Tree Feed by pengtt


									                                Tree Feed    News on trees as fodder

    Issue No 2                                                                                        June 2002

From the Project Leader
                            In introducing this second issue of Tree Feed, I feel that there is plenty
                            of information from the last six months to report to you.

                            The tree-feeding trial at Massey University’s Riverside Farm is now into its second year
                            and giving very positive results. These results, achieved by Eileen McWilliam and
                            Professor Tom Barry, have been achieved with the help of nursery and support staff from
                            the Wellington Regional Council (WRC). AGMARDT, assisted by Massey University
                            and WRC, are funding this project.

                            In addition, an on-farm poplar and willow feeding trial was conducted on the dryland
    Peter Gawith            farm of Mike and Anthea Potts, supervised by Professor Barry.

 Associate Professor Peter Kemp, also of Massey University, has determined quantity of feed in a tree, funded by
 WRC, Massey University, and MAF’s Sustainable Farming Fund (SFF).

 This SFF fodder tree project will fund more on-farm work in the next two years and will need farmer participation to
 determine the integration and management practices needed to give the best on-farm results.

 I would welcome interested farmers willing to help with this on-farm work, which will be supported by our team.
 These participating farmers will reap the benefit of being “first out of the blocks” with the new technology. Please
 contact us – our details are at the end of this newsletter.
                                                                                  Peter Gawith, Project Leader
                                                                                           Gladstone, Wairarapa

Progress through Year One                                From Project Manager, Dr Grant Douglas

It is hard to imagine that we have reached the end of the first year of this Fodder Tree project. The time certainly seems
to have gone fast! Some of our many achievements during the year include, in no particular order of priority:

                                       •    Forming farmer-based groups in Rangitikei and Hawke’s Bay using the
                                            well-established Wairarapa group as a model.
                                       •    Interviews to gather and collate information on farmer experiences with
                                            fodder trees in Hawke’s Bay, Rangitikei and Wairarapa.
                                       •    Determining the edible fodder yield of willow and poplar trees on Wairarapa
                                            farms; determining the regrowth of ‘Tangoio’ willow in Hawke’s Bay,
                                            following various cutting regimes.
                                       •    A first on-farm trial to determine the benefit of willow supplementation for
                                            ewe reproductive performance.
                                       •    Establishment of willow coppice blocks at Massey University’s Riverside
                                            Farm in March and a Combined Project Meeting in May at AgResearch.
                                       •    Holding a special project demonstration field day at Riverside Farm.
                                       •    Conducting an economic analysis of the results from the 2001 Riverside
                                            Farm grazing trial.
         Grant Douglas                 •    Profiling the project in several newspaper and popular magazine articles,
                                            and radio and television interviews.

You will read more about some of these achievements in this newsletter.

For me, the achievements of the project a third of the way through provide strong evidence of how well numerous
organisations and individuals can work together and in partnership with farmers, to deliver practically useful and
relevant information and techniques. To all project participants, I wish to express my appreciation for your efforts
during the year, and I shall look forward to working with you as we face the challenges and opportunities in the next
phases of the project.

I hope that you enjoy the rest of this newsletter, and please remember to contact us if you wish to request an article on a
particular subject pertaining to tree fodder use, in future issues of Tree Feed, or perhaps even offer to submit your own

On - Farm Trial underway

From Mike and Anthea Potts, Atea, Ngaumu, Wairarapa,
Professor Tom Barry and Associate Professor Peter Kemp,
Massey University

Supplementary feeding with willow commenced on Mike and
Anthea Potts’ farm at Ngaumu in eastern Wairarapa on 26 February.

One hundred ewes were fed ‘200kg’ of willow three times per week
(equivalent to 0.86 kg/ewe/day) for 8 weeks, including mating.

A similar group of ewes acted as control. Supplemented and control
ewes grazed similar areas of the same paddock at the same time and
were separated by an electric fence.

This was not a drought year and pasture mass was more than twice
that in the Riverside Farm trial (which was run at levels typical of a
severe drought).

Despite an abundance of pasture the sheep still readily ate the
willow and consumed all the leaves and thin stems. Supplementation
ceased on 23 April, when the groups were weighed again and joined.
Scanning will be done in mid-June.

Total time needed to cut, transport, weigh and feed the willow                             Pruning for feed
fodder was 2 hours per occasion, but the time needed first to cut the                    (Photo: Anthea Potts)
willow was 45 minutes per occasion or 2.25 hours per week.

                                                       Control Ewes           Supplemented Ewes

               Pasture cover (kg DM/ha)                         2602                                2627

               Dead matter (%)                                        25                               27

               Initial liveweight (kg)                           61.5                                61.4

               Liveweight change (g/day)                              -7                              -24

               Diameter of willow eaten (mm)                     --                                   3.3

               Initial condition score                           2.96                                3.03

               Condition score change                           -0.11                               -0.21

Riverside Report
From Professor Tom Barry and Associate Professor Peter Kemp, Massey
University and Peter Cameron, Wellington Regional Council

We have now entered the second year of the project at Massey University’s Riverside Farm,
near Masterton, which aims to define the effects of willow/ poplar supplementation during
summer/autumn upon the whole-year productivity of ewes. This work is funded by
AGMARDT, Riverside Farm Research Trust, and Wellington Regional Council, and is part
of a PhD programme being undertaken by Eileen McWilliam.

2002 Riverside Reproduction Experiment
Groups of 95 ewes were grazed on drought pasture for 12 weeks, with mating occurring
during the last five weeks. Mean initial ewe weight was 55.2 kg. Groups of ewes were
supplemented with willow or poplar (1.4 kg fresh/ewe/day) every day for 12 weeks, whilst
                                                                                                    Prof. Tom Barry
the third group, not supplemented, acted as the control. The willow and poplar foliage was
cut from the Wellington Regional Council’s Wairarapa nurseries.
Pasture mass was low, both before and after grazing, with a high dead matter content, as would typically occur during a
drought. Pasture masses and the estimated quantities of pasture eaten were similar for all groups; as expected, willow
and poplar supplementation increased the quantity of food consumed.

                                                                                   Control       Willow         Poplar

                                    Pasture mass (kg DM/ha)      Pre-grazing          909          968           949
                                                                 Post-grazing         420          450           497

                                    Pasture Dead Matter (%)                           64            61            63

                                    Feed eaten (kg DM/day)       Pasture             0.60          0.64          0.55
                                                                 Tree                              0.25          0.27
                                                                 Total               0.60          0.89          0.82

                                    Diameter eaten (mm)                                             3.9           6.4

                                    Liveweight loss (g/day)                           104           86            95
     Eileen McWilliam

                  Riverside sheep love their tree fodder                                      What they left…

 The control group ewes lost significant weight, as would be expected in a severe drought, and whilst willow and
 poplar supplementation appeared to reduce this, the effect was small considering the quantities of willow/poplar
 eaten (as was also found in the 2001 Riverside Experiment). Pregnancy scanning of the ewes will take place at
 Riverside on 17 June and we look forward with interest to seeing the treatment effects on reproductive rate, which
 were very large in the 2001 Riverside experiment.
Digestibility Trials with Poplar
Three trials have been conducted at Riverside Farm in the past summer/autumn, with six very quiet cryptorchid lambs
being kept indoors in metabolism cages and fed chopped poplar. In between the three trials, the animals returned to
grazing pasture. These trials were conducted by Eileen McWilliam and were funded by the MAF Sustainable Farming

Digestibility of poplar dry matter (DM) declined by only a small percentage over the summer/autumn period and was
still higher than the digestibility of drought pasture (approx 55%).

                                                    Trial 1           Trial 2           Trial 3

                      Date                      28 Jan – 6 Feb     10 –18 March      14 – 22 April

                      DM (%)                          25.3              34.9              37.0

                      DM eaten (kg/day)               0.70              1.05              1.14

                      DM digestibility (%)            66.9              59.1              60.5

With forages, the quantity of feed eaten normally declines as the digestibility percentage declines. However in this case,
feed intake increased as summer/autumn progressed and seemed to be related to an increase in DM percentage in the
poplar used (the same trend as found in grazing experiments). Following laboratory work, the content of Metabolisable
Energy (ME) in the poplar will be calculated.

Coppice Development
From Professor Tom Barry and Associate Professor Peter Kemp, Massey University,
Dave Cameron and Don Bell, Wellington Regional Council

There has been progress on development and utilisation of coppices for animal
feed at Riverside Farm and at Jeff Ravenwood’s farm at Homewood, near
Riversdale, funded by SFF.

Four hectares of willow coppice, spaced at 1.2 m between stakes, are now planted
on Riverside, on what were originally rush-infested swamps. These were sprayed
with glyphosate before planting.

The blocks were grazed during April with sheep and cattle to reduce the height of
the trees and to control grass, and were then cut with a scrub saw during May.
These areas will be used for grazing during the 2003 summer/autumn, when they
are aged approximately 20 months.

The 1.6 hectares cuddy grass-infested swamp on Jeff Ravenwood’s farm was                   Riverside coppice block
sprayed by helicopter in March. The cuddy grass is now dead and the area will be
planted with willow during the 2002 winter.

Jeff is interested in developing further areas of swamp into coppices, as part of a drought protection plan for his
property. These areas will be used for “on farm” animal evaluation of coppices as part of the SFF programme.

We aim to start a new PhD student in January 2003 on the value of grazing willow coppices as animal feed. It is
suggested that the student would be based in Wairarapa and would work on the coppices at both Riverside Farm and
Jeff’s farm at Homewood.

Researching Willow Sawfly
From HortResearch hardwood tree breeder, Dr Lindsay Fung

Willow sawfly (Nematus oligospilus) was first recorded in February 1997 in
Auckland and it has since spread throughout the country. This pest is a major
threat to willow plantings that have vital roles in stabilising pastoral hill country,
and protecting shelter systems and riverbanks. As interest grows in using willow
as fodder for livestock, it is timely to update research progress on willow sawfly.

We have estimated that the sawfly will spread naturally in New Zealand at a rate
of about 300 km per year. Field observations since 1997 consistently show that
most of the commonly planted tree willows can be defoliated by sawfly.
                                                                                                   Willow sawfly

So how do repeated defoliations affect willow root growth over a growing season? Recent trials using newly planted
cuttings of ‘Moutere’ willow showed that regular defoliations every eight weeks reduced root biomass by 70% over the
growing season. More frequent defoliations had an even greater impact on root and leaf biomass (see table below).

The table shows mean shoot height and leaf and root biomass for different defoliation treatments after 24 weeks. Means
are also expressed as a percentage of control growth (in bold).

                          Defoliation         Shoot                 Leaf              Root
                            period         Height (mm)           Biomass (g)       Biomass (g)
                          4 week            512     29%            4.1    8%         7.0    4%
                          8 week           1673     96%           27.7   51%        49.7   31%
                          Control          1749 100%              54.1 100%        158.8 100%

The visible impact of defoliation seen on plant leaves and shoots is significantly less than the impact on the plant's root
system. On the farm, this impact is likely to be more severe if water or nutrients are also limiting growth. Mature trees
in the Bay of Plenty are already dying after experiencing several consecutive seasons of defoliations.

Understanding the sawfly
Continuing research into this insect pest has determined that:
•   Sawfly larvae stop growing at temperatures below 8oC.
•   Laboratory trials have shown fastest development at about 23oC.
•   The number of generations per year almost entirely depends on temperature - we might expect up to seven
    generations per year in northern North Island, but only three in Southland.
•   Larvae develop at different rates depending upon their host plant. Adults that took longer to develop from larvae
    (when reared on one willow species) also tended to lay fewer eggs than those that developed faster (on a different
    willow species). This effect is related to leaf chemical composition and we are now examining this in more detail.

Developing sawfly resistant willows
We are taking a two-pronged approach to developing willows that can tolerate, or be resistant to sawfly:
1) Screening existing New Zealand material for phenolglucosides (leaf chemicals that inhibit larval development and
2) Expanding our willow genetic pool to include populations of willows from areas where sawfly is endemic.

Phenolglucoside Screening
Initial research has shown a wide variation of phenolglucoside concentrations between different willow species. The
species that are readily attacked in the field also generally have low phenolglucoside concentrations.

We are currently testing a wider range of species and will relate these results to larval development. In terms of fodder
use, phenolglucoside levels may be important, as these are linked to insect development and therefore may have a
similar influence to condensed tannins on internal parasites. However stock palatability may also be affected by certain
phenolglucosides and ‘bitterness’ certainly seems to be very prevalent in willow species that show the greatest tolerance
to sawfly attacks.

Willow Genetic Resources
Only a handful of species or tree willow hybrids are commonly used in New Zealand, and several are closely related.
Because material is mostly vegetatively propagated, the genetic base is very narrow. Of course, this increases the risk
from pests and diseases.
To help broaden the genetic base we have recently acquired seedlots of a willow species from northern California and
southern Oregon. Seedling populations of this material will be assessed for resistance to sawfly, and selected plants will
form the basis for breeding new willow varieties that combine sawfly resistance, appropriate characteristics for end use
(riverbank control, soil conservation, fodder, shelterbelt, phytoremediation etc.), and reduced potential for weediness.

This winter HortResearch, in conjunction with Regional and District Councils from the Willow and Poplar Research
Collective, will be establishing field trials to examine several experimental willow varieties for tolerance (i.e. being able
to survive attacks from sawfly) or resistance (i.e. sawfly will actively avoid egg laying and eating of the foliage) to
sawfly. Much of the contents of this article has been lifted from the HortResearch website: Information on the identification and basic biology of the
sawfly is available from

Farmer case study: Alec Olsen, Rissington, Hawke’s Bay
From Communications Manager, Dr Deric Charlton

Alec Olsen farms a beautiful property on Glengarry Road, near the Napier-Taupo highway, in
northern Hawke’s Bay. The enterprise is sheep and beef production, with trees very much in
                                             The Olsen family has farmed Valhalla (“resting place of the
                                             warriors”) since 1949 and Alec Olsen has run the farm since
                                             1966. Within a total area of 407 ha, 300 ha is effective pasture.
                                             Forty ha is in trees and a similar area is being retired under the                 Deleted: and the Farm Forestry
                                             QEII Trust.                                                                        Association’s Award last year, I

                                                             Hawke’s Bay students regularly visit the farm and learn much
                                                             in this “outdoor classroom” and Alec Olsen and partner Heather
                                                             Bell were awarded the Hawke’s Bay Regional Council’s
                                                             Environmental Award in 1999 and North Island Farm Forester
                                                             of the Year in 2001.

                                                             The Farm
                                                             Valhalla lies at 150 - 250 m asl and is an easy contoured farm
                                                             for this district, with a mosaic of land use on loess-type soils
                                                             formed from windblown ash over an impervious pan at 70 cm.
      Alec Olsen has used tree fodder for 20 years           All trees on Valhalla have their roots above this pan.

Average annual rainfall is 600-1400 (1200 average) mm. De-stocking is not necessary until drought develops. The farm
is well subdivided with 35 paddocks, each about 8 ha on average. Pasture renewal began in 1997 and is now a regular
practice, using perennial ryegrass and clovers to improve pastures. Fodder crops have not been successfully managed,
however, so a grass-to-grass process is being used instead.

Livestock - 3,000 sheep and 150 cattle in winter. The animals are set stocked lambing to docking, and rotationally
grazed most other times. In serious droughts, however, the gates tend to be left open in larger management blocks for
water access. When drought hits, trading stock are sold first, then up to 20% of capital stock. Feeding supplements
however, is avoided, except for poplars and willows.

Tree use
Many species and types are growing at Valhalla, including:
•   Timber trees – Pinus radiata, redwood, eucalypts, cypresses and cedars (especially Cedrus deodara).
•   Fodder trees: Mostly willows, especially Matsudana, and old hybrid poplars. Poplars also have timber potential here.
Trees have been cut for supplementary fodder since the 1982-83 and 1989 droughts – Alec now has 20 years of
experience. He still grows some willow trees that he harvested during these droughts, and they look as good now as
they did then (see the photograph).

He pollards a young tree at 2.0-2.5 m high so that its regrowth ultimately forms a “pruning nest” that enables him to
harvest the trees for fodder safely at above cattle height.

Safety is paramount When harvesting or pruning trees he uses a forestry
pruning ladder, a small pruning chainsaw and supporting forestry safety
equipment. He says it is important to create a “safe nest” when cutting
trees for fodder supply. The animals are often milling around and keen to
eat the branches, so using a short ladder has to be undertaken with care and

Forming a nest makes the pruning operation safer and easier under such
circumstances. The young trees should be first cut at 2-2.5 m to prevent
cattle from grazing the regrowth. As a chainsaw should not be used when
held above shoulder height, a short ladder will help in this first cutting. In
any case, trees grown for fodder should not be allowed to grow too tall, as
the greater height implies greater danger when cutting and pruning.

When using a chainsaw, it is most important to prevent danger of
“kickback” by the chainsaw. In addition to wearing suitable protective
clothing, Alec says you must make sure that the risk of kickback has been
minimised by using the right bar with a bar guard.

Alec uses a special chainsaw made by Husqvarna, which has a short chain                    Pruning chainsaw
bar, high power and high chain speed, is lightweight, and has a bar guard
fitted that can reduce risk from the moving chain in most circumstances (shown in the photograph). However, he
believes that maintaining fodder trees - keeping them in a good shape - is essential for better overall safety, and makes
harvesting easier and safer.

Seasonal tree growth and use
Like pastures, tree growth is seasonal. Weeping willows are the earliest to burst into leaf during spring, followed by
Matsudana willows then the poplars. Even in dry seasons, the spring pasture flush provides adequate feed until January,
when summer droughts usually develop. Poplar leaves start to fall in late January at Valhalla, and these leaves are eaten
avidly by stock. Poplar rust can develop in summer and this causes further leaf fall, but these leaves seem less palatable
to stock. Alec usually feeds tree fodder in late autumn, during a drought, but the willows are still usually in full leaf.

Alec Olsen firmly believes that obtaining supplementary fodder from trees is cost-effective. Planted poles must be
protected from farm livestock for up to two years, but from then on, the trees supply valuable fodder for many years –
and also supply shade, shelter and encourage bird life. Alec Olsen has 30-year-old trees that have been used for fodder
many times, and remain as productive as ever. Trees add to the farm’s beauty and sustainability, and when grown and
managed properly, also add to the farm’s value and production base.

                                           The cost of harvesting trees is mostly the farmer’s time and effort in
                                           planning, growing and harvesting the trees. The benefit is having a reliable
                                           supplementary feed with good nutritional value, for use in droughts and pinch
                                           periods, except during winter.

                                           Fallen branches
                                           Fallen branches remaining after fodder harvesting can be a nuisance when
                                           left on a pasture. Sheep can become wedged in them, and they can help weed
                                           establishment, especially blackberry. Such branches are better removed and
                                           burned, or bigger logs can be cut for firewood where this is profitable.
                                           However, fallen branches that have regrown because they remained partially
                                           connected to a tree, are much more dangerous to harvest.

                                           Branches being cut may fall prematurely and subsequently regrow if not
                                           completely removed. The increased harvesting danger arises because it
 Alec feeding stock in the 1989 drought    becomes almost impossible to find a safe position for harvesting with a
 (Photo: Hawke’s Bay Herald Tribune)       chainsaw. In these situations it is also possible to use a suitable hand saw for

pruning, especially to cut a difficult branch from a more precarious position, but this can take much longer. On
horizontal fallen branches, there are almost no safe handholds to hang onto, but it is important that these branches are
pruned and then completely severed from the original tree, to prevent future danger.

Bark stripping Farm livestock under feed stress will chew and remove tree bark, especially when trees are less than
five years old, but mature poplar and willow trees are usually stock-proof.

Native trees Livestock will also graze on some native species, notably Pittosporum species and five-finger. Given free
access, stock will destroy these trees very quickly, and allowing animals into a native bush block will leave only very
unpalatable species.

Tree planting Alec Olsen was one of the first farmers in his area to plant pines for timber, on an area of poor pasture
(and this wasn’t popular with neighbouring farmers at the time). He planted Flevo poplars within the plantation in a wet
area to “create a visual balance” for a neighbour, and the contrasting foliage shades, and the canopy development
provides good colour contrast.

Planting for fodder Alec planted his first trees specifically for use as fodder in the mid 1980s. These have been
harvested twice and had poles removed for other plantings. The Hawke’s Bay Regional Council poles are excellent in
quality and generally establish better than home-cut poles, but the latter can be adequate and are very cheap.

He plants his fodder trees at least 15 m apart, to reduce pasture shading, but they can be planted closer initially
providing some are removed (as fodder) before shading ensues. Felling tall trees should only be undertaken if the
necessary level of competence exists as they can easily kill cattle or people when falling. With larger trees weighing a
tonne or more, hang-ups and other problems become much more serious. Netlon sleeves are used at Valhalla for
protecting poles.

Poles can be cut on the farm during winter and planted in wet soil using a pole driver after sharpening the lower end
with a chainsaw. Large cuttings covered with coarse bark, which replaces a sleeve, can also be established in moist
areas by using a post-hole borer or a spade.

Pruning young poplars
Poplar scientists at HortResearch and AgResearch are now into the second year of a joint
project at AgResearch's Ballantrae Hill Country Research Station, near Woodville.

They aim to determine the effects of 6-year old Veronese poplars on light distribution patterns, understorey pasture
growth, and the water balance of the site. This research is relevant to tree fodder users because it is also determining the
effects of tree pruning on the environment around the trees, to help weigh up the costs and benefits of conventional

The research team comprises Sarah Hurst, Ian McIvor, Carlo van den Dijssel, Steve Green and Lindsay Fung from
HortResearch, and Grant Douglas and Lex Foote from AgResearch.

“We have established relationships between branch
diameter and leaf area, and leaf weight and leaf area,”
says Sarah Hurst. “This has allowed us to quickly
calculate the proportion of leaf area removed from a
tree during pruning that could be used for fodder. Leaf
area directly relates to the amount of water the tree

So far the researchers have shown that in February-
March 2002 a typical poplar (with a height of 12 m and
diameter at breast height of 17 cm) used an average of
110 litres of water per day from the soil (equivalent to
1.7 mm/day at 8 × 8m spacings).

Pruning to 5 m reduced this water uptake by 30%.
During summer the tree canopy intercepted 5% of the                          Sarah Hurst and Ian McIvor
rain falling on the site, of which 1% ran down the tree

trunks as stem flow.

“Over a longer time period we expect soil and pasture differences to emerge between the pruned and unpruned site,”
says Sarah. “We will use the results to help develop guidelines for the best planting and management strategies for
poplars used in soil conservation.”

The results will also assist with promotion of poplars for multiple goals such as timber and forage, in addition to their
primary role in stabilising soil.

Tree Pasture Workshop
Around 40 people attended a workshop on trees and pasture, sponsored by the Willow and
Poplar Research Collective, held at AgResearch Grasslands in Palmerston North in late March.

The meeting aimed to update those interested on current research on tree-pasture systems, and to identify knowledge
gaps and future needs, and facilitator Victoria Westbrooke of AgResearch ensured that the participants focused only on
relevant matters.

The first afternoon session dealt with effects of trees on pasture growth, with a range of short presentations by
researchers from Massey University, AgResearch and HortResearch, usually working together on particular aspects.
These included topics such as tree fodder value for farm livestock, poplar root growth and water use, and an update on
the SFF Tree Fodder project. On the following morning, the workshop ventured outside to see the latest progress at
HortResearch’s nursery at Aokautere and the joint research being undertaken at Ballantrae, the AgResearch hill country
station near Woodville.

Further details may be obtained by contacting Dr Alec Mackay, AgResearch Grasslands.

Akura Conservation Centre
From Dave Cameron, Soil Conservator, Wellington Regional Council

The Akura Conservation Centre is a business unit operating within the Soil
Conservation section of the Wellington Regional Council. The Centre operates
two functions, a nursery for growing poplars and willows, and a trading enterprise
selling a range of trees, chemicals and planting aids. It is the nursery operation
that provides considerable support to the current trials in Wairarapa.

The nursery is located 1.5 kilometres from Masterton. It covers 25 ha, and is
supported by the Mangapakeha nursery of 11 ha, which is located on the
Masterton - Castlepoint road some 30 kilometres from Masterton.

Before 1984 the Wairarapa Catchment Board operated a range of small nurseries.
These were difficult to manage collectively and were not always located on good
land. The Board also operated many farm nurseries that were small, fragmented
and often poorly managed.

The Akura nursery was established in 1984 to produce poplar and willow trees for
the Council’s soil conservation and river control programmes and perhaps more
importantly, to centralise the operations onto high quality land. It is a highly                Dave Cameron
mechanised operation producing up to 35,000 poles per annum.

Irrigation has been installed this year to realise the full production potential in a summer dry area. The trading operation
was developed through the late 1980’s and now has a turnover of $400,000. The nursery operation has a turnover of

The present mix of species in the nurseries is 60:40 poplar to willow, reflecting the strong influence of poplars in soil
conservation programmes. Ten poplar species and five willow species are currently planted at the nursery, with an
emphasis on Tangoio willow and Veronese poplars. It is the trimmings from these and other species that have provided
the fodder for the trials at Riverside Farm. Material for the coppice blocks is also supplied from the nursery and the on-
farm trials utilise poles already established for soil conservation purposes.

Involvement in the trials is seen to fit the Council’s desire to support work that further emphasises the multiple use of
these trees for soil conservation, shade and shelter, drought fodder supplements, and increases in ewe productivity.
These attributes contribute a wide range of benefits to landowners and fit comfortably within the framework of
environmental, economic and social sustainability.

Communicating tree fodder information
From Communications Manager, Dr Deric Charlton

Disseminating relevant information on tree fodder use began last
December with the first issue of Tree Feed and has since developed through
media releases and some coverage on television and radio.

It usually pays to keep interested people updated directly through a regular newsletter, because
we check that its content is as accurate as possible before publication. This minimises possible
incorrect interpretation by readers, and conveying messages that we did not intend.
                                                                                                        Deric Charlton
Project newsletters also enable us to ensure that the generous support from our sponsors is acknowledged, as indeed it
should in all communications about the project. Tree Feed has been distributed to more than 100 contacts in the lower
North Island (immediate project area) and nationally, and the list is steadily growing. Feedback to date has been
positive and we are happy to receive your comments, suggestions, and potential items for future issues.

Massey University journalist Rachel Donald has also publicised the benefits from the Riverside Farm trials with ewes
eating poplar and willow foliage in autumn, and the demonstration day at Riverside Farm in March attracted some
interest, including coverage on Television One’s Telstra Business, which showed the high value of this technology.

A recent announcement by AgResearch, that farm livestock eating plants containing condensed tannins reduced
methane emission rates, created an opportunity for a release by us, highlighting that poplars and willows already on
farms, also contain condensed tannins and could have a similar effect, (see the following article). This release was
distributed to farming media in the southern North Island and project leader Peter Gawith was interviewed on National
Radio’s Rural News programme. This practice will continue as suitable information becomes available and when
worthwhile events are being organised.

Reducing methane emission
This release was sent out from AgResearch Grasslands:

AgResearch scientists Garry Waghorn and Michael Tavendale have recently proved that
condensed tannins (CT) found in pasture species such as lotus, birdsfoot trefoil and sulla (and
in the foliage of poplars and willows) can directly reduce methane emissions.

Methane, one of the major greenhouse gases, is a by-product of rumen fermentation in farm livestock and is expelled in
their breath. And approximately 90 percent of New Zealand’s methane emission comes from our farm animals. New
Zealand is committed to ratifying the Kyoto Protocol that aims to restrict worldwide greenhouse gas emission, and there
could be future financial penalties if emission exceeds that for 1990. But methane emission will increase along with our
agricultural production, so any discovery that reduces this problem will be welcomed.

AgResearch is studying methane production and emission by evaluating grasses and legumes fed to cows and sheep to
understand how they contribute to methane production. The scientists are also trying to minimise energy losses to
methane, and identifying microbes producing methane in the animal rumen.

CT are diverse compounds that occur naturally in wine, apples, cocoa and some pasture species. They are also present in
poplars and willows, along with salicins (of which aspirin is best known).

This is thought to be the first animal study that clearly shows dietary CT reduce ruminant methane emission, and it has
Dr Tavendale and the rest of the methane research team excited. This discovery is only the first step. Future research
will involve understanding more about CT that are reducing methane emission from the rumen and how they work.

And it may mean that trees containing CT, especially poplars and willows, are more likely to feature prominently in the
future of New Zealand farming. CT have a variety of other animal related benefits, such as increased liveweight gain,
improved milk yield and reduced internal parasite burden, bloat, dags and fly strike.

   Putting methane production into perspective
   The average New Zealand dairy cow produces about 90 kg of methane per year - equivalent in
   energy to 120 litres of gasoline.
   In a 200-cow dairy herd the “petrol equivalents” are 24,000 litres per annum, enabling a reasonable
   sized vehicle to be driven 200,000 kilometres.

Economic analysis
From Sam Orsborn, Consultant, Baker & Associates, Masterton

Our part of the SFF project has been to apply a financial analysis to the physical results from the 2001 Riverside animal
feeding trial. Please note that these results have been standardised to reflect the added benefit of increased conception
rates through supplementing poplar forage prior to and after mating. The trial was conducted with 100 ewes in three
different treatment mobs. These ewe weights were recorded at the start of the feeding period and in this financial
analysis we have valued this liveweight using market values at the start of feeding (Table 1).
                                                                                                                             There was on
Table 1 Treatment                    High          Low       Control     There was one main anomaly - ewe deaths
                                                                                                                             between the t
Number of ewes at start of trial       100          100          100     between the three treatment mobs. Deaths
                                                                                                                             through the w
Weight of ewes (kg)                   57.5         57.6         56.4     couldn't be attributed to the ewes fed or not fed
                                                                                                                             to the ewes
Price/kg liveweight                  $1.10        $1.10        $1.10     poplar. This was evident at scanning - in the
                                                                                                                             poplar. This is
Ewe Price                              $63          $63          $62     high and control treatment mobs there were 99
                                                                                                                             the high and
Total ewe price                     $6,325       $6,336       $6,204     ewes, whereas in the low treatment mob four
                                                                                                                             were 99 ewes
                                                                         ewes had died, leaving 96.
                                                                                                                             mob four ewes

Wastage The scanning percentage used             the
Scanning The actual wastage for the trial isranged
                                                           Table 2 Scanning                   High      Low      Control
between percentage again the number of ewes
scanning 23% and 27%, over with no trend favouring
                                                           Number of ewes scanned               99       96          99
scanned. The important information for this analysis
                                                           Scanning (%)                        163      147         122
is the number of lambs at scanning.
                                                           Number of lambs at scanning         161      141         121
Wastage The actual wastage for the trial ranged between 23% and 27%, again with no trend favouring the fed or unfed
mobs. Therefore we have assumed that the wastage percent from scanning to weaning is 25%. This equates to 39
percentage points (161% down to 122%) for the high treatment mob.

For the control mob, a 25% drop equates to 29 percentage points i.e. from 121% to 92%. Using these figures and
considering that each mob had 100 ewes at the start of the trial, the high treatment mob weaned 122%, the low treatment
mob weaned 110%, and the control mob weaned 92% (Table 3):

               Table 3                                                     High                  Low             Control
               Ewes adjusted for deaths                                      96                    96                96
               Adjusted number of lambs at weaning                          122                   110                92
               Adjusted loss from scanning to weaning                      25%                   25%               25%

Weaning As would be expected, given that the supplementation only happened over mating and that the high
treatment mob reared more lambs, the control mob weaned the heaviest at an average lamb weaning weight of 31.4 kg
and the high treatment mob weaned at 29.4 kg per head. Adjusting this figure to lamb weaning weight per ewe, using
the lambing percent in Table 3, tells a different story. Lamb weaning weight per ewe for the control mob equated to 28.8
kg/head, whereas the high treatment mob was 35.9 kg/head (see Table 4).

The second section of Table 4 values this                 Table 4 Weaning weight (kg/head)                 High            Low        Control
lamb weaning weight. The lamb price per kg                Total lamb weight weaned (kg)                     3586          3338          2878
liveweight at weaning last year was                       Lamb weaning weight (kg/ewe)                      35.9           33.4          28.8
approximately $2.40/kg liveweight.                        Weaning price ($/kg liveweight)                  $2.40          $2.40         $2.40
                                                          Total income from lambs                         $8,606         $8,011        $6,908
Therefore we have used this price in valuing              Total lamb income/ewe                           $86.06         $80.11        $69.08
this lamb weaning weight. Lamb income per                 Difference from control                         $16.98         $11.03
ewe for the control mob equated to $69
whilst the high treatment mob equated to $86 per ewe. This was a difference of $17 in lamb income per ewe.

Standardising the ewe death to 4% for each mob makes ewe weaning numbers equal 96 in each mob. Ewe weaning
weights were recorded and showed that the control mob weaned heavier than the high treatment mob. This is simply
due to greater energy put into lactation due to a higher lambing percent. However this loss in liveweight had to be
valued for a number of reasons. Firstly, there is going to be extra feed required to get these lighter ewes back up to the
weight of the control mob ewes.

Secondly, people might argue that the high treatment ewes                    Table 5                       High          Low          Control
are more fertile therefore worth more but these ewes were                    Number of ewes                   96            96             96
drafted randomly therefore should have the same fertility                    Ewe deaths (%)                    4             4              4
potential. Again we have valued these ewes at market rates                   Ewe weight (kg)                60.3          62.2           63.0
at weaning. The high treatment mob equated to $54/head                       Price/kg liveweight           $0.90         $0.90          $0.90
whilst the control mob was $57/head (Table 5).                               Ewe Price                       $54           $56            $57
Shearing Using standardised ewe numbers (i.e. 96 per mob
                                                                             Total ewe price              $5,210        $5,374         $5,443
and actual wool weights per ewe harvested at weaning), the
                                                                             Table 6 Shearing                   High        Low       Control
wool data was very similar per mob (Table 6). In this
                                                                             Number of ewes shorn                  96         96           96
analysis actual weights have been used although the
                                                                             Wool weight/ewe (kg)                3.01       3.08         3.04
differences didn't show any trends and were very minimal.
                                                                             Total wool weight (kg)               289        296         292
The wool price used is the average wool price in last year's
                                                                             Wool price ($/kg)                  $2.87      $2.87       $2.87
Baker & Associates financial survey at $2.87 per kg greasy.
                                                                             Total wool income                   $829       $849        $838
Overall Results
Table 7 shows the overall trial results, taking into account the adjustments that have been assumed above. The loss in
ewe value is simply the value of the 96 ewes at weaning (Table 5) less the value of 100 ewes when feeding started
(Table 1). The gross margin is lamb income plus wool income minus the loss in ewe value. The gross margin for the 100
ewes in the control mob was $6,985 whilst for the high treatment mob was $8,320. This equates to $69.85 per ewe in the
control mob compared to $83.20 per ewe in the high treatment mob. Given the assumptions stated above, this is a
difference of $13.36 per ewe between the high treatment mob and the control mob.
Sensitivity Analysis                                           Table 7 Overall Results                     High           Low         Control
                              Difference between               Lamb income                                $8,606        $8,011         $6,908
                         Control and High mob/ewe              Wool Income                                 $829           $849           $838
                                                               Loss in ewe value                         -$1,115         -$962          -$761
+/- 20c/kg liveweight for lamb                   $1.42         Gross margin                               $8,320        $7,897         $6,985
+/- 20c/kg liveweight for ewes                   $0.73         Gross margin/ewe                           $83.20        $78.97         $69.85
+/-10% conception rate                           $0.70         Difference from control/ewe                $13.36         $9.13

  Want to know more?
  If you are interested in this project and its results, please contact any of the following:
  Mr Peter Gawith, Longbush, Gladstone, RD4, Masterton.
  Ph/Fax 06 372 7743. Email:
  Dr Grant Douglas, AgResearch, Private Bag 11008, Palmerston North.
  Ph 06 351 8072. Fax 06 351 8032. Email:
  Dr Deric Charlton, Greenfields Communications, 17 Cremorne Avenue, Palmerston North.
  Ph/Fax 06 356 9799. Email:

 PLEASE NOTE: While this publication has been prepared in good faith from a number of sources that are believed to be reliable, The Lower
 North Island Group for Drought Relief from feeding Willow/Poplar does not give any warranty that all information contained is accurate or that
 all advice given in the publication will be appropriate for all circumstances. The Lower North Island Group for Drought Relief from feeding
 Willow/Poplar shall not be liable to anyone in respect of any damages suffered as a result of their reliance on this publication.


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