal objectives in teaching, research and
forest development processes. In addition he visited the Northwest SciTech University of Agriculture and Forestry in the Shaanxi
Province. The forestry departments of the two universities comprise some 300 academics and cater to 2300 forestry students.
They also integrate scientific activities of several research institutes. It is hoped the visit will lead to the initiation of collaborative
research projects and academic exchange.
Contact: Janusz Zwolinski, zwolinski@nu.ac.za
The latest ICFR Bulletins
04/2002: Final results of the first rotation of a residue management trial in Zululand. C A Rolando, K M Little and
C H Norris
05/2002: Performance of the 3-PG model in predicting forest productivity of Eucalyptus grandis using preliminary
input parameters. L J Esprey and C W Smith
Produced & Distributed
by the
Institute for Commercial Forestry Research, ICFR
26th Zululand Regional Committee Field Day
“Vegetation management and an introduction to the network
of Sustainability Trials” Contact: denis@icfr.unp.ac.za
P.O. Box 100281
Scottsville 3209
Pietermaritzburg
tel: +27 33 386 2314
fax: +27 33 386 8905
January 2003
20th – 23rd Combined Jubilee congress of Soil Science Society,
SA Society for Crop Products and SA Society for Horticultural
Science.
http://www.icfrnet.unp.ac.za
Page 8
Editor: Sally J Upfold
sally@icfr.unp.ac.za
ICFR News – November 2002